Brief article A perceptual interference account of acquisition difficulties for non-native phonemes Paul Iverson a, * , Patricia K. Kuhl b , Reiko Akahane-Yamada c , Eugen Diesch d , Yoh’ich Tohkura e , Andreas Kettermann f , Claudia Siebert f a Department of Phonetics and Linguistics, University College London, 4 Stephenson Way, London NW1 2HE, UK b Center for Mind, Brain, and Learning, University of Washington, Seattle, WA, USA c ATR Human Information Science Laboratories, Kyoto, Japan d Department of Cognitive and Behavioral Neuroscience, Central Institute of Mental Health, Mannheim, Germany e NTT Science and Core Technology Laboratory Group, Atsugi-shi, Kanagawa, Japan f Institute of Psychology, Technical University of Berlin, Berlin, Germany Received 17 May 2002; accepted 11 October 2002 Abstract This article presents an account of how early language experience can impede the acquisition of non-native phonemes during adulthood. The hypothesis is that early language experience alters relatively low-level perceptual processing, and that these changes interfere with the formation and adaptability of higher-level linguistic representations. Supporting data are presented from an experi- ment that tested the perception of English /r/ and /l/ by Japanese, German, and American adults. The underlying perceptual spaces for these phonemes were mapped using multidimensional scaling and compared to native-language categorization judgments. The results demonstrate that Japanese adults are most sensitive to an acoustic cue, F2, that is irrelevant to the English /r/-/l/ categorization. German adults, in contrast, have relatively high sensitivity to more critical acoustic cues. The results show how language-specific perceptual processing can alter the relative salience of within- and between-category acoustic variation, and thereby interfere with second language acquisition. q 2002 Elsevier Science B.V. All rights reserved. Keywords: Phonetic perception; Language acquisition; Perceptual magnet effect 1. Introduction Exposure to speech during childhood alters neural organization such that individuals, P. Iverson et al. / Cognition 87 (2003) B47–B57 B47 Cognition 87 (2003) B47–B57 www.elsevier.com/locate/cognit 0010-0277/02/$ - see front matter q 2002 Elsevier Science B.V. All rights reserved. doi:10.1016/S0010-0277(02)00198-1 * Corresponding author. E-mail address: paul@phon.ucl.ac.uk (P. Iverson).