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Title: Perceptual squelch of room effect in listening to speech
Creator: Shore, Aimee Elizabeth
Date: 2018
Collection: Electronic Theses & Dissertations
Description: Squelch is an effect in which the human auditory system is said to suppress room effects such as reverberation and coloration. Of particular interest is the squelch of room effects in everyday listening conditions: a listener listening to conversational speech in an ordinary room, with the talker and listener separated by a few meters. Traditionally, squelch has been considered a binaural effect- that is, attributable to the ears receiving somewhat different acoustical signals that lead to...
Show moreSquelch is an effect in which the human auditory system is said to suppress room effects such as reverberation and coloration. Of particular interest is the squelch of room effects in everyday listening conditions: a listener listening to conversational speech in an ordinary room, with the talker and listener separated by a few meters. Traditionally, squelch has been considered a binaural effect- that is, attributable to the ears receiving somewhat different acoustical signals that lead to interaural timing and level differences. Few experiments have been done that attempt to further elucidate the mechanism or mechanisms underlying squelch. A major obstruction to studying squelch is that it is a subjective effect, and as such it is difficult to quantify in absolute terms.Three pilot experiments (PE1-PE3) were conducted to investigate squelch under everyday listening conditions. In these experiments, parameters thought to affect squelch were varied, sometimes in a multidimensional way, in a series of real room recordings. Listenersreported their perceptions of room effects after listening to the recordings over headphones, either via questionnaire (PE1) or rank-ordering (PE2,PE3). Parameters found to affect perceptions included distance between sound source ("talker") and recording microphones ("listener"), sound presentation level, presence of a spectral tilt, and binaurality. Interestingly, differences in experimental methodology apparently influenced listeners' experiences. Some listeners' responses were consistent with anti-squelch in PE1, but were consistent with binaural squelch in the other pilot experiments. Collectively, results of the pilot experiments suggested that squelch is not a purely binaural effect.It was hypothesized that the head related transfer function (HRTF) plays a role in squelch- specifcally, that a listener's own HRTF leads to the least amount of room effect being perceived, relative to "other" HRTFs. Two experiments were conducted to investigatethe effect of HRTF on listeners' perceptions of room effect. Both used the binaural synthesis technique to deliver psychoacoustically-accurate stimuli to listeners. The first experiment presented stimuli to listeners over headphones. Variations could be multidimensional. The experiment revealed significant effects of source distance and binaurality for all listeners. The second experiment utilized probe microphone recordings in the ear canals to present stimuli over loudspeakers. Results indicate a statistically signicant effect of at least some HRTFs on listeners' perceptions of room effect.
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Title: Acquisition of L2 vowel duration in Japanese by native English speakers
Creator: Okuno, Tomoko
Date: 2013
Collection: Electronic Theses & Dissertations
Description: Research has demonstrated that focused perceptual training facilitates L2 learners' segmental perception and spoken word identification. Hardison (2003) and Motohashi-Saigo and Hardison (2009) found benefits of visual cues in the training for acquisition of L2 contrasts. The present study examined factors affecting perception and production of vowel duration (i.e., long versus short) in Japanese and benefits of waveform displays as visual cues on the acquisition of vowel duration in L2...
Show moreResearch has demonstrated that focused perceptual training facilitates L2 learners' segmental perception and spoken word identification. Hardison (2003) and Motohashi-Saigo and Hardison (2009) found benefits of visual cues in the training for acquisition of L2 contrasts. The present study examined factors affecting perception and production of vowel duration (i.e., long versus short) in Japanese and benefits of waveform displays as visual cues on the acquisition of vowel duration in L2 Japanese by native speakers of L1 English, and transfer to production. Vowel length in Japanese is a contrastive feature, important for communication, and a challenge for many L2 learners. A pretest-posttest design with controls was used. A between-subject variable was training type: auditory visual (AV), auditory-only (A-only), and no training (controls). Within-subject variables were vowel type, preceding consonant, and pitch pattern. Participants were 64 learners of Japanese whose L1 was American English. Testing and training materials were 40 bisyllabic-words containing long and short vowels. To create the stimuli, two Japanese vowels (/a, u/), two consonants (/k, s/), and 10 pitch patterns were selected. The stimuli, produced by six NSs of Japanese, were recorded. Production and perception pre- and post-tests were administered to assess the effects of training on perception accuracy and reaction time (RT). During production testing, participants produced 16 bisyllabic words in isolation. For perception testing, they completed a forced-choice, four-alternative identification task for 18 stimuli, the bisyllabic words. Perception training, conducted between the pre- and post-tests, involved eight sessions, each 25 minutes; the participants also completed the same identification task, using a computer. During training, feedback was provided on both correct and incorrect responses; immediately after the choice, correct words appeared on the screen. Results indicated significant improvement on identification accuracy for both groups, but the rate of improvement of the AV group was greater. On the other hand, RTs of the two groups became slower after the training. In addition, it was found that vowel type, preceding consonant, and pitch patterns in addition to the talker's voice in the training together affected L2 learners' perception of vowel duration. The results suggested that the learners' stages of L2 perceptual development involve the evaluation of input based on context- and talker-dependent perceptual categories.
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Title: Performance-by-intensity functions of normal hearing children on two multiple-choice type picture tests of speech discrimination
Creator: Culbertson, William Richardson
Date: 1981
Collection: Electronic Theses & Dissertations

