|Slater I 192
Categorical perception/CP/psychological theories: Categorical Perception (CP): This special mode of perception was characterized by two crucial properties:
(a) tokens presented from a physical continuum were identified (labeled) as a member of one category or the other, with a sharp transition in identification (ID) at the category boundary, and
(b) failure of within-category discrimination and a peak in between-category discrimination for tokens that straddled the category boundary. >Language development/psychological theories. Cf.>Language development/Eimas, >Phonetics/psychological theories, >Phonetics/Eimas.
Around 1957 [when Chomsky(1) and Liberman(2) published] CP was only present for speech, and only for the components of speech when they are heard as speech (not when these same components are heard as non-speech). This led to the proposal that humans have evolved a special neural mechanism — the speech mode — that is innate and dedicated to the interpretation of articulatory signals that are produced by the human vocal tract.
(…) [T]he goal of the Eimas et al. (1971)(3) study was to determine whether very young infants, who had no experience producing speech or speech-like sounds, and only limited exposure to the sounds of their native language, perceived these sounds in a categorical manner.
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Kuhl and Padden (1982)(4) tested rhesus monkeys and confirmed these findings with a species more similar to humans.
Categorical perception: Thus, the presence of CP is not a sufficient argument for the operation of a linguistically relevant speech mode, since no one claims that chinchillas or monkeys achieve anything remotely like language, and certainly no ability to produce speech. Subsequent research by Kluender, Diehl, and Killeen (1987)(5) has shown that the fundamental properties of CP are not even unique to mammals (…). Cf. >Animal Language.
Problem: CP is not nearly as definitive as the claims made by Liberman and his colleagues (1957(6), 1961(3), 1967(7). See Pisoni and Lazarus (1974)(8), Miller (1997)(9).
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(…) infants are remarkably sensitive to the distributional properties of their linguistic input. (…) speech productions measured along a physical dimension such as VOT (voice onse time) from a given community of talkers cluster into modal categories. Maye, Werker, and Gerken (2002)(10) (…) found that 6—8 month olds exposed to a distribution of tokens with a single peak had the effect of reducing discrimination performance, as if the infants learned that the two categories were now collapsed into a single category. Similarly, Maye, Weiss, and Aslin (2008)(11) showed that eight-month-olds who did not discriminate two categories could be induced to do so by listening to a distribution that had two peaks.
These results have two important implications.
1) The only way that infants could utilize the distributional properties of the input along a dimension like VOT is if they could discriminate one value of VOT from another. If they could not, as claimed by classical CP, then all tokens would be identified as equivalent (within a category).
To break a category apart into two new categories, infants must have the capacity to discriminate within-category differences, as supported by the adult findings from Pisoni and colleagues (Pisoni & Lazarus, 1974(8); Pisoni & Tash, 1974)(12) and from Miller (1997)(9), as well as the infant study by McMurray and Aslin (2005)(13). As infants approach the end of the first year of life, the speed with which they are affected by lab-based distributions of phonetic tokens begins to decrease (Yoshida, Pons, Maye, & Werker, 2010)(14).
2) The Eimas et al. (1971)(3) results, which showed evidence of putatively innate VOT categories (>Chomsky/psychological theories), could have been based, at least in part, on a learning mechanism. This Hypothesis seemed extremely implausible at the time because the youngest infants tested by Eimas et al. were only one month old. But if there is a powerful distributional earning mechanism, and this mechanism is presented with highly consistent (voiced, voiceless) categories in the listening environment, then at least some of the early evidence of robust and seemingly universal VOT categories could be due to postnatal learning and not innate categories. For recent computational models see Vallabha, McClelland, Pons, Werker, & Amano, 2007(15); McMurray, Aslin, & Toscano, 2009)(16).
1. Chomsky, N. (1957). Syntactic structures. Mouton: The Hague.
2. Liberman, A. M., Harris, K. S., Hoffman, H. S., & Griffith, B.C. (1957). The discrimination of speech sounds within and across phoneme boundaries. Journal of Experimental Psychology, 54, 358—368.
3. Eimas, P. D., Siqueland, E. R.,Jusczyk, P., & Vigorito, J. (1971). Speech perception in infants. Science, 171, 303-306.
4. Kuhl, P. K., & Padden, D. M. (1982). Enhanced discriminability at the phonetic boundaries for the voicing feature in macaques. Perception and Psychophysics, 32, 542—550.
5. Kluender, K. R., Diehl, R. L., & Killeen, P. R. (1987). Japanese quail can learn phonetic categories. Science, 237, 1195—1197.
6. Liberman, A. M., Harris, K. S., Hoffman, H. S., & Griffith, B.C. (1957). The discrimination of speech sounds within and across phoneme boundaries. Journal of Experimental Psychology, 54, 358—368.
7. Liberman, A. M., Cooper, F. S., Shankweiler, D. P., & Studdert-Kennedy, M. (1967). Perception of the speech code. Psychological Review, 74, 431—461.
8. Pisoni, D. B., & Lazarus, J. H. (1974). Categorical and non-categorical modes of speech perception along the voicing continuum. Journal of the Acoustical Society of America, 55, 328—333.
9. Miller, J. L. (1997). Internal structure of phonetic categories. Language and Cognitive Processes, 12,
10. Maye, J., Werker, J. F., & Gerken, L. (2002). Infant sensitivity to distributional information can affect phonetic discrimination. Cognition, 82, B 101-Bill.
11. Maye, J., Weiss, D. J., & Aslin, R. N. (2008). Statistical phonetic learning in infants: Facilitation and feature generalization. Developmental Science, 1 1, 122—134.
12. Pisoni, D. B., & Tash, J. (1974). Reaction times to comparisons with and across phonetic categories.
Perception and Psychophysics, i 5, 285—290.
13. McMurray, B. & Aslin, R. N. (2005). Infants are sensitive to within-category variation in speech perception. Cognition, 95, B15-B26.
14. Yoshida, K. A., Pons, F., Maye, J., & Werker, J. F. (2010). Distributional phonetic learning at 10 months of age. Infancy, 15,420—433.
15. Vallabha, G. K., McClelland, J. L., Pons, F., Werker, J., & Amano, S. (2007). Unsupervised learning of vowel categories from infant-directed speech. Proceedings of the National Academy of Science, 104,
16. McMurray, B., Aslin, R. N., & Toscano, J. C. (2009). Statistical learning of phonetic categories: Insights from a computational approach. Developmental Science, 12, 369—3 78.
Richard N. Aslin, “Language Development. Revisiting Eimas et al.‘s /ba/ and /pa/ Study”, in: Alan M. Slater and Paul C. Quinn (eds.) 2012. Developmental Psychology. Revisiting the Classic Studies. London: Sage Publications_____________Explanation of symbols: Roman numerals indicate the source, arabic numerals indicate the page number. The corresponding books are indicated on the right hand side. ((s)…): Comment by the sender of the contribution. The note [Author1]Vs[Author2] or [Author]Vs[term] is an addition from the Dictionary of Arguments. If a German edition is specified, the page numbers refer to this edition.
Alan M. Slater
Paul C. Quinn
Developmental Psychology. Revisiting the Classic Studies London 2012