Modeling Infant Speech Sound Discrimination Using Simple Associative Networks
Graham Schafer
Department of Psychology, University of Reading
Denis Mareschal
Centre for Brain and Cognitive Development, Birkbeck College

Infants’ responses in speech sound discrimination tasks can be nonmonotonic over time. Stager and Werker (1997) reported such data in a bimodal habituation task. In this task, 8-month-old infants were capable of discriminations that involved minimal contrast pairs, whereas 14-month-old infants were not. It was argued that the older infants’ attenuated performance was linked to their processing of the stimuli for meaning. The authors suggested that these data are diagnostic of a qualitative shift in infant cognition. We describe an associative connectionist model showing a similar decrement in discrimination without any qualitative shift in processing. The model suggests that responses to phonemic contrasts may be a nonmonotonic function of experience with language. The implications of this idea are discussed. The model also provides a formal framework for studying habituation–dishabituation behaviors in infancy.
Further details about the simulations presented in this article and discussion of the results and their implications can be found at:
www.rdg.ac.uk/~sxs97gws/discrim.html