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This is to certify that the

dissertation entitled

Age and Prospective Memory: A Neuropsychological
Account Based on Executive Functioning

presented by
Karen Klein Villa

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AGE AND PROSPECTIVE MEMORY:
A NEUROPSYCHOLOGICAL ACCOUNT BASED ON
EXECUTIVE FUNCTIONING
By

Karen Klein Villa

A DISSERTATION

Submitted to
Michigan State University
in partial fulﬁllment of the requirements
for the degree of

DOCTOR OF PHILOSOPHY

Department of Psychology

1997

 

 

 

ABSTRACT

AGE AND PROSPECTIVE MEMORY: A NEUROPSYCHOLOGICAL ACCOUNT
BASED ON EXECUTIVE FUNCTIONING

By

Karen Klein Villa

Prospective memory (PM) has been described as the realization of delayed
intentions. The impact of age, attention, retrospective memory (RM) and executive
ﬁmctions (EF) on PM was examined in a sample of able elderly (N = 115; 42 males and 73
females). In addition, it was hypothesized that PM would be poorer aﬁer longer intervals
when external memory aids were unavailable. The ﬁnal hypothesis considered self-
perception of PM and actual performance when the use of external cues was controlled.

An age-associated decline in PM was observed in the present sample (1 = -.29, p <
.01) and Age predicted 9% of the variance in PM performance (p_< .01) in a hierarchical
regression equation. In the second step, RM performance provided additional information
(p_< .05) beyond the eﬂ‘ects observed for Age alone. Next, three BF variables were added
to three control variables (Age, Attention, and RM) in predicting PM, all of which
accounted for 28% of the variance (p_< .001). The increase in R2 over the control variable
model was signiﬁcant (p < .05), suggesting that EF contributed signiﬁcantly to PM.

A Generalized Estimating Equation (GEE) was used to explore the variables of
Cue, Time and Age on PM. The analyses did not reveal a signiﬁcant three-way
interaction; however, the Cue x Time interaction term was meaningful (p = .00) as was a

main effect for Age (2 = .02) suggesting age does effect PM, but it does so regardless of

the eﬁ‘ects of cue and time interval. A relationship did not emerge between self-
assessment of PM capability and actual performance on uncued PM performance. A
preliminary investigation into the remediation of PM declines revealed that participants (N
= 68; 27 male and 41 female) did improve from pre- to post-testing.

Overall, the data support current theoretical explanations of the construct of PM,
especially that the cognitive requirements of planning and monitoring are unique aspects of
PM which differentiate it from its retrospective counterpart. Both research and clinical

applications of the ﬁndings are discussed.

This dissertation is dedicated to my father,
Eugene P. Klein (1939-1997), whose love, kindness and support
opened the door to my education
and to
Dr. Edward Gibeau whose exceptional insight and patience
taught me to understand
what I found on the other side.

iv

ACKNOWLEDGEMENT S

I am indebted to many people for their wise and helpﬁil guidance during my
graduate education. I would like to particularly acknowledge Dr. Norman Abeles, my
dissertation chair for his consistent and thoughtful contributions during my development as
a researcher and clinician. His dedicated and generous support in his roles as mentor,
teacher, experimenter, clinician, and leader has had a substantial and meaningful impact on
my professional growth. I would also like to extend my appreciation to my committee
members, Dr. Bob Caldwell, Dr. John Hurley, and Dr. Ellen Strommen, for their scholarly
insights and thought-provoking comments. I am also grateful for the statistical acumen of
Dr. Rick DeShon whose help was invaluable in completing the analysis of the data in this
study. Also, to my very competent undergraduate research assistants, Kristy Sirnpkins and
Stacy Fox, who made the many hours of data collection pass by more quickly with their
laughter and good-natured dispositions.

More personal thanks is owed to my family and friends. I am deeply appreciative
to my husband, Paul, whose love and faith in me has kept me grounded and provided me
with the courage to grow both personally and professionally. He brings possibility,
adventure, and hope to my life. And, ﬁnally, special thanks to my sister, Cynthia Auen,

who has been a true and steady ﬁiend and who ﬁlls my heart by sharing her joyous spirit.

TABLE OF CONTENTS

List of Tables ..................................... viii
List of Figures ...................................... ix
Introduction ....................................... 1
A Theoretical Framework of Prospective Memory ................... 4
Fundamental Differences Between Prospective and Retrospective Memory ....... 9
Prospective Memory and Aging ............................. 12
Laboratory Studies ............................... 14
Naturalistic Settings ............................... 19
Metamemory Investigations of Prospective Memory ............... 20

Neuropsychological Models of Frontal Lobe Functioning and Prospective Memory. . .24

Anatomical Considerations ........................... 25
Neuropsychological Considerations ....................... 28

Aging and Frontal Lobe Functioning ....................... 31
Prospective Memory and Frontal Lobe Functioning: Clinical Evidence ..... 35
Prospective Memory and Frontal Lobe Functioning: Aging Investigations . . .38
Statement of Study Objectives ............................. 41
Method: Experiment One ................................ 44
Participants ................................... 44
Experimental Measures ............................. 45
Prospective Memory Experimental Measures .............. 45

The Rivermead Behavioral Memory Test ............. 45

The Prospective Memory Screening Test ............. 47

Retrospective Memory Experimental Measures ............. 49

The California Verbal Learning Test ............... 49

Experimental Measures of Metamemory ................. 51

Memory Assessment Clinic Self-Report Scale .......... 51

Executive Functioning Experimental Measures .............. 52

The Ruﬁ‘ Figural Fluency Test .................. 53

The Wisconsin Card Sorting Test ................ 54

Trails B ............................. 56

Experimental Measures of Potential Moderating Variables ........ 57

The American Version of the Nelson Adult Reading Test . . . .57

Wechsler Adult Intelligence Scale-Revised Digit Span Subtest . .58

Beck Depression Inventory and Geriatric Depression Scale . . .59

Mini-Mental Status Examination ................. 60

Procedure .................................... 60
Results: Experiment One ................................ 64
Statement of Hypotheses and Statistical Analysis ................ 64
Hypothesis 1A .................................. 64
Hypothesis lB .................................. 65
Hypothesis Two ................................. 68
Hypothesis Three ................................ 69
Method and Results: Experiment Two ......................... 72
Participants ................................... 73
Experimental Measures ............................. 74
Procedure .................................... 75
Statement of Hypotheses and Statistical Analysis ................ 76
Discussion ....................................... 78
Age and Prospective Memory .......................... 78

The Impact of Retrospective Memory on Prospective Memory Performance. . .79
The Impact of Executive Functioning on Prospective Memory Performance. . .81
The Role of Environmental Support and Trace Memory Decay Over Time in

Prospective Memory Performance .................... 86

The Correspondence Between Self-Reported Prospective Memory Capabilities and

Actual Performance ........................... 89

Remediation of Prospective Memory Declines in the Able Elderly ........ 92
Limitations of the Present Study and Future Directions ............. 95
Appendix A: Prospective Memory Screening (PROMS) Items ............ 105
Appendix B: Cued and Uncued Prospective Memory Items ............. 106
Appendix C: MAC-S Prospective Memory Items ................... 107
List of References ................................... 108

vii

Table 1A:

Table 1B:

Table 2:

Table 3:

LIST OF TABLES

Means, Standard Deviations and Correlations For Prospective Memory,
Age, and Retrospective Memory ............................. 100

Means, Standard Deviations and Correlations For Prospective Memory,
Age, Attention, Retrospective Memory and Executive Function Measures.
...................................................... 101

Prospective Memory Score Values for the Solved Generalized Estimating
Equation: Hypothesis Two ................................ 102

Descriptive Statistics for Prospective Memory Performance for the
Everyday and Lab Groups in the Sample ....................... 103

viii

LIST OF FIGURES

Figure 1: Prospective Memory Scores for the Cue x Time Interaction .......... 104

ix

INTRODUCTION

Recently, there has been a growing interest in the investigation of memory
processes in the elderly which have ecological validity (Conway, 1991; Harris, 1984;
Larrabee & Crook, 1989; Schaie, 1974). Traditionally, older individuals often complained
of failing memory in everyday situations; the scientiﬁc community, however, would
attempt to understand this area of decline through laboratory study using artiﬁcially
presented memory situations (Maylor, 1993). The scientiﬁc trend toward delineating the
nature of memory ﬁmctioning in an aging population by focusing on real-er processes has
brought to the foreground the study of a speciﬁc memory component, namely prospective
memory (Meacharn & Leirnan, 197 5). In general, prospective memory can be described
as the mechanism of remembering to carry out activities in the future such as remembering
to attend an appointment or to take one's medication at a speciﬁc time.

The explicit consideration of forgetting intentions in everyday life can be traced to
Freud and his seminal work The Psychopaﬁrology of Everyday Life (1901). He wrote:

"IfI form an intention in the morning which is to be carried out in the evening, I

may be reminded of it two or three times in the course of the day. It need not

however become conscious at all through the day. When the time for its execution

draws near, it suddenly springs to mind and causes me to make necessary

preparations for the proposed actions." (p. 152)

In this context, the forgetting of intentions in everyday functioning was considered to be

2

due to the process of repression. The neuropsychological ramiﬁcations of the process of
"forgetting to remember" is the focus of the present study. The ﬁrst experimental
investigation of remembering intentions was carried out in the mid-1920's by Birenbaum
(193 0) under the guidance of Kurt Lewin. In her worlg Birenbaum (1930) asked subjects
to sign a sheet of paper after solving problems and writing their answers on the sheet. The
purpose of her investigation was to determine under what circumstances the subjects
would forget to carry out the request. Since that time, a number of authors have studied
the prospective aspect of memory; however, the various experimental contexts in which
this has occurred has led to a multiplicity of labels. Prospective memory has been widely
referred to as "remembering to remember" (Schonﬁeld & Stones, 1979), remembering to
recall (Wilkins & Baddeley, 1978), remembering to do things (Harris & Wilkins, 1982),
remembering intentions (Loﬁus, 1971), remembering future actions (Morris, 1979) and
operational remembering (Kantor & Smith, 197 5).

Even though prospective remembering has been well-established as a psychological
phenomenon, it has not been given much experimental attention until recently when a
growing concern with understanding memory processes in the elderly emerged.
Prospective memory is probably the most important aspect of everyday memory since it is
necessary for successﬁil independent ﬁmctioning (Maylor, 1990). Sinnott (1989) indicates
that it is valuable to pursue the study of prospective or intention memory since prospective
memories are highly relevant and adaptive and have many interpersonal implications. In
addition, prospective recall has been scarcely studied in the context of its meaning for the

elderly (Devolder & Pressley, 1991; Einstein & McDaniel, 1990). The experimental

3

investigation of the prospective memory construct is necessary in elucidating those factors
which contribute to successﬁil memory functions in the elderly.

Following a theoretical account of prospective memory processes, this proposal
will outline the distinction between retrospective and prospective memory operations.
The importance of this diﬁ‘erentiation will be apparent in the review of prospective
memory and aging. Speciﬁcally, the prospective memory process is considered to draw
upon various cognitive capacities, including retrospective memory. Therefore, the explicit
consideration of retrospective memory is required in any study of age-associated decline
of intention memory. A review of the literature on prospective memory and aging
suggests that this memory process may decline across the life span when tested under
controlled conditions. As such, the question becomes what neuropsychological processes
might account for an age-related deﬁcit in "remembering to remember?" In this context,
the ﬁontal lobes and the speciﬁc neurocognitive ﬁmctions which are subserved by this
brain region (e.g., executive functions), especially as they relate to memory and aging, are
reviewed. Both anatomical, functional, and clinical aspects are considered as they relate
to the domains of prospective memory, aging, and ﬁontal lobe efﬁciency. Subsequently,

the objectives for the current study are described.

A THEORETICAL FRAMEWORK OF PROSPECTIVE MEMORY
Beyond the need to investigate a neglected area in aging and memory, there are

cogent theoretical grounds for studying prospective memory abilities in the elderly. One
inﬂuential theory of memory and aging has been developed by Craik (1986) who suggests
that prospective memory may be particularly susceptible to age-related decline in the
elderly. Craik's (1986) suppositions focus on the ﬁmctional nature and the process of
memory rather than its structural components. Until more recently, a structural account of
memory processes has been an empirical emphasis in a large majority of scientiﬁc
investigations and theoretical formulations of memory (Atkinson & Shiﬁ‘rin, 1968;
Tulving, 1983).

Additional theoretical accounts of the vulnerability of prospective memory to the
aging process hypothesize that fewer information processing resources may be available
(i.e., resource deﬁciency hypothesis; Salthouse, 1991) and that a larger number of
cognitive operations are called upon in prospective memory each being subject to age-
associated decline (i.e., probability model; Levy & Loftus, 1984). These theoretical
suppositions will be discussed below.

Craik's functional account of memory processes differs ﬁom a structural one in the
respect that he considers any instance of recall to entail an interaction of environmental
and organismic (i.e., internal mental operations) factors. Therefore, he surmises that recall

will be enhanced to the extent that the original context of the memory store is replicated

5

during retrieval, thus emphasizing environmental factors. When these external cues are
not present, recall relies to a greater extent on the self-initiated mental operations of the
rememberer (i.e., organismic operations). Craik (1986) suggests that self-initiated cueing
is least required in tasks such as recognition and cued recall which can rely upon external
information to enhance recallability. Conversely, self-initiation is required to execute
memory traces which have fewer environmental cues to draw upon (e.g., free recall; Craik
& Jennings, 1992; e.g., less organization of stimuli; Norris & West, 1993). According to
this author, "remembering to remember" or prospective memory requires the greatest
amount of self-initiation. In addition, Craik (1986) goes on to hypothesize that the ability
to self-initiate memory searches becomes increasingly dimcult with age. Craik's (1986)
theoretical perspective draws upon Hasher and lacks (1979) "levels of processing"
paradigm to explain why these age related differences might exist. He suggests self-
initiated memory operations require more effort and deeper processing resources in order
to bring them into action and that the elderly are less likely to engage in the deeper levels
of memory processing needed to carry out self-initiated memory ﬁmctions.

Similar to the "levels of processing" theory proposed by Hasher and lacks (1979),
the resource deﬁciency hypothesis (Salthouse, 1991) posits that age-related memory
decline can be attributable to increasing limitations in information processing resources. In
other words, memory decline can be due either to the decreasing efﬁciency of such
resources or to the less efﬁcient use of memory strategies (i.e., those requiring less time
and energy). As will be discussed below, some possible explanations for discrepancies in

research ﬁndings on age and prospective memory decline is the diﬁ‘erential use or control

6

of external memory strategies. It seems reasonable to assume that the resource deﬁciency
hypothesis may explain the tendency for older individuals to rely more on external memory
strategies when intemally-generated approaches become less efﬁcient.

Verhaegen, Marcoen, and Goossens (1993) cited the resource deﬁciency
hypothesis to explain their ﬁndings in a meta-analytic review of the aging and memory
literature which included studies from 1975 to the present. Overall, their results indicated
that age differences in memory abilities are quite "large and omnipresent. " These authors
conclude that, potentially, a general factor is responsible for the majority of observed
memory proﬁciency decline across the adult life span. Namely, a deﬁciency or ineﬂiciency
in information processing resources (Salthouse, 1991) was forwarded as an explanation
for the observed age main effect.

Hasher and lacks (1988) have developed a theoretical framework regarding
inhibitory mechanisms and aging. In this particular framework, the performance of
cognitive tasks (e.g., prospective remembering) involves the limited-capacity operations of
working memory. According to this theory, prospective memory and other age-related
declines may result from an inability to inhibit irrelevant or minimally pertinent stimuli,
thoughts, or information. In a recent investigation in which both young (N = 40, mean
age = 18.9) and old (N = 37, mean age = 69.5) subjects were asked to read one word in a
pair of a certain color while ignoring the other, older subjects were found to show a
signiﬁcantly greater diﬁculty in suppressing distractors and avoiding interference ﬁ'om
distractor items (Kane, Hasher, Stoltzfus, lacks, & Connelly, 1994). A deﬁcit in

inhibitory mechanisms might account for an age-related decline in self-initiated pfOSpecthC

memory functioning.

Consistent with the theoretical frameworks discussed above, Levy and Loftus
(1984) have developed a probability model which identiﬁes potential variables which
collectively function to cany out a memory operation in the absence of environmental cues
(e.g., the absence of the person who assigned the to-be-remembered action). Speciﬁcally,
Levy and Loﬁus (1984) suggest that the probability of remembering to perform an act is a
function of the joint probabilities of (a) generating a cue that a particular action will be
carried out at the appropriate time; (b) remembering the contents of the action itself (i.e.,
retrospective memory); and (c) the probability that the action is actually carried out given
the previous two components. Traditional studies, which usually entail investigation of
the recallability of past information (i.e., retrospective memory), have focused on the
second aspect of this probability model (i.e., the probability of remembering some piece of
information given some cue). In fact, Winograd (1988) discusses the existence of a
dichotomy between these two memory systems in that retrospective remembering is often
facilitated by external cueing, whereas remembering future actions, in its purest form,
relies on self-generated cueing. This supposition about "remembering to remember" is
consistent with Craik's (1986) theory of prospective memory and aging.

Huppert and Beardsall (1993) suggest that the above probability model
presupposes that prospective memory may be more vulnerable to cognitive impairment
than other aspects of memory given the involvement of a variety of cognitive operations
(e.g., the joint probability of the three components), any of which could break down. In

other words, the invocation of the prospective memory process is complex and therefore,

8

it is logical to assume that such a process summons the capacities of other systems (e. g.,

retrospective memory, executive ﬁmctioning) which may be vulnerable to the effects of

aging.

FUNDAMENTAL DIFFERENCES BETWEEN PROSPECTIVE AND
RETROSPECTIVE MEMORY

Prior to summarizing the research on prospective memory and aging, it may useful
to delineate the differences between the two major memory categories of prospective and
retrospective memory. As will become apparent in the review on aging and prospective
memory, intentional (i.e., prospective) memory is reliant upon the abilities of the
retrospective memory system and the present study will differentiate performance in these
domains in order to draw deﬁnitive conclusions about age-associated decline. Prospective
memory does entail some retrospective memory operations, since planning the action has
occurred in the past. However, it is fundamentally distinct from retrospective memory
because intentional memory includes more than just recalling past events. For example,
prospective recall also includes memory for events that will continue through time and are
personally motivating and relevant for the remember (Sinnott, 1989). Furthermore,
remembering to execute some future activity involves planning, organizing, and other
strategic aspects of learning and memory (Shimamura, 1990).