Title: Perception of frequency modulation width at low modulation frequencies
Creator: Klein, Mark Allen
Date: 1980
Collection: Electronic Theses & Dissertations

Title: Children's perception of temporally distorted sentential approximations and normal sentences
Creator: Flaherty, Anne K.
Date: 1974
Collection: Electronic Theses & Dissertations

Title: Neural responses to auditory rhythms in the zebra finch
Creator: Lampen, Jennifer A.
Date: 2017
Collection: Electronic Theses & Dissertations
Description: Rhythm is important in the production of motor sequences such as speech and song. Deficits in rhythm processing have been implicated in a range of human disorders including some that affect speech and language processing, including stuttering, specific language impairment, and dyslexia. Songbirds provide a tractable model for studying the neural underpinnings of rhythm processing due to parallels with humans in neural structures and vocal learning patterns. In the experiments conducted for...
Show moreRhythm is important in the production of motor sequences such as speech and song. Deficits in rhythm processing have been implicated in a range of human disorders including some that affect speech and language processing, including stuttering, specific language impairment, and dyslexia. Songbirds provide a tractable model for studying the neural underpinnings of rhythm processing due to parallels with humans in neural structures and vocal learning patterns. In the experiments conducted for this dissertation, I investigated the effect of rhythmicity of song stimuli on expression of the immediate early gene ZENK in the adult zebra finch brain. I also investigated development of rhythmic discrimination in the juvenile brain, and estradiol (E2) effects on rhythm perception in adult birds.In adult zebra finches, ZENK was increased in response to arrhythmic compared to rhythmic song in the auditory association cortex homologs, caudomedial nidopallium (NCM) and caudomedial mesopallium (CMM), and the avian amygdala, nucleus taeniae (Tn). CMM also had greater ZENK labeling in females than males. These auditory areas may be detecting errors in arrhythmic song when comparing it to a stored template of how conspecific song is expected to sound. CMM may also be important for females in evaluating songs of potential mates. Increased neural activity in Tn may be related to the value of song for assessing mate choice and bonding or to perception of arrhythmic song as aversive.Before formation of the template for song that young birds memorize, expression of ZENK was increased in NCM of birds exposed to rhythmic relative to arrhythmic song. During template formation, ZENK expression was increased in CMM of birds exposed to arrhythmic relative to rhythmic song. These results suggest that the youngest birds may be predisposed to respond to a more natural stimulus, and a template may be required for arrhythmic song to elicit increased neural activity. Rhythm discrimination in CMM may be strongest at life stages, such as during template memorization, when birds are most focused on external auditory signals. Compared to data from adults, it also appears that functional development across the brain regions investigated continues to maturity. In adult zebra finches treated with a control or E2 or the aromatase inhibitor fadrozole (to increase or decrease estrogen availability), ZENK mRNA was significantly greater in the left hemisphere within NCM, CMM, and Tn. The overall pattern for left lateralization parallels the left lateralization of language processing in humans and may suggest that this hemisphere is specialized for processing conspecific vocalizations. Main effects of sex were detected in both auditory regions, with increased ZENK in males in NCM and in females in CMM. The reversed sex differences in NCM and CMM suggest that males and females differentially rely on components of the auditory forebrain for processing conspecific song. In CMM, an effect of hormone treatment also existed. While no pairwise comparison was statistically significant, the pattern suggested greater ZENK expression in control compared to both fadrozole- and E2-treated birds. In NCM, an interaction between sex and hormone treatment suggested that the sex effect was restricted to control animals. The hormone effects suggest that an optimal level of estradiol may exist for processing rhythmicity of auditory stimuli. Together, these studies represent the first step in establishing the zebra finch as a model for human rhythm perception and disorders with disruptions in rhythm processing. This work suggests multiple brain regions that should be assessed in more detail for their involvement in human rhythm processing and disorders. A potential for a learned aspect of rhythm discrimination is also indicated, suggesting that rhythm training may aid those with disorders involving rhythm processing deficits. In addition, the establishment of the zebra finch as a model provides the opportunity to conduct more mechanistic studies into the basis of rhythm perception.
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Title: Auditory localization in primates : the role of stimulus bandwidth
Creator: Brown, Charles H., 1947-
Date: 1976
Collection: Electronic Theses & Dissertations

