TRAINING JAPANESE LISTENERS TO IDENTIFY ENGLISH R AND L .2. THE ROLE OF PHONETIC ENVIRONMENT AND TALKER VARIABILITY IN LEARNING NEW PERCEPTUAL CATEGORIES

Two experiments were carried out to extend Logan et al.'s recent study [J. S. Logan, S. E. Lively, and D. B. Pisoni, J. Acoust. Soc. Am. 89, 874-886 (199 1) ] on training Japanese listeners to identify English /r/ and /l/. Subjects in experiment 1 were trained in an identificatio n task with multiple talkers who produced English words containing the /r/-/l/ contrast in initial singleton, initial consonant clusters, an d intervocalic positions. Moderate, but significant, increases in accu racy and decreases in response latency were observed between pretest a nd posttest and during training sessions. Subjects also generalized to new words produced by a familiar talker and novel words produced by a n unfamiliar talker. In experiment 2, a new group of subjects was trai ned with tokens from a single talker who produced words containing the /r/-/l/ contrast in five phonetic environments. Although subjects imp roved during training and showed increases in pretest-posttest perform ance, they failed to generalize to tokens produced by a new talker. Th e results of the present experiments suggest that variability plays an important role in perceptual learning and robust category formation. During training, listeners develop talker-specific, context-dependent representations for new phonetic categories by selectively shifting at tention toward the contrastive dimensions of the non-native phonetic c ategories. Phonotactic constraints in the native language, similarity of the new contrast to distinctions in the native language, and the di stinctiveness of contrastive cues all appear to mediate category acqui sition.