Retrospective, or declarative, memory skills are those which are typically assessed
in standard tests of memory. This trend is partially attributable to the emphasis on the
laboratory setting for studying memory as well as the prevailing tenet that remembering
information ﬁom the past is the hallmark of memory ability. It is well known in the

literature on aging that age-related decline on episodic retrospective memory tasks is

10
ﬁrmly established (Einstein, Holland, McDaniel, & Guynn, 1992; Lezak, 1983; Light,
1991). Conversely, subjects in prospective memory experiments are instructed by the
experimenter to perform a task at some speciﬁed point in the future (Maylor, 1993).
Therefore, prospective memory can be considered a "means to an end" and in the ﬁnal
outcome, goal accomplishment is the indicator of memory success in this domain
(Sohlberg, White, Evans & Mateer, 1992). As such, one ﬁmdamental distinction
between retrospective and prospective memory systems is that the former emphasizes
one's ability to store and retrieve information whereas the latter requires the ability to
manipulate and organize memory for the purposes of future retrieval.

A number of studies suggest that the prospective memory system is dissociated
from the retrospective memory system. In other words, performance on prospective
memory tasks is apparently uncorrelated with retrospective memory performance (Einstein
& McDaniel, 1990; Maylor, 1990; Meacham & Leiman, 1982; Wilkins & Baddeley,

197 8). This distinction has been empirically demonstrated by Kvavilashvili (1987) in a
study which required subjects to ask a question at some future point. Results ﬁom this
study indicate that remembering to ask the question was independent of remembering the
content of the question, thus concluding that these types of recall rely on diﬁ‘erent
processes. Hitch and Ferguson (1991), in a similar vein, developed an objective
breakdown of the processes required in prospective recall. Parelleling the probability
model of Levy and Loftus (1984), they divided the prospective memory task into a series

of stages including the ability to form an intention, holding the intention in memory during

11

a speciﬁed time interval, and executing an action for the intention at the required time.1
This last stage of the prospective memory task is often referred to as "remembering to
remember" and it is thought to be the deﬁning characteristic which diﬁ‘erentiates intention

memory from memory for past events (Kvavilashvili, 1992).

 

1

Maylor (1993) would add an additional stage to the three identiﬁed by Hitch and Ferguson
(1991) above. She states that prospective memory also requires that an individual
remember that a task has been performed in the past so that it not be repeated at some
later point. This area of prospective remembering has been the focus of recent aging and
memory research which investigates the use of compensatory strategies for memory
failures in everyday life (e.g., ways to remember whether or not medication has been
taken; Backman, 1989) and is often referred to as output monitoring (Koriat, Ben-Zur, &
Sheffer, 1988).

PROSPECTIVE MEMORY AND AGING

In reviewing the literature on age-associated effects on prospective memory, an
age-related decline in "remembering to remember" (Cockbum & Smith, 1988) has
sometimes been observed. However, other empirical investigations have found results of
no signiﬁcant effect of age (Sinnott, 1986) as well as an increasing prospective memory
capability with age (Moscovitch, 1982). These contradictory ﬁndings are ﬁirther
confounded by the fact that intentional remembering has been tested in varying contexts
and under diverse conditions including both laboratory and naturalistic settings using
either prospective memory tasks or self-report measures.

Maylor (1993) suggests that a signiﬁcant factor in beginning to understand these
contradictory ﬁndings is whether or not there is control of the use of external memory aids
within the study. For instance, Patton and Meit (1993) found that older subjects (N = 17)
performed relatively better than younger subjects (N = 24) on prospective memory tasks
(e.g., mailing postcards) when they were allowed to supplement their remembering with
memory aids. In addition, results indicated that subjects who exhibited a greater degree of
motivation (i.e., rating of task importance) employed external memory aids more
eﬁ‘ectively. Maylor's (1993) contention is that these results must be interpreted with
caution since the experiment did not explicitly control for the use of memory aids. Rather,
subjects were allowed free access to memory aids and were then questioned about their
use of such aids in a post hoc fashion. Subjects reported using both internal and external

memory aids to varying degrees.

12

13

Although it is unclear which is more beneﬁcial, internal or external cues, a number
of authors have concluded that older subjects demonstrate better aided prospective
memory when compared to a younger cohort group (Devolder, Brigham, & Pressley,
1990; Martin, 1986; Moscovitch, 1982); such studies, however, cannot demonstrate
deﬁnitively if prospective memory remains intact in older cohorts or whether deﬁcient
prospective memory is compensated for through the use of external cues. In general,
when both older and younger subjects are denied access to external memory aids, the
advantage that older subjects enjoy with respect to superior prospective memory
performance seems to disappear. Under these controlled conditions (e.g., laboratory
study), younger subjects often display relatively greater intentional recall capabilities. In
fact, when both students and older adults are asked about their use of memory aids
(Jackson, Bogers, & Kerstholt, 1988), older subjects report relying more extensively on
external cues for prospective memory tasks. Interestingly, in the case of retrospective
memory, both groups employed internal and external cues equally.

The review below will consider prospective memory ﬁndings in various contexts
and will demonstrate that the control of cues is imperative in understanding the
relationship between age and prospective remembering. In order to understand the
prospective memory and aging research, investigations will be summarized according to
whether they have been conducted in the laboratory or in more naturalistic settings. This
dichotomy is necessary in demonstrating that laboratory studies have more conclusively
established an age-associated decline in prospective memory due to the increased ability to

control for the use of memory aids. In addition, results of investigations using self-report

14

measures will be summarized to demonstrate that the successful implementation of
external memory aids may lead the elderly to perceive that their prospective memory
capabilities have improved.

Laboratory Studies. Despite the current trend in memory research to focus on
ecologically valid measures and settings, it is noteworthy that laboratory settings have
proven effective in controlling for the use of external memory aids while simultaneously
employing prospective memory proxies of everyday memory tasks. As discussed
previously, controlling for the use of external memory aids is imperative in studying this
memory domain given that mnemonic devices can be employed to such a degree as to
mask an underlying characteristic of "absentrnindedness. "

According to Maylor (1993 ), the majority of laboratory based investigations which
control for the use of external memory aids ﬁnd a negative relationship between
prospective memory and age. For example, Dobbs and Rule (1987) instructed a series of
age cohorts (i.e., 30-3 9, 40-49, 50-59, 60-69, and 70+ year olds) to request a red pen at a
later point in the session when they were asked to draw a cube and a circle. Nearly all of
the subjects 30-60 years old successﬁrlly completed the prospective memory task (i.e.,
remembering to request the red pen) whereas only 70% of the 70+ year olds completed
the task successfully thus diﬂ‘ering signiﬁcantly from the other age groups. Furthermore, a
multiple regression analysis performed using age, education, and gender as potential
predictors found only the age variable to be a reliable predictor of performance on the
prospective memory task.

Cockburn and Smith (1991) have employed the Riverrnead Behavioral Memory

15

Test (RBMT; Wilson, Cockburn, & Baddeley, 1985) as a means of assessing prospective
memory. The RBMT is a laboratory measure which includes three prospective memory
items embedded within a series of everyday memory tasks. In this particular study
(Cockbum & Smith, 1991), 94 elderly subjects (70-93 years) were administered the
RBMT. Results indicated that all three prospective memory items showed a signiﬁcant
decline. In addition, age was found to be a signiﬁcant predictor of performance on these
items to a greater extent than measured intelligence. Taken together, these two studies
(Cockbum & Smith, 1991; Dobbs & Rule, 1987) suggest that age can account for a
greater degree of variance in prospective memory performance than other variables
including gender, intelligence, or education.

In an additional study of prospective memory and aging, West (1988) asked both
students (N = 26; 19-23 years) and elderly subjects (N = 26; 63 -83 years) to remind the
experimenter to check the tape recorder and get a pen out of a folder. These tasks were
prompted by a verbal cue from the experimenter (e.g., "This is the end of the passage
recall test"). Results revealed that younger adults remembered signiﬁcantly more
message details than older adults pointing again to a signiﬁcant eﬁ‘ect of age. Age
accounted for approximately 25% of the variance when assessing the accuracy of the
completion (i.e., within two minutes of the cue) of the prospective memory task. West
(1988) posits that the contextual cues provided in the laboratory may be less personally
relevant or meaningful (e.g., experimenter generated vs. self-generated) than those cues
available to subjects in more familiar settings such as their home, thus accounting

somewhat for the main effect of age on prospective memory performance. The nature of

16

the cues in this study was such that they were less likely to compensate for an underlying
prospective memory deﬁciency given that they were generated by the experimenter, were
unfamiliar, and less personally relevant.

The studies cited above have generally concluded that intentional remembering
declines with age; however, there are also a limited number of laboratory-based
investigations which have not found signiﬁcant age eﬂ‘ects for prospective memory
performance. Sinnott (1986) asked older and younger subjects (N = 79; age 23-93) to
recall both incidental and prospective information. Results demonstrated a signiﬁcant
effect of age for the incidental, but not the prospective, tasks. Nevertheless, it should be
noted that Maylor (1993) cautions against the signiﬁcance of these ﬁndings based on three
arguments including (a) ceiling eﬁ’ects were likely present for prospective memory items;
(b) prospective items were rated as more important by subjects than incidental items; and
(c) Sinnott (1986) may have been investigating the retrospective aspect (i.e., memory for
acquired information) rather than the prospective aspect of the tasks (i.e., goal
completion).

Einstein and McDaniel (1990) did not ﬁnd a signiﬁcant effect for age in either of
two experiments in which a prospective memory task was embedded in a retrospective
memory task. They did ﬁnd signiﬁcant main effects for variables such as the use of
memory aids and the familiarity of the event which triggers the required prospective
memory response. Nonetheless, in a subsequent study using the same experimental
paradigm but an increased memory task complexity, a signiﬁcant effect for age did emerge

(Einstein et al., 1992). In this more recent study, these authors differentiate between

17

event-based tasks and time-based tasks. Event-based prospective memory tasks are those
in which an external event triggers the to-be-remembered activity (e. g., remembering to
press a key when a target word appears). Time-based tasks are those which involve only
time monitoring (e.g., remembering to press a key in 10 minutes). It is argued that time-
based tasks require more self-initiation than event-based tasks and are therefore, more
susceptible to the effects of aging (Craik, 1986; Craik & Jennings, 1992). Despite ﬁnding
no signiﬁcant effect for age in their previous study (Einstein & McDaniel, 1990), age
diﬁ‘erences did emerge in this study for event-based prospective memory tasks.2
Therefore, increasing the complexity of the task may have dealt with the possible
confounding of results due to a ceiling effect in the initial study.

In an interesting study of prospective memory over time, Maylor (1993) did not
ﬁnd age differences on initial performance, but did observe a "forgetting curve" over trials
for older subjects. Both young-old (mean age = 57.3 years; N = 43) and old-old (mean
age = 74.6 years; N = 43) subjects were instructed to write the names of famous persons
in response to a slide. The prospective element of the task required subjects to circle the
number on their paper when they viewed a person with a beard and put a cross through
the number of the slide when a person with a pipe appeared. Subjects were exposed to
four trials of 30 slides each. Results indicated that younger subjects demonstrated

generally better performance on the prospective task than older subjects. Furthermore,

 

2

While the authors constructed the distinction between event-based and time-based
prospective memory tasks, an event-based task was the only one to be included in the
study. However, this construct of prospective memory will be explicitly considered in the
present study.

18

the performance of both groups was equivalent during the ﬁrst trial, but performance
diﬂ‘erences between the two age cohorts increased signiﬁcantly on subsequent trials. In
explaining the signiﬁcance of these results, Maylor (1993) draws a noteworthy distinction
between retrospective and prospective memory. She indicates that the literature on aging
and retrospective memory suggests that age impairs initial performance, but not
subsequent forgetting; however, a diﬁ‘erent pattern emerges for prospective memory.
Qualitatively, Maylor (1993) posits that age does not affect initial performance on
prospective memory, but does affect subsequent forgetting. Therefore, she suggests, that
learning, rather than retrieval, may be an important determinant in observed age-related
eﬁ‘ects on intentional memory.

In reviewing empirical investigations of prospective memory, Maylor (1993)
outlines four necessary factors in designing a study of prospective memory and aging.
First, a large number of subjects covering a wide age range is required. Second,
prospective and retrospective memory performance acquired under the same experimental
conditions is necessary in parcelling out which factors account for observed ﬁndings. The
absence of ﬂoor and ceiling effects is also imperative in drawing deﬁnitive conclusions
based on discriminative performance. Third, it is necessary to demonstrate that if no age
effects on prospective memory are detected, that the dependent variable of prospective
memory was sensitive to other experimental manipulations. Last, external cues must be
controlled in any investigation in order to account for the potentially compensating eﬁ‘ects
of cues on declines in intentional memory. For this reason, laboratory studies seem to

demonstrate most deﬁnitively that a relationship between prospective memory and age

19

may exist. Naturalistic studies, on the other hand, have not been able to control for this
potentially confounding variable. Nevertheless, several naturalistic investigations will be
brieﬂy reviewed below to demonstrate this experimental bias more explicitly.

Naturalistic Settings. Although inconsistent, nonlaboratory studies of
prospective memory generally reveal that this facet of memory function improves as age
increases (Maylor, 1993). For instance, in an archival study of attendance records at a
research laboratory, Martin (1986) found that older individuals were less likely to miss
appointments than younger subjects (i.e., 0.9% and 4.4% appointments missed,
respectively). What this trend reﬂects, however, may be an increasing proﬁciency in using
external memory aids given that the majority of naturalistic studies of intentional memory
do not control for this factor (Harris, 1984).

For example, in a series of studies by Moscovitch (1982), college students and
older college graduates (age 65-75) were asked to telephone the experimenter at speciﬁed
times and dates. Results revealed that the older subjects carried out the task more
successfully than their younger counterparts. However, when examined more closely, it
appears that the superior performance of the older individuals could be attributable to their
use of mnemonic devices whereas the younger subjects relied on more internal methods to
generate recall as indicated in their proclamation that they simply "trusted their memory."
A subsequent experiment instructed subjects not to employ any external aids when
carrying out the prospective memory tasks. In this case, the advantage that older subjects
had demonstrated on the prospective memory task disappeared. In a comparable

paradigm, Poon and Schaffer (1982) found a prospective memory advantage for their

20
older subjects (mean age = 73.2 years) over the younger individuals (mean age = 25.3
years); however, this study again did not control for how the subjects chose to carry out
the prospective task (aided vs. unaided) once they left the laboratory.

These ﬁndings are consistent with more recent studies as well (Maylor, 1990;
Experiment 1, West, 1988). While a number of design ﬂaws can be cited as accounting
for these ﬁndings such as small sample sizes, ﬂoor/ceiling eﬁ‘ects, and social/motivational
factors, it appears that in all cases a signiﬁcant factor seems to be that external aids are not
controlled. When data regarding the utilization of mnemonic aids was obtained in a post
hoc fashion (Maylor, 1990), the results point toward the use of aids as the signiﬁcant and
determining factor in the observation of a positive relationship between prospective
performance and age. A number of explanations have been forwarded in explaining the
observed relationship between intentional memory and age including the idea that external
aids serve an adaptive function in optimizing everyday memory capabilities (Sinnott,
1989). In addition, some authors have recognized that the elderly may structure their
environment to compensate for deteriorating prospective memory (Maylor, 1993;
Moscovitch, 1982). The possibility, however, that prospective memory may diﬁ‘erentially
decline in the elderly has not been deﬁnitively ascertained through naturalistic studies of
intention memory due to the confounding effect of uncontrolled use of mnemonic aids.

Metamemory Investigations of Prospective Memory. As with other
prospective memory investigations, self-reports of memory failures may be minimized by
the effective use of external memory aids (e.g., calendars, diaries, lists). Furthermore,

little empirical investigation has been done which considers the correlations between age,

 

21

self-report of ability, and actual performance on aided and unaided prospective memory
tasks. Only two studies have been cited in the literature related to these variables, each
with conﬂicting ﬁndings. Dobbs and Rule (1987) found a negative correlation between
metamemory scores and prospective remembering performance; while, Harris and Wilkins
(1982) found self-reported failures in everyday life to positively correspond to failures on
similar laboratory tasks. Given this gap in the literature, one aspect of the present
investigation will be to explore the relationship between prospective memory performance
(aided vs. unaided) and self-assessment of these abilities on a metamemory questionnaire
(i.e., The Memory Assessment Clinic Self-Report Scale, MAC-S; Crook & Larrabee,
1990). It should be noted that studies exist (Larrabee and Crook, 1989) which have
attempted to correlate age, "everyday memory" performance, and metamemory using such
measures as the MAC-S; however, these studies include both retrospective and
prospective tasks under the rubric of everyday memory assessment and therefore, do not
speciﬁcally assess the functional construct of prospective memory.

Rather than focusing on actual memory performance, self-report measures aim to
delineate older individuals' perceptions of their memories. This aspect of memory study is
referred to as metamemory and can be assessed in respect to both prospective and
declarative (i.e., retrospective) memory. Metamemory can be broadly deﬁned as
"cognitions about memory" (Hertzog, Dixon, & Hultsch, 1990) as well as an individual's
assessment of their intentional memory capabilities and an understanding about what
strategies might be employed to improve memory (Shimamura, 1990). Such an awareness

is necessary for and inherent in successful prospective remembering given that the

22

remembering of intentions, more than any other memory capacity (i.e., retrospective
memory), relies on one's ability to plan, monitor, and organize one's memory. Older
adults, for instance, have been found to be less emcient in using "metacognition" to judge
the usefulness of different memory strategies and effectively choose which strategy to
employ (Brigham & Pressley, 1988).

According to Maylor's (1993) review of this dimension of prospective memory,
ﬁndings generally indicate a positive relationship between age and self-reports of
prospective remembering (i.e., as age increases, intentional remembering is perceived as
improving). Conversely, predominantly negative correlations have been observed in the
literature with regard to self-reports of retrospective memory and age (i.e., decreasing
capability with increasing age). For example, several studies (Cohen & Faulkner, 1984;
Martin, 1986) queried young, middle-aged, and older individuals about their memory.
Results have indicated that age was not a signiﬁcant factor on items of prospective
memory (e.g., attending appointments, taking medication, and answering letters) whereas
older subjects consistently give decreased ratings for subsets of retrospective items (e.g.,
remembering telephone numbers and names of famous people). The present study will
attempt to determine if indeed perceptions of prospective ability correspond with
demonstrated capabilities and explore how this relationship changes across the life span.

The clinical relevancy of studying prospective memory can be found in a recent
study in which prospective memory impairment was demonstrated to be an early indicator
of dementia (Huppert & Beardsall, 1993). In the study, subjects classiﬁed as having a

minimal level of dementia performed as poorly on prospective memory tasks as subjects

23

displaying a more advanced stage of dementia. On the other hand, performance on
retrospective memory tasks for subjects with minimal dementia fell somewhere in between
normal control and more demented subjects. One of the most clinically challenging tasks
facing the neuropsychologist is to differentiate the early stages of dementia ﬁ'om either
age-associated cognitive decline or depression in the elderly (Lamberty & Bieliauskas,
1993). In other words, it is generally diﬂicult to delineate what various
neuropsychological proﬁles might look like in the early stages of a disease process and a
large gap exists in the neuropsychological (and medical) arena in determining what
subgroups of elderly individuals might be at risk for developing a more serious
neuropathological condition. From a clinical perspective, beginning to determine the age-
associated nature of prospective memory may help to elucidate the ﬁne gradations which
are necessary in specifying early neuropsychological correlates of dementia processes.
Given that an age-associated decline of prospective memory does emerge in laboratory
studies in which the use of mnemonic devices can be controlled, the next section will

attempt to identify neurological substrates which might account for this relationship.