Title: The perceptual processing of rhythmic auditory pattern temporal order
Creator: Wood, Robert William
Date: 1980
Collection: Electronic Theses & Dissertations

Title: Native and nonnative differences in the perception and production of vowels
Creator: Hoopingarner, Dennie
Date: 2004
Collection: Electronic Theses & Dissertations

Title: Psychoacoustical theory and experiments on human auditory organization of complex sounds and the critical bandwidth
Creator: Lin, Jian-Yu
Date: 1996
Collection: Electronic Theses & Dissertations

Title: Detection and localization of sounds : virtual tones and virtual reality
Creator: Zhang, Peter Xinya
Date: 2006
Collection: Electronic Theses & Dissertations

Title: Pitch perception of mistuned harmonics in a complex tone
Creator: Smith, Sandra Louise
Date: 1989
Collection: Electronic Theses & Dissertations

Title: Neural systems supporting nonlinguistic auditory processing in young children who persist and recover from stuttering
Creator: Roehl, Laney
Date: 2018
Collection: Electronic Theses & Dissertations
Description: Stuttering is a speech disorder characterized by disruptions in speech fluency, typically marked by the presence of prolongations, repetitions, and blocks. There is no single known cause of stuttering. Instead, stuttering is thought to be a dynamic, multifactorial disorder resulting from interactions between genes, language, motor, and other cognitive skills, and the environment (Smith, 1999). Among preschool-age children who begin to stutter, approximately 80% will recover naturally (de...
Show moreStuttering is a speech disorder characterized by disruptions in speech fluency, typically marked by the presence of prolongations, repetitions, and blocks. There is no single known cause of stuttering. Instead, stuttering is thought to be a dynamic, multifactorial disorder resulting from interactions between genes, language, motor, and other cognitive skills, and the environment (Smith, 1999). Among preschool-age children who begin to stutter, approximately 80% will recover naturally (de Sonneville-Koedoot, Stollk, Rietveld, & Franken, 2015; Yairi & Ambrose, 2005; Yairi & Ambrose, 1999; Yairi & Seery, 2015). However, to date it is not clear why some children persist in stuttering while others recover. One potential factor that may contribute to stuttering is auditory processing. Previous studies have found that nonlinguistic auditory processing differs between adults and children who stutter (CWS) and their fluent peers (Hampton & Weber-Fox, 2008; Kaganovich et al., 2010). The current study aimed to extend previous findings by evaluating neural indices of nonlinguistic auditory processing in young CWS who will eventually persist (CWS-ePer) and eventually recover (CWS-eRec). CWS-ePer exhibited atypical early neural markers of auditory processing compared to CWS-eRec and fluent peers. Additionally, with increased cognitive demands, or short recovery time between sounds, CWS-ePer and CWS-eRec both exhibited atypical early auditory processes. Together, these findings indicate that early auditory processing and attention skills may play a role in persistence of developmental stuttering.
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