Categorical perception

In phonetics, the mechanism of categorical perception enables listeners to focus on distinctive acoustic features in speech.

Example
the difference between the phonemes /d/ and /t/ in 'bead' and 'beat'

Comments
Furthermore, the mechanism enables listeners to ignore irrelevant acoustic differences, such as differences in pronunciation when two different speakers produce the same word. Categorical perception is acquired as part of the acquisition of the native language. The listeners learns to be sensitive to differences between phoneme categories and, at the same time, to be less sensitive to differences within a phoneme category.

Links

 * Utrecht Lexicon of Linguistics
 * A short tutorial and experiment on categorical perception
 * Audiodemonstrations categorical perception

Reference
Schouten, M.E.H. & van Hessen, A.J. 1992. Modeling phoneme perception. I: Categorical Perception. Journal of the Acoustical Society of America 92 (4), 1841-1855.