NEUROPSYCHOLOGICAL MODELS OF FRONTAL LOBE FUN CTIONING
AND PROSPECTIVE MEMORY
It has been hypothesized, ﬁ'om a neuropsychological perspective, that the

prospective memory operations require access to an "executive role" in the memory
system including such ﬁmctions as monitoring, organizing, and retrieving memory
representations needed to execute future activities (Shimamura, 1990). Given these
characteristic performance features of the construct of prospective memory, it has been
inferred that intentional memory is reliant upon the integrity of the ﬁ'ontal lobes (F urst,
1986; Shirnarnura, 1990). Theoretical accounts of the tie between prospective memory
and frontal lobe functioning can be traced to distinctions drawn between different types of
memory. For instance, Squire (1987) has posited that the ﬁtnction of the frontal lobes
involves a special kind of memory. Namely, specialized working-memory capacities (e.g.,
keeping a memory trace active for future use as with prospective memory) are considered
to be functionally present in the prefrontal cortex whereas the general capacity for long-
term memory (i.e., retrospective memory) depends to a greater degree on the ﬁmctional
integrity of the medial temporal region and diencephalic brain structures (Squire, 1987).
Recently, Shimarnura and Jurica (1994) have suggested that in normal aging, observed
cognitive decline associated with frontal lobe integrity may precede that associated with
medial temporal lobe dysﬁanction. For purposes of the present investigation, it is argued
that intact frontal lobe functioning contributes to efficient prospective memory functioning

(although other functional connections may augment) and that this association may decline

24

25

across the life span.

Much literature has been generated which attempts to link memory changes in
normal aging to amnesia. The classical arnnestic syndrome involves the diencephalon (e.g.,
the hippocampus) and age-related loss of neurons in this area (Miller, Alston, Mountjoy,
& Corsellis, 1984; Zola-Morgan, Squire, & Amara], 1986) has been observed.
Neuropsychologically, hippocampal dysﬁinction has been linked to retrospective memory
decline in laboratory studies (Lezak, 1983). However, this aspect of the neurological
literature will not be considered here given that the focus of the present study is how
changes in the preﬁontal cortex result in behavioral disturbances of memory in the elderly.

Anatomical Considerations. Squire (1987) identiﬁes three types of
neurostructural changes which have been studied with regard to memory and aging.
These include (a) neuronal loss; (b) changes in neuronal size and in the relative number of
synaptic connections; and (c) the ﬁ'equency of neuropathological structures within neurons
(e. g., neuroﬁbrillary tangles, senile plaques). Squire (1987) 11.111th suggests that it is the
ﬁrst of these, neuronal loss, which has offered the most unambiguous ﬁndings with regard
to the aging brain. For example, Haug, Barmwater, Eggers, Fischer, Kuhl, and Sass
(1983) conducted a morphometric analysis of neuronal loss in the aging brain by using
automated equipment and correcting for total tissue volume to control for biased eﬁ‘ects.
Their results indicate that a number of cortical areas (e.g., parietal cortex, striate cortex)
do not lose a signiﬁcant number of neurons during the life span; however, the neostriatum
and the preﬁontal cortex were found to have lost 15-20% of neurons between young

adulthood and old age. Furthermore, several studies have observed the most intense

26

changes in the aging mammalian brain to take place to a greater extent in the ﬁontal
cortex (Mervis, 1981; Vemadakis, 1985). Therefore, one cortical region that appears to
be differentially affected by normal aging is the prefrontal cortex (J emigan, Archibald,
Berhow, Sowell, Foster & Hesselink, 1991; Lim, Zipursky, Watts & Pfeﬁ‘erbaum, 1992).
According to several leading theoreticians in the area of brain functioning and
memory, the prefrontal cortex serves a specialized function in the memory process (Luria,
1966, 1973; Squire, 1987; Stuss & Benson, 1986). Luria (1973) suggests that frontal lobe
pathology leaves the operation of primary memory intact, but :
". . .the ability to create stable motives of recall and to maintain the active eﬁ’ort
required for voluntary recall, on the one hand, and the ability to switch from one
group of traces to another are deﬁcient, with the result that it is the mm of
recall and reproduction of material which is signiﬁcantly impaired." (p. 211)
Stuss and Benson (1986) suggest, therefore, that the ﬁ'ontal lobes are intimately involved
with the memory process; however, their function is to organize strategies for storage and
retrieval as well as to compare the results of remembrance with original intentions. In his
work with ﬁontal lobe patients, Luria (197 3) concluded that these patients are particularly
susceptible in their ability to monitor irrelevant, interfering, or inappropriate information.
One can see how this pattern would be speciﬁcally related to prospective memory. If
prospective memory entails the ability to hold some future intention in memory and then
carry it out at some later point, then age-associated ﬁontal lobe inefﬁciency could result in
any interference causing remembrance of that intention to disintegrate.

In particular, lesions to the inferior convexity and dorsolateral cortex of the ﬁ'ontal

27

lobes have been shown to result in a particular pattern of inﬂexibility, perseverative
responding, and the inability to alter one's response to changing environmental demands
(Mishkin & Manning, 197 8). The perseverative response tendencies observed in the
animals with inferior convexity lesions was hypothesized to be due to an inability to
overcome responses that compete with to-be-leamed responses. This supports the notion
that, in general, frontal lobe inefﬁciency results in memory traces which are vulnerable to
the eﬂ‘ects of interference. Luria (1973) coined the term "pathological inertia", or the
inability to switch from one trace to another, in referring to the perseverative tendency he
observed in his patients with lesions of the ﬁontal lobes. In describing this syndrome
further, he states that pathological inertia coupled with aspontaneity also resulted in an
inability to compare the results of one's actions with the original plan. For the purposes
of the present study, it is suggested that such changes in frontal lobe emciency in the
elderly would interfere with their ability to generate and carry out ﬁrture intentions as well
as monitor the outcome of these goal-directed behaviors. Obviously, substantial
differences exist between changes in frontal lobe functioning due to normal, age-
associated processes and those seen in various clinical samples with neurostructural
impairment. However, the investigation of cerebral changes following neurostructural
damage has provided a great deal of material in understanding the processes of the healthy

brain.

28

N europsychological Considerations. Craik's (1986) theory on the functional
aspects of prospective memory suggests that older individuals perform more poorly on
memory tasks which require them to execute self-initiated operations. For example, older
individuals have been shown to perform more poorly on free recall tasks than tasks of
cued recall and more poorly on tasks of cued recall than recognition, each requiring
varying degrees of self-initiated memory processing. This is true even when these tasks
are equated for task diﬁculty (Craik, 1986). Clinical investigations of ﬁontal lobe patients
and memory reveal a similar pattern. In other words, normal subjects are able to
demonstrate skills in organization and strategy implementation in free recall tasks, while
ﬁ'ontal lobe patients are not (Squire, 1987 ; Stuss, Alexander, Palumbo, Buckle, Sayer &
Pogue, 1994). Stuss, Eskes and Foster (1994) summarized the ﬁrnctional impairments of
memory and learning which are associated with frontal lobe damage. These deﬁcits
include (a) working memory capacity impairment; (b) susceptibility of learning to the
eﬂ‘ects of interference; (c) limits in context learning; ((1) impaired memory of source and
order of recall information; and (e) deﬁcits in metamemory.

Prospective memory can be identiﬁed as involving the capability to remember
information that is tied to its temporal orientation. For example, individuals must
remember to take their medication at a certain point in time and also recall how recently
this act was completed. This is what Koriat and his colleagues (1988) have described as
output monitoring or the memory that a planned action has already been performed.
These authors further stipulate that perseveration might be deﬁned as a failure in output

monitoring. Furthermore, memory functions related to frontal lobe eﬁciency (e.g.,

29

prospective memory) have been considered to involve the ability to manipulate and
retrieve associations within a temporal-spatial context (Butters, Kaszniak, Glisky, Eslinger
& Schacter, 1994; Shimamura, 1990). This can include source amnesia in which an
individual can remember what is said during a conversation, but have difﬁculty recalling
who said it, or where and when the information was obtained (i.e., the contextual aspects
of the memory). Shirnamura (1990) suggests that remembering what was said in a
conversation, for instance, is a distinct process from recalling who said it and where and
when it was said. This latter aspect of recallability requires a search of memory which is
thought to rely on the capabilities of the prospective memory system because access to
these spatial-temporal aspects of information is necessary in making contextual
associations to memory traces.

Source memory as a speciﬁc function of frontal lobe capacity has been shown to
be impaired in older adults (Craik et al., 1990; Janowsky, Shimamura, & Squire, 1989).
The relation of frontal lobe functioning to the spatial-temporal context of memory
information was demonstrated in a study by Milner (1971) which required both unilateral
temporal lobe and unilateral ﬁ'ontal lobe lesioned patients to recall the temporal order of a
series of 184 stimuli. After presenting the stimuli, subjects were asked to recall which of
two stimuli were presented most recently. Those subjects with ﬁ'ontal lobe pathology, but
not those with temporal lobe involvement, displayed signiﬁcantly impaired performance
when making these judgments of recency. Furthermore, in a well-designed study of
temporal order and interference conducted by Petrides and Milner (1982), subjects were

exposed to twelve pictures of either objects, abstract designs, or words. All the stimuli

30

appeared together on each page, but with successive pages the stimuli were in varying
arrangements. The task of each subject was to point to a new and different stimulus on
each page which required recalling which items had been selected on previous pages. This
task required that the subjects be able to relate information about their own actions and
subsequently make selections among repeatedly presented items. Results revealed that
patients with frontal lobe lesions were most severely impaired on this task. Petrides and
Milner (1982) interpreted this apparent deﬁcit in frontal lobe patients to be related to
symptomatic difﬁculties with planning and organizing memory recall.

Shimarnura and Jurica (1994) recently employed this same experimental paradigm
to investigate memory interference eﬁ‘ects and aging. The sixteen stimuli of visual
patterns were presented on a computer screen. Subjects were instructed to select a design
that had not been selected on a previous trial, the interfering stimuli, therefore, being the
other ﬁfteen designs present on the screen. Three groups of subjects participated in the
study including college students (N = 41, mean age = 20 years) and two groups of healthy
elderly individuals (N = 17, mean age = 66 years and N = 11, mean age = 75 years).
Results indicated an age-related impairment on this measure sensitive to ﬁ'ontal lobe
dysﬁrnction. Moreover, this cognitive impairment pattern was more pronounced for
subjects in their seventies than those in the sixth decade. Results were interpreted as being
consistent with a deﬁcit in working memory.

From this review, it is apparent that the diﬁiculties with recall seen after frontal
lobe impairment cannot be attributed to a primary memory deﬁcit alone. Stuss and

Benson (1986) refer to amnesia associated with ﬁontal lobe involvement as a disorder of

31

organization. Changes in frontal lobe functioning do not produce classical disorders of
memory (e. g., impaired recall only), but do result in deﬁcits which inﬂuence the overall
functioning of memory. On a posterior-anterior brain axis, posterior brain lesions
produce more primary disturbances of memory which are considered to be modality-
speciﬁc. On the other hand, memory disturbances associated with loss of ﬁontal lobe
integrity affect the memory systems "executive" role or its operational capabilities.
Goldberg and Bilder (1987) indicate that deﬁcits of the preﬁ'ontal cortex are universal in
terms of their impact rather than modality speciﬁc because of the superordinate nature of
this brain region and its "executive" role in functioning. Moreover, to Luria (1973),
frontal lobe impairment leads to mnemonic activity which "easily yields to uncontrollable
irrelevant associations, or the inﬂuence of existing stereotypes. . .and goal-directed activity
is replaced by the recall of irrepressible associations, with no attempt at correction" (p.
345). It is these elements of ﬁ'ontal lobe functioning and memory which are hypothesized
in the present study to account for potentially observed deﬁcits in prospective memory in
the elderly.

Aging and Frontal Lobe Functioning. While the above mentioned studies
attempt to tie the phenomena of an age-associated decline in prospective memory to
possible ﬁontal lobe dysfunction, it may be worthwhile to also explore recent studies
which point to neuropsychological changes in ﬁ'ontal lobe functioning which accompany
the aging process. It is often cited in the literature that attentional resources are more
limited for older than younger adults and therefore a geriatric population is considered to

perform more poorly on tasks because they may involve "effortful or attention-demanding

32

processing" (Hasher & Zacks, 1979; Salthouse, 1991). Shimamura (1990) rejects the
notion that most patterns of age-associated cognitive decline can be attributed to deﬁcits
in attention and disregards this theoretical account based on several arguments. First, he
cites an inadequacy of theories of cognitive decline in deﬁning "eﬁ‘ortful" processes and
indicates that when common deﬁnitions are employed, older individuals do not exhibit
deﬁcits on "eﬁ‘ortful" tasks (Light & Burke, 1991). Furthermore, Shimamura (1990)
suggests that some tasks which are considered to be "eﬂ‘ortless" do show age-associated
performance decrements (e.g., simple classical conditioning).

Instead, Shimamura (1990) suggests that it is possible to integrate the attentional
resource perspective into contemporary neuropsychological thought. He surmises that
observed attentional deﬁcits can be attributed to frontal lobe dysfunction and therefore,
subsequent prospective memory impairment. It is well documented that frontal lobe
pathology often involves attentional deﬁciencies and this neurostructural region has
extensive connections with systems of arousal (Luria, 1966; Stuss & Benson, 1986). In
addition, Shimamura (1990) hypothesizes that descriptions of "eﬁ‘ortful" processing and
prospective memory are similar since both require planning, self-initiation, selection of
responses, monitoring, and cognitive mediation. Therefore, he suggests that demonstrated
attentional diﬁculties observed in the elderly can be traced to an ineﬁciency in ﬁ'ontal
lobe ﬁmctioning.

Shimamura's (1990) suppositions have been supported by a growing body of
research which suggest that the prefrontal cortex may be particularly vulnerable to the

eﬁ‘ects of aging. The implicit assumption growing out of this area of study is that

33

"normal" aging is associated with cognitive impairments that approximate (i.e., are milder
than) those seen in frontal lobe patients. It was originally argued by Klisz (1978) that
older persons, in the absence of pathology, have similar neuropsychological patterns to
individuals with right hemisphere involvement. This aging and lateralization hypothesis
continues to permeate the aging literature; however, it has been challenged in the more
recent past. Neurophysiological studies have suggested that such indicators as regional
cerebral blood ﬂow show signiﬁcant declines in prefrontal regions beyond the sixth decade
while corresponding changes are not observed in posterior cerebral regions (Shaw,
Mortel, Meyer, Rogers, Hardenberg, & Cutaia, 1984; Warren, Butler, Katholi, & Halsey,
1985). Contemporary neuroradiologic techniques, such as magnetic resonance imaging,
have been employed in recent investigations which also point to age-related changes in the
ﬁ'ontal lobes (Jernigan et al., 1991; Lirn et al., 1992). Furthermore, a number of
qualitative studies have conﬁrmed the supposition that anterior-posterior changes in brain
functioning occur to a signiﬁcantly greater degree than left-right lateralization changes
(Albert & Kaplan, 1980; Veroff, 1980). Hochanadel and Kaplan (1984) early on
hypothesized that a prefrontal model of normal brain aging exists based on their
observations of the behavior of geriatric subjects, especially with regard to inﬂexibility of
response sets (i.e., perseveration). These authors contend that a tendency toward
perseveration is at the heart of their prefrontal model of aging. In support of this
theoretical supposition, Ruﬁ‘, Light and Evans (1987), in addition to decreased ﬂuency,
found perseverative errors on a design ﬂuency test to be highly correlated with age.

Findings ﬁom qualitative studies which have observed age-associated decline in

34

frontal lobe functioning have been corroborated by normative, quantitative studies of
frontal lobe functioning in the elderly. For instance, Whelihan and Lesher (1985)
completed a neuropsychological assessment with groups of young-old (N = 31; 60-70
years) and old-old (N = 48; 76-92 years) cognitively intact subjects. Results revealed that
the old-old cohort performed signiﬁcantly below the young-old group on frontal lobe
measures whereas only minimal differences were observed on nonfrontal measures. These
authors suggest that "normative and nonpathological age-associated changes" accounted
for their ﬁndings. Similarly, Mittenberg, Seidenberg, O'Leary and DiGiulio (1989)
evaluated ﬁve groups of subjects (20-35, 55-59, 60-64, 65-69, and 70-75 years) on a
neuropsychological test battery. A stepwise multiple regression of all measures included
in their study revealed that frontal lobe functions best discriminated older from younger
cohorts, and explain "essentially all of the variability in age-related performance decline. "
A study conducted by Daigneault, Braun, and Whitaker (1992) also lends support to the
notion that frontal lobe functions are among the ﬁrst to decline in normal aging. Their
results suggest that noted age-associated decline in frontal lobe functioning may occur as
early as 45-65 years and includes deﬁciencies in the ability to regulate behavior based on
plans, environmental feedback, abstract concepts, or one's own responses.

The evidence regarding the decline of frontal lobe functions in the elderly is
certainly compelling and beyond theoretical explication, its relationship to noted declines
in prospective memory is as yet unexplored. On a cautionary note, however, Boone,
Miller, Lesser, Hill, and Elia (1990) suggest that cross-sectional data may artiﬁcially

enhance the ﬁndings related to frontal lobe ineﬂiciency in the elderly. Moreover, after

35

strictly controlling for medical, neurological, and psychiatric illnesses in their sample of 61
rniddle-aged and elderly individuals (50-59, 60-69, and 70-79 years), few statistically
signiﬁcant diﬁ‘erences among groups emerged. Even so, some trends did emerge related
to frontal lobe inefﬁciency including dimculties with verbal ﬂuency and ineﬁcient
selection of problem-solving strategies. These authors, therefore, have suggested that in a
medically and psychiatrically healthy population of older adults, minimal evidence emerges
for age-associated decline in frontal lobe abilities.

Elsewhere it has been suggested that these results may be inconclusive given that
range restriction in the age of the sample (i.e., lack of inclusion of an age group 380
years) as well as a cohort which demonstrated high intelligence (mean WAIS-R Full Scale
IQ = 113.79) and education (mean = 14.24 years) may have attenuated the reported
ﬁndings (U chiyama, Mitrushina, D'Elia, Satz, & Mathews, 1994). In addition to
controlling for medical and psychiatric illnesses in a sample of geriatric (N = 68; mean age
= 78) and nongeriatric (N = 193; mean age = 48) individuals, Uchiyama and his colleagues
found frontal lobe functions to be decreased in their elderly sample and were able to rule
out education, gender, and decreased psychomotor abilities as possible moderating
inﬂuences for the noted eﬂ‘ect.

