Generalizability and representation in studies of infant perceptual narrowing: Considerations for future research.

Forty years ago, Werker and Tees (1984) published a seminal finding which launched a proliferation of new research on early language learning. Their startling discovery, that infants demonstrate high initial sensitivity to phonetic contrasts which then attenuates over the first year of life, has provided deep insights into the origins of language learning. It has since stimulated a significant body of research investigating this early developmental process. This vast body of empirical work led to a theory of perceptual narrowing, which prevails today as a domain-general mechanism of environmental adaptation. In this article, I offer future directions for empirical and theoretical growth of perceptual narrowing theory with particular attention to issues of diversity, representation and generalizability. In addition, I discuss the importance of integrating empirical variation into perceptual narrowing theory.