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DEVELOPMENT OF HANDEDNESS, LANGUAGE, AND GESTURES

IN INFANTS 9, 13, AND 20 MONTHS OF AGE

by

Karen SUe Cornwell

A THESIS

submitted to
Michigan State University
in partial fulfillment of the requirements

for the degree of

MASTER OF ARTS

Department of Psychology
1985

ACKNOWLEDGMENTS

I would like to thank Hiram Fitzgerald for his advice
and support; Lauren Harris for his editorial patience; Wade
Horn for helpful suggestions; Kathy Cirner for her valuable
assistance in data collection; and also the parents and
infants for their enthusiastic participation. During the
conduct of this research, I was supported by an AURI Grant
#11-6253, NIMH Training Grant #MH-l4622-09, and by the

Spencer Foundation.

ii

TABLE OF CONTENTS

LIST OF TABLES ........................................ v
LIST OF FIGURES ...................................... vi
INTRODUCTION .......................................... 1
REVIEW OF THE LITERATURE .............................. 5

Early lateralization
Transitional postnatal period
7-9 month transition

Other transitions

SUBJECTS 0.0.0.0...0...0OOOOOOOOOOOOOOOOOOOOOOOOOOOOOO 22
METHOD COCOOOOOO0..OOOOO‘OOOOOOOOOOOOOOOOOO00.0.0000... 23

Procedure

Home visit
Laboratory visit
Unimanual task
Bimanual task
Language assessment
Analysis

RESULTS 0.0.0.0....CO...0.0.0.0...OOOOOOOOOOOOOOOOOOOO 33

Overview of results

Unimanual handedness

Bimanual handedness

Language assessments (SICD)

Gestures

Interrelationships between gestures, language
and handedness

HOME scores

iii

DISCUSSION .0..000.0.000...00.000000.0.000.000.00.000.

Handedness

Handedness and communication skill

Gestures

HOME

Conclusion
APPENDIX A Research Description Letter .............
APPENDIX B Parental consent form .0..00000000..0.000
APPENDIX C Parental Handedness Questionnaire .......
APPENDIX D Demographics Questionnaire ..............
APPENDIX E caldwell HOME Inventory 00.....0000000..0
APPENDIX F Coding Sheet for Gestures ...............
APPENDIX 61 SICD Receptive Language ................
APPENDIX 62 SICD Expressive Language ...............
APPENDIX HI Bayley Items Coding Instructions .......
APPENDIX H2 Scoring Sheet: Bayley Items ............
APPENDIX II Bimanual Manipulation Coding

Instructions 00000000000000.00.

APPENDIX 12 Scoring Sheet for Bimanual Manipulation
REFERENCES 0.00000000000000.0..0.00.00.00.000000000...

iv

49

71

85
91
93

 

LIST OF TABLES

TABLE PAGE

1. Correlations between laterality scores for

each unimanual task and overall unimanual

laterality scores ................................. 35
2. Percentage of points, extensions, and reaches

while looking at objects or persons

(at each age tested) .............................. 44
3. Percentage of infant gestures with and without

vocal accompaniment (at each age tested) .......... 46

LIST OF FIGURES

FIGURE PAGE
I. Percentages of bimanual hand preferences
(in each age group) ................................ 40
2. Percentage of points, extensions, and reaches

used by infants .................................... 42

vi

ABSTRACT
DEVELOPMENT or HANDEDNESS, LANGUAGE AND GESTURES
IN INFANTS 9, 13, AND 20 MONTHS OF AGE
by

Karen Sue Cornwell

The relationship between the development of oral and
gestural communications in the pre-linguistic infant and the
development of lateral limb differences (and subsequent
handedness) was studied in 63 female infants (22 nine-month-
olds, 18 thirteen-month-olds, and 23 thirteen-month-olds).

A cross-sectional design was used, with observations in the
infant's home and in the laboratory. Results indicate that
the development of unimanual skill (as indexed by a prefer-
ential use of one hand in a unimanual task) precedes the
development of gestural communication and speech. The 9-
month group showed significant correlations between the
presence of reliable hand preference, and the measures of
language and gestural use. Use of right-handed gestures
accompanied by a vocalization was associated with higher
expressive language scores, but only at 9 months. Infant
hand preference for reaching or bimanual handedness did not
predict hand preference for gesturing. The 13- and 20-month
groups did not show the predicted relationship between the
various gestural, language, and manual preference measures,
as did the 9-month group. The results suggest that emerging
skills are likely to be more closely associated with each

other than are more highly organized behaviors.

I NTRODUCTI ON

Two major areas of infant research are currently being
explored with curiosity and enthusiasm: the development of
communicative behavior in the pre-linguistic infant, and the
development of lateral limb differences (and subsequent
handedness). Although each of these topics has received
much attention, there has been little systematic investiga-
tion of the relationship between them, particularly during
the infant period.

The idea that language and handedness are interrelated
is not a new one. Since Broca (1865), considerable research
has been undertaken to discover the nature of this relation-
ship. Baldwin (1890) noted the connection between the
beginnings of speech and handedness, thereby extending the
interest in cortical localization to the realm of develop-
mental psychology. Baldwin believed handedness to be "a
form of expressive differentiation of movement" (p.66),
which precedes and is less complex than speech, yet performs
a similar utility (enabling increased control over the
environment). He reported that his daughter first showed a
right hand preference for reaching (between 7 - 8 months) at
the same time that she began to babble syllables. Nice

1

2
(1918), commenting on the association between the lack of
differentiated handedness and delayed speech, noted that
there was almost nothing known about the relationship of the
development of language and the development of handedness.
It remained an almost untouched area until Ramsay's work
eventually corroborated and extended Baldwin's observations
nearly 100 years later. Ramsay (1982) found evidence for a
relation between the onset of duplicated syllable babbling
(e.g. gaga, dada), and the onset of unimanual preference.
Ramsay states that although a developmental relation between
Speech and handedness may reflect developmental change in
hemispheric processing, it may also be that these relation-
ships reflect changes in asymmetrical brain organization at
different levels. Ramsay further calls for a resolution of
this argument and argues that research using other measures
of changes in infants' vocalizations is needed. It would
also be useful to look at the communicating system as a
whole, as a way of getting a boader perspective on the
relationship between lateralization of language and motor
skills.

It is the purpose of this study to investigate and to
further describe the relationship between the sequence of
communication development and lateralized skilled behavior.
I have chosen to study this relationship by using a cross-
sectional methodology with infants 9, l3, and 20 months of
age. These ages were chosen for theoretical as well as

practical reasons. The first reason is that these ages are

3
presumed to reflect approximate times when infants experience
a reorganization of various social and motor behaviors (Emde,
1981). In addition, normative data from studies of the
development of handedness (Ramsay, 1980) and language
(McCall, 1979) suggest that these three ages are associated
with the acquisition of increasingly complex language and
lateralized motor behavior.

The second reason these ages were chosen is a more
practical one. These transitional periods during infancy
are also expected to show increased variability within the
9-, 13-, and 20-month age groups (McCall, 1979). According
to McCall, the continuous or discontinuous character of
developmental function is potentially independent from the
instability of individual differences (particularly during
the early months of life), which show less stability across
'stage' boundaries at 2, 9, 13, and 20 months of age. That
is, within-subject correlations of various behaviors are
greater between 'stage' boundaries than across them. It was
hoped that this design would allow us to take advantage of
this increased variability, in order to group infants
according to an early- or late-to-speak criterion, within
each age group. The extent of the association between
handedness and speech could then be determined within each
age group. Information about this relationship across age
groups will extend previous findings about the integration
of handedness and speech in infants. The clinical signi-

ficance for assessing communication development without

4
using speech as a necessary component could be especially
useful for the evaluation of children who lack normal speech
potential (e.g., cleft-palate infants).

Gestures were included in the current study in order to
promote a broader look at the development of communication
skill. The intent was also to address an issue that has
never been directly studied--whether the hand used for
gesturing is the same as the hand used for reaching and for
manipulating objects. Although it has been noted that
right-handed pointing, in particular, has been associated
with early vocalizations, it is not clear whether this pref-
erence is linked to eventual hand preference. The hope is
that this study will contribute to the increasing body of

literature linking handedness with speech development.

REVIEW OF THE LITERATURE

Earlnyateralization

One of the earliest behavioral expressions of lateral-
ization during the neonatal period is the asymmetric tonic-
neck-reflex (ATNR). The ATNR can be elicited by turning the
infant's head to one side, resulting in an extension of the
arm and leg on the face side, and flexion of the limbs on
the skull side (Vasella & Karlsson, 1962). The ATNR is
defined as a nonobligatory postural attitude that is assumed
when the infant's head is turned (Gesell & Ames, 1950).
Appearance of the ATNR is correlated with conceptional age
(Prechtl, Fargel, Weinmann, & Bakker, 1979; Fox a Lewis,
1982). It is first seen shortly after birth, peaks at about
6 - 8 weeks after birth (Coryell & Cardinalli, 1979; Coryell
& Michel, 1978), and declines thereafter until it's eventual
disappearance at about 4 - 5 months (Gesell & Ames, 1950;
White, Castle, & Held, 1964). The spontaneous ATNR shows a
similar developmental sequence.

As mentioned before, the ATNR is described as a whole-
body posture involving not only the head but also the limbs
in relation to the lateral position of the head. This is
distinct from those observations of head orientation that do
not necessarily take into account limb position. Although
it is clear that head orientation and ATNR lateral head

5

6
position are not the same (Liederman & Coryell, 1981), the
association between head orientation and later lateral pref-
erence has been shown (Coryell & Michel, 1978; Goodwin &
Michel, 1981), and an association between ATNR head position
and later handedness in early childhood has also been
reported (Gesell & Ames, 1947; Vivani, 1978).

Although this rightward bias persists, it may become
disassociated from the reflex mechanism governing the ATNR
because reflex-like movements appear first and are later
integrated into more complex patterns (Easton, 1972; McGraw,
1932). Rightward head orientation is thought to influence
lateralization, since movements occurring in the majority of
infants while their heads are turned right are less reflex-
bound than movements occuring while their heads are turned
left (Liederman & Coryell, 1981). Gesell and Ames (1947)
also note that the extended arm of the ATNR performs fewer
coordinated movements than the flexed arm.

Limb use during the first three months may result from
general postural asymmetry induced by the infant's supine
head orientation (Coryell & Michel, 1978). Since activity
is a crucial factor in learning (Rosenbloom, 1975), and the
right arm and hand of the infant are generally more active
than the left (Stubbs & Irwin, 1933), lateralization may
result from an initial bias combined with visual and motor
learning. Michel (1983) also believes that the ATNR may be
a factor in "producing lasting effects in the cortical

mechanisms involved in hand use. Early use and experience

7
may produce neural changes favoring the establishment of
preference" (p.28). He cites a report by Spinelli, Jensen,
and Viana DiPrisco (1980) that neural changes in cell-
monitoring processes between laterally-trained forelimbs
could be seen in kittens trained before 11 weeks of age, but
not in kittens trained after that period. Michel argues
that although the ATNR may be distinct from subsequent
lateralization, it may still be an important factor in
rightward orientation, eventually culminating in infant
laterality. The implication seems to be that there is a
period of change in organizational mode, not necessarily in
a gross neurological manner, but at some discrete level.
Thus, although the ATNR may eventually disappear, discrete
changes may have occurred that continue to bias infant
lateral orientation in the 'preferred' direction. In
addition, these periods of reorganization have been impli-
cated with other behavioral reorganizations occurring at
approximately the same time.
Transitional Postnatal Period

The first transitional period (2 months) is associated
with major transitions from reflexive to more voluntary
communicative and motor behaviors. The idea of a postnatal
period during which a transition from endogenous to exo-
genous control is accomplished has been addressed by Emde
(1983). He proposes that endogenous smiling is neuro-
logically organized at sub-cortical (mid-brain and brain

stem) levels (Harmon & Emde, 1972), declining at about the

8
time that exogenous smiling increases (smiling elicited from
outside stimulation). Harmon and Emde (1972) are convinced
that certain ages have associated with them new levels of
organization and modes of operation. The 'biobehavioral
shifts' are associated with changes in social, emotional
and cognitive processes, in sleep-wake cycles, and EEG
changes at around 2 months and again at about 7 - 9 months
(Emde, 1983).