Prospective Memory and Frontal Lobe Functioning: Clinical Evidence.
Clinical samples of patients with neurostructural damage to the frontal lobes are often
described as displaying a clinical syndrome which includes difﬁculties in planning,
categorizing, attention, output monitoring, verbal ﬂuency, and inferential problem solving

(Janowsky, Shimamura, Kritchevsky, & Squire, 1989). Yet this same group of patients

36

can display relatively well preserved capabilities in the area of declarative or retrospective
memory. Such a deﬁcit, again, demonstrates the ﬁrnctional distinction between
retrospective and prospective memorial systems. Luria (1966) observed frontal lobe
patients to be able to verbalize a desired response (i.e., the retrospective component of
prospective memory), but unable to carry out the requested action (i.e., the measure of
successful prospective memory), thus exhibiting a disconnection between knowing and
doing. Hecaen and Albert ( 1 97 8) characterized this deﬁcit as "forgetting to remember", a
familiar descriptive nomenclature for intentional memory processes. Despite a
preservation of retrospective memory in patients with frontal lobe involvement, other
aspects of memory impairment are present. These patients exhibit difﬁculty with memory
tasks which require organization, memory access, metamemory, and spatial-temporal or
source memory (Shimamura, 1990), or in other words, diﬂiculty in varying aspects of
prospective memory mechanisms.

To demonstrate the effect of frontal lobe lesions on prospective memory,
J anowsky, Shimamura, and Squire (1989) presented patients with frontal lobe lesions (N =
7; mean age = 64 years), age-matched control subjects (N = 9; mean age = 62 years), and
younger control subjects (N = 6; mean age = 51 years) with facts and then asked the
subjects to categorize the information. After a two hour retention interval, subjects were
asked to indicate whether or not a fact had been presented and to identify its source. In
this experiment, frontal lobe patients recalled as many facts as their age-matched controls
and the younger subjects; however, both frontal lobe patients and the older subjects

displayed more source errors than younger subjects. These authors (J anowsky et al.,

37

1989) interpret these results as indicating that the frontal lobes are particularly crucial in
associating facts to the context in which they occurred. Unfortunately, the noted age
decline in source memory (i.e., a special aspect of prospective memory) was not discussed.
Other neuropsychological evidence suggests frontal lobe functioning is relatively
important for prospective memory. For example, Korsakoff‘s patients are noted to
experience diencephalic damage and subsequent impairments in retrospective memory;
however, neuroradiologic studies indicate that these patients also experience frontal lobe
damage (Shimamura, Jernigan, & Squire, 1988). What is of interest in this context is that
individuals with Korsakoﬁ’s syndrome display prospective memory impairments in
addition to documented retrospective deﬁciency. Notable impairment is observed, for
instance, on tasks of planning, attention, metamemory, organizing, and inferential
reasoning (J anowsky, Shimamura, Kritchevsky & Squire, 1989; Oscar-Berman, 1980).
Furthermore, Huppert and Beardsall (1993), as previously mentioned, conducted a
study in which the results suggest that prospective memory impairment is a sensitive, early
indicator of dementia. Normal control (N = 27), normal subjects with slightly lower
scores on the MMSE (N = 26), individuals with a minimal level of dementia (N = 12), and
mildly/moderately demented subjects (N = 5) were administered the Rivennead Behavioral
Memory Test (Wilson et al., 1985). A battery of retrospective memory tests was also
administered. Results indicated that the minimally demented group was signiﬁcantly
impaired on the prospective memory component of the memory tasks and this impairment
was noted to be greater than that shown on the retrospective components of the battery.

These authors surmise that prospective memory requires the integration of a number of

38

cortical structures and their respective processes and the integrative aspect may fail prior
to individual components. Such an argument is consistent with a frontal lobe explanation
of prospective memory function given this neurostructural region's extensive
interconnections with other cortical regions (Luria, 1966).

It should be noted that speciﬁed memory dysfunction which is associated with
frontal lobe dysﬁrnction has been observed in other clinical populations as well including
individuals with multiple sclerosis (Beatty, Goodkin, Beatty, & Monson, 1989) and
individuals with closed head injuries (Sohlberg, White, Evans & Mateer, 1992). For
example, sequelae of head injuries are considered to differentially eﬁ‘ect the dorsolateral
convexity of the frontal lobes and therefore, ubiquitous difﬁculties with prospective
memory have been observed in this population (Sohlberg et al., 1992). Of clinical interest,
is that these observed prospective memory deﬁcits have been shown to be amenable to
remediation through cognitive rehabilitative eﬁ‘orts (Sohlberg, Mateer, & Stuss, 1993).

Prospective Memory and Frontal Lobe Functioning: Aging Investigations.
A review of the literature suggests empirical emphasis has been given to aging and
prospective memory or conversely, aging and ﬁontal lobe ﬁmctioning, but little has been
done in the memory and aging ﬁeld to consider these three domains concurrently.
Consequently, only a few studies were found that addressed aging, prospective memory,
and ﬁ'ontal lobe functioning even indirectly.

For example, McIntyre and Craik (1987) assessed source amnesia in younger and
older individuals by presenting ﬁctitious facts using one of two speakers (male or female),

and then asking subjects not only to recall the facts themselves, but also to recall the

39

sources of the fact (i.e., which speaker presented the information). Older adults proved to
be signiﬁcantly impaired in recalling who presented the fact. These authors were also able
to show that memory for source information was correlated with performance on the

WC ST (Heaton, 1981), suggesting a parallel between age-related deﬁcits and ﬁontal lobe
eﬂiciency.

Failures to remember the last spatial-temporal context in which a behavior was
enacted could lead one to repeat actions inappropriately (e.g., taking one's medication
twice in the course of a day). Such memory deﬁcits have been observed in the elderly and
are a common complaint in metamemory studies of older individuals' perceptions of their
memory ﬁmctioning (Larrabee & Crook, 1989). This deﬁciency in monitoring of actions
already performed was observed in Koriat et al.'s (1988) study of an elderly population.
Speciﬁcally, young (mean age = 24.5; N = 40) and old (mean age = 71.2; N = 40) persons
were asked to classify words according to whether or not they had appeared on a
previous study list (input monitoring) and whether or not they had been recalled following
a previous word list presentation (output monitoring). Older individuals were found to be
deﬁcient in both types of monitoring; the noted declines, however, were signiﬁcantly
greater for output monitoring which was considered to rely more heavily on the contextual
cues of the learning situation and, therefore, to draw upon skills mediated by frontal lobe
integrity.

Craik, Morris, Morris, and Loewen (1990) speciﬁcally assessed the interaction
between normal aging, source amnesia, and frontal lobe functioning. Elderly community

residents (mean age = 71; N = 24) were asked to recall where they had learned new

4o

factual information. Performance on this measure was correlated with measures of ﬁ'ontal
lobe functioning (W CST; Heaton, 1981) and verbal ﬂuency (Thurstone & Thurstone,
1949). Results conﬁrmed the hypothesis that source amnesia in a normal elderly
population is related to frontal lobe functioning. In particular, analyses revealed that
source memory correlated reliably with verbal ﬂuency, number of categories achieved,
total errors, and perseverative errors on the WC ST. Interestingly, source amnesia did not
correlate with Performance IQ or with a measure of retrospective memory (e. g., a
measure of the recallability of the presented facts). This study supports the notion that an
interaction exists between aging, aspects of prospective memory, and frontal lobe

integrity.

STATEMENT OF STUDY OBJECTIVES

The major objective of this study is to ascertain if an age-associated decline in
prospective memory exists and to delineate the cognitive aspects of this decline.
Underlying Craik's (1986) theory of the functional aspects of memory ﬁrnctioning is the
hypothesis that older individuals tend to rely more on external memory strategies as
intemally-generated approaches become less eﬂicient. Prospective memory, or
remembering to remember, is considered to require a greater degree of self-initiation and
to eventually decline over the life span. Dobbs and Rule (1987) and Cockbum and Smith
(1991) both controlled for the use of mnemonic aids and found prospective memory to
decline with increasing age. No study to date, however, has considered the comparison of
cued and uncued prospective memory performance measured under the same experimental
conditions. The present investigation will attempt to determine if age differences exist for
intentional memory capabilities, and if so, are the differences present to a greater degree in
conditions in which external memory aids are not employed. Individuals will also be
assessed according to their performance on retrospective memory tasks given that such
abilities are implicit in the successful completion of prospective memory tasks. It will be
necessary to experimentally differentiate performance in these domains in order to draw
deﬁnitive conclusions about age-associated decline in prospective memory.

Furthermore, in an attempt to understand the relationship between age and
prospective memory from a neuropsychological perspective, ﬁ'ontal lobe ﬁrnctioning as it

relates to memory will also be assessed. It is hypothesized that ﬁontal lobe performance

41

42

will account for the observed variance between age and intentional memory capabilities.
In other words, it is argued that intact ﬁ'ontal lobe functioning contributes to eﬂicient
prospective memory functioning and this association may decline across the life span.
Given the outlined review of frontal lobe ﬁrnctioning and memory, it is hypothesized that
interference eﬁ’ects will be greatest for prospective memory items which have the longest
delay period. In other words, prospective memory will deteriorate to a greater extent
during longer intervals between task assignment and execution of the intention. This
discrepancy will be greatest for uncued items.

An additional aspect of the present investigation will be to explore the relationship
between prospective memory performance (aided vs. unaided) and self-assessment of
these abilities on a metamemory questionnaire. It is hypothesized that external memory
aids may be employed by the elderly to compensate for an underlying decline in
prospective memory and, subsequently, an older cohort may perceive their memory in this
domain as improved. Therefore, self-rating of intentional memory abilities and actual
performance will be discrepant, especially when prospective memory is assessed without
the beneﬁt of cues.

Finally, a second experiment will be conducted to determine if subjects show
improvement in prospective memory function after participating in an intervention
designed to enhance their memory capabilities by providing training in individual memory
strategies. This is considered to be a pilot study because it will not offer speciﬁc training
in prospective memory. Its focus is to ascertain if concentrating on speciﬁc memory

strategies and practicing information organizing techniques increases prospective memory

43

capability. It is hypothesized that prospective memory will improve ﬁom pre-intervention
to post-intervention and this improvement will be greatest for unaided prospective
memory. The purpose of this study is to determine if this domain of memory ﬁrnction is
amenable to remediation. The clinical utility of focusing on improving prospective
memory capabilities for the elderly is reﬂected in the potential consequences for daily
living and functional adjustment. Beyond practical implications (e.g., not taking
medications more than once on a given day), being able to carry out ﬁrture intentions
enhances an individual's sense of self-eﬁcacy in day-to-day living and strengthens a

future-time perspective.

METHOD: EXPERIMENT ONE

Participants. A cohort of healthy, elderly individuals were recruited through their
response to advertisements in a local paper to participate in a larger project addressing
mood, memory, and aging. Each subject received a pre-assessment of their abilities in a
number of relevant domains including memory, attention, executive functioning, and
mood. Subjects then participated in a seven session workshop to teach cognitive
strategies and relaxation to improve memory skills and relieve emotional symptomatology
(e.g., anxiety, depression) contributing to memory difﬁculties. A power analysis
conducted prior to beginning the study (Cohen, 1992), suggested 102 subjects would be
needed in order to obtain a medium effect size (a = .05) and statistical power equal to .80
using a multiple regression statistic with seven predictor variables. A cohort of 115
participants completed the assessment thus exceeding the recommended sample size.
Subjects ranged in age from 55 to 90 years old (>‘< = 67.75; SD = 7.64). Ofthe 115
participants, 73 were women and 42 were men. The group had a mean education of 15.14
years (S_D = 2.83; range = 8-20 years).

Persons who reported a history of neurological or psychiatric illness (e.g.,
hypertension; Willis, Yeo, Thomas & Garry, 1988) were excluded from the analyses. This
information, as well as demographics (e. g., education, occupation), was obtained from a
self-report version of the Multilevel Assessment Inventory (MAI; Lawton, Moss,
Fulcomer, & Kleban, 1982). In addition, subjects who obtained a score of less than or

equal to 24 on the Folstein Mini Mental Status Examination (MMSE; Folstein, Folstein &

44

45

McHugh, 1975) or greater than or equal to +50 on the Storandt Brief Dementia Battery
(Storandt, Botwinick, Danziger, Berg, & Hughes, 1984) were excluded ﬁom the analyses.
Persons scoring 20 or more on either the Beck Depression Inventory (BDI; Beck, 1987)
or the Geriatric Depression Scale (GDS; Yesavage, Brink, Rose, Lum, Huang, Adey &
Leirer, 1983) were also omitted from data analysis since moderate to severe levels of
depression have been known to deleteriously effect memory performance (Lamberty &
Bieliauskas, 1993; O'Connor, Pollitt, Roth, Brook & Reiss, 1990).

Experimental Measures. The following measures which were employed to
assess identiﬁed dependent variables. These have been divided according to the cognitive
domain addressed including prospective memory, retrospective memory, metamemory,
and executive functioning. A number of additional measures were also included to assess
the potential effect of certain moderating variables such as intelligence, attentional
capacity, depression, and mental status.

Prospective Memory Experimental Measures

The Rivermead Behavioral Memory Test. Three items ﬁ'om the Rivermead
Behavioral Memory Test (RBMT; Wilson, Cockburn, & Baddeley, 1985) were used to
assess prospective memory. The RBMT is a laboratory measure which includes three

prospective memory items within a series of everyday memory tasks:

(1) Remembering a belonging. This RBMT item entails remembering to ask for
the return of a personal item of the subject's choosing (e. g., comb, pencil) which

the interviewer places out of sight. The subject is instructed to ask for it to be

46

returned at the end of the session as well as identify the location in which it was
hidden. There is no speciﬁc cue to prompt the execution of the action, although
the experimenter states "That is the end of the testing session." Ifthe subject does
not spontaneously request the belonging, the interviewer gives a prompt (e. g.,

"Was there something you were going to ask me for?").

(2) Remembering an appointment. This item involves remembering to ask about
an appointment which is initiated by an alarm ringing after 20 minutes. Subjects
are instructed to ask the experimenter something to the eﬁ‘ect of "When will I see
you again?" This task involves an experimenter-generated nonspeciﬁc cue for the
execution of the required action. Ifthe subject does not respond spontaneously
when the alarm sounds, a prompt is given such as "What were you going to do

when the alarm rang?"

(3) Remembering to deliver a message. This item requires remembering to pick
up and deliver a message. This task is embedded within the sequence of another
task. The experimenter asks the subject to observe while he/she traces a path
around the room. The interviewer goes from a chair to a table, picks up an
envelope marked "MESSAGE", then walks to a window, then to the door and
then back to the table where the envelope is placed, and then returns to the chair.
The experimenter subsequently asks the subject to carry out the sequence. Points

are provided for picking up the envelope and delivering it to the appropriate

47

location without a prompt. Recall is assessed both immediately and following a 20

minute delay.

The RBMT has been found to discriminate between the everyday memory
capabilities of high- and low-functioning neurologic patients with the former group
performing signiﬁcantly better (Wilson, 1989). In that study, 176 persons with brain-
damage (age range = 14-69 years) were administered the RBMT. RBMT scores were
correlated with performance on existing tests, subjective ratings from patients and
caregivers, and observations by therapists of everyday memory lapses. Interrater reliability
(i.e., 100% scoring agreement), and test-retest reliability (.85) were considered to be
high. In addition, scores on the RBMT correlated highly with other measures of memory
(e. g., .63 with the Warrington Recognition Memory Test) and with therapist observations
of memory lapses (e.g., -.75 between RBMT and number of memory lapses), suggesting
that the instrument is a valid measure of everyday memory. In another study, the RBMT
was found to be a valid measure of memory and was able to predict staﬂ‘ assessments of
patient's everyday adaptive capabilities (Malec, Zweber, & Depompolo, 1990) or parental
assessment's of children's everyday memory skills (.71; Wilson, Ivani-Chalian, Besag, &
Bryant, 1993).

The Prospective Memory Screening Test (PROMS; Sohlberg & Mateer, 1993).
This measure is designed to assess the ability to initiate and cany out planned actions at
designated ﬁxture times. It was originally designed as a screening measure to assess

prospective memory diﬁculties in a head injured population (Sohlberg, Mateer, & Geyer,

48

1985) but may be a useful research tool in the present context. The PROMS measures
prospective memory ability at one, two, ten and twenty minutes as well as twenty four
hours. The target items are simple, one-step commands; although, some items have been
modiﬁed to accommodate the laboratory setting and the population being studied.
PROMS items are listed in Appendix A.

In addition to the time dimension, the screening measure also examines the
parameter of cueing as some of the tasks are initiated by the experimenter. Associative
cue items require the subject to perform a prospective memory task when another event
occurs (e.g., the examiner snaps his/her ﬁngers); whereas, with the time cue, the subject
monitors time and initiate an activity at a speciﬁed time without the beneﬁt of a cue. This
latter set of items is considered to require a greater degree of self-initiation. The PROMS
is speciﬁcally designed so that the subject is never keeping track of more than two
prospective memory tasks at one time. To test the hypotheses stated above, the PROMS
diﬁ‘erentially assesses performance on cued (i.e., event-based) prospective memory items
versus self-timed items and allows for monitoring performance based on the length of the
interval between the request and the execution of the intention (e.g., 10 minutes vs. 20
minutes).

Since the PROMS is a relatively new instrument (Sohlberg & Mateer, 1993 ), only
limited data is available on its reliability and validity as a screening instrument. The
PROMS has been found to discriminate between normal (N = 34; age = 20-59) and brain-
injured (N = 25; age = 21-56) individuals (Sohlberg & Mateer, 1993). Out of a total score

of seven, 82% of the normal control subjects scored either 6 or 7, while only 36% of the

49

brain-injured group scored in this range. Therefore, the PROMS appears to have some
discriminative validity for prospective memory performance. In this same study, PROMS
scores were also compared to other memory measures (e.g., Randt Memory Test).
Results indicated that the PROMS was assessing a speciﬁc type of memory, as a wide
range of PROMS scores were demonstrated in individuals scoring both low and high on a
measure of retrospective memory.
Retrospective Memory Experimental Measures

The California Verbal Learning Test. The CVLT (Delis et al., 1988) assesses
verbal memory for a list of sixteen grocery items presented in ﬁve learning trials.
Assessment of memory occurs after each trial. An interference list is presented after the
ﬁfth learning trial and both immediate and delayed (30 minutes) recall and recognition of
the original list is assessed. Sex and age-adjusted performance norms are provided.

