A LIMIT ON BEHAVIORAL PLASTICITY IN SPEECH-PERCEPTION

It is well attested that we perceive speech through the filter of our native language: a classic example is that of Japanese listeners who c annot discriminate between the American /1/ and /r/ and identify both as their own /r/ phoneme (Goto, H., 1971. Neuropsychologia 9, 317-323. ). Studies in the laboratory have shown, however, that perception of n on-native speech sounds can be learned through training (Lively, S.E., Pisoni, D.B., Yamada, R.A., Tohkura, Y.I., Yamada, T., 1994. Journal of the Acoustical Society of America 96 (4), 2076-2087). This is consi stent with neurophysiological evidence showing considerable experience -dependent plasticity in the brain at the first levels of sensory proc essing (Edeline, J.-M, Weinberger, N.M., 1993. Behavioral Neuroscience 107, 82-103; Merzenich, M.M., Sameshima, K., 1993. Current Opinion in Neurobiology 3, 187-196; Weinberger, N.M., 1993. Current Opinion in N eurobiology 3, 577-579; Kraus, N., McGee, T., Carrel, T.D., King, C., Tremblay, K., Nicol, T., 1995. Journal of Cognitive Neuroscience 7 (1) , 25-32). Outside of the laboratory, however, the situation seems to d iffer: we here report a study involving Spanish-Catalan bilingual subj ects who have had the best opportunities to learn a new contrast but d id not do it. Our study demonstrates a striking lack of behavioral pla sticity: early and extensive exposure to a second language is not suff icient to attain the ultimate phonological competence of native speake rs. (C) 1997 Elsevier Science B.V.