Asymmetries in the Processing of Vowel Height PurposeSpeech perception can be described as the transformation of continuous acoustic information into discrete memory representations. Therefore, research on neural representations of speech sounds is particularly important for a better understanding of this transformation. Speech perception models make specific assumptions regarding the representation of mid vowels (e.g., [ɛ]) that are ... Article
Article  |   June 01, 2012
Asymmetries in the Processing of Vowel Height
 
Author Affiliations & Notes
  • Mathias Scharinger
    University of Maryland, College Park
  • Philip J. Monahan
    Basque Center on Cognition, Brain and Language, Donostia-San Sebastián, Spain
  • William J. Idsardi
    University of Maryland, College Park
  • Correspondence to Mathias Scharinger: mscharinger@cbs.mpg.de
  • Editor: Sid Bacon
    Editor: Sid Bacon×
  • Associate Editor: Emily Tobey
    Associate Editor: Emily Tobey×
Article Information
Speech
Article   |   June 01, 2012
Asymmetries in the Processing of Vowel Height
Journal of Speech, Language, and Hearing Research, June 2012, Vol. 55, 903-918. doi:10.1044/1092-4388(2011/11-0065)
History: Received March 21, 2011 , Accepted October 10, 2011
 
Journal of Speech, Language, and Hearing Research, June 2012, Vol. 55, 903-918. doi:10.1044/1092-4388(2011/11-0065)
History: Received March 21, 2011; Accepted October 10, 2011
Web of Science® Times Cited: 7

PurposeSpeech perception can be described as the transformation of continuous acoustic information into discrete memory representations. Therefore, research on neural representations of speech sounds is particularly important for a better understanding of this transformation. Speech perception models make specific assumptions regarding the representation of mid vowels (e.g., [ɛ]) that are articulated with a neutral position in regard to height. One hypothesis is that their representation is less specific than the representation of vowels with a more specific position (e.g., [æ]).

MethodIn a magnetoencephalography study, we tested the underspecification of mid vowel in American English. Using a mismatch negativity (MMN) paradigm, mid and low lax vowels ([ɛ]/[æ]), and high and low lax vowels ([i]/[æ]), were opposed, and M100/N1 dipole source parameters as well as MMN latency and amplitude were examined.

ResultsLarger MMNs occurred when the mid vowel [ɛ] was a deviant to the standard [æ], a result consistent with less specific representations for mid vowels. MMNs of equal magnitude were elicited in the high–low comparison, consistent with more specific representations for both high and low vowels. M100 dipole locations support early vowel categorization on the basis of linguistically relevant acoustic–phonetic features.

ConclusionWe take our results to reflect an abstract long-term representation of vowels that do not include redundant specifications at very early stages of processing the speech signal. Moreover, the dipole locations indicate extraction of distinctive features and their mapping onto representationally faithful cortical locations (i.e., a feature map).

Acknowledgments
The research for this study was funded by National Institutes of Health Grant 7ROIDC005660-07 to the third author and David Poeppel. We thank David Poeppel and Aditi Lahiri for invaluable comments on this research. We are similarly indebted to the sound group at the University of Maryland and the audience of the 12th Conference on Laboratory Phonology (July 2010, Albuquerque, New Mexico) for helpful discussion. We also thank Ariane Rhone for helping prepare the stimuli and Max Ehrmann for laboratory assistance.
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