The reliability of the CVLT has been established in a study of 133 subjects ﬁ'om a
normal reference group which assessed both internal consistency and test-retest
coefﬁcients (Delis, Kramer, Kaplan & Ober, 1987). The authors attempted to address the
diﬂiculties in establishing reliability for recall measures given the inherent problems of item
interdependency (e. g., repeated items over trials). In doing so, the authors analyzed the
total trial scores (i.e., a global indicator of learning and memory) and found a split-half
reliability estimate of .92 in the normative sample. As additional measures of reliability,
these authors correlated scores on two independent halves of the CVLT. These analyses
yielded coefﬁcient alphas of .74 and .69, respectively. In a second study designed to

establish test-retest reliability, twenty-one normal adults were re-administered the CVLT

50

after a one year interval. Thirteen of 18 CVLT test-retest scores were found to be
signiﬁcant including total immediate recall of List A across the ﬁve trials, percent primacy
region recall, learning slope, semantic-clustering score, Short- and Long-Delay cued
Recall, Long-Delay Free Recall, number of recall errors, and hits/false positives on
recognition testing. Signiﬁcant correlations ranged from .47 to .79.

A factor analysis of the CVLT has also been conducted to determine its
components as a measure of the memory construct (Delis et al., 1988). To ascertain if the
various CVLT indices clustered in linearly independent performance domains that
paralleled experimental constructs, or whether a single learning factor would emerge, it
was administered to 399 normal subjects and neurological patients. A varimax rotation
yielded a six factor structure for CVLT indices that were consistent for normal as well as
neurological subjects by either age-residualized or age-uncorrected scores. These six
factors include general verbal learning, response discrimination, serial position eﬂ‘ect,
learning strategy, and retroactive/short-delay eﬁ‘ect.

In the same studies, Delis and his colleagues (1987) also found support for the
CVLT's criterion-related validity. In this aspect of the studies, the CVLT was correlated
with various scores on the Wechsler Memory Scale (WMS; Wechsler, 1945). The total
immediate recall of List A for ﬁve trials correlated .66 with the WMS Memory Quotient
and in this same range with several additional WMS variables. Validity has also been
established for the CVLT by determining patterns of scores for various neurological and
clinical groups including chronic alcoholics as well as individuals with Parkinson's disease,

multiple sclerosis, Huntington's disease, and Alzheimer's disease (Delis et al., 1987).

51

Experimental Measures of Metamemory

Memory Assessment Clinic Self-Report Scale (MAC-S; Crook & Larrabee,
1990). The MAC-S is a self-rating scale of everyday-memory abilities which contains an
Ability scale, a Frequency of Memory Failure scale, and four global-memory rating items.
The Ability scale contains 21 items (rated on a 5-point Likert scale ranging from very poor
to very good) concerning one's overall ability to remember things such as verbal directions
to a geographic location given minutes earlier. On the other hand, the Frequency scale
contains 24 items (rated on a 5-point Likert scale ranging from very often to very rarely)
concerning the subject's frequency of memory failure for such things as forgetting the
name of a familiar object. For both scales, only those items which reﬂect prospective
memory situations (e. g., # 11 "To write letters you intend to write or make telephone calls
you intend to make. ") will be used in assessing the relationship between judgments of
prospective memory and actual performance. These items are listed in Appendix C.

Test-retest reliabilities of the various self-rating factors on the MAC-S exceeded
.80 in a normative study of 1,106 subjects (Crook & Larrabee, 1992). In their original
test-retest reliability study, Crook and Larrabee (1989) tested 52 subjects on four
occasions, each separated by three weeks. For the Ability and Frequency measures, the
reliability coeﬁicients were uniformly high (i.e., the majority falling in the range of .80).
The reliability coeﬁcients were notably lower for global rating items, due to restriction in
the range of measurement.

The factor structure of the MAC-S was assessed in two related investigations,

Winterling, Crook, Slama and Gobert (1986) and Crook and Larrabee (1990). The factor

52

structures were reported to be equivalent across these studies and include ﬁve orthogonal
"Ability to Remember" and ﬁve orthogonal "Frequency of Occurrence" factors. The ﬁve
Ability factors include remote personal memory, numeric recall, everyday task-oriented
memory, word recall/ semantic memory, and spatial/topographic memory. The ﬁve
Frequency factors include word/fact recall (i.e., semantic memory),
attention/concentration, everyday task-oriented memory, general forgetfulness, and facial
recognition. This factor structure appeared unaﬂ‘ected by age or sex. In addition,
concurrent validity has been established between memory self-ratings on the MAC-S and
objective computer-simulated everyday memory performance (Larrabee, West & Crook,
1991). In this study, 125 normal adults were administered the MAC-S and concurrently,
completed several other measures of objective memory performance. A canonical
correlational analyses revealed that both types of measures shared 28% to 29% of
common variance.
Executive Functioning Experimental Measures

Daugneault, Braun, and Whitaker (1992) identiﬁed several measures believed to
measure prefrontal functions and associated with normal aging after 60-70 years. These
include perseverative errors on the WC ST (Heaton, 1981), performance on the Category
Test (Halstead, 1947), verbal ﬂuency (Thurstone & Thurstone, 1949), nonverbal ﬂuency,
judgments of recency, and interference eﬂ‘ects. Several of these measures were employed
in the present study including the WC ST and nonverbal ﬂuency in an attempt to explore
the relationship between aging, frontal lobe efﬁciency, and prospective memory. Three

measures were used to assess executive functioning in the experimental sample. These

53

were then be covaried with prospective memory performance in a multiple regression
analysis.

The Ruﬂ' Figural Fluency Test. The assessment of nonverbal ﬂuency was ﬁrst
extended from verbal productivity by Jones-Gotman and Milner (1977). The design
ﬂuency measure used in the present investigation was the RuffFigural Fluency Test
(RFFT; Ruﬂ‘, Light & Evans, 1987), a measure of speed of productivity, visuospatial
creativity, and the ability to monitor ongoing activity. Performance on this measure is
enhanced by the use of strategies. This test consists of ﬁve trials, each on a page with 40
contiguous squares printed in a 5 x 8 array. Each square on the page contains ﬁve
identically arranged dots. The page for each trial differs in that the dots in the ﬁrst three
trials are symmetrically arranged; however, interference patterns are included on trials two
and three. The remaining trials (i.e., four and ﬁve) are arranged in an asymmetrical pattern.
The subject is instructed to make as many diﬂ‘erent patterns or ﬁgures as possible within a
60 second time period for each trial. This is accomplished by connecting any two or more
dots with straight lines without repeating any pattern. This measure is scored for both the
number of unique patterns and the number of repetitions of a pattern (i.e., perseverations).

The RFFT has been found to be differentially sensitive to right frontal lobe dysﬁrnction
(Ruff, Allen, Farrow & Neiman, 1994). j

The test-retest reliability of the RFF T was demonstrated using one-third (N = 95)
of the original normative sample who were retested following a six month interval (Ruﬂ;
Light & Evans, 1987). On initial testing, this subgroup generated an average of 100.6

designs (sd = 21.8) while on retesting the group averaged 108.6 designs (sd = 22.0). The

54

correlation coefﬁcient was .76. On the other hand, perseveration scores were found to
diﬁ‘er only slightly from the ﬁrst to second administration; however, a greater degree of
variability (i.e., less stable scores) was observed on retesting (initial: 6.53, sd = 5.8;
second: 7.76, sd = 4.8). This pattern resulted in a correlational coeﬁicient of .36.

The RFFT has been factor analyzed to assess its validity as a measure of planning,
initiation, and divergent reasoning (Baser & Ruﬁ‘, 1987). Baser and Ruff (1987) explored
the factor structure of the RFFT in a group of normal subjects and in a head-injured
population. Their analysis revealed that total unique designs loaded moderately on two
factors including initiation and complex intelligence. In addition, the ratio of errors to
unique designs loaded on a planning factor. Similar factors emerged for both samples with
the exception that the RFFT failed to reveal a complex intelligence factor in the clinical
sample; however, a planning ﬂexibility factor did emerge instead.

The Wisconsin Card Sorting Test (WCST; Grant & Berg, 1948; Heaton, 1981).
This test involves "working memory" and the ability to adapt behavior based on
performance feedback (Lezak, 1983). The WCST is considered to be one of the most
useful measures of executive function integrity and recently, the performance on the test
was found to correlate with increased regional cerebral blood ﬂow (i.e., a neuroimaging
technique) in the dorsolateral and medial prefrontal cortex (Marenco, Coppola, Daniel,
Zigun & Weinberger, 1993).

In the WCST, the subject is provided with a deck of sixty-four cards on which are
printed one to four symbols (e.g., triangle, star, cross, circle) in various colors (e.g., red,

green, yellow, blue). No two cards in the deck are identical. The subject's task is to place

55

them one by one under four stimulus cards (i.e., one red triangle, two green stars, three
yellow crosses, and four blue circles) according to a principle that the subject must infer
from the pattern of the examiner's response to the subject's placement of the cards. After
a series of ten consecutive correct responses, the examiner shifts the sorting principle,
indicating the shift only in the changed pattern of his/her "right" and "wrong" statements
to the subject. The test continues until the subject has made six runs of ten correct
placements or gone through two decks of sixty-four cards each. Relevant measures of
executive ﬁmctioning include the number of categories completed, the number of
perseverative responses and errors as well as the number of "failures to maintain set."
This measure has been associated with declines in normal aging after the age of 60-70
years (Daigneault et al., 1992; Haaland, Vranes, Goodwin & Garry, 1987; Whelihan &
Lesher, 1985).

In establishing the reliability of the WCST, Heaton and his colleagues (Heaton,
Chelune, Talley, Kay & Curtiss, 1993) employed generalizability coefficients rather than
reliability coeﬁicients. Generalizability coeﬁicients reﬂect how well the instrument
measures a subject's true score whereas traditional reliability coemcients might focus on
the similarity of test-item content. In a sample of 46 children and adolescents who were
administered the WC ST on two separate occasions (i.e., approximately one month apart),
the average generalizability coeﬂicient fell at .57 (range = .39-.72). This suggests that the
WC ST has good scale reliability as a measure of executive function.

This instrument has been studied in a wide variety of clinical populations including

seizure disorder, multiple sclerosis, Parkinson's disease, brain lesions of other etiologies,

56

and schizophrenia. In each case, impaired performance has been found relative to normal
control subjects (Heaton et al., 1993 ), thus supporting the WCST's validity as a measure
of executive functioning. Furthermore, physiological studies of WC ST performance
indicate that this measure is sensitive to executive functioning in particular. Recent
regional cerebral blood ﬂow investigations have found that blood ﬂow increases during the
WC ST to the right anterior dorsolateral prefrontal cortex as well a the medial prefrontal
cortex (Marenco et al., 1993). In another investigation, a SPECT analysis of regional
cerebral blood ﬂow was found to increase during WC ST performance for both
neuroleptic-treated schizophrenic patients and healthy controls to the left lateral prefrontal
region (Kawasaki, Yoshiki, Michio, & Katsumi, 1993). It should be noted that some
authorities question the validity of the WCST as a measure of frontal lobe function
(Reitan, 1993; Axelrod, Goldman, Heaton, Curtiss, Thompson, Chelune, & Kay, 1996).

Trails B. Trails B is a test of visual conceptual and visuomotor tracking which is
considered to be sensitive to the effects of ﬁ'ontal lobe integrity (U chiyarna et al., 1994)
since it requires that the subject be able to shift mental sets. It has been described as a
measure of visual search, attention, mental ﬂexibility, and motor function (Spreen &
Strauss, 1991). The subject is instructed to draw lines which connect consecutively
numbered and lettered circles on a work sheet by alternating between the two sequences.
Subjects are encouraged to complete the test "as fast as you can."

Lezak (1983) reported a moderate reliability coeﬂicient of concordance of .67 for
Trails B and found that practice eﬁ‘ects were not noted over the course of three

administrations (i.e., at six month intervals). In addition, Snow, Tierney, Zorzitto, Fisher,

57

and Reid (1988) in a sample of 100 elderly subjects reported a one-year retest reliability of
.72 for Trails B. Similarly, Goldstein and Watson (1989) found reliability coeﬁcients of
.66-.86 for various neurological groups and .63 for schizophrenics.

A factor analysis of Trails B found the instrument to load on both "rapid visual
search" and a "visuospatial sequencing" factors (desRosiers & Kavanagh, 1987).
Construct validity for visual search has been established by correlating performance on
Trails B with an object ﬁnding test and a hidden pattern test obtained for aphasic and
nonaphasic individuals (N = 92, correlations ranging from .36 to .93; Ehrenstein, Heister
& Cohen, 1982). In addition, Alekoumbides, Charter, Adkins and Seacat (1987) reported
signiﬁcant differences on Trails B between normal control subjects and three clinical
groups (i.e., Korsakoﬂ‘s syndrome, diffuse lesions, and focal lesions) with respect to
correct classiﬁcation rates. As ﬁrrther evidence of the measures validity as a
neuropsychological instrument, several authors have found Trails B to be highly sensitive
to brain damage (desRosiers & Kavanagh, 1987; Dodrill, 1978; O'Donnell, 1983).

Experimental Measures of Potential Moderating Variables

Several additional measures will be included in the neuropsychological test battery
to assess potential factors which might contribute to ﬁnal outcomes. These include
intellectual ﬁrnctioning, attention, depression, and mental status. Measures for each will
be brieﬂy described here.

The American Version of the Nelson Adult Reading Test. Intellectual
functioning was assessed using the American Version of the Nelson Adult Reading Test

(AMNART; Nelson & O'Connell, 1978). The AMNART is a test of the ability to

58

pronounce a list of ﬁfty phonetically irregular words. Measures of verbal ability are
considered to be the best predictor of intellectual levels since vocabulary correlates best
with overall ability level and tends to resist the eﬂ‘ects of brain impairment more than any
other intellectual capacity (Lezak, 1983). The AMN ART authors developed regression-
based formulas which estimated concurrent scores on intellectual measures such as the
Wechsler Adult Intelligence Scale-Revised (W AIS-R). AMN ART scores have been found
to correlate fairly well with obtained WAIS-R Full Scale IQ scores in older individuals (r =
.70; Berry, Carpenter, Campbell, Schmitt, Helton & Lipke-Molby, 1994).

The AMN ART is considered to have high internal and test-retest reliability and
does provide a better estimate of WAIS-R IQ than Vocabulary subtest scores (Crawford,
1992). Furthermore, Blair and Spreen (1989) reported a coeﬂicient alpha (i.e., a measure
of internal consistency) of .94. In this same normative sample, correlations between actual
WAIS-R VIQ, PIQ, and F SIQ, and predicted IQs on the basis of AMNART scores were
.83, .40, and .75, respectively (Blair & Spreen, 1989). From this data, it appears that the
AMNART is a good predictor of VIQ and F SIQ, but is a relatively poor predictor of PIQ.
Other authors report that deterioration in reading performance does occur with cerebral
dysfunction and the AMN ART is, therefore, best regarded as providing an estimate of the
lower level of premorbid functioning (Stebbins, Giley, Wilson, Bernard & Fox, 1990).

Wechsler Adult Intelligence Scale-Revised Digit Span Subtest. WAIS-R Digit
Span (W echsler, 1981) is considered to be a test of short-term auditory memory and
attention/concentration (Spreen & Strauss, 1991). Digit Span requires the subject to

recall and repeat auditory information in a proper sequence. The task consists of two

59

parts: Digits Forward requires the subject to repeat sequences of 3-9 digits while Digits
Backwards sequences are 2-8 numbers long and the subject must say them in the reverse
order.

Digit Span is considered to load heavily on a "memory/freedom ﬁom
distractibility" factor (Kauﬁnan, 1979; Sattler, 1988; Spruill, 1984). This measure is also
considered to be one of the most sensitive tests to brain damage, mental retardation, and
learning disabilities (Mishra, Ferguson & King, 1985). In addition, Wielkiewicz (1990)
has suggested that the factor which this task measures may reﬂect executive and short-
term memory processes including monitoring and evaluating task performance.

Beck Depression Inventory and the Geriatric Depression Scale. Two self-
report measures of depression were completed by the subjects including the Beck
Depression Inventory (BDI; Beck, 1987) and the Geriatric Depression Scale (GDS;
Yesavage, Brink, Rose, Lum, Huang, Adey & Leirer, 1983). While both measures assess
the general construct of depression, the BDI is considered to be more sensitive to somatic
correlates of dysphoric mood while the GDS is considered to more sensitive to the
behavioral and cognitive symptoms of depression. Individuals scoring greater than 20 on
either of these measures were excluded from the current analyses.

The test-retest reliability of the BDI in a sample of 38 patients was found to be
greater than .90 (Beck, 1970). In addition, Spearman-Brown reliability has been
demonstrated to fall at a level of .93 and internal consistency for test items at .86
(Reynolds & Gould, 1981). With regard to validity, the BDI has been show to yield

concurrent validity coeﬂicients of .38-.50 with Lubin's Depression Adjective Checklist for

6O

psychiatric patients and .66 in normal control subjects; and .79 in psychiatric patients and
.54 in college students for the lung Self-Rating Depression scale (Kemer & Jacobs,
1983)

Mini-Mental Status Examination. The Mini-Mental Status Examination
(MMSE; Folstein, Folstein & McHugh, 1975) was designed to test cognitive functions in
an eﬁicient and accurate manner. This measure is useful in providing gross estimates of
cognitive functioning (Spreen & Strauss, 1991). The test is comprised of eleven questions
and concentrates on cognitive aspects of mental ﬁmctions, and speciﬁcally excludes
questions regarding mood, abnormal mental experiences and the form of thinking.

Reliability and validity were established in the original standardization sample
(F olstein et al., 1975). Test-retest reliability coefﬁcients were found to fall at .89 for a 24
hour retest administration by a single examiner and .83 when separate examiners
readministered the test. A 28 day retest of elderly depressed and demented subjects
yielded a correlation of .98. With a maximum obtainable score of 30, the elderly control
subjects and younger patients with ﬁrnctional psychiatric disorders achieved scores in the
25 to 28 range. Scores of several groups of senile patients ranged form 9.6 to 12.2. No
overlap between the aged control subjects and the senile patients was observed. For
purposes of the present study, no subject scoring less than 24 on the MMSE was included
in the analyses.

Procedure. Controlling for the use of external mnemonic devices addresses the
ﬁrst requirement outlined by Kvavilashvili (1992) for the experimental study of

remembering intentions. Besides the necessity of monitoring the employment of assisted

61

memory strategies (Maylor, 1993), the experimenter can also ensure that all subjects are
exposed to a standardized set of procedures and activities during the interval between the
formation of an intention and its completion at a later point in time. Secondly,
Kvavilashvili (1992) suggested that experiments in remembering intentions must minimize
the chances that an intention will be remembered without undermining the possibility that
the intention will be carried out. In the present investigation, subjects were provided with
a timer so they could monitor and complete the action at the requested time; however, the
intervening period was ﬁlled with other neuropsychological measures (none of which had
a prospective component) to simulate everyday memory situations (i.e., other activities
ﬁlling time before an action needs to be completed). In this way, activities during the
interval were consistent across subjects and ceiling effects could be avoided (Kvavilashvili,
1992; Maylor, 1993). Ceiling effects were also avoided in this study by employing a
number of items of prospective memory, some of which were considered to be more
difﬁcult since they rely entirely on self-initiated execution by the subject. In addition, all
subjects were assumed to have the same level of motivation since each had responded to a
newspaper ad in order to participate in the project. Lastly, the experimental procedure
was considered to be ecologically valid given that prospective memory items were
representative of real-life situations; although, nuances of everyday ﬁrnctioning cannot
entirely be reproduced in the laboratory and to this extent, prospective memory items were
considered to be artiﬁcial.