In addition to the previously mentioned smiling
behaviors, voicing also undergoes a transition from endo-
genous to exogenous control. In newborns, voicing is
primarily associated with crying and fussing; in lesser
states of distress an infant has to struggle to voice at
all. As the infant matures, it is able to use voiced
sounds in non-crying states (Stark & Nathanson, 1974).

Stark (1978) suggests that features of cry-discomfort sounds
and vegetative sounds are incorporated into cooing/comfort
sounds. Cooing, like other early vocalizations, can be
maintained and increased in frequency by a socially respon-
sive environment (Ziajka, 1981). Trevarthen (1977) mentions
pronounced differences in infant responses to objects and
persons at 2 months of age.

Lateralized motor behavior also undergoes a change at
about 2 months of age (Michel, 1981). A preliminary
analysis of the data from the Infant Motor Skills Project

(Cornwell, et al., 1984) indicates a major transition in

9

head orientation behavior, after a lateral hold, between
one and two months. For this study, a second-by-second
recording was made of the infant's head orientation after
the head was held for 60 seconds in each of the following
positions; midline, left, right, and midline again (during
a 14 day, 1 month, 2 month and 3 month visit). At 14 days
and at 1 month, infants were more likely to maintain the
orientation of placement (for the next 60 seconds).
However, at 2 and 3 months, head orientation is less
controlled by prior placement (i.e., more symmetrical).
These findings agree with Michel's idea that head orienta-
tion declines rapidly after the second month, as does it's
effect on the neuromotor activity of the limbs (Michel,
1983).

Reaching behavior in infants shows some comparable
changes at about this time. Reaching in infants less than
1 month old was studied by DeFranco, Muir, and Dodwell
(1978), who found that early reaching was uncorrelated with
visual regard, differentiating this behavior from later
reaching. This later reaching (3-5 months) is described as
visually guided arm movements that bring the hand into
contact with an object (Coryell & Michel, 1978; Field, 1977;
White, Castle & Held, 1964). The infant also begins to show
a more voluntary lateral preference for reaching, although
some researchers report a left hand bias (Seth, 1971; Gesell
& Ames, 1947), whereas others report a right hand bias in

early reaching (Coryell & Michel, 1978; Hawn & Harris, 1984;

10

Bresson, et al., 1977). It must be noted that this dis-
crepancy and the apparent lack of continuity between earlier
lateralized behaviors and later reaching preferences may be
due to methodological factors, since continuity of behavioral
responses can be demonstrated only if eliciting conditions
are consistently defined, which is not always the case.

There have been a few studies, in particular, that
report the task-dependent aspect of lateral motor skill
development. Gesell and Ames (1947) noted that weak trends
in lateral preference are affected by stimulus properties.
For example, they found that 4-month-old infants were less
likely to reach for a small object and were more likely to
shift hands after an initial reach if the stimulus was large.
At 6 months, objects that were difficult to grasp or 'hard
to reach' were more likely to be approached bilaterally.
Adequate definition of reaching behavior also needs further
clarification, as right and left hands have been shown to
be preferred for handling and localizing, respectively
(Bresson, Maury, Peiraut-le-Bonniec, and de Schonen, 1977;
see also Young, 1977). Although preference might be
inferred in either case, object size, distance from the
infant, and interest value might affect the outcome (Seth,
1971; Field, 1976) as well as the individual preference
shown. For example, Gottfried and Bathurst (1983), in a
study with infants 18 and 42 months old, found that the hand
used for drawing was the most reliable measure of unimanual

hand preference. Consistency in approach may a factor in

ll
explaining why this task seems a more reliable predictor of
hand preference. It is worth noting here that writing is
one of the most lateralized skills for adults.

The relationship of vocal and motor development in
early infancy is not well understood. Tipps, Mira, and
Cairns (1981) discussed this relationship in terms of
general categories of motor and vocal responses. Tipps,
et al., studied infants from 3 to 41 weeks and found an
inverse relationship between the infant's repertoire of
motor responses and the variety and acceleration of
frequency of all vocalizations. In other words, an increase
in the infant's motor skill acquisition was accompanied by a
decrease in vocal activity, and vice versa. Although Tipps
and his associates found an inverse relation between motor
and vocal elements, their conclusions were based on the drop
in frequency of both speech-like and non-speech-like vocal-
izations at 13 to 18 weeks and at 30 weeks, with an accom-
panying increase in overall motor skill acquisition.

The specific developmental relation between infant
'handedness' and articulation during this period has been
addressed by Ramsay (1982). He suggests a possible reorgan-
ization in asymmetrical control of motor functions that may
influence the appearance of the first nonreflexive vocal
utterances. He also adds that in order to infer this, a
clear temporal correspondence between the decline of early
reflexive asymmetries and later unimanual preferences must

be demonstrated.

12
7 - 9 Month Transition

At approximately 7-9 months of age, another transition
in vocal and motor behavior is apparent. From the previous
vocal experimentation there now emerges more mature vocal
behavior and a more stable preference for mature reaching.
The infant also begins to actively imitate the consonant and
vowel syllables of adult speech (babbling). This more
sophisticated option is used by the pre-linguistic infant,
at this period, for interacting with significant adults
(Ziajka, 1981). Babbling begins at about 7 or 8 months,
which is also about the same time that unilateral preferences
emerge in a more stable form (Ramsay, 1982; Woolley, 1910).
Ramsay (1984) found a lack of unimanual skill in S-month-olds
(early reaching) and no hand preference, whereas reaching
preferences were apparent by 7 months. In other words, the
early development of a motor skill begins with unskilled,
motor behavior (not showing lateral preference), and proceeds
to a more skilled form of a similar motor behavior (with
lateral preference more apparent).

Currently there is little integrative research on the
development of early communication and handedness preference
during this time of early skill development. Yet the infant
begins to make gestures at about the time that hand prefer-
ence is developing. By gestures, I mean those intentional,
communicative actions (Stark, 1978) that may (or may not)
function to integrate nonverbal communication skills and

lateralized motor skills. A developmental milestone related

13
to early communication typically seen at this time is the
infant's ability to follow a point and look at an object
when a caretaker's hand and the object are in the same
visual field (Murphy & Messer, 1977). The infant is also
more likely to respond to gaze direction if the caretaker
uses a simultaneous gesture (e.g. point) than if the
infant's attention is solicited by gaze alone (Scaife &
Bruner, 1975). Masur (1983) argues that the infant's abil-
ity to combine at least two gestures (separately) with dual-
directional signalling precedes one-word speech.

Motor behavior also seems to follow an analogous
progression of skill development that has been associated
with early communication. Open-handed reaching begins at
8 - 9 months, with extension of objects and pointing
appearing somewhat later (Masur, 1983). Woolley (1910)
found right-handed waving (bye-bye) at 9 months in her
infant. Meyer (1911; cited in Harris, 1984) also discussed
the simultaneous appearance of babbling and right-handed
pointing preference. Meyer's findings also hint that
right-handed pointing may be somewhat independent of hand-
edness. An independence between gestural and reaching
preference would suggest that the development of speech may
bring about the use of the right hand, prior to and inde-
pendent from reaching preference. Baldwin (1890) also
expected that a synchrony in the development of speech and
handedness should be found, since they share a common

cortical system.

14

The first appearance of gestures is frequently without
vocal accompaniment (Masur, 1983). Although the data are
incomplete, a preliminary examination of a specific gestural
imitation task used in the Infant Motor Skills Project,
mentioned previously, shows that 96% of the infants first
waved 'bye-bye' without vocal accompaniment. Gesturing
'bye-bye' with vocal accompaniment followed approximately
2 - 3 months later (11 - 12 months), in these same
infants. Similarly, McCall (1979) notes that vocal
imitation generally lags behing gestural imitation.

Although a stage-like conceptualization is being
inferred, what needs to be accentuated is the sequence and
association of the specific attributes of motor and
communicative development mentioned. Since the time span
during which the infant moves from endogenous to exogenous
control of motor and communicative behavior (and thus its
environment) is a relatively short one, associations between
various aspects of this specialization that are clustered at
apparent junctures become important.

Other Transitions

McCall (1979) also proposes "potentially independent...
points of discontinuity in developmental function and...
nodes of instability of individual differences" (p. 193),
occurring at approximately 2, 7, 13, and 21 months of age
(these ages also roughly correspond to Piagetian sensori-
motor stages). At 13 and 21 months of age, however,

research is scanty concerning the relationship of handedness

15
and language. One reason for this, according to Nelson
(1979), is that from a linquistic point of view little is
accomplished from the time the first words are spoken (end
of the first year) to the combining of words into simple
sentences (beginning of the second year). Although gross
motor skills undergo rapid development at this time, unless
there is a focus on the development of communication and
language, an explanation of any possible relationship is
merely conjecture.

Ramsay (1983) is a strong advocate of the idea that
certain aspects of speech may be integrally related to the
development of lateral and bilateral hand preferences.
According to Ramsay, there is a developmental association
between speech (different consonant and vowel sounds across
syllables as opposed to multi-syllable expressions) and the
onset of preference for bimanual manipulation. Although
the developmental relationship Ramsay found in his research
was not a clear one, his findings warrant further explor-
ation. Dreifuss (1963) and Nice (1910) also postulated an
association between delayed speech and delayed recognition of
hand preference. However, a study comparing lateral pref-
erence and language skill (Treves, Goldshmidt, & Korczyn,
1983) in 12 to 36-month-old infants found no relationship
between the strength of right-limb preference and language
ability. Treves, et al. used a unimanual reaching task to
measure hand preference. Yet Ramsay's earlier work indi-

cated a specific developmental relation between unimanual

l6
handedness and duplicated syllable babbling, as mentioned
before. The apparent contradiction indicates the need for
clarification of the relationship between components of
language skill acquistion and motor skill development.

Other evidence bearing on the possible temporal
sequence of various aspects of the development of handedness
and the acquisition of language can be found in Bonvillian,
Orlanski, Novak, Folven, and Holley—Wilcox (1983).
Bonvillian, et a1. studied the acquisition of American Sign
Language (ASL) in normal-hearing children of deaf parents.
Rather than finding that the onset of non-linguistic
gestures (communicative pointing, showing, giving, and
ritualized requests) preceded the onset of language, they
found that the onset of signing and the use of nonlinguistic
gestures tended to co-occur (at about 9 months). Bonvillian,
et al. found an accelerated acquisition of sign language
vocabulary in the deaf children, meaning that speech may be
primarily a matter of motor coordination, once a certain
level of interactive understanding and intentionality has
been achieved. Their findings support those of Morford and
Goldin-Meadow (1983), whose research on the development of
the gestural and linguistic aspects of early communication
indicates that children may be able to combine two semantic
elements, gesturally, before their first two-word sentence.

