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Perceptuomotor biases in vowel imitation.
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Abstract:
The method of imitation provides an alternative approach to longstanding problems in speech research such as the organization of the vowel space and its relation to linguistic categories. Imitation of self-produced targets is particularly useful because (a) it allows a subject to report the quality of a multidimensional percept quickly and efficiently and (b) the subject is in principle capable of matching the target perfectly, so systematic deviations in the imitation can be ascribed to perceptuomotor biases. ; The self-imitation task was used to study perceptuomotor bias in the F1 x F2 vowel spaces of native speakers of American English, using two kinds of tasks. In "Serial Imitation", the imitations of a subject were played back to him for further imitation, thereby creating a set of trajectories in the vowel space. In "Multiple Imitation", each target was imitated several times, thereby allowing the perceptuomotor bias and variability to be calculated. Both tasks showed that subjects were consistently inaccurate in imitating themselves and that different subjects had different patterns of bias directions over the vowel space. The bias did not seem to be influenced by the temporal structure of the target nor by the subject's linguistic background and phonetic training. Articulatory modeling further showed that the bias was not due to low-level noise during production. The cause of the bias is posited to be the subject's psychological set, viz. his or her tacit notion of what aspects of the target are to be attended to and emphasized. An additional result was that while the bias directions differed across subjects, the distribution of bias magnitude and formant variability were remarkably consistent across subjects and sessions. In particular, F1 and F2 varied independently of each other and the formant standard deviations were similar to the formant discrimination limen. It is proposed that the psychological set is akin to a cognitive "policy" that can vary across subjects and sessions, while the underlying mechanism that carries out the policy is relatively unchanging. ; Thesis (Ph.D.)--Florida Atlantic University, 2003. ; The method of imitation provides an alternative approach to longstanding problems in speech research such as the organization of the vowel space and its relation to linguistic categories. Imitation of self-produced targets is particularly useful because (a) it allows a subject to report the quality of a multidimensional percept quickly and efficiently and (b) the subject is in principle capable of matching the target perfectly, so systematic deviations in the imitation can be ascribed to perceptuomotor biases. ; The self-imitation task was used to study perceptuomotor bias in the F1 x F2 vowel spaces of native speakers of American English, using two kinds of tasks. In "Serial Imitation", the imitations of a subject were played back to him for further imitation, thereby creating a set of trajectories in the vowel space. In "Multiple Imitation", each target was imitated several times, thereby allowing the perceptuomotor bias and variability to be calculated. Both tasks showed that subjects were consistently inaccurate in imitating themselves and that different subjects had different patterns of bias directions over the vowel space. The bias did not seem to be influenced by the temporal structure of the target nor by the subject's linguistic background and phonetic training. Articulatory modeling further showed that the bias was not due to low-level noise during production. The cause of the bias is posited to be the subject's psychological set, viz. his or her tacit notion of what aspects of the target are to be attended to and emphasized. An additional result was that while the bias directions differed across subjects, the distribution of bias magnitude and formant variability were remarkably consistent across subjects and sessions. In particular, F1 and F2 varied independently of each other and the formant standard deviations were similar to the formant discrimination limen. It is proposed that the psychological set is akin to a cognitive "policy" that can vary across subjects and sessions, while the underlying mechanism that carries out the policy is relatively unchanging. ; School code: 0119. ; hdl
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Keyword:
Cognitive.; Psychology
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URL: http://digitool.fcla.edu:80/R/?func=dbin-jump-full&object_id=12028
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http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3080490
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