Previous research indicates that for adults and children the perception of speech can be significantly influenced by watching a speaker's mouth movements. For example, hearing the syllable /bi/ while watching a speaker mouth the syllable /vi/ results in reports of a 'heard' /vi/. Some evidence suggests young infants also may be able to integrate heard and seen speech. One theory suggests that an innate link between perception and production (Liberman & Mattingly, 1985) accounts for this phenomenon while another theory suggests that experience (e.g., producing speech sounds) may be necessary into order to develop fully the underlying representation of visible speech (Desjardins, Rogers & Werker, in press; Meltzoff & Kuhl, 1994). My dissertation addresses the above controversy by examining whether the integration of heard and seen speech is obligatory for young infants as it is for adults. In Experiment 1, 4-month-old female infants habituated to audiovisual /bi/ showed renewed visual interest to an auditory /bi/-visual NM suggesting that they may have perceived the auditory /bi/-visual /vi/ as /vi/, as do adults. In Experiment 2, neither male nor female infants showed renewed visual interest to a dishabituation stimulus which represents only a change in mouth movements. In Experiment 3, male infants looked longer to an audiovisual /bi/ than to an audiovisual /vi/ following habituation to an audio /bi/-visual /vi/, while female infants tended to look only slightly longer to an audiovisual /vi/ than to an audiovisual /bi/. Taken together these experiments suggest that at least some infants are able to integrate heard and seen speech, but that they do not do so consistently. Although an innate mechanism may be responsible for integration, a role for experience is suggested as integration does not appear to be obligatory for young infants as it is for adults. / Arts, Faculty of / Psychology, Department of / Graduate

In the present study, the dichotic perception of "automatic" speech in normal subjects was investigated. Four dichotic tapes were presented, under both single-pair and double-paired conditions. The first tape consisted of "automatic" word pairs, and the second contained "propositional" word pairs. The third and fourth tapes, which were identical but presented on opposite channels, consisted of "automatic-propositional" word pairs. Subjects responded orally to the stimuli. Differences in order of report and distribution of errors were evaluated by means of Wilcoxon's Matched-Pairs Signed-Ranks Test. A significant right ear advantage was found for both automatic and propositional stimuli, indicating lateralization of processing to the dominant hemisphere. Responses to the third and fourth tape varied significantly, suggesting that automatic and propositional words constitute different modes of language, and therefore undergo different sub-cortical processing. The results of the present investigation are examined in relation to the existing model of automatic speech representation. Certain contradictions are noted. The limitations of the experiment, as well as suggestions for further research, are discussed. / Medicine, Faculty of / Audiology and Speech Sciences, School of / Graduate

In speech perception tasks young infants show remarkable sensitivity to fine phonetic detail. Despite this impressive ability demonstrated at early ages, studies of word learning in young toddlers indicate that they have difficulty learning similar-sounding words. This evidence suggests that infants may not be using this speech-perception ability as they begin to learn words. The studies in this thesis were designed to test how infants' speech-perception skills are used in the early stages of word learning. Using a simple habituation procedure, we have shown in earlier work that 14-month-old infants, but not younger infants, are able to learn the association between novel nonsense words and objects (Werker, Cohen, Lloyd, Casasola, & Stager, 1998). The current series of experiments used this simple habituation procedure to test whether infants use minimally contrastive phonetic detail in the very early stages of word learning. In this thesis, I show that 14-month-old infants, who are on the cusp of word learning, while still able to discriminate phonetically-similar words in a speech perception task, do not incorporate minimally contrastive phonetic detail when first forming word-object associations. Infants of 8 months of age do, however, appear to use fine phonetic detail in a similar task. Taken together, these results suggest a decline in the phonetic detail used by infants as they move from processing speech to learning words. I hypothesize that this decline may occur as infants move from treating the task as one of speech perception to treating the task as one of word learning. / Arts, Faculty of / Psychology, Department of / Graduate

Listeners' perceptions of the cognitive, social, and physical competence of a speech impaired individual were investigated. Thirty-eight adults (31 female and 7 male) between 19 and 51 years of age listened to prerecorded audiotape interviews; one with a speech impaired speaker, or one with a normally speaking peer. Listeners rated the perceived cognitive, social, and physical competence of both a speech impaired speaker and a normal speaker using a modified version of the Teacher's Rating Scale of Child's Actual Competence. An independent two-sample t-test statistic resulted in significant difference between the groups in cognitive, social, and physical competence subscales. The speech-impaired individual was perceived as less competent than his normally speaking peer in cognitive, social, and physical competence.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.