The relationship of language to cognitive development
has been well-researched, yet it is difficult to interpret

the various findings since cognition and its behavioral

l7
concomitants are not well understood. Although the dev-
elopment of hand preference has been found to be related to
overall developmental status (Cohen, 1966), attempts to link
specific aspects of (Piagetian) cognition to language
acquisition have not been entirely successful (Corrigan,
1979). Bonvillian et a1. (1983) warn against the strict
reliance on cognitive precursors to explain the development
of language. For example, their own results did not
support Piaget's view that attainment of Stage VI functions
is necessary for language acquisition. To avoid the diffi-
culty of defining specific cognitive behaviors according
to task analysis and administration procedures, the current
research focused on more easily defined constructs (i.e. the
possible relationship of preferential hand use and rate of
language acquisition).

In order to enhance the validity of findings from the
present study, two measures were added to the design, as a
link to previous research in both language and motor skill
development. First, recognizing that the infant is not
independent of his environment, an environmental measure
(HOME) was included. The Caldwell HOME Inventory has been
shown to have predictive value for later language develop-
ment, independently of SES (Bradley, 1981; Silva & McGee,
1982; Wulbert, et a1, 1975; Siegel, 1982). Second, recog-
nizing the continuity between gestural and verbal means of
communication during the development of socio-cognitive

skills (Wilkinson & Rembold, 1981), a gestural measure was

18
also added. It was hoped that a gestural measure would
help bridge the gap between laterality and language research
by providing information about both handedness and communi-
cative ability for the infants in this study.

The subjects in the study were selected to meet certain
requirements: Female, familial right-handed, and without
birth complications. Girls were chosen for two reasons.
First, it was more practical to limit subject selection to
either boys or girls. Since girls have been shown to develop
language earlier than boys (Smith, 1926), girls would be more
likely to show a measurable language skill at the earliest
age used. Secondly, since Ramsay (1980) found the relation-
ship between speech and handedness to be stronger for girls
than boys, it seems reasonable to expect that the same would
be true for the predicted relationship between language and
handedness.

The original intent of the research plan was to limit
subjects to infants whose parents were both right-handed.
This decision was based on reports that familial handedness
is a relevant variable in the development of handedness,
such that infants with one or both parents left-handed show
a higher proportion of eventual left-handedness (Annett,
1972). It also is known that among adults, left-handers
generally show smaller behavioral asymmetries than right-
handers (Buckingham, 1984). Right-handers also are
considered to be a more homogeneous group with respect to

lateralized behaviors. For all these reasons, familial

19
right-handers were chosen. Unexpectedly, however, a high
proportion of left-handed parents replied to the request
for participation. Therefore, familial left-handed infants
were included in addition to the 15 infants tested in each
age group.

Finally, only infants were chosen who had no birth
complications, since it is known that birth complications
and prematurity are sometimes associated with developmental
delays (Sugar, 1977). Even though there may be an assoc-
iation between uncertain or slow to develop manual pref-
erence and delayed speech development, there are problems
in determining whether slow development merely constitutes
a normal variation or is actually pathological (Dale &
Ingram, 1978). To avoid this complication, variability
was investigated within a normal population. Thus, we avoid
trying to explain more qualitative differences between those
slow-to-acquire-language and those with developmental dis-
abilities in language acquisition. Clearly, this may be of
interest in future research.

In summary, the following predictions concerning the
association between language and handedness were proposed:

Prediction 1: Within each of the age groups (9-, 13-,
and 20-months), infants scoring in the upper quartile of
the language assessment will show a stronger hand preference
(right or left) than infants scoring in the lower quartile
of the language assessments. This would indicate that the

communicative element of language is closely associated with

20
strength of handedness preference. On the other hand, a
finding of no association between handedness and language
skills would indicate that it is only the motoric aspect of
speech that is associated with the development of lateral-
ized motor skills.

Prediction 2: Regarding the gestural measure (a
combination of both handedness and communication skills) it
is expected that within each of the groups, the frequency of
gesture use will be correlated with language scores. This
measure was also included as a pilot measure to help clarify
results stemming from tests of the first prediction, but
primarily to serve as a means of comparing research from
both language and laterality studies. In particular, it is
expected that the hand used for gesturing will be pre-
dominantly right, yet will not necessarily be associated
with the hand preferred for motor tasks.

Finally, a positive correlation will be expected
between HOME scores and language scores, as suggested by
previous research (Siegel, 1982).

In addition to these specific predictions, it was
hoped that the research would shed some light on the
following questions:

1) Which of the various unimanual tasks used will be a
more reliable predictor of unimanual hand preference at each
age tested?

and finally,

21
2) What is the relationship between unimanual and
bimanual handedness at each age tested? That is, does
unimanual handedness preference show within-subject
consistency with bimanual hand preference, given that very

different objects are used?

SUBJECTS

The sample consisted of twenty-two 9-month-old,
eighteen lB-month-old, and twenty-three 20-month-old
infant girls (total sample = 63). The names of
potential subjects were obtained from the birth
announcements in a local newspaper. A cover letter
explaining the study was sent to the parents. Parents
were contacted by phone if they returned a post-card
(enclosed with the letter), indicating that they were
willing to participate in the study. All infants in-
cluded in the study were free of birth complications
according to parental reports. Of the infants who were
included, forty-seven were familial right-handed and 16
were familial left-handed. Information about parental
handedness was obtained by using a shortened version (see
Appendix C) of the Edinburgh Inventory of Handedness
(Oldfield, 1971). The mean age of the mothers was 29.2
years (range 21-40 years), the fathers, 31.3 years (range
22-42 years). Mean number of years of schooling was 15
(range 12-20) for the mothers, and 15.5 (range 9-22 years)
for the fathers. The average family income was under
$30,000 (range <$l0,000 - >$50,000). All subjects came
from intact families with an average of 1.67 children

(range 1-3).

99

METHOD

Procedure

 

The data were collected during two separate sessions.
The first session, at the infant's home, was intended to
allow a more relaxed atmosphere in which to interview the
parents, and to view the infant in a natural situation. In
addition, by giving the infant an opportunity to get
acquainted with the researcher, it was hoped that the home
visit would lessen the possibility that the infant would
experience stress during the laboratory session (an un-
familiar environment). During the laboratory session,
language and handedness assessments were administered and
video-taped with a Sony Video Camera (AVC-325DX). Each
testing session was conducted when the infant was awake and
alert. Each session lasted approximately one hour.

Home visit

 

After introductions, the general purpose of the study
was explained. Parents were encouraged to ask questions and
informed consent was obtained. During approximately the
first half-hour of the session, the Caldwell HOME inventory
was completed (see Appendix E). The HOME is a 45-item
observation/interview procedure designed to assess the
quality and quantity of support for development available to

23

24
the infant in the home environment. Items are scored 'yes-
no' by the researcher, and are clustered into six subscales:

(l) emotional and verbal responsivity of the mother (or

primary caregiver),

(2) avoidance of restriction and punishment,

(3) organization of the physical and temporal environment,

(4) provision of appropriate play materials,

(5) maternal involvement with the child, and

(6) variety of daily stimulation (primarily contact
with relatives).

Items are scored on the basis of information obtained
by observation and semi-structured interview with the
infant's primary caregiver. During the interviews, attempts
were made to ensure that the caregiver was relaxed and
comfortable. The parents seemed comfortable with the
interview procedure and gave extensive descriptions of toys,
outings, and daily schedules of their infants.

Following the administration of the HOME, the caregiver
was asked to fill out a demographics questionaire listing
family composition, education, and general income. While
the caregiver was filling out the questionnaire the re-
searcher checked to see that the coding for the HOME was
complete.

During the entire visit (56% of all home visits) or
during a 15 minute parent/infant play session at the end of

the visit (44% of all home visits), spontaneous gestures

25
made by the infant were scored. The caregiver was encour-
aged to go on about the normal household routine (i.e., it
was not necessary to 'perform'). An observer was present
for recording gestures during 56% of the home visits. The
following criteria were used to score the infant's
spontaneous gestures (Masur, 1983):

l) Pointing to an object (extensions of the index finger
toward an object, excluding exploratory poking or
manipulation),

2) Extensions of an object toward the primary caregiver
(extensions of the arm in the direction of the
caregiver while holding an object,

3) Open-handed reaching toward an object (extensions of
the arm with the hand open, excluding movements that
are simply the first phase of grasping the object.

For each gesture, the following information was also recorded:
a) The identity of the object involved, if any,
b) The hand (or hands) used (left, right, or both),
c) Whether or not the gesture was accompanied by a
vocalization (except crying, burping, and sneezing),
d) Direction of the infant's gaze (toward a person
or object).
During the scoring of the infant gestures, caregiver was
instructed to go about their normal routine, as if no one
were present. None of the caregivers seemed uncomfortable

with the silent observation time, and they either played with

26
their infant or went about normal household routines. A
prepared form was used to code gestures (see Appendix F).
At the end of the home visit, arrangements were made to
have the infant infant and at least one parent come to the
laboratory for the second and final session.

Laboratory visit

 

The final session was conducted in the Developmental
Psychobiology Laboratory in the Psychology Research Building
at Michigan State University. The room was equipped with a
table, two chairs, a video camera, and a video recorder. At
least one of the infant's parents was present during the
testing session. The researcher sat across the table from
the infant and her parent. The video camera was placed
approximately 4 ft. behind and to the left of the researcher,
in clear view of the infant. The parent was instructed to
hold the infant on his/her lap and, during handedness
assessments, to hold the infant directly in front so that
the infant's shoulders were horizontal to the table edge.
During this session the various assessments of language and
handedness were given in the following manner (depending on
the interest and cooperation of the infant): Bimanual
handedness, Bayley items (unimanual tasks), and language
assessment (SICD). Order within and between tasks was
sometimes intermixed in order to maximize the infant's
attention, but the handedness assessments were usually given

first.

27
Unimanual handedness task
Four tasks taken from the Bayley Scales of Infant
Development (1969) were used to determine infant unimanual
hand preference:
Item 90 - 'puts cube in cup on command',

(The cubes were placed midline, one at a time)

Item 92 - 'stirs spoon in imitation',
(The spoon were placed midline, left, then
right, for 3 trials).
Item 111 - 'builds tower of 2 cubes' (3 trials), and
Item 118 - 'pegs placed (in pegboard) in 70 seconds'.

A crayon task was also used. For the crayon task, the
researcher first drew circles on a sheet of paper, alter-
nating the hand used for drawing, before placing the crayon
in front of (or beside) the infant. The crayon crayon was
first placed at the infant's midline (for the first trial),
then to her left, and finally to her right. The hand used
for the initial reach as well as the hand used to secure or
manipulate the object was scored for all the unimanual tasks
(see Appendix H2 for coding sheet).

Bimanual handedness task

The procedure used to assess bimanual handedness was
similar to Ramsay's (1979, 1980). Infants received a maxi-
mum of three trials (in order to obtain at least one
scorable trial), with each of four toys (a car-in-a-jar, a
nut-and-bolt, a ball-in-a-box, and a pinwheel). The hand

used for the initial reach as well as the hand used to

28
secure or manipulate the object was scored (see Appendix 12
for coding sheet).

