Cognition: the developmental trajectory approach

One emphasis of this volume is on the use of developmental trajectories in the study of developmental disabilities. This chapter focuses on theoretical, methodological, and analytical issues surrounding trajectories, but it is grounded in examples drawn from one aspect of research on Williams syndrome (WS), that of figurative language development. Figurative language is relevