The role of indexical cues in the distributional learning of phonetic categories.
Theories of the distributional learning of phonetic categories assume that input provides reliable distributional cues for the categorization of speech sounds. In the real world, however, not all talkers produce exactly the same distributions of speech sounds, and the talker-dependent variation may undermine the reliability of the distributional cues. In this study, we investigated how learners might overcome talker-dependent variation. Specifically, we tested whether adults can learn two phonetic categories from input in which talker-dependent variation introduces potential ambiguities into the categorization of speech sounds. The results suggest that they can overcome this kind of ambiguity by using indexical information (i.e., the identity of talkers).