The researcher first demonstrated each toy by alter-
nating active (manipulating) and inactive (holding) hands.
For example, the jar would first be held with the left hand,
while the right hand was used to pull off the top, and then
the process would be reversed. After each demonstration,
the toy was presented to the infant at midline, and she was
encouraged to handle it appropriately. Infants were class-
ified as right-preferring if they held the base of each toy
in their left hand while attempting to manipulate its move-
able portion with their right hand. Infants were considered
left-preferring if they attempted to manipulate the toy's
moveable portion with their left hand while holding it with
their right hand. Each trial ended when the infant attempted
either a right- or left-handed strategy or when she performed
some other action with the toy, such as shaking or mouthing
it. On any trial infants were credited with the use of
either strategy no matter how clumsy or successful their
attempt to manipulate the given toy. A clear hand preference
was assumed if the infant used a preferred strategy with all
four toys. If a preferred stragegy was used 3 out of 4
times, the infant was assumed to have a preferred, although
not necessarily a stable, strategy. It was also assumed
that the infant's bimanual handedness preference was not
developed if she used a right-hand strategy with half of the
toys, and a left-hand strategy with the remaining two toys

(or if she showed no consistent bimanual strategy).

29
Language assessment

The Sequenced Inventory of Communication Development
(SICD; Hedrick, Prather, & Tobin, 1975) was also given to
the infants during the laboratory session. The SICD
assesses the sequence of receptive and expressive communi-
cation development for children aged 4 months to 4 years.
The behaviors sampled are not necessarily linguistic but
are representative of early communication skills. The
instrument consists of two parts: an expressive measure and
a receptive measure. Factors of the receptive scale are
awareness, discrimination, and understanding. The behaviors
examined are motor responses to sounds or speech, and
parental reports of the child's motor responses to sounds
or speech in the home environment. Factors of the ex-
pressive scale include initiating, imitating, and responding
(communicative behaviors), and verbal output and articul-
ation (linguistic behaviors). Tests for expressive and
receptive behaviors are sequenced according to the chrono-
logical age at which at least 75 percent of the children
exhibit them.

Communicative behaviors examined also include assumed
levels of progression from motor to vocal to verbal. For
example, the child may first point to, touch, and/or mani-
pulate objects or pictures (motor response). Later, the
child may respond by uttering a sound or group of sounds
that cannot be classified as belonging to the linguistic

codes of the child's environment (vocal response).

30
Eventually, the child responds by uttering a sound or group
of sounds that can be classified as a word or words.

One of the advantages of the SICD is that it makes use
both of parental report and behavior in the testing situa-
tion. This allows for a reasonable one-time assessment of
language skills. This is different than the extended prep-
aration usually necessary to look at specific aspects of the
development of language. Familiarization of task require-
ments reportedly allows for more detailed information about
emerging aspects of language ability (Carolyn Mervis,
personal communication). Yet for the current study, our
need was to include a language assessment that would allow
comparison between individual infants of the same age. In
any case, the SICD, that is based on the development of
sequential communicative behaviors, could be very useful
for diagnostics with younger infants. Success or failure
patterns may suggest possible routes for assessment of
children without normal speech potential (e.g., cleft palate)
and for remediation of such problems (Hedrick et al., 1975).

The laboratory visit lasted approximately 1 hour, with
30 to 45 minutes for the language assessment, and approxi-
mately 15 minutes for the handedness measures. Afterwards,
the parents were thanked for their participation and were
reminded that they would be sent a copy of the general

results.

31

Analysis

Within each of the three age groups, it was hoped that
infants could be divided into three groups according to their
scores on the language assessment. That is, infants scoring
in the upper quartile (for their age group) would be placed
in the early-to-speak group (I), while infants scoring in the
lower quartile would be placed in the late-to-speak group
(III). An intermediate group (II) was to be formed by those
infants with scores midway between the extremes. An analy-
sis of variance then could be performed using the independent
variables of age and language group, with strength of hand-
edness as the dependent variable. This analysis would
determine whether the groups differing on language skills
also differ according to the strength of unimanual and bi-
manual preference. An additional analysis of variance was
planned to determine the association between strength of
handedness, gesture used, and language skill. However, the
original analysis plan was not deemed appropriate, since the
normally distributed language scores made equal or at least
reasonably close group divisions impossible. An analysis on
the basis of a median split was also inappropriate, since
infants scoring at the mode on the expressive language test
comprised 50-75% of each age group. The same was true for
receptive language scores, although the same infants were not
necessarily included in the modal groups.

Reliability for in-home gestural measures was obtained

by independent scoring using a trained observer (present

32

during 56% of the home visits). Reliability for overall
category (points, reaches, and extensions) was .77 (kappa)
and .81 (kappa) for each within gesture category (hand used,
object involved, looking direction). Since errors for over-
all category were errors of omission rather than of commis-
sion, gestures not scored by both observers were eliminated
from the within-category reliability analysis. Gestures for
the remaining 44% of the home visits were scored by the
researcher during a quiet time at the end of the visit.

Reliability for the in-lab measures was determined by
scoring 24% of the video-tapes using 2 independent coders;
unimanual (kappa = .92), bimanual (kappa = .87). All dis-

agreements for the bimanual coding were resolved by consensus.

 

RESULTS

Overview of results

The first prediction for this research was that
language ability would be positively related to the dev-
elopment of handedness preference. The results did not
support the prediction for all age groups. However, an
association between handedness and language was found for
the 9-month-olds. Analyses of gesture scores indicate that
the development of preferential hand use may serve as a
mediator of communication development in that, for the 9-
month-olds, language skill and development of preferential
hand use were related to gestural use. The second pre-
diction of the study was that there would be a link between
the development of gesture, language, and handedness. This
prediction, too, was supported only for the 9-month group.
The hand preferred for gesturing, however, was shown to be
not necessarily the hand that was preferred for reaching.
These results thus help to define the relationship between
handedness and language via an intermediary variable of
gestural skill.

Although unequal cell sizes did not allow statistical
comparison between the familial left-and familial right-
handed groups, a preliminary look at the data showed both

33

34
groups to be similar, on all of the variables and tasks used,
in this study. Therefore, the data were combined for all
subjects within each age group.
Unimanual handedness

To assess performance on the unimanual tasks, the
results from each infant's scores on the five individual
unimanual tasks were summed and converted to a laterality
score according to the formula, (R-L/R+L) X 100. In
addition, an overall laterality index was computed for all
unimanual tasks tasks combined (total possible observations
= 48) according to the formula, R-L/R+L.

The results showed that at every age more infants were
right- than left-preferring and that the margin of pref-
erence increased with age. Eleven of the infants in the
9-month group showed an overall right unimanual hand
preference, 10 showed an overall left preference, and 1
showed no preference for either hand. Twelve of the 13-
month-old infants showed an overall right hand preference
and 6 showed an overall left preference. All 23 of the 20-
month-olds showed an overall right unimanual hand preference.

The data indicate that the drawing task is a more
reliable predictor of overall unimanual handedness preference
than the other reaching tasks that were used. Intratask
correlations were computed in order to determine whether the
unimanual tasks used were reliable predictors of overall uni-
manual laterality preference. Table 1 shows the zero-order

correlations between laterality scores for each unimanual

35

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36

task used and the overall uni-manual laterality scores for
each age group. The significance levels reported for each
Pearson correlation coefficient are derived from the use of
Student's t with 2 degrees of freedom, one-tailed test. The
unimanual laterality index scores were significantly
correlated with the overall unimanual laterality scores at
13 months for each of the five unimanual tasks: r z .87;
r = .95; r a .69; r = .84; and r = .89. Correlations between
the individual tasks and the overall unimanual laterality
scores were significant only with the crayon task for all
of the 3 ages tested: r = .62; r = .84; and r = .67. The
laterality scores for the pegboard task were also signi-
ficantly correlated with the overall unimanual laterality
scores at 13 months (r = .89), and at 20 months (r a .73).
Bimanual handedness

Bimanual preference differs from unimanual (reaching)
preference in that bimanual preference indicates the degree
to which one hand is preferred over the other in a task
that requires two hands for successful manipulation. The
preferred hand is seen to be the one that manipulates,
rather than stabilizes an object in order to manipulate it.

Bimanual handedness scores were summarized two dif-
ferent ways. First, a laterality index was computed
(R-L/R+L) across all four of the tasks used, in order to
quantify direction of preference. Secondly, the following
ordinal coding scheme was used to summarize stability of

bimanual handedness (BIPREF):

37

0 - if the infant used no bimanual strategy (used only
only one hand for banging, manipulating, or grasping);

l - if the infant used a bimanual strategy but showed no
no preference for the right or left hand (in 50% of
the trials completed, a right-handed strategy was
used, whereas a left-handed strategy was used in the
remaining completed trials);

2 - if the infant showed a preferred but not stable bi-
manual hand preference strategy (four trials were
completed but only 3 were consistently right or left);

3 - if the infant completed only 3 trials (because of
parental interference or because the infant refused
to play with the toy) and all 3 trials were right or
all were left;

4 - if the infant showed a strong right or left preference
(all four trials were completed and all disclosed a
consistently right- or left-handed bimanual strategy).

Using this coding scheme, a strong, consistent right or left
bimanual preference would both be indicated by a +4.

Bimanual strategy use The developmental sequence shown
by this study indicates an increased percentage of skilled,
stable bimanual preferences in the older groups. In the 9-
month group, with one exception, infants either used no
bimanual strategy (10 infants) or had no preference (11

infants). The exception was an infant who showed a strong

38
right bimanual hand preference (she also had a strong right
unimanual hand preference). Generally, the lB-month-olds
first reached with one hand, and then used the remaining
hand to manipulate the toy(s). Ten of the 13-month infants
showed no bimanual preference, 6 showed a preferred but not
stable right hand preference, and 2 showed a strong right
bimanual hand preference. The 20-month-olds, in contrast,
reached with both hands simultaneously, with one hand grasp-
ing and the other manipulating the toy. In this group 5
showed a-strong right preference, 1 showed a strong left
preference, 10 showed a preferred but not stable right hand
preference, 3 showed a preferred but not stable left bi-
manual hand preference, and 4 showed no preference for
either a right or a left bimanual strategy.

Figure 1 summarizes these scores for the 9-, 13-, and
20-month groups by showing the percentages of infants at
each age using a bimanual preference or no preference--no
strategy. The percentages of infants with bimanual
preference/no preference as reported by Ramsay (1980) are
also shown in Figure 1 for comparison. The comparison
reveals that among the 13 and 20 month old infants in the
current study, the percentage of infants with a right, left,
or no bimanual strategy is similar to that found in the 14
to 16 and 18 to 21 month old infants in Ramsay's study.

Direction of bimanual hand preference To determine
whether lateral preferences from different handedness tasks

show within-subject consistency, correlations between infant

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40
unimanual and bimanual laterality indices were computed.
Responses to both tasks were correlated only for the 9-month
group (r z .67). The results from both handedness tasks
showed a non-significant correlation for the 13-month group
(r = .17), and for the 20-month group (r = -.10). These
findings may result from the 9-month group showing few
bimanual strategies, since they seemed to treat both tasks
in a similar manner (as a reaching task).
Language assessments (SICD)

On the language test (SICD), all 3 age groups generally
scored above the norm for their age. Normative data for the
SICD were obtained from sample of equal male and female
infants (Hedrick, et al., 1975). The 9-month group scored
an average of 11.8 months on the expressive scale (range
8-16 months) and an average of 9.27 months on the receptive
scale (range 8-12 months). The 13-month group scored an
average of 16 months on both the expressive (range 8-20
months) and the receptive (range 12-20 months) scales. The
20-month group averaged 23.1 months on the expressive scale
(range 16-32 months) and 22.1 months on the receptive scale
(range 16-28 months).

Overall the language scores were not significantly
related to strength of unimanual or bimanual handedness.

The one exception was a significant correlation between
unimanual preference and receptive language scores at 9
months (see end of section).

The relationship between language and the development

41

of bimanual handedness was analyzed by computing an analysis
of covariance with strength of bimanual preference (BIPREF)
as the independent variable, language scores as the
dependent variables, and age as the covariate. The results
showed a non-significant relationship between the strength
and consistency of bimanual handedness for both the re-
ceptive scale, F(8,63) = .89, ns.; and the expressive scale,
F(8,63) = 1.87, ns. An additional analysis of covariance
using overall unimanual preference as the independent
variable, language scores as the dependent variables, and
age as the covariate was also computed. Infants' unimanual
preference scores did not differentiate between the high-
scoring and low-scoring infants on either the expressive
scale, F(10,63) = .55, ns.; or the receptive scale,
F(10,63) T .55, ns. However, correlations between the
unimanual scores and the receptive language scores were
significant (r = .64), but only at 9 months. There were
no significant correlations between bimanual handedness
scores and language scores at any age.
Gestures

Gesture use for the 9-, 13-, and 20-month groups
indicates that extensions appear first, pointing later.
Reaching appears to be an early occuring and fairly constant
gesture across these ages. Figure 2 illustrates the general
findings regarding the percentage of points, extensions, and
reaches for each age group. The 9-month group made an

average of .18 gestures/minute. Of these gestures, 9% were

42

 

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infants.

 

43
points, 36.5% were reaches, and 54.5% were extensions. The
13-month group made an average of .63 gestures/minute. Of
these, 26% were points, 25% were reaches, and 49% were
extensions. The 20-month group made an average of .57
gestures/minute with 54% points, 36% reaches, and 10% ex-
tensions.

Not only did the frequency of gestures increase (between
9 and 13 months), the percentage of gestures in each
category showed differences between age groups. At 9 months,
there was relatively little pointing, and over 50% of the
gestures made were extensions. At 13 months, the relative
frequency of pointing increased, while the relative frequency
of extensions decreased. At 20 months, the majority of
gestures used were points and the relative frequency of ex-
tensions was decreased further. The frequency of reaching
gestures was relatively constant across each age tested.

A chi-square analysis was used to determine whether the
right/left differences between gesturing hand (for all
gestures) were significant, at each age tested. The results
revealed that for all 3 types of gestures combined, there
was a nonsignificant right preference at 9 months, x2(2,

N s 63) = .36, ns.), and significant right preferences both
at 13 months, x2(2, N = 63) = 12.96, p .001, and at 20 months,
x2(2, N = 63) = 24.01, p .001).

A chi-square analysis was also used to determine whether

there were significant differences between person/object

gestures at different ages. Table 2 shows the percentage of

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45

points, extensions, and reaches used by each age group, and
whether or not the infant was looking at the object involved
in the interaction or at a person's face (the family member
or experimenter involved in the interaction). At 9 months,
infant extensions and reaches were used more frequently while
looking-at-person, X2(l, N = 63) = 26.5, p .001, and X?(l,
N = 63) = 8.0, p .01, respectively. At 13 months, infant
extensions and reaches were used more frequently while
looking-at-person, X2(l, n = 63) = 24.5, p .001. At 20
months, there were more looking-at-person reaches than
looking-at-object reaches, X2(l, N = 63) = 9.0, p .01). There
were no significant differences between looking-at-person
and looking-at-object points for any of the age groups.

Infant gestures with vocalizations also showed a dev-
elopmental sequence of extensions, reaches, and points, with
a right-handed vocal component at every age. Table 3 shows
the percentage of right or left handed gestures that were
used with and without vocal accompaniment (chi-square
analysis also used). At 9 months, infants who vocalized
while either pointing or reaching showed no significant
right/left differences between points and reaches without
vocalizations. The same analysis for extensions, however,
showed significant hand differences, with the right hand
associated significantly more often than the left with
vocalizations, x2(l, N = 63) 325.92, p .001. At 13 months,

when infants extended or reached with the right hand, those

movements were significantly more likely to be accompanied

46

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47

by vocalizations than when the movements were made with the

left hand; x2(l, n = 63) = 14.99, p .001, and x2(1, n 63)
= 18.2, p .001, respectively. The 20-month-old infants used
more right-handed points with vocalizations, x2(1, N = 63)
= 30.01, p .001). There was an increase in right-handed
points accompanied by vocalizations, and little change in
right/left differences in points without vocalization, in
each subsequent age group.
Interrelationships between gestures, language and handedness
A significant relationship was shown between gestural
use and language overall, but this was explained primarily
by right-handed gestures that were accompanied by a vocal-
ization. The high frequency of right-handed gestures was
not necessarily related to infant hand preference, however,
since hand preference for gesuring, as shown by using the
laterality index, was not significantly correlated with
overall unimanual hand preference. Correlational analysis
showed that frequency of overall gesture use was related to
language ability (expressive (r = .28), receptive (r = .35))
overall groups, yet no such association was found in any of
the groups individually. Assuming that a more specific
aspect of gestural behavior must be responsible for the
overall association found, correlations between gesture
types (including hand used) and language showed that the
relationship was specific to right-handed vocal pointing
(expressive r = .40, receptive r = .45). At 9 months,

there was also a significant association between unimanual

48

hand preference and the number of points used (r = .34).
HOME scores

The final component of this research is concerned with
the relationship between HOME scores and language skill. On
the 45 point HOME, the average score was 40.67 (range 34-45).
An analysis of variance, using receptive and expressive
scores as the independent variables and overall HOME scores
as the dependent variable, showed a nonsignificant relation-
ship between the receptive score and the HOME score, F(ll,63)
= .53, ns. SICD scores and the individual HOME sub-scales
indicated a significant correlation between expressive
language scores and HOME subscale l (emotional/verbal
responsivity of the primary caregiver) at 9 months (r = .62),
and between receptive language scores and HOME subscale 5
(maternal involvement with the child), also at 9 months (r =
.58). HOME subscale 6 (variety of daily stimulation) showed
a significant negative correlation with expressive language
scores at 20 months (r = -.44). There were no other signi-
ficant relationships between SICD scores and individual HOME

subscales.

DI SCUSSI ON

The results of this study indicate a developmental
sequence of increasingly skilled motor behaviors, with
unimanual skills preceding gestural use and bimanual pref-
erence. The 9-month-old infants showed primarily right-
preferring unimanual handedness with either no bimanual
strategy or no bimanual preference (the one exception will
be discussed later). Gestures at 9 months were primarily
reaches and extensions, with and without vocalizations, and
with little bias for either the right or left hand. The
20-month-old infants, on the other hand, showed a higher
percentage of consistent right-preferring bimanual strate-
gies, with an increased incidence of right-handed gesture
use (particularly pointing) overall. These findings agree
with Baldwin (1890) that handedness is "a form of expres-
sive differentiation of movement" (p.66), which precedes
and is less complex than speech, and yet performs a similar
function (to enable increasing control of the environment).
Indeed, in the current study, gestures appeared in the
infant's behavioral repertoire before speech and also
seemed to perform a similar function (control of the
environment).

In addition, communication ability also showed a
developmental sequence. The properties of the instrument

49

50
(SICD) are such that a sequence of motor to vocal to verbal
behaviors was expected and was found. That is, the 9-month-
old group's language scores were more dependent on respond-
ing and initiating behaviors (motor) than were the 13- and
20-month groups' scores, which included both motor and
verbal behaviors. Overall, the SICD scores were generally
higher than expected, which may be partially explained by
the fact that the subject selection process was generally
biased towards a higher socio-economic group and higher
educational backgrounds. The selection process was biased
in that parents, who were sent letters of introduction,
were selected on the basis of geographical closeness to
Michigan State University (from a pool of new parents in
the Lansing/East Lansing area). In addition, the fact that
all of the infants were female made it likely that the
language scores for the group as a whole would exceed the
SICD norms, that were based on data from both sexes, since
girls generally outpace boys in language acquisition
(Schachter, et al., 1978). Scores for the 9-month group,
however, were at the norm for the receptive language scale,
a finding that cannot be explained by the previous argument.
It may be that the 8-12 month receptive language items (SICD)
are especially appropriate for both male and female infants
in this age group, because of the high reliance on product-
ive responses to stimuli that comprise the earlier items of

the receptive scale.

51

The predicted relationship between handedness and com-
munication skills was confirmed for only the 9-month-olds.
The inclusion of gesture and language use measures was based
on the assumption that all three skills show a high degree
of lateralization and so should be highly inter-correlated.
The 9-month group did show associations between receptive
language, unimanual handedness preference, and frequency of
gestures, but the 13- and 20-month groups did not. This
finding is consistent with the 'focal periods hypothesis'
(Blank, 1964) that handedness development precedes from
highly correlated behaviors (focal period) to decreasing
correlations between various tests of hand skill.
Similarly, this hypothesis may be extended to other earlier
lateralized behaviors and to the associations between them.
Indeed, as the potential for experience to influence
behavioral outcome becomes more prevalent the association
between language and handedness may weaken.
Handedness

Across the 9-, 13-, and 20-month age groups, unimanual
hand preference preceded bimanual preference, a finding con-
sistent with previous research (Ramsay, 1979; 1980). The 9-
month group demonstrated unimanual preferences for reaching
and grasping but did not show consistent bimanual strategy
use. The 13-month-old infants also demonstrated unimanual
preferences, and a greater percentage of consistent bimanual
strategies, than did the 9-month group. All of the 20-month

infants showed a unimanual preference, and most showed a

52
clear, consistent bimanual preference. In addition, bi-
manual strategies in the 20-month group were generally more
skilled than those shown by the lB-month-old infants; that
is, the strategies used by the 13-month-olds appeared to be
discovered almost by accident, whereas the strategy used by
the 20-month-olds seemed more purposeful. As mentioned
before, the older infants approached a bimanual toy with
both hands, with hands generally assuming a more adult-like
grasp (one hand on the top of the jar and with the other
hand stabilizing the body of the jar, for example).

As expected, older infants showed a greater consoli-
dation of use of the right hand for reaching. Bimanual
manipulation preference showed a similar sequence that
lagged behind reaching-hand preference, which is consistent
with the idea that simple tasks are mastered before more
difficult ones. In addition, results from the unimanual
and bimanual tasks indicate that 9-month-olds may approach
both tasks in the same manner, whereas older infants may
show different and more task-dependent approaches.

The 9-month-o1d infants showed similar hand pref-
erences in both the unimanual and bimanual tasks, whereas
the 13-, and 20-month-olds showed different hand preferences
for each task. The fact that unimanual and bimanual scores
were highly correlated at 9 months, but were unrelated at 13
and 20 months, may have implications for recurrent questions
about the development of handedness. Several studies have

shown that hand preference fluctuates during the early

53
months (Liederman, 1984; Gesell & Ames, 1947). Sometimes
there is a reported shift in hand preference (Ramsay, 1979),
while others show periods of left preference for certain
tasks preceding the appearance of right-hand preference
(Hawn & Harris, 1979). One explanation may be that dis-
agreements in results are a product of the scoring criteria
used as well as differences in the age of the infant tested
(as related to skill development).

The pattern of correlations found, between unimanual
and bimanual laterality scores, may reflect the increasing
ability of the infant to differentiate between tasks.
Initial reach is considered to reflect hand preference in
most age groups (Scaife & Bruner, 1975), yet the definition
of a reach might depend on the competence level of the
child. For example, at 9 months of age an infant's one-
handed reach to localize or obtain an object is most likely
not the same as a one-handed reach at 13 months, since the
older infant's behavior may be part of a task-dependent
strategy with a more skilled manipulative component. Thus,
depending on the infant's competence level, a reach might be
performed for increasingly complex strategies of motor
skill. Bresson and his colleagues (1977) found that right
and left hands are used primarily for handling and local-
izing, respectively. It may be that 9-month-olds approached
both handedness tasks in this study as 'localizing' tasks,
whereas the lB-month-olds may have begun to differentiate

between tasks. The 20-month-olds would then be expected to

 

54
show a relatively higher differentiation between unimanual
and bimanual tasks. The pattern of correlations between
the unimanual and bimanual laterality scores found agree
with this hypothesis of an increasing ability for older
infants to differentiate between both tasks, an indication
of greater skill.