The current investigation was part of a larger project assessing memory and mood

in the elderly. Incentive was provided by offering subjects the opportunity to participate

62
in workshops aimed at enhancing memory functioning through training in speciﬁc memory
strategies. This intervention component was the focus of Experiment Two. Interested
subjects were initially contacted by phone during which the purpose of the investigation
was explained and assignment to an intervention group was determined. For the purposes
of Experiment One, subjects were asked to participate in an approximately 2.5 hour pre-
testing session in which they completed the experimental measures described above.
Informed consent was obtained and subjects were provided with a copy. Subjects then
spent approximately one-half hour in a group setting completing self-report measures.
Following these initial steps, subjects were then individually assigned to an experimenter
who was an advanced clinical psychology student in the Ph.D. program at Michigan State
University. Examiners were trained by peers who observed the administration of each test
in the battery. The tests were administered in a standardized order so that each subject
was exposed to the same activities during delay periods. Breaks were oﬂ‘ered to subjects
as needed.

Subjects were provided with a timer placed in front of them on the testing surface
so that they could monitor delay periods for self-timed prospective memory tasks.
Additional testing materials were provided for subjects as needed (i.e., pencil and paper).
At the end of the PROMS, subjects were provided with an addressed and stamped
postcard to be mailed the next day in order to obtain a 24 hour measure of prospective
memory. The use of external memory aids for this task was not controlled for; however,
the completion of the task does contribute to an overall prospective memory score.

Subjects were contacted at a later date by the examiner to provide them with feedback

63

regarding their performance on assessment measures. Feedback was general so as not to

confound post-testing.

RESULTS: EXPERIMENT ONE

Statement of Hypotheses and Statistical Analysis. The present investigation
sought to determine if prospective memory decreases across the life span. In fact, an age-
associated decline in prospective memory was observed (r = -.29, p < .01). This study
then addressed three related questions with regard to prospective memory and aging.

Hypothesis 1A. The ﬁrst hypothesis focused on whether or not prospective
memory performance would be affected by subject performance on retrospective
measures. Results conﬁrmed that retrospective memory performance accounted for a
signiﬁcant portion of the variance in prospective memory performance above and beyond
the variance accounted for by age. Zero order correlations are listed in Table 1A As
expected, age and retrospective memory were signiﬁcantly correlated with prospective
memory performance.

The major question was whether or not retrospective memory would account for
the variance in prospective memory performance above and beyond that accounted for by
age. Age and retrospective memory (i.e., CVLT raw score) were entered into a
hierarchical regression equation to determine if prospective memory performance (e.g.,
RBMT, PROMS) declined as a ﬁinction of these variables. In the ﬁrst step, Age was used
to predict Prospective Memory. Consonant with the signiﬁcant correlation, Age predicted
9% of the variance in Prospective Memory performance (R2 = .09, E (1, 111) = 10.50, p <
.01). In the second step, Retrospective Memory was added to the equation. By adding

Retrospective Memory, the equation then was able to predict 20% of the variance in

64

65

Prospective Memory performance, which was a signiﬁcant increase (difference E (1, 110)
= 15.25, p < .05). These results suggest that Retrospective Memory performance
provided additional information above and beyond the effects observed for Age alone in
predicting Prospective Memory performance.

Hypothesis 1B. The next objective of the study was determine if measures of
executive ﬁmctioning would account for the observed performance in prospective
memory beyond the eﬂ‘ects of a set of proposed control variables including age, attention
(e.g., total Digit Span score) and retrospective memory. The hypothesis that executive
ﬁrnctions contribute to successful prospective memory performance above and beyond the
control variables was conﬁrmed; however, only one of the four executive function
measures contributed signiﬁcantly to prospective memory performance.

All of the control variables correlated with the outcome. Speciﬁcally, the
correlations amongst the variables revealed Age, Attention and Retrospective Memory
were signiﬁcantly correlated with Prospective Memory. Executive Function variables
included total number of categories on the WC ST, Failure to Maintain Set on the WCST,
total number of designs on the RFF T, and Trails B. With the exception of Failure to
Maintain Set on the WC ST, all of the Executive Function variables correlated with
Prospective Memory (refer to Table 1B). The Failure to Maintain Set variable was not
retained in subsequent analyses as the nonsigniﬁcant correlation was considered suﬁcient
indication that it did not contribute to Prospective Memory performance. The correlations
amongst the variables are presented in Table 18.

A hierarchical regression was employed to determine if the addition of

66

performance on measures of Executive Functioning improved prediction of Prospective
Memory performance beyond that aﬁ‘orded to the contribution of Age, Attention and
Retrospective Memory. In the ﬁrst step, the three covariates were used to predict
Prospective Memory Performance. The three variables combined (i.e., Age, Attention,
and Retrospective) predicted 21% of the variance (R2 = .21, E (3, 102) = 9.09, p < .01).
It should be noted that the majority of this effect was attributable to Retrospective
Memory (beta = .07, t = 3 .42, p < .01) as both of the beta weights for Age and Attention
were nonsigniﬁcant (Age beta = -.05, t = -1.67, as; Attention beta = .06, t = .87, as).
Again, the latter two variables were retained for the analysis given that the theoretical
question was whether the predictors would explain variance above and beyond all three
covariates.

In the second step, three Executive Functioning variables were added to the
control variables in predicting Prospective Memory performance. The ﬁrll model
including all three Executive Functioning variables (i.e., WCST Categories, RFF T Number
of Designs, and Trails B) and all three control variables (i.e., Age, Attention, and
Retrospective Memory) accounted for 28% of the variance in Prospective Memory
performance (R2 = .28, E (6, 99) = 6.31, p < .001). Most importantly, the increase in R2
over the control variable model was signiﬁcant (difference E (3, 99) = 3.00, p < .05),
suggesting that Executive Functioning abilities contributed signiﬁcantly to Prospective
Memory performance above and beyond that accounted for by the three control variables.

Given the established reliability and validity of the Wisconsin Card Sort, it seemed

possible that the additional Executive Functioning (e.g., RFFT Number of Designs and

67

Trails B) variables could simply be redundant with the Wisconsin Card Sort Test.
Therefore, it was important to establish whether or not the Wisconsin Card Sort alone
explained the variance in the Prospective Memory performance beyond the control
variables (i.e., Age, Attention, and Retrospective Memory) and, if not, determine which
additional Executive Functioning variables explained variance above and beyond that
accounted for by the Wisconsin Card Sort. The decision to enter the WCST ﬁrst in the
hierarchical regression was made in a post-hoc manner. The WCST did not explain a
signiﬁcant portion of the variance above and beyond the control variables (diﬂ‘erence E (1,
101) = 2.85, p < .10). Given that there were no theoretical expectations about which of
the remaining two Executive Functioning variables were most important, they were
entered together into a regression equation including all variables. The beta weights were
then considered to determine which of the remaining Executive Functioning variables
contributed a signiﬁcant and unique portion to the variance in Prospective Memory
performance after controlling for all the other variables in the equation. The total number
of designs on the Ruff Figural Fluency Test did produce a signiﬁcant beta weight (beta =
.04, t = 2.42, p < .05); however, the other measure, Trails B, was not signiﬁcant. In
addition, the beta weight for the WC ST in the full model was nonsigniﬁcant. The results
of these analyses suggest that Executive Functions do explain variance in Prospective
Memory performance above and beyond the eﬁ‘ects of Age, Attention, and Retrospective
Memory. Speciﬁcally, the Ruff Figural Fluency is related to Prospective Memory
performance after controlling for the effects of Age, Attention, and Retrospective

Memory. The WC ST Number of Categories and Trails B, on the other hand, were

68

correlated with Prospective Memory performance but these correlations were largely
redundant with the information provided by the other Executive Function variable (i.e.,
RFFT). And ﬁnally, the Failure to Maintain Set variable was not signiﬁcantly correlated
with Prospective Memory performance and therefore, did not add any useful information
to understanding the variance.

Hypothesis Two. A second objective of the current investigation was to explore
the eﬁ‘ect of cued and uncued performance on prospective memory. In other words, this
study attempted to determine if the use of external memory aids would enhance
prospective memory performance. Furthermore, prospective memory items were also
divided according to the length of the interval between the request and the execution of
the intention to determine if indeed, this type of memory is susceptible to the interference
effects described in connection with executive ﬁinctioning. Therefore, it was hypothesized
that older individuals would perform poorest on uncued prospective memory tasks
initiated after the longest time interval (i.e., 20 minutes). This hypothesis was conﬁrmed
in a signiﬁcant interaction between the variables of Cue and Time and a separate main
eﬂ‘ect for the Age variable; however, a three way interaction between the variables of Age,
Cue, and Time was not observed.

To accommodate the speciﬁc statistical properties of this analysis including
repeated measurements of both categorical (e.g., binary outcomes; performed the
prospective memory task or not) and continuous (i.e., age) variables, a Generalized
Estimating Equation (GEE; Stokes, Davis & Koch, 1995) was used. Solving the GE is

the same as ﬁtting the usual regression models for independent data by treating the

69

correlations among a subject's observations over time as a nuisance variable and partialling
this factor out. Cue (cued vs. uncued), Time (10 minutes vs. 20 minutes), and Age were
entered into the GEE. The analyses did not reveal a signiﬁcant three-way interaction
among the variables. The two-way interactions among the variables were then
investigated and these variables converged after six iterations. The Cue x Time interaction
term was meaningful (B = -l .90, p = .00) suggesting that uncued tasks requiring greater
self-initiation and longer intervals leading to more interference effects contribute to poorer
performance on prospective memory. The solved generalized estimating equation is
depicted in Table 2 and in Figure l which show that the eﬁ‘ect of Cue decreases across
time. In addition, the analyses revealed a main eﬂ‘ect for Age ([1 = -.04; p = .02);
however, this variable did not interact with either Cue or Time. These results suggest that
age does effect prospective memory performance (i.e., as age increases, prospective
memory performance declines) but it does so regardless of the effects of cueing or time
interval.

Hypothesis Three. A third objective of the current study was to explore the
relationship between prospective memory performance and self-assessment of these
abilities on a metamemory questionnaire (i.e., The Memory Assessment Clinic Self-Report
Scale, MAC-S; Crook & Larrabee, 1990). A review of the literature suggested that
individuals typically rate themselves as performing well in situations which involve
intention memory (Cohen & Faulkner, 1984; Martin, 1986). However, self-reports of
memory failures were considered to be diminished due to the effective use of memory aids

in everyday life (e.g., calendars, lists). Little has been done to link self-reported

7O

prospective memory to actual performance. Therefore, it was hypothesized that when
older individuals rated themselves as high on prospective memory performance that such
ratings would be negatively correlated with time-based (i.e., self-initiated, unaided)
prospective memory tasks only. This hypothesis was also conﬁrmed in that a relationship
did not emerge between subjective reports of prospective memory ability and actual
performance on measures of prospective memory.

First, an inter-item reliability check, using Cronbach's (1951) alpha, was conducted
to determine if adequate reliability existed to justify combining thirteen items from the
MAC-S which reﬂected subject's self-report of their prospective memory capabilities.
These thirteen items are listed in Appendix C. Analysis revealed an internal consistency
coefficient (alpha = .84) which suggested that there was adequate reliability to support
combining this series of items from the MAC-S into a prospective memory factor.

As with the previous analysis, a Generalized Estimating Equation (GEE) was also
appropriate for this analysis given that it involved repeated measures data as well as
categorical (cued vs. uncued) and continuous (age and self-report of prospective memory
abilities) variables. To analyze the hypothesis regarding the relationship between self-
report of prospective memory and actual performance on cued/uncued prospective
memory tasks, Self-report, Cue, and Age were entered into the GEE. The analyses did
not reveal signiﬁcant ﬁndings for either the three-way or the two-way interaction terms.
Main effects were then investigated and the variables converged after nine iterations. As
with the previous analysis, a main effect for Age emerged ([3 = -.05; p_ = .02). In addition,

results revealed a main effect for Cue (B = .88; p = .00) but no main effect for Self-

71

Report. These results suggest that a relationship does not exist between self-assessment
of prospective memory capability and actual performance on cued and uncued prospective

memory performance.

METHOD AND RESULTS: EXPERIMENT TWO

The purpose of the second experiment was to determine if subjects would show
improvements in prospective memory function after participating in an intervention
designed to enhance their memory capabilities by providing training in speciﬁc memory
strategies. It is rarely sufﬁcient to say that age-associated cognitive decline exists in the
elderly without offering potential eﬂ‘orts at remediation. Much clinical and experimental
literature has been generated with regard to memory assessment of the elderly, whereas
limited resources have been allocated for treating assessed deﬁcits. One reason is the lack
of developed programs with proven eﬂicacy. Much of the available information on the
remediation of prospective memory deﬁcits is anecdotal and relies on the use of such
common sense strategies as making lists or using a diary to record activities (Cockburn,
1996). Additionally, limited treatment availability is based on the assumption that
underlying organicity is irreversible. However, the sparse available research suggests that
when targeted, documented declines can be improved through individualized training
sessions (Perlmutter, 1978; Schaie & Willis, 1986; Weingartner, Cohen, Murphy, Martello
& Gerdt, 1981).

For example, Schaie and Willis (1986) found that individual training sessions can
reverse documented declines (e.g., over a 14 year period) in the areas of inductive
reasoning and spatial orientation. Training was oﬂ‘ered to both those who had remained
stable and those who had displayed cognitive decline. While both groups improved, the

most signiﬁcant gains were in those who had experienced decline (i.e., 39% and 55%

72

73

improvement, respectively, for the spatial-orientation training). Based on ﬁndings such as
these, the area of cognitive rehabilitation is rapidly expanding.

Sohlberg and Mateer (1993) recently developed a training program for individuals
with head injuries that was speciﬁcally designed to improve prospective memory
dysfunction and alleviate impaired adjustment in everyday living. Initial results have been
very promising (Sohlberg, White, Evans & Mateer, 1992). In addition, a host of
alternative treatments have been developed which focus on the remediation of executive
control deﬁcits (Sohlberg, Mateer & Stuss, 1993) which have been shown to impair
memory ﬁrnctions in various dimensions (Luria, 1973; Stuss & Benson, 1986) outlined in
the literature review above.

Participants. A power analysis conducted prior to the experiment using the
method outlined by Cohen (1992) suggests that for a medium effect size (a = .05), 67
subjects would be needed to obtain statistical power equal to .80. Of the 115 subjects
who participated in Experiment One, 68 completed a seven session workshop designed to
teach cognitive strategies and relaxation in order to improve memory functioning and
alleviate mood symptomatology (e.g., anxiety, depression) which potentially contributed
to memory difﬁculties. Those participants who completed the memory workshops ranged
in age from 55 to 81 years (32 = 67.37; SD = 7.39). Of the 68 participants to complete the
curriculum, 41 were female and 27 were male. The group had a mean education of 15.16
years (SD = 2.74). Thirty-eight were randomly assigned to a group intervention which
employed ecologically valid stimuli while the remaining 30 participated in a group which

utilized lab-generated stimuli.

74

Of course, attrition was expected ﬁ'om pre- to post-testing; consequently, an
analysis of various demographic variables was conducted to determine if noncompleters
diﬁ‘ered in any way ﬁ'om completers. Forty-seven individuals or 41% of the sample
dropped out of the study prior to participating in the workshop. Seven of these
individuals attended all seven sessions, but did not complete post-testing. Four attended
between one and four sessions and the remaining thirty-six did not attend any sessions.
Thirteen dropped out after being assigned to the Everyday Group, 15 were assigned to the
Lab Group, and 19 dropped out before they were assigned to either of the two
intervention groups. Of the noncompleters, 16 were male and 31 were female. The mean
age of those who dropped out was 68.30 years (S_D = 8.05) and the mean education level
was 15.15 years (S_D = 3.01). A series of independent samples t-tests between the two
groups on a number of variables indicated that completers did not differ signiﬁcantly from
noncompleters. Analyzed variables included age, education, and performance on
measures of estimated intelligence and mental status. The analysis of these latter measures
suggests that those subjects who remained in the group did not have signiﬁcantly different
cognitive capacities (i.e., greater or lesser) than those subjects who chose not to receive
the intervention.

Experimental Measures. The same measures were employed for Experiment
Two. Alternate forms of the RBMT were available and used during post-testing. The
identical prospective memory items were utilized during both testing sessions for the
RBMT and the PROMS. Items from these two measures were combined to form a single

measure of prospective memory performance. Practice effects may have occurred to the

75

extent that subjects were aware of the experimental demands of these measures; however,
speciﬁc prospective memory tasks are often repeated in activities of daily living (e.g.,
remembering to attend a regular appointment) in analogous or very similar form.
Therefore, using the same items ﬁom pre- to post-assessment was not considered to be an
artiﬁcial representation of everyday memory.

Procedure. Following pre-assessment, subjects participated in a seven session
training group which was designed to enhance memory. Subjects received information on
several memory strategies including strategies for remembering discrete pieces of
information (e.g., lists), text material, and names. The use of mental imagery and the
value of using internal memory strategies in combination or in lieu of external memory
strategies was communicated throughout the curriculum. Furthermore, subjects were
given information on how to improve attention and concentration skills and on how mood
related symptomatology might aﬁ‘ect memory performance. In addition to the educative
component, participants were guided through a relaxation and mental imagery exercise
during each session to facilitate the development of these abilities as well as emphasize the
importance of relaxation as a means of improving memory capabilities. Group attendance
was monitored and subject feedback was obtained to evaluate participant perspectives of
the intervention. Post-testing, as described above, followed delivery of the memory
enhancement curriculum and subjects were again given feedback about their performance.

Two distinct memory enhancement workshops were oﬁ‘ered. While the
information and strategies taught in each group remained consistent, they diﬁ‘ered in

whether teaching examples and homework assignments employed ecologically-valid (e.g.,

76

grocery lists, newspaper articles) or laboratory-generated (e.g., random lists of words,
stories ﬁ'om a text recall task) stimuli. Groups were conducted by advanced clinical
psychology students in the Ph.D. program at Michigan State University. Each group
leader was trained by a peer and observed four sessions conducted by an experienced
group leader. This same group of experimenters conducted the post-assessment once the
intervention was completed.