Developing a new skill is decidedly more difficult than
performing an already acquired skill. With older children,
Steingruber (1975) has shown that as task complexity
increases, the differences between the hands becomes more
apparent. A similar argument may well apply in the case of
hand use in much younger children during the time when
skills are still developing.

This age-dependent difference in competence and strat-
egy use was most apparent in the l3-month-old infants, who
seemed to be in the process of developing a bimanual handed-
ness skill (see also below). Thus, the hand used (by an
infant) for an initial reach was not necessarily the hand
eventually used for manipulating the object. Yet both uni-
manual and bimanual preferences and strategies are an
integral part of the infant's developing motor skills. In-
asmuch as skills are well-learned strategies for efficiently
accomplishing goals (Kelso, 1982), it follows that adjusting
motor strategies in a task-dependent manner would be an
important part of skill building.

Previously noted 'shifts' in lateral preference might
also be a manifestation of the development of these context-

dependent motor strategies, since the definition of a task

55
depends not only on the characteristics of the stimulus but
also on the characteristics of the infant (age, experience,
interest). This can be illustrated by the sequence of bi-
manual handedness development that was apparent in the
current data. At 9 months, bimanual tasks were approached
in the same manner as the unimanual tasks, with one hand
used for reaching and exploring while the other hand was not
used (and did not usually touch the object). The l3-month-
old infants generally reached for and grasped the object
with only one hand initially, and then the remaining hand
was used for either holding or manipulating the object.
Most of the 13-month-olds who used a bimanual strategy did
so somewhat inconsistently. At 20 months, the infants used
a more consistent bimanual strategy. Generally, infants
reached with both hands simultaneously, with one hand
stabilizing (holding) the object and the other hand mani-
pulating it (twisting, pulling, turning).

The sequence of increasing bimanual strategy use and
consistency closely follows Ramsay's findings (1983).
Ramsay found the earliest, consistently right or left bi-
manual strategy to occur at 10 months. In the current
study one 9-month-old infant demonstrated an unskilled yet
consistently right-handed bimanual strategy. This infant
should be considered to be at one end of a continuum, with
age of onset showing considerable variation. Also, as
illustrated, a comparison of 13- and 20-month-olds (in the

current study) and infants in Ramsay's longitudinal study

56
indicates similar percentages of infants with a right, left,
or no bimanual strategy, a further validation of the current
findings.

Stability in hand preference has been previously shown
to be achieved at about the same time (approximately 1 year)
that infant object handling resembles the more purposeful
adult object handling (Gesell & Ames, 1947). Measuring
handedness on the basis of a prototypical adult model of
skill building may be problematic since purposive behavior
is not constant across development. Clearly, tasks that are
likely to show the most consistency across time are those
whose task dimensions are likely to be perceived as similar
by different age groups. That is, those tasks with the
least potential variability in behavioral response should be
the tasks that are the more reliable indicators of handedness
preference.

Reliability of unimanual handedness tasks Analysis of

 

within-task reliability scores reveal that the crayon task
(drawing) was the most reliable predictor of unimanual hand
preference. Failure to find a significant relationship
between the overall unimanual laterality scores and some
individual task scores agrees with Gesell and Ames' (1947)
suggestion that hand preference may be task dependent. The
tasks involving the spoon or the blocks, in particular, were
not reliable predictors of overall unimanual preference. The
intra-task correlations also indicated that some tasks are

better than others at measuring lateral preferences. In

57

particular, the crayon task proved to be the most reliable
predictor of overall unimanual preference at each age tested.
These results extend the findings of Gottfried and Bayhurst
(1984), who found that drawing hand was the most reliable
predictor of hand preference in 18- and 42-month-old infants.
Although the 9-month olds in the current study did not
attempt to draw with the crayon, but rather simply grasped
and mouthed it, the strength of their unimanual preference
is consistent with the preference scores reported by
Gottfried and Bayhurst.
Handedness and communication skill

The 13- and 20-month groups' scores for hand use and
frequency of gesturing showed no association to either
receptive or expressive language scores. The fact that
the strength of unimanual and bimanual handedness was not
related to language skills at 13 and 20 months agrees with
research by Treves, Goldshmidt, and Korczyn (1983), who
found that strongly right-handed infants are not necessar-
ily more advanced in either their expressive or receptive
language development. Using regression analyses with age
and language scores, they found that scores for children
with a right-sided preference were practically identical to
language scores of children without a clear hand preference.
However, Ramsay's (1980) research, which shows a relation-
ship between bimanual handedness and multi-syllabic babbling
(i.e., one-word stage), does not seem to agree with the

current findings or with the Treves et a1, study. However,

58
Ramsay does not contend that bimanual handedness is related
to the development of 'language', but rather to advances in
certain motoric aspects of speech. That is, ”advances in
articulatory control reflect advances in finely tuned
sequential motor activity" (Ramsay, 1984, p.162), which in
turn may be related to left-hemisphere specialization and
therefore to the speech act.

Clearly, if the underlying component of the relation-
ship between language and handedness is the motoric
component, then it makes sense that the relationship
between handedness, language scores, and gestures would be
more apparent at 9 months, when these skills are emerging,
than at 13 or 20 months when they are more established.

At 9 months, SICD scores were more dependent on motor
responses. Gesturing, another motor response, seems to

play an important role in early parent/infant communication,
especially since speech has not yet begun to develop at

this time. The 13-month and 20-month-old infants, whose
language scores were dependent on both motor and verbal
components, may not have shown the same association because
of a divergence of the gross motor and fine motor components
of language skill. These results may be in part a reflec-
tion of the developing competence of the infant. If so, the
crucial difference between assessments may be that, at 9
months, infants are still so generally incompetent that
manipulatory, gestural and speech acts are highly inter-

dependent. However, by 13 months and beyond, communicative

59
ability, handedness, and speech have reached a level such
that increasing differentiation is required for optimal
development.

The fact that the SICD is constructed to measure a
general communicative ability may have contributed to the
pattern of results found. The SICD was developed to test
even very young infants (4 months), and especially as a
diagnostic tool, and so does not use a primarily verbal
criterion (in contrast to the majority of language assess-
ments). For these reasons, I consider the SICD to be a
very useful tool for assessing overall language ability.

By overall language skill I include other general skills
used for communication in addition to the skills trad-
itionally measured. Vocal output (speech) and behavioral
indications of speech comprehension are also included.
Language skill is thus seen as including the total system
of communication ability, including verbal output
(linguistic behaviors) and initiating and responding
(communicative behaviors).

The definition and assessment of language as including
both communicative and verbal behaviors is high-lighted by
the work of Volterra and Caselli (1983) who contend that
communicative and linguistic development proceeds according
to a similar timetable for hearing and deaf children. They
indicate that a slight advantage may occur (for gestural
motoric elements) in the early stages of language develop-

ment, since the neuromuscular functions that control the

60

hands mature earlier than those that control the vocal
apparatus. According to Volterra and Caselli, this could
explain why both hearing and deaf children use gestures
early for intentional communication. This argument may
also be extended further to explain the positive association
between communication and motor skill, as a function of the
neuromuscular maturational timetable for the development of
motor functions, at the earliest age tested (9 months). At
13 and 20 months, however, at about the time of early
speech, no such association was found.
Gestures

A unique feature of the current study was that it
assessed the hand used for gestures as well as the actual
gestures used. The sequence of gestural development
indicated that extensions and reaches preceded pointing
behavior. Leung and Rheingold (1981) also found that
reaching developed earlier than pointing. They estimated
that the age when 50% of infants can be expected to point
was 12.56 months. Although the present study did not
address that issue, the temporal sequence reported by Leung
and Rheingold fits the current data. Masur (1983) found
open-handed reaching in infants by 8 or 9 months, with
extending and pointing appearing somewhat later. Mean age
for first appearance of pointing in his study was 12.25
months. Frequency of reaching behavior was fairly constant
across the 9-, l3-, and 20-month period.

The current study also found that the hand used for

61
gesturing changed across age groups. The developmental
sequence of extensions, reaches and points, from 9 to 20
months, also show a right-handed vocal component at 9, l3,
and 20 months, respectively. In addition, the previously
mentioned sequence of gestural development showed an
additional right-handed vocal component for the gesture(s)
used most frequently at each age period. For example, at
9 months, right-handed extensions were accompanied by a
vocalization more often than left-handed extensions at
either 13 or 20 months. At 13 months, right-handed
extensions and reaches were both accompanied significantly
more often by a vocalization. The 20-month-old infants
used more right-handed points with vocalizations than left-
handed points accompanied by a vocalization.

This right-handed component of gesturing was indepen-
dent of unimanual or bimanual preference. That is, the high
proportion of right-handed gestures was not a direct re-
flection of hand preference for manual skill. This right-
handed vocal component of gestures has not been studied
adequately and warrants further research. If early commun-
icative vocalizations are accompanied by right-handed
gestures, as this study suggests, then this bias may be a
reflection of the reorganizations of left hemisphere spec-
ialization for the sequential aspects of language and motor
skills.

The current study agrees with other reports that

gestures are an early communicative skill that precedes

62
'language'. In a longitudinal study with infants from 9.5
months to 12.5 months of age, Bates et a1. (1979) found
that production of pointing, as well as ritualized re-
questing gestures (open-handed reaching) and two kinds of
object extensions (giving and showing), were significantly
correlated with each other and with several measures of
receptive and productive language behavior. The current
data agree with Bates et al., since at 9 months a similar
result was found. However, this study does not indicate a
correlation between language and gestures used beyond the
age period studied by Bates and her colleagues, since
gesture use was correlated with language at 9 months but
not at 13 and 20 months.
Gestures with Vocal Accompaniment Gestures were used with
and without vocal accompaniment by all 3 age groups. This
finding agrees with Bates et al.'s conclusion (1975), that
the infant's earliest communicative intentions are expressed
gesturally before they can be encoded in conventional verbal
symbols. Open-handed reaching toward an object has been
considered a "proto-imperative" (Bates et al., 1977) whose
object-requesting function is later expressed in verbal
directives. This is also reflected in general observations
taken from parental replies to the SICD questions about
their infant's use of consistent sound combinations for
objects. Some parents said that although their infant did
not use any sound combination that resembled a 'word', in

respect to particular objects, many times the infant

63
vocalized "eh" while simultaneously reaching or pointing,
particularly for the l3-month-o1d group. This finding
agrees with Bates, who suggests that extending objects
toward others forms part of giving, showing, and exchanging
rituals that come to include verbal elements (Bates et al.,
1979).
Looking behavior accompanying gestures Results of the
current study concur with the finding that looks at mother
and looks associated with vocalizations are not predictive
of later communication ability (Masur, 1983). Looking
behavior, as defined in this study, was not shown to
differentiate between age groups. Although dual-directional
signaling information was not observed in the current study,
Masur (1983) found that verbal accompaniments appeared with
gestures only when the infants had mastered dual-directional
signaling. Dual-directional signalling is the ability to
combine a look-at-mother and a gesture directed toward an
object (when object and mother are separated by at least 90
degrees relative to the infant). In the current study,
direction of infant looks was the only looking behavior
scored, yet these results concur with the finding that there
is a qualitative difference between an infant's gaze toward
mother (person) which may primarily be an indication of
preference for looking-at-person, and dual-directional
gestural signaling that involves the coordination of di-
vergently directed signals (Masur, 1983). Masur found that

only the emergence of truly dual-directional signaling had

64

predictive value for language development. Indeed, the
present study found no relationship between looking behavior
and either receptive or expressive language scores.