Statement of Hypotheses and Statistical Analysis. For the purposes of
Experiment Two, it was hypothesized that subjects would improve in prospective memory
after participating in an intervention designed to build memory skills. Due to this
educative component and focus on memory building, subjects would become more
focused on their individual memory skills (i.e., enhanced metamemory), rely to a greater
extent on internally generated memory processes, and have more available memory
strategies in problem solving situations. It was hypothesized that improvements would be
greater for older individuals participating in the group whose content was ecologically
valid as opposed to laboratory generated. Results revealed a signiﬁcant improvement in
prospective memory performance from pre- to post-testing; however, no differences were
observed in the Group (Everyday vs. Lab) condition.

A repeated measures ANOVA was conducted in order to determine if diﬁ‘erences
on prospective memory performance from pre- to post-testing (Time) were present and to
determine the signiﬁcance of group assignment (Everyday vs. Lab) intervention. In this
instance, Time served as a within subject factor, while Group Assignment served as a

between subjects independent variable. Analyses did not reveal a Time by Group

77

interaction or a main eﬂ‘ect for the Group intervention. However, analyses did reveal that
Prospective Memory performance did improve ﬁom pre- to post-testing (13 (1,65) =
10.05, p_ < .01). Given the lack of an appropriate control group, it is difﬁcult to say if it
was the group intervention or the demand characteristics of the testing situation which
accounted for the improvement in prospective memory performance; however, it is
apparent from these data that declines in prospective memory capacity are reversible in the
able elderly. Means and standard deviations for prospective memory performance at pre-

and post-testing and for each of the two groups are presented in Table 3.

DISCUSSION

Age and Prospective Memory. Results in this study revealed a signiﬁcant
negative relationship between prospective memory and age. The aging and memory
literature has deﬁnitively demonstrated that memory declines with age (Light, 1991);
however, these age-related deﬁcits are likely to be larger on some tasks than others. Craik
(1986) theorized that older individuals have greater diﬁculty on self-initiated memory
tasks and that prospective memory relies extensively on self-initiated retrieval processes.
It has further been hypothesized that older individuals have fewer attention resources
(Salthouse, 1991) and working memory capacities (Moscovitch & Winocur, 1992) to
devote to the dual task requirements necessary in prospective memory tasks (i.e., carrying
out other activities while needing to remember to perform a future action). In addition,
the cognition literature has demonstrated that older individuals are also prone to make
other types of errors which might lead to prospective memory failures. These include both
errors in reality monitoring (i.e., mistaking the memory of the intention for the action
itself; Johnson & Raye, 1981) and in output monitoring (i.e., remembering that a planned
action has already been performed so as not to repeat it; Koriat, Ben-Zur, & Sheffer,
1988). These cognitive failures could potentially lead to both errors of omission and
commission, respectively, in carrying out a ﬁxture intention.

Despite these potential changes in cognitive processing in the elderly, it should be
noted that the elderly possess other information processing capacities which might

contribute to successful prospective memory performance. For example, the accumulation

78

79

of experience often results in an awareness of one's errors and the subsequent
development of compensatory strategies and environmental/cognitive support systems
(Salthouse, 1990; Backman, 1989) to overcome possible deﬁcits in ability.

The Impact of Retrospective Memory on Prospective Memory Performance.
Several studies have failed to ﬁnd correlations between performance on retrospective and
prospective memory tasks (Einstein & McDaniel, 1990; Huppert & Beardsall, ,1993;
Maylor, 1990) suggesting that the processes involved in the two types of tasks are
different. On the other hand, the construct of prospective memory as a distinct entity has
been criticized as entailing little more than retrospective memory capabilities. The present
analyses revealed that retrospective memory is a necessary component of prospective
memory performance, but is not entirely sumcient for successful completion of
prospective memory tasks. The results of this investigation revealed a signiﬁcant positive
correlation between prospective memory and retrospective memory performance. In
addition, the results indicated that retrospective memory accounted for a substantial
portion of the variance in prospective memory performance above and beyond that
accounted for by age. These data support the supposition that prospective memory tasks,
at least to some degree, rely on retrospective memory capabilities. Speciﬁcally, one
cannot carry out an intention in the future without remembering the content of that
intention (the retrospective component). For example, Einstein and colleagues (Einstein,
Holland, McDaniel, & Guynn, 1992) found that when prospective memory performance
was made dependent on retrospective memory for the target events, an age deﬁcit

disappeared. In other words, age-related differences for the prospective memory tasks

80

were attributed to poorer retrospective memory for the target events.

The present results suggest that retrospective memory ability is an important
component of prospective memory but certainly does not account ﬁrlly for the variance
associated with intention memory tasks. Both types of memory were important in the
present sample for functioning adequately. The contrast between the two is often thought
of as memory for intention (e. g., remembering to pass a message onto a ﬁiend,
remembering to pay a bill or take one's medication) versus memory for content (e.g.,
recalling a list of words previously learned, recalling the state capitols). Some have
suggested that prospective memory tasks may be encoded more elaborately than to-be-
recalled tasks. For example, prospective memory tasks, since they have different retrieval
requirements than their retrospective memory counterpart (i.e., subjects need to
"remember to remember" on their own), may be held in a state of heightened activation to
keep them accessible for potential use (Glisky, 1996). The two types of tasks also differ
in the attention which is allocated for retrieval. Usually during retrospective memory
recall, full attention can be allocated to the task while in prospective memory, recall occurs
while other activities are occurring simultaneously. In addition, retrospective memory is
usually elicited by an external prompt, while in prospective memory retrieval is begun
when a ﬂow of thoughts of the prospective memory task interrupts ongoing activities and
comes to mind (i.e., prospective memory retrieval occurs as a result of time and context
monitoring). For example, a teacher can prompt students to remember the content of a
seminar, but they cannot rely on this type of prompting when needing to return a library

book or attend an appointment. The former is a direct type of remembering that involves

81

consciously controlled processes while the latter type of remembering is more spontaneous
and arises into consciousness involuntarily (Ste-Marie & Jacoby, 1993).

Furthermore, some authors have suggested that prospective memory and
retrospective memory may rely on different encoding and storage processes which effect
subsequent retrieval requirements. For example, Koriat, Ben-Zur and Nussbaum (1990)
theorized that encoding and rehearsal for prospective memory tasks relies on an internal
visualization process (i.e., an enactment of the task) to create a multimodal representation
(i.e., visual and motor code in addition to verbal coding) which makes it more likely that
the memory representation will be activated during retrieval conditions. As will be
demonstrated in the next section, prospective memory is a multidimensional cognitive
process which is "more than memory" and may be distinguished ﬁ'om retrospective
memory by its reliance on executive functions and the integrity of the ﬁ'ontal lobes (Glisky,
1996)

The Impact of Executive Functioning on Prospective Memory Performance.
Prospective memory requires such skills such as planning, organizing, and self-initiation
that may not be present in various types of retrospective memory searches. For instance,
demands on the executive ﬁinctions of the ﬁ'ontal lobes are likely to be present "when
demands on working memory are considerable, when preliminary planning is necessary,
when tasks are not routine, when temporal tracking or time estimation is required, when
ongoing behaviors have to be interrupted and when environmental or contextual stimuli
need to be monitored" (Glisky, 1996, p. 258). Many prospective memory tasks require

these executive skills.

 

82

In the present study, the entire group of executive function measures contributed a
substantial portion to the variance associated with prospective memory beyond the eﬁ‘ects
associated with the other variables of age, attention, and retrospective memory. This
analysis was considered to be a conservative measure of the contribution of executive
ﬁrnctions given that the control variables already accounted for a signiﬁcant portion of
variance in prospective memory. However, not all of the measures included in the
regression equation contributed signiﬁcantly in predicting prospective memory
performance. Executive function measures which assessed the ability to shift and maintain
a mental set (i.e., WCST Total Number of Categories and Failure to Maintain Set) or the
ability for visuospatial sequencing and mental ﬂexibility (i.e., Trails B) did not predict
successful prospective memory performance despite being signiﬁcantly correlated with the
outcome variable. Indeed, the only executive ﬁinction measure which contributed
signiﬁcantly to the variance in prospective memory was a measure of visuospatial
creativity, speed of productivity and the ability to monitor ongoing activity. In addition,
this executive ﬁrnction measure has been shown to load heavily on an "initiation" factor
(Baser & Ruﬂ‘, 1987). In the Ruff Figural Fluency Task, monitoring is an important
component as subjects are instnrcted to produce "as many designs as possible that are all
diﬁ‘erent." Therefore, subjects must "monitor" what designs have already been produced
(background activity) while creating new designs (foreground activity). This measure of
executive ﬁrnction is similar to what is required during prospective memory tasks in which
other activities are being carried out during the interval prior to the completion of the

intention.

 

 

83

The monitoring component appears to be a central feature in completing
prospective memory tasks successfully. This process of monitoring can also be thought of
as "behavioral inhibition" in that the eﬁ‘ects of other competing, distracting processes over
a delay period must be ignored and a task must be avoided until a certain time interval has
passed. Studies have shown that the prefrontal cortex is implicated in these types of
working memory tasks (Cohen & O'Reilly, 1996) given that they require delayed
responses to stimuli as well as inhibition of competing information (Stuss, Eskes, &
Foster, 1994).

Dobbs and Reeves (1996) have identiﬁed monitoring as one of a number of
prospective memory components necessary in the completing these types of tasks. These
authors also differentiated between monitoring behaviors (i.e., implicit and explicit
checking to determine if the appropriate circumstances to act are present) and monitoring
accuracy (i.e., knowing when to respond regardless of whether or not one can remember
the content of the intended action or whether they wish to comply with the task demands).

Harris and Wilkins (1982) proposed a test-wait-test-exit model to explain monitoring
behavior during a prospective memory task. While waiting to perform a ﬁrture action, a
person must check to see if the critical period for canying out the intention has arrived. If
not, the person continues to wait; however, if the critical period has arrived a person must
"exit" the waiting period and perform the activity. Some studies have speciﬁcally
considered external indicators of monitoring behavior and their inﬂuence on successful
task completion. Ceci and Bronfenbrenner (1985) have observed how individuals check

time on a clock and found that subjects used both linear and U-shaped patterns of

84

checking, the latter being more efficient. Similarly, Einstein and McDaniel (1996) have
observed that clock-checking increases in the one minute preceding the completion of the
prospective memory task and that monitoring ﬁequency was strongly correlated with
successful memory performance.

Therefore, the present results would seem to suggest that the cognitive
requirements of planning and monitoring are unique aspects of prospective memory which
differentiate it from its retrospective counterpart. This set of data supports current
theoretical explanations of the construct of prospective memory (Craik & Kerr, 1996). In
addition, Biasiacchi (1996) discusses the role of prefrontal cognitive capacities and
prospective memory. He refers to the executive ﬁrnctions of planning as a type of
temporal organization which entails going over potential actions as well as evaluating and
selecting the optimal strategy and optimal order in which to execute them in the
prospective memory task. In addition, he indicates that planning also involves a control
mechanism which entails switching between different actions and permitting the inhibition
of one task in favor of another. This would entail switching between two or more
diﬁ‘erent tasks or responses (i.e., cognitive ﬂexibility).

Why the present investigation did not ﬁnd measures of cognitive ﬂexibility to
signiﬁcantly predict prospective memory performance remains open to question. One
possibility is that event-based and time-based prospective memory tasks were combined
and the role of executive ﬁrnctions in these two types of tasks were not considered
separately. One might assume that time-based tasks require a greater degree of

monitoring than event based tasks. For event-based tasks, subjects would not have to

85

engage in switching mental sets between monitoring the clock and engaging in the current
activity given their only requirement was to wait for an environmental cue to initiate the
prospective memory task. Another possibility to explain the apparent lack of inﬂuence of
cognitive ﬂexibility on prospective memory tasks may be that it is redundant with the
predictive information provided by the attention factor in the regression equation. The
attentional requirements of the other ongoing activities during the retention intervals were
not speciﬁcally assessed in this study. These conditions were held constant for all
participants, but a more careﬁrl exploration of the role of monitoring in foreground and
background tasks can be a fi'uitﬁil area for future investigation.

An additional dimension of the Ruff Figural Fluency Test (i.e., RFFT) which may
contribute to prospective memory performance is that of perceptual ﬂuency. J acoby and
Kelley (1991) have indicated that perceptual ﬂuency and context recognition can evoke
feelings of familiarity which can be followed by controlled retrieval processes which
attempt to connect the familiarity to a source. For example, as a subject is constructing a
new design on the RFFT, he/she must "notice" if the design is familiar which may
subsequently direct a search to determine if the design has been constructed before. The
RFFT requires that a subject maintain a constant awareness of contextual and perceptual
information and the quicker and more emciently one can carry out this search activity the
more optimal his/her performance.

The data from the present investigation suggest that both retrospective memory
and executive functions are signiﬁcant predictors of successful prospective memory

performance. From a neurostructural perspective, Cohen & O'Reilly (1996) postulate an

 

 

86

interactive system between processes localized in the preﬁontal cortex and the
hippocampus as contributing to different facets of prospective memory performance.
Speciﬁcally, they speculate that the preﬁ'ontal cortex is important in directing attention to
task-relevant representations and inhibiting task-irrelevant ones. The hippocampus, on the
other hand, serves to recall the intention prior to the initiation of its completion. The role
of hippocampal function is to "bind" together and mediate novel associations (e.g., build
stirnulus-response associations) until they can be encoded in the mnemonic system. In this
manner, hippocampal processes serve or complement ﬁ'ontal lobe processes (Shallice,
1996) in completing prospective memory tasks. These neurostructural areas share
numerous cortical connections (Luria, 1966) between themselves and with other cortical
substrates (e.g., diencephalon, basal ganglia) which may also have a role in prospective
memory performance (Bisiacchi, 1996; Eslinger & Grattan, 1993).

The Role of Environmental Support and Trace Memory Decay Over Time in
Prospective Memory Performance. This portion of the investigation considered the
eﬁ‘ect of external cueing and the interval between the request and the initiation of the to-
be-remembered action on prospective memory performance. The results revealed a Cue x
Time interaction indicating that older individuals performed more poorly on prospective
memory tasks with little environmental support (e. g., less cues) and which had to be
initiated after longer intervals. These analyses revealed that both the effects of cueing
and time interval have a signiﬁcant impact on prospective memory performance,
apparently to a greater extent than the eﬁ‘ects associated with age itself. In other words,

prospective memory deteriorated during longer intervals between task assignment and

87

execution of the intention and this discrepancy was greatest for uncued items. These data
support the hypothesis that older individuals have greater difﬁculty on tasks in which the
need for self-initiated activity is high and when the potential for interference is greater.

In the present study, two types of cues were given. The subjects were either
provided with an external, associative cue or were provided with a clock and required to
monitor time (e.g., an internal cue was needed).3 In addition, prospective memory tasks
were carried out after 10 and 20 minute intervals. One preliminary study which
investigated prospective memory in older adults and the use of cues found that reliance on
external cues does increase with age, but may depend on the type of task to be carried out
(Reeves & Dobbs, 1992). Speciﬁcally, these authors found that older subjects were
signiﬁcantly more likely than younger subjects to use external cues for tasks which
occurred infrequently and for tasks which were "habitual" (e.g., occur with a regular time
interval) but did not have an environmental cue. Therefore, older subjects adopted an
external cueing system for those tasks under which their prospective memory was likely to
deteriorate. In effect, these subjects converted time-based tasks into event-based tasks in
order to assist in remembering the future intention.

Maylor (1990) conducted one of the largest "naturalistic" studies of prospective
memory in the elderly in which she assessed inﬂuences on performance for a telephone

task (i.e., subjects were asked to phone the experimenter once per day Monday through

 

3

It should be noted that any one may have both internal and external characteristics. For
instance, activity required to construct an external cue may inﬂuence a cognitive (i.e.,
internal) representation of the intention (Itons-Peterson & Fournier, 1986).

88

Friday). Those subjects who relied on internal cues to remember the task (e. g., "I tried to
condition myself to remember without any aid) showed the worst performance. Subjects
who chose a "conjunction cue" (e.g., telephoned in conjunction with another routine event
such as breakfast) carried out the task in the most consistent manner, while those who
used an external cue (e.g., reminder note) performed in between the other two groups.
Maylor (1990) also noted positive effects of age such that older subjects appeared better
at using external or conjunction cues than were younger subjects, possibly because they
had more experience in using them.

Cue type appears to be an important factor in completing prospective memory
tasks successfully. For example, recent research has demonstrated that performance is
better with unfamiliar rather than familiar cues (Einstein & McDaniel, 1990), speciﬁc
rather than general cues, distinctive rather than nondistinctive cues (McDaniel & Einstein,
1993), and elaborate rather than simple cues (Loftus, 1971). Dobbs and Reeves (1996)
have also reported that subjects perform better on prospective memory tasks which follow
cues related to the task rather than unrelated cues and which follow perceptual cues rather
than semantic cues.

The eﬁ‘ects of the twenty-minute retention interval on prospective memory
performance can best be explained by executive functioning and monitoring ability
discussed in the previous section. The twenty-minute retention interval between the
request to carry out the prospective memory task and the execution of the intention can be
regarded as a "divided attention" task given that the subjects are asked to perform other

activities during the time interval while also remembering to perform the task in the future.

89

These types of attentional and monitoring cognitive tasks require greater processing
resources (Salthouse, 1991; Moscovitch & Winocur, 1992) and research has indicated
that memory traces decay more quickly over time in working memory of the elderly due to
the inability to inhibit competing, distracting stimuli (Hasher & Zacks, 1988). These
factors make it diﬁcult to switch from the intervening activity to the prospective memory
task. Therefore, prospective memory performance is inﬂuenced by the requirements of
tasks carried out between the formation of the intention and its initiation (Brandirnonte &
Passolunghi, 1994). While it was not explored explicitly in this study, individuals may
vary on their susceptibility to the inﬂuence of the intervening activity on the intended
action due to such factors as personality and motivation.

The Correspondence Between Self-Reported Prospective Memory
Capabilities and Actual Performance. As discussed in the previous section, the present
study revealed that when the use of cues was controlled for, a decline in prospective
memory ability emerged. The results from the present study also revealed that a
relationship does not exist between self-assessment of prospective memory capability and
actual performance on cued or uncued prospective memory performance. The use of
external memory aids may conceal actual prospective memory deﬁcits. As a matter of
fact, when subjects have been asked to rate themselves on various prospective memory
tasks (e.g., "How often do you forget to take your medication?"; "How often do you
forget to write letters you intended to write or make telephone calls you intended to
make? "), evidence for age-related declines in prospective memory do not emerge (Maylor,

1993). Some studies that have measured self-reports of prospective memory have even

90

demonstrated improvement in prospective memory (Harris, 1984; Martin, 1986).
However, other studies show that as individuals age, they have poor metamemory or
insight into their own memory capabilities (Cavanaugh, 1988; McGlynn, 1993).

Few studies have simultaneously considered self-perceptions of prospective
memory and actual performance. Dobbs and Rule (1987) did not ﬁnd a correspondence
between rated ability and actual performance in any of the adult groups studied.
Furthermore, the same null result was obtained when comparing self-rated ability and
performance in groups of mildly head injured individuals (Dobbs, Reeves & Rule, 1995).
However, neither of these studies asked subjects to rate their performance on the
prospective memory task to be carried out in the study, but instead asked them to rate
their potential performance in hypothetical prospective memory tasks. This was also true
for the present study. Conversely, one study conducted by Devolder, Brigham and
Pressley (1990) did ﬁnd that older adults were able to accurately rate their performance on
a prospective memory task, and were better at predicting than younger adults. It is
possible that this study found a correspondence between self-rated ability and performance
because the hypothetical task in the rating and the task to be carried out in the experiment
were one and the same.

The most likely explanation for the present data is that outside of the laboratory,
older individuals rely on external memory aids to a greater extent and therefore, do not
notice potential deﬁcits in prospective memory ability. The other side of this argument is
that older individuals who have little insight or awareness into their memory capabilities

will be unable to implement appropriate memory strategies (J anowsky, Shimamura, &

91

Squire, 1989) or fail to acknowledge memory lapses. External cues for completion of
prospective memory tasks, in addition to reminding one to complete the intention, also
function to cue an awareness that one has forgotten. Such external supports for
remembering do not provide the opportunity for individuals to make an accurate
assessment of memory capabilities. Of course, other interpretations are likely including
the inherent difﬁculties in using questionnaires to assess competency in aging (Rabbitt &
Abson, 1990), including a heightened need in the elderly to respond in a socially desirable
manner.

Individual diﬁ‘erences also might account for whether or not people can accurately
assess their prospective memory ability and whether or not they can complete intention
memory tasks in their everyday environment. As people age, they often have the beneﬁt
of experience which can lead to improved problem-solving abilities and thus successful
prospective memory (Andrzejewski, Moore, Corvette & Henmann, 1991). The subjects
in the present sample may have had a great deal of experience with the types of
prospective memory situations outlined in the self-report measure, but none with types of
tasks with which they were presented during the assessment. Research regarding other
individual difference variables has shown that Type B personalities tend to be less accurate
in remembering intentions than Type A personalities (Searleman & Gaydusek, 1989) and
that a heightened emotional state, such as seen in anxiety, has been shown to have a
deleterious effect on prospective memory (Meacham & Kushner, 1980). Finally,
individuals may vary in the extent to which they ruminate about "unfulﬁlled intentions"

(Zeigarnik-eﬁ‘ect; Goschke & Kuhl, 1996) keeping the intention in a heightened state of

92

activation. Again, subjects may have been more ambitious about the types of prospective
memory tasks outlined in the self-report measure while the laboratory prospective memory
tasks may not have carried the same psychological valence.

Remediation of Prospective Memory Declines in the Able Elderly. Few
studies to date have systematically investigated the remediation of prospective memory in
the elderly despite the fact that adaptive prospective memory ability has a signiﬁcant
impact on daily functioning. The clinical importance of remediating cognitive declines
associated with prospective memory was demonstrated by Huppert and Beardsall (1993)
in a study which revealed that prospective memory declines are an early indicator of
dementia. F urtherrnore, cognitive declines can be part of normal aging and, therefore, not
part of a disease process, with prevalence rates in the able elderly ranging from 45% to
86% for persons over the age of 80 years old (Crook, 1993). Interventions have proven
eﬁicacious in reversing cognitive changes in old age (Crook, 1993) and may potentially
contribute to circumventing a more serious disease process.

Our intervention was designed to enhance prospective memory performance by
training group participants in inforrnation-organizing techniques as well as strategies to
increase attention/concentration abilities. In addition, procedures aimed at decreasing the
impact of mood-related symptomatology (e.g., depression, anxiety, stress) were provided
as the literature has shown that these can increase certain types of prospective memory
errors (Cockbum & Smith, 1994, 1996; Meacham & Kushner, 1980). In our sample, a
signiﬁcant increase in prospective memory capacity was observed following the group

intervention. However, no diﬁ‘erences were observed between the group employing

93

ecologically valid stimuli and the group using laboratory stimuli. The overall intervention
appeared to have an impact on prospective memory performance; however, the Everyday
and Lab group intervention may not have been distinctive enough to yield signiﬁcant
differences.

A strong component of the training paradigm was to encourage subjects to
supplement external memory aids with internally generated strategies which provided a
structure for subjects to cognitively rehearse to-be-remembered material. For example,
many of the techniques (both relaxation and memory strategies) involved the use of visual
imagery. Subject's prospective memory performance may have improved with the
development of the ability to imagine oneself performing the intended action in the context
where it is supposed to occur (i.e., increased rehearsal during a retention interval).

Dobbs and Reeves (1996) have developed a heuristic which delineates various
qualitative aspects of prospective remembering. They have labeled six steps in prospective
remembering which include metalmowledge (i.e., knowing the speciﬁc demand of the task;
being able to know one's own abilities), planning (i.e., formulating a plan of how to
remember a future intention), monitoring (i.e., periodically recalling when the task needs
to be completed and evaluating whether or not the requirements for recall are currently
met), content recall (i.e., remembering what the prospective memory task is; retrospective
memory component), and output monitoring (i.e., recalling that the task has already been
carried out).

Some authors have indicated that the most important aspects of prospective

memory tasks are the monitoring and planning components (Craik & Kerr, 1996).

94

Planning and monitoring has been the focus in several studies which trained intention
memory capabilities. For example, Stevens and colleagues (1992) trained Alzheimer's
disease patients to consult a calendar and to carry out the activities identiﬁed for that day.
In effect, individuals were trained to use a "good strategy" to increase the likelihood of
completing prospective memory tasks. Similarly, Park and Kidder (1996) have developed
a sequence of memory aids which they use to increase medication adherence in the elderly
(e. g., organizational charts, reminders, calendars). In addition, Camp and his colleagues
(1996) focused on the monitoring component of prospective remembering when they used
a spaced retrieval technique to successfully train a group of subjects with Alzheimer's
Disease to improve their prospective memory performance. Their techniques involved a
shaping procedure for memory in which subjects are trained to recall information over
increasingly longer periods of time.

As opposed to the studies just mentioned, the group training paradigm in this study
did not focus on speciﬁc aspects of prospective remembering. Prospective memory is a
multidimensional task which involves a variety of processes such as planning capabilities
(e.g., appropriate setting of environmental cues; planning how to remember), attention
abilities needed for time monitoring and holding intentions in working memory, and the
memory component itself (e.g., remembering the intention and the action to be
performed). Future training groups in prospective memory might speciﬁcally deﬁne these
aspects of memory for intentions and then develop individually tailored programs to
compensate for whichever aspect is problematic. For example, if an individual is able to

assess which aspect of the prospective memory task he/she is likely to fail, then steps can

95

be taken to change the nature of the task (e.g., using a clock alarm to circumvent
prospective memory failures arising out of time monitoring deﬁcits). However, this
approach is confounded by the fact that individuals often are unable to accurately assess
their prospective memory ability in order to plan for speciﬁc deﬁcit areas.
Limitations of the Present Study and Future Directions

Methodological

The present ﬁndings should be considered in the context of the sample which was
studied. There was no way to determine the unique characteristics of those who
responded to the advertisement to participate in the study and those who did not. The
present sample was highly educated and may, therefore, have been more "psychologically
minded" than those who chose not to respond to the advertisement. The present sample
might have also diﬁered on factors such as social relatedness, personality, and
psychological well-being factors. The workshop provided participants with the
opportunity to interact with peers who may have been experiencing similar adjustment
reactions to the aging process. Those who did not respond to the advertisement may have
had an adequate social support network or, on the other extreme, have been isolated with
limited contact with others. In addition, the present sample was predominantly female and
racially homogeneous (i.e., the majority of the sample being Caucasian). Therefore, the
results ﬁom the present sample cannot be generalized to groups that differed from the
present sample. Furthermore, 58% of the original sample remained in the study to
participate in the seven session workshop which was oﬁ‘ered to participants. This group

did not diﬂ‘er signiﬁcantly from the other 42% on the variables of age, education, and

96

performance on measures of estimated intelligence and mental status. Again, other
variables which were not analyzed might have accounted for those individuals who
dropped out of the study including personality (e.g., depression, anxiety) and cognitive
factors (e. g., differences in memory capacity).

The ﬁndings associated with the intervention component of the present
investigation should also be interpreted with caution due to reasons of sampling. The
present study did not include a waiting-list control group so that pre- and post-measures
of performance might be compared to those who received the seven session training
group. Given the lack of an appropriate control group, conclusions cannot be drawn
about whether or not the intervention contributed to improvements in prospective memory
performance beyond changes which might have been due to practice effects with repeated
assessment or simple demand characteristics of the testing situation.

Another methodological limitation of the present investigation refers speciﬁcally to
the prediction that self-report measures of prospective memory would not correspond to
actual abilities as measured in the laboratory. In this case, the null hypothesis of no
differences was being predicted. The results supported the null hypothesis of no
diﬁ‘erence; however, this should be interpreted with caution since from a statistical
standpoint, hypothesis testing is biased toward ﬁnding a null result. F rick ( 1995) outlines
the interpretive bias that exists in predicting the null hypothesis.

Measures
The present ﬁndings must also be considered in the context of the measures used

to assess various facets of prospective memory, retrospective memory, and executive

97

functions. There is a diﬁculty in designing tasks which provide pure measures of
prospective memory and which are uncontaminated by other factors such as compliance
and motivation. Prospective memory failures could occur for any number of reasons. For
example, poor performance could be due either to a lack of compliance, lack of motivation
(e. g., needing to pay a bill, but not having the money), or to a retrospective memory
failure. Measures were not taken in the present sample to assess how much importance
subjects attributed to the assessment process. Subjects may have accurately monitored
when tasks were to be completed and recalled the content of the intended action but not
have been motivated or willing to complete tasks. Oftentirnes, when people fail to
remember something in the future, there is some kind of social obligation that has been
neglected. People may attribute retrospective memory failures to a deﬁcit in one's
memory while prospective memory failures are attributed to personal preference (i.e.,
intention). It was assumed in the present investigation, but not speciﬁcally explored, that
subjects were motivated to complete the tasks given their self-initiated participation and
expressed interest in completing the workshops provided.

Furthermore, the signiﬁcant positive correlation between prospective memory
tasks and retrospective memory tasks should be interpreted with caution since these tasks
were not comparable in the encoding demands necessary for each nor in the retention
interval which occurred prior to recall. Retrospective memory was assessed by using the
CVLT Raw Score for which encoding occurs over ﬁve trials and recall is assessed
immediately after encoding. Many of the prospective memory tasks required encoding

after only one presentation and were recalled alter retention intervals of up to 20 minutes.

98

In addition, the cognitive and attentional demands of the interfering activities and tasks
(i.e., those occurring between formation of a prospective memory intention and the
completion of the intention) were not assessed. This issue was partially addressed by
ensuring the same testing sequence for each subject; however, some prospective memory
tasks may have followed high demands for attentional and information processing
resources while others may not have. One strength of the present investigation was that it
considered multiple subgoals for prospective memory tasks which is more reﬂective of real
world situations for intention memory. Most studies of prospective memory utilize a
single instruction or procedure for prospective memory. Using multiple subgoals of
prospective memory increased the predictive power in assessing intention memory
ﬁrnctions; however, speciﬁc conclusions cannot be drawn about the diﬂ‘erent kinds and
amounts of demands that apparently similar tasks make on working memory.
Future Research

Prospective memory is pervasive in everyday life and has important implications
for adequate functioning in daily living. Delineating the nature of prospective memory
failures appears to be important in understanding memory processes in the elderly and how
they affect overall adjustment. Future research might speciﬁcally focus on the reasons for
prospective memory failures including both errors of omission and commission and
whether or not retrospective memory, time monitoring, or motivation was responsible to
instances of forgetting.

However, as some have stated prospective remembering is "more than memory"

(Dobbs & Reeves, 1996; Maylor, 1996) since it entails a set of abilities that depend on a

99

broad range of underlying processes involving the timely performance of planned actions.
It is surprising that the WCST Number of Categories and Trails B were not distinguishing
features in predicting successful prospective memory performance completion given that
such tasks require mental ﬂexibility and the ability to switch mental sets. Future research
might focus more speciﬁcally on the interaction of attentional and executive functions in
predicting prospective memory performance. The fact that monitoring as a speciﬁc
cognitive requirement of the RFFT emerged as an important predictor in successﬁrl
prospective memory completion is an important contribution to the literature on
prospective memory. However, the behavioral dimensions of monitoring in the
prospective memory task were not correlated with monitoring behaviors required in the
RFFT in order to conﬁrm the validity of this ﬁnding.

Finally, ﬁiture research will consider which speciﬁc components of the intervention
led to improved performance and how participants compare to a waiting-list control
group. A workshop designed with interventions more speciﬁcally geared to prospective
memory ﬁrnctioning would certainly provide information beyond that garnered from the
present preliminary investigation. Ideally, the present data might have been more
informative if considered in the context of a control group of younger cohorts to more

clearly delineate the nature of the age-associated decline in prospective memory.

TABLES

100

Table 1A
Means, Standard Deviations and Correlations For Prospective Memory, Age, and
Retrospective Memory

 

 

 

Variables Prospective Memory QDV) Age CVLT
AGE -.29*

CVLT .42* -.40*

Means 14.90 67.71 45.49
SD 2.56 7.71 11.49
N = 113

*p < .01

101

Table 1B
Means, Standard Deviations and Correlations For Prospective Memory, Age,
Attention, Retrospective Memory and Executive Function Measures

 

Variables Pros. Mem. (DV) Age Attn Retro Cat. FTMS Des TrB

 

AGE -.31*

ATTENTION 22* -.23*

RETROSPECTIVE .43 * -.39* .3 1*

WCSTCAT .35* -.48* .45“ .35*

WCST FTMS -.08 .16" -.29* -.10 -.40*

RFFTDES .40* -.34* .42* .36* .40* -.15

TRAILSB -.25* .43* -.37* -.30"' -.42* .15 -.54*
Means 14.83 67.48 14.48 45.37 4.88 .85 67.84 108.35
SD 2.59 7.67 3.70 11.99 1.60 1.06 19.65 65.00
N=106

*p _<_ .01; “p < .05
(W CST CAT = total number of categories on the WCST; WCST F'I'MS = failure to
maintain set on WC ST; RFFT DES = total number of designs on the RFFT)

Table 2

102

Prospective Memory Score Values for the Solved Generalized Estimating Equation:

Hypothesis Two

 

f. .
.1 2‘_ _‘= "V. ., -. ~ _ . _"Z‘.'. V '
.. ~’ .~.,'_ . {iv

. @c “'4

N=115

4.97

2.30

 

8.35

 

3.78

 

 

103

Table 3

Descriptive Statistics for Prospective Memory Performance for the Everyday and
Lab Groups in the Sample

 

 

Group N Pre-Test Prospective Memory Post-Test Prospective
Memory

Mean SD Mean SD
Everyday 38 14.97 2.31 16.16 1.59

Lab 30 15.45 2.81 16.17 1.93

 

FIGURES

104

 

 

Prospective Memory Scores for
the Cue x Time Interaction
Figure 1

 

moo

Pros
O

  
 

tive Memoryﬁcore
C

see.

 

Time

.CUED
- UNCUE

 

 

APPENDICES

105
Appendix A
Prospective Memory Screening (PROMS) Items

1) Twenty minute prospect memory task with associative cue.
Directions: "The ﬁrst thing I want you to remember is to make a ﬁst (examiner
models) when I show you a picture of a boat sometime during the next hour."

2) Two minute prospective memory task with time cue.
Directions: "From when I say "begin", wait exactly two minutes, then write your
name on this paper. "

3) One minute prospective memory task with associative cue.
Directions: "This time, I want you to draw a square on the paper when you see
me clap my hands. " (Examiner claps hands in 60 seconds)

4) Ten minute prospective memory task with time cue.
Directions: "In exactly ten minutes ﬁom right now, I would like you to put this
letter in this envelope. While you are waiting, we are going to do a couple of
other tasks. "

5) Ten minute prospective memory task with associative cue.
Directions: "OK, now I ’d like for you to remember to stop and tap the table
(examiner models) when I snap my ﬁngers. While you are waiting, we are going
to work on some other tas ."

6) Twenty minute prospective memory task with time cue.
Directions: "In twenty minutes from right now, I want you to stand up. While you
are waiting, we will work on some other tasks. "

7) Twenty four hour prospective memory task.
Directions: "The next task you need to remember is to mail this postcard I want
you to put it in the mail tomorrow. I will look at the postmark date to see when it

was mailed It already has the address and stamp. All you need to do is drop it
in the mail tomorrow."

106
Appendix B
Cued and Uncued Prospective Memory Items

1) Cued Prospective Memory Items:

Immediate:
1) PROMS Item #3 --Examinee remembers to draw a square when

examiner claps hand (cue) after one minute interval

10 minute interval:
1) PROMS Item #4--Examinee taps table when examiner snaps ﬁngers

(cue) after 10 minute interval

20 minute interval:
1) RBMT "Remembering an Appointment": Cue: Alarm ringing after 20

minute interval
2) PROMS Item #1--Examinee makes a ﬁst when presented with a picture

of a boat 20 minutes after instruction
II) Uncued Prospective Memory Items:

Immediate:
1) PROMS Item #2--Examinee remembers to write name after two minute

interval

10 minute interval:
1) PROMS Item #4--Examinee places letter in envelope after self-timed 10

minute interval

20 minute interval:
1) RBMT "Remembering a Belonging"-Examinee remembers to ask for a

belonging at the end of the test
2) PROMS Item #6--Examinee stands up after self-timed 20 minute

interval

III) Uncategorized Prospective Memory Items:

1) PROMS Item #7--Examinee is instructed to mail postcard after 24 hour

interval--extemal aids not controlled.
2) RBMT "Remembering to Deliver a Message"--Embedded in a sequence

3) RBMT Delay of "Remembering to Deliver a Message"

107
Appendix C
MAC-S Prospective Memory Items
I) Ability Items:

Item #4: To turn out lights, turn off appliances, and lock doors when leaving
home.

Item #11: To write letters you intend to write or make telephone calls you intend
to make.

Item #16: To take along, when leaving the home or oﬁce, any items that you
intended to take (for instance, an umbrella or a letter to mail).

11) Frequency Items:
Item #23: Go into a room to get something and forget what you are after.

Item #24: Forget to bring up an important point you had intended to mention
during a conversation.

Item #25: Forget that you told someone something and tell that person the same
thing again.

Item #30: Feel that a word or name you want to remember is "on the tip of your
tongue" but cannot be recalled.

Item #34: Dial a number and forget who you were calling before the phone is
answered.

Item #35: Forget an appointment or other event that is very important to you.
Item #38: Forget which waiter took your order in a restaurant.

Item #40: Pass the point where you intended to exit while driving a car or taking
public transportation.

Item #43: Arrive at the grocery store or pharmacy and forget what you intended
to buy.

Item #46: Store an important item in a place where it will be safe and then forget
where it is.

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