Consequently, although looks-at-mother are uSually seen
as an indicator of communicative intent (Harding & Golinkoff,
1979; Leung & Rheingold, 1981), looks-at-mother, may serve
a more fundamental social purpose instead. Leung and
Rheingold (1981) also describe pointing, for example, as
a social gesture (looking while pointing). In their study,
even the two points by the youngest child (10.5 months) were
described as social in nature, one being accompanied by a
vocalization, the other being by a look at the mother. The
implication is that before a gesture can be considered an
early communicative attempt, it must include both a vocal
and looking-at-mother component. Goldminz (1984), in her
longitudinal study of infants 6-12 months and 9-15 months,
defined intention to communicate a request in terms of the
relative frequency of looks-at-mother versus not looking at
mother. She found an 'intention to communicate', or the
occurrence of simultaneous looking and vocalization, already
present at 6 months. However, a preference for looking at-
mother's-face in acts of communications was demonstrable
only by 10 months of age. Her study also illustrates the
difference between looking-at-person as a social gesture and
looking-at-person as a demonstration of a developing

intention to communicate.

65

Masur (1983) found that early gestures first appeared
without vocal accompaniment. In Masur's study, vocal
production was related to age, such that 37% of gestures
made included vocalizations at 9-12 months, 69% at 13-15
months, and 72% at 16-18 months. The current study did not
find a comparable increase of gestures with vocalizations,
with 21% of all 9-month gestures, 24% of all 13-month
gestures, and 24% of all 20-month gestures made with an
accompanying vocalization. The conflicting results from
these two studies may be a reflection of the difference in
looking behaviors coded, such that bi-directional looking
with gestures may be increasingly accompanied by a vocal-
ization (right-handed, perhaps), whereas looks-at-mother
are not shown to reflect development of communication skill
directly.

Although this study did not consider the emotional
tone of the vocalizations that infants used with gestures,
Leung & Rheingold (1981) found that demanding vocalizations
were more often associated with the infants' reaches,
whereas positive vocalizations more often accompanied points.
Clearly, a more detailed, longitudinal study looking at
emotional content of early gestures, vocalization, looking
behaviors, as well as the hand used, would be an important

contribution.

66
HOME

The final component of this study looked at the
relationship between HOME scores and language skill. In
contrast to previous research showing the HOME inventory to
have predictive value for later language (Bradley, 1981;
Silva & McGee, 1982; Wulbert, et a1, 1975; Siegel, 1982),
the data from the current study did not show a strong
correlation between HOME scores and language skill. Again,
the 9-month group did show a correlation between 2 subscales
of the HOME and language scores. Expressive language scores
were associated with higher emotional/verbal responsivity of
the primary caregiver (subscale 1), and receptive language
scores were associated with higher Maternal involvement with
the infant (subscale 5), but only at 9 months. These
findings closely parallel those found by Bradley (1981).

The slight overall association between HOME scores and
overall language development might be considered as part of
a small effect that, over a longer period, might have a
cumulative effect on language and cognitive development.
Indeed, most studies that report associations between HOME
scores and language (in normal populations), are longi-
tudinal designs that assess the environment (HOME) during
early infancy and correlate this information with language
or cognitive assessments beyond the second year of life
(Siegel, 1972).

Mother responsivity may be more influential to the

infant's developing competence, and an influence that

 

67

weakens with time. A study by Penman, Meares, Baker &
Milgrom-Friedman (1983) indicate that synchrony in
mother-infant interaction (synchronization of activity
levels and cycles of engagement and disengagement) in the
early months, have a positive effect on infant responsivity.

Since infant responsivity is linked to cognitive
development (Siegel, 1982), it is reasonable to expect an
association between maternal responsiveness and developing
infant competence. Penman et a1. (1983) found a significant
correlation between neonatal responsivity to stimuli and
three measures at 3 months: motor maturity, maternal
stimulus screening capacity and the nature of the mother-
infant interaction. They also found that infants who were
more socially responsive and attentive to stimuli had
mothers with a greater capacity for 'screening out'
redundant stimuli. Similarly, Klaus and Kennell (1976)
also report that maternal sensitivity to infant cues
appears related to the overall cognitive development of
young children. The finding of a negative association
between receptive language and HOME subscale 6 (variety of
daily stimulation) at 20 months is difficult to interpret,
however. Perhaps 20 month old infants require a more
restricted and stable audience with which to practice newly
acquired vocal abilities. Again, the need for longitudinal
work on the changing relationship of these issues is very

apparent.

68

Conclusion

 

Unimanual handedness was shown to develop earlier than
bimanual handedness, as were early gestural skills shown to
develop earlier than other language elements (communica-
tion/articulation). That is, these data indicate that the
development of unimanual handedness precedes the development
of gestural communication and language. Although the
9-month group showed a correlation between strength of uni-
manual handedness, gestural skills, and language development,
the 13- and 20-month groups did not show the hypothesized
association. Language skill at 9 months was found to be
more dependent on communicative behaviors (initiating,
responding) than on speech behaviors, whereas language
scores at 13 and 20 months were dependent on articulation
as well as communicative skills. All 3 measures of
handedness, language, and gesture use were associated only
at one time period (9 months) and not at the other two (13-
and 20-months). Although unimanual handedness precedes
vocal language, both are associated with communication
intent and development, particularly at 9 months. At 13
months, the vocal and manual aspects of communication
separate so that one-word utterances and bimanual skills
emerge independently (and are more behaviorally separable).
Only future research can tell us whether a similar
association might be found at an earlier 'transition', at
2 months, for example. Research by Cornwell et a1. (1984),

together with work by Trevarthen (1977), suggests that

69
such an association might be found. Both a transition in
lateralized motor behavior (head orientation) and in early
communication occur at about 2 months. A positive assoc-
iation between early communicative behaviors and early
lateralized motor responses, such as that found in the
current study, indicates that an even stronger association
should be found at 2 months. The additional question of
whether lateral biases and communicative behaviors are
similarly associated in the same infant can be answered
only by longitudinal research.

Gestural skills were found to develop in much the
same integrated manner as were handedness and language.
Thus, gestures appear intermediate to unimanual and bi-
manual motor skills, and also intermediate to early
social skills and later behavioral expressions of
communicative intent (speech). Gestural development at
9 months was related to communication ability and uni-
manual handedness, but the 13- and 20-month groups, however,
did not show a similar association. As mentioned before,
this could mean that at 13 months the communicative and
manipulative functions of handedness, speech, gesture, and
communicative language may begin to show more between-skill
variation in development.

The only significant positive correlation between
language scores and HOME scores was also at 9 months. One
explanation for the fact that 2 of the HOME subscales of

the HOME were correlated with language scores (also at 9

 

70

months), might be that before the average age of walking
the infant's responsiveness to the environment is inex-
tricably related to the behavior of the primary caregiver.
Communicative behavior at this time may be partly a
reflection of the responsiveness of the caregiver. Beyond
this period, given the infant's new mobility, language
behavior may not be affected by environmental correlates
in such a direct manner. Yet the cumulative effect of a
less-than-optimal environment becomes apparent at a later
age (Siegel, 1972). i

The current study points to the need for a longitudinal
investigation of the development of language and handedness.
Particularly useful would be extensive study of hand
preference for gesturing and how that preference is related
to handedness and both linguistic and nonlinguistic vocal

behaviors.

 

APPENDI CES

APPENDI X A

Research Description Letter

71
Research Description Letter

Researchers in the Developmental Psychobiology Labora-
tory at Michigan State University are conducting a study of
the development of handedness and language, in normal,
healthy infants. We are looking for parents of babies 9
months, 13 months, and 20 months of age, who would be will-
ing to help us.

As a participant in this study, you will be asked to
answer questions about parental handedness as well as some
family background information. The study will consist of
two one-hour periods, the first being an interview with you
and your child, in your home. The final testing period,
within the week, will be conducted in the Infant Research
Laboratory at the University. At this time your child will
be given several tests for assessing handedness and language
skills. This final session will be videotaped (for viewing
later).

This letter is to inquire whether you might be inter-
ested in participating in this research. I would like to
add that strict confidence and anonymity are assured. If
you have any further questions or would like to participate,
please call Karen Cornwell at 353-3933 or 353-6468. If I
am not immediately available, please leave your name and
phone number, so I can contact you to answer your questions
or to arrange an interview. If you wish you may simply
return the enclosed card.

Thank you.

APPENDIX 3

Parental Consent Form

72

Michigan State University - Department of Psychology

CONSENT FORM

 

1.

I have freely consented to take part in a scientific
study being conducted by Karen Cornwell, a graduate
student, under the supervision of Drs. Hiram Fitzgerald
and Lauren Harris, Professors of Psychology at Michigan
State University.

The study has been explained to me and I understand the
explanation that has been given and what my and my
child's participation will involve.

I understand that I am free to discontinue our parti-
cipation in this study at any time without penalty.

I understand that the results of the study will be
treated in strict confidence and that we will remain
anonymous. Within these restrictions, the general
results of the study will be made available to us at
our request. I also understand that no video tape
demonstrations will be made without my further written
consent.

I understand that my participation in the study does not
guarantee any beneficial results to me or to my infant.

Signatures:

 

Mother

 

Father

 

Date

APPENDIX c

Parental Handedness Questionnaire

 

PLEASE NOTE:
Copyrighted materials in this document
have not been filmed at the request of
the author. They are available for
consultation. however, in the author's
university library.
These consist of pages:
Appendix C, page 73
Appendix Gl,_pages 80-84

Appendix 02, pages 85-90

 

 

 

 

Universty'
Micro ilms
lntemational

300 N. ZEEB 90., ANN ARBOR, Ml 48106 (313) 761-4700

APPENDIX D

Demographics Questionnaire

74

Subject No.

 

Date
Age

Sex

 

FAMILY DEMOGRAPHICS
PARENT INFORMATION

*Note - Please fill out this Information sheet, putting your
answers in the appropriate places.

MOTHER FATHER
“hat is your birthdate?
How many years of schooling have you had?

Are you employed?
(l-part time, 2-fu11 time)

Uhst is your occupation?

Are you attending school?
(l-yes, Z-no)

 

ADDITIONAL FAMILY INFORMATION

which of the following describes the arrangements made for the care of your baby while
you are working or in school--

bebysitter--re1ative in your home
_____ babysitter--re1atiwe in their home
_____’babysitter--nonrelatiwe in your home
______bebysitter--nonre1ative in their home
__ family daycare
group daycare

other

 

How many other children live in the home?

 

what is your total family income?

under $10,000
$10,000 to $20,000
$20,000 to $30,000
$30,000 to $40,000
$40,000 to $50,000
over $50,000

APPENDI X E

Caldwell HOME Inventory

75

{03! 1mm)!!! (Iirth to Three)

 

 

 

 

lJ
Child's lame Date oi Interview
Child's Iirthdate human: '
Relationship of person Place of
interviewed to child Interview

 

 

P’s-ily Coupe-idea
(Indicate persons living in household, including as: and age of children)~

 

Persons present in hoes at tins of interview

 

 

 

 

 

 

 

 

 

 

 

Cosments
1
0 1 2 3 ""350! of lteas Correct (Subscales)
Scale 4 l J i ? 1 t I I I l? 11
l [ fill/1171]][eteeuuueeaeeeem
n l JIM/1111......“nqm:
u; | pueueaeueflm
IV I JLULIHIIIZIII“*“flflflfiflflm

 

 

V | Jlllulfluenaeaunam:
V! I jeaeeeeeaum

 

 

 

 

 

 

 

 

 

 

 

 

totall' , Jill/[[[neeeeaenauuau '
I I Q J -l I 1
t 5 ”10 T" 13 10 15 30 ‘ 35
Nunber of Its-s Correct (Total Scale)
L Ill/UJIIIHIIII] *********“***“1 1

Lower Lower: Riddle Upper Upper
10! 252 50! 251 10:
Subucnlc Raw Score Percentile

land

 

l lootionel and Verbal Responsivitz of Mother

ll Avoidance of Restriction and Punishment

 

 

 

lll Organisation of the Physical and Temporal
Eummnt

IV Provision of Appropriate Play Materials

V Haternal lnvolvenent with the Child

VI opportpnities for yariety in Daily S'tieulation

Total

 

 

 

 

 

 

 

 

76

1‘ NONE OBSERVATION FOR MEASUREMENT OF THE ENVIRONMENT

INVENTORY (Birth to Three)

 

1. 90mm AND VERBAL atsrousxvm of norm

YES

 

l. Nether spontaneously voca'lizes to child at least twice
duri isi excludi sco d

 

2. Mother responds to child's vocalizations with a verbal
respggse.

 

3. Mother tells child the name of sons wject during visit or
me i rson r b ect in each " style.

 

4. Mother's spgggh is distinctI clearI and audible.

 

5. Rather initiates verbal interchanges with observer-asks
ues ions lakes s ntaneous ents.

 

6. Mother expresses ideas freely and easil and uses statnents
of appropriate length for conversation Ie.g.. gives eore
than rief answers .

L

 

 

*7. lbther pemits child occasionally to engage in “messy”
types of play.

 

8. Mother spontaneously praises child's qualities or behavior
twi e duri visit.

 

9. when speaking of or to child, nother's voice conveys
positive feeling.

 

l0. Nether caressg or kisses child at least once durinuisit.

 

ll. Mother shows some positive emotional responses to praise
of child offered by visitor.

 

SIB SCORE

 

 

 

__v

II. AVOIDANCE OF RESTRICTION AND PUNISHMENT

 

l1. Ether does not shout at 5:_hild durimisit.

 

l3. Mother doesn't express overt annoyance with or hostility
toward child.

 

 

(* lteas iron Categories I and II which nay require direct questions.)

 

 

 

 

77

15

 

14. lbther neither slaps nor spanks child dpripg visit.

 

*ls. Nether reports that no sore than one instance of

 

pgygical punishment pppprped duripg thp past week.

6. ther does t scol or re te c ild duri visit.

 

l7. Mother does not interfere with child‘s actions or
restrict child's love-ants sore than three tines

_'__d_u::1m "5"-

 

]8. At least-ten books app pppspnp and visible.

 

*l9. ngily hp; a pet.

 

SUBSCORE

 

 

I III. OMANIZATION OF HiVSICAI. AND TEMPORAL ENVIRONIENT

 

20. Hhen nether is away, care is provided by one of three
fi_§pgular substit tes. ‘

 

2l. Sausage takes child into grocery store at least once
a wee . .

 

22. Child gets put of house at least four times a week.

 

23. Child is taken pgpularly pp doctor's offipp pr clinic.

 

 

'24. Child has a special place in which to keep his toys
and “treasures.“

 

25. Child'sgplay environment appears safe and free of hazards.

 

 

SUBSCORE

 

 

IV. PROVISION OF APPROPRIATE PLAY MATERIALS

 

26. Child hp; some muscle actiyity toys or gguippgnt.

 

 

27. cum has ppsrh or pull toy.

 

28.. Child has stroller or walker, kiddie car, scooter,
or tricycle.

 

 

 

 

 

 

 

 

'78

16

YES

 

29. Nether provides toys or interggti ‘
child dur intervigglgi "O OCt vities for

 

30. Provides learning equipnent appropriate to age--
cuddly toy or role-playing toys,

 

3l. Provides learning equipnent a re rigt. to g -.
noblle, table and chairs, higg chgir, plgy p23,

 

32. Provides eye-hand coordination toys--itens to go in

png pg; of receptacle, fit ppgether poyp, beads.

 

33. Provides eye-hand coordination toys that per-nit
cenbinations--stacking or nesting toys. blocks or

building toys.

 

3- Provides toys for literature or nusic.

 

SUBSCORE

 

 

 

V. NATERNAL INVOLVEMENT NITN CNILD

 

35. Mother tends to keep child within visual
rapge and to look at hin often.

 

36. Nether “talks" to child while doipg her work.

 

 

37. Mother consciously ppcourages develpppgntal advances.

38. Mother invests hnaturing' toys with value via her
attentipp.

 

39. Nether structures child's playlperieg§£_

 

 

40. Mother rovides toys that challenge child to develop
new ski ls.

 

SUBSCORE

 

 

 

VI. OPPORTUNITI§§ FOR VARIETY INyQAILY STIHQLATION

 

il. Father provides sone caretakiqg every day.

 

42. upther reads stories at least three lines weekly.

 

43. Child eats at least one seal per day with nether
_§ father.

 

‘-

44.. Fanily visits or receives visits from relatives.

 

as. fiCpild has three or here books of rm own.

 

SUBSCORE

 

 

 

 

 

 

 

 

 

APPENDI X F

Coding Sheet for Gestures

 

 

79

Subject 0 Time Begin

Date Time End

 

POINTINC TO.- EXTENDING— OPEN-PMDED REACII

ob ec look at hand

.ONOUO-UNe-s

”Ne-Heneve-e-Ie-e-e-e-s
HOpOQOUl-UNe—g

 

APPENDIX 62
Sequenced Inventory of Communication Development
(SI CD)

Expressive Language

 

 

 

 

APPENDI X I-Il
Bayley Items:
Instructions for Administration, Scoring, and Videotaping

(unimanual handedness)

91

BAYLEY ITEMS: Instructions for Administration, Scoring, and
videotaping

Puts cube in cup on command (Bl)

Infant seated on mother's lap at a table. Examiner seated
in front of infant. Place a cube on the table and attract
the infant's attention to it; then place a cube in the cup,
take it out and hand it to the child. By word and gesture
encourage the infant to put it in the cup. Take care not

to leave your cube in the cup. After the child has put a
cube in the cup, place 8 more cubes in front of the infant-
one at a time-~and repeat verbal instructions, if necessary.

 

Record: Hand used to pick up cube and place in cup. (Note:
record only hand behaviors involving cubes 2 through 9).

Cube/cup placements: lst cube, hand to the infant. Cubes
2 - 9, place each at midline, in front of the cup.

Stirs with spoon in imitation (BZ)

Same set up as in (B1). Rattle a spoon in the cup with a
stirring motion. Place the cup before the child with a
spoon beside it. Cup always at midline.

Record: a. Hand used to pick up spoon.
b. Hand used to rattle spoon in cup.

Spoon Placements: (With spoon handle facing infant)
McMidline in front of cup.
L=To left of cup.
R=To right of cup.

Builds tower of cubes (BB)

Same set up as in (Bl). Place several cubes before the
child and stack 3 of them saying, ”Let's make a house,
see?" Then by word and gesture, ask the child to make a
house too. Present only 3 cubes at a time. (A cube should
not be counted unless the child releases it).

Record: Hand used to pick up each cube.

Cube placement: In groups of 3. All midline.

92
Places pegs in pegboard (B4)

Same set up as in (Bl). Place the peg board with the pegs
in front of the infant. In full view of the child, remove
the pegs and place them in a pile on the table. Pointing
first to the pegs and then to the holes, say, "Put them in.
You put them in the holes.” Children who do not understand
that they are to fill all of the holes may place, remove and
replace a single peg. Attempt to persuade the child to
leave in the pegs that are already placed by saying, "Put
them all in.”, but if the child is still cooperative, the
pegs may be placed one at a time in front of the infant,
and the trial may be ended after an attempt is made to
record 6 placements (even if they are replacements).

Record: Hand used to place each peg.
Drawing with crayon (B5)

Same set up as in (Bl). Place paper in front of the infant.
Demonstrate crayon by drawing a circle on the paper with
each hand separately before placing the crayon before the
infant. Place a fresh sheet of paper in front of the infant
prior to placing crayon.

Crayon Placement:
MsMidline in front of infant.
L=To infant's left.
R-To infant's right.

Record: a. Hand used to grasp crayon.
b. Hand used to draw on paper with crayon.

 

 

APPENDIX H2
Scoring Sheet: Bayley Items

(unimanual handedness)

. H‘F—fi .

 

 

SCORING SHEET:
Put check mark
Item Trial

(Bl) Puts Cube

(82) Stirs with

Pick
Rat.

Pick
Rat.

Pick
Rat.

\DmflmmeNH

m
’0
O
O
3

M1
M2

L1
L2

R1
R2

Rt.

(B3) Builds Tower

Put

la
2a
3a
lb
2b
3b
1c
2c
3c

BAYLEY ITEMS

Lft.

93

in Cup / Command

in appropriate place

Age

Item Trial

(B4) Places

Place

Place

(BS) Drawing

Pick
Dr.

Pick
Dr.

Pick
Dr.

M1
M2

L1
L2

R1
R2

Pegs

la
lb
1c
1d
1e
lf

2a
2b

with

Subject

Rt. Lft.

crayon

 

 

 

 

APPENDI X I 1

Instructions for Scoring Bimanual Manipulation

 

94
BI MANUAL MAN I PULATI ON - SCORI NG

Score this task by noting which hand the infant uses to
manipulate each toy after it has been grasped.

(Each toy is demonstrated twice, alternating grasping
hand, and manipulating hand, before presentation at the
infant's midline).

Focus in initial behaviors (no matter how clumsy), that
is, once the initial reach and some attempt at manipulating
has been made----discontinue coding the item.

Mouthing or shaking the toy, itc., will also terminate
the coding for that individual item. Exception: If the
experimenter redemonstrates the toy and places before the

infant again you may attempt to score the item again.

PLEASE - Any additional comments will be appreciated.

If there are any questions about behaviors that seem to defy
judgement, please make you uncertainty known, either by
writing it on the scoring sheet and/or contacting me about

it.

 

APPENDI X I 2

Scoring Sheet for Bimanual Manipulation

 

rm“

B I MANUAL MANI PULATI ON
Score this task by noting which hand the

to manipulate the toy after it has been grasped.

Toy
Nut & Bolt
Car in Jar
Blue Box a Ball

Pinwheel

Subject Code:

 

Grasping Manipulating

(moving)

 

 

 

 

 

infant uses

Initial
Stabilizing
Hand
(holding)

Right Left

 

 

 

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m—‘e . a
.l ' i.-

 

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73

__l“bther Subject Code I
____Fadum Date

 

Hand Preference

Please check the category that most accurately describes
your hand preference for each task. Since hand use may
differ from item to item, please consider each of your
answers carefully.

 

Indicate hand Always Usually loth hands Usually Always Don‘t
preference left left equally right right Know

 

 

I. To write a
' letter
legibly

 

2. To draw a
picture

 

3. To throw a
ball.to
hit a
target

 

4. To hold a
racquet in
a game
like
tennis or
ping-pong

 

5. To hammer
a nail
into wood

 

6. To hold a
toothbrush
while
cleaning
teeth

 

 

 

 

 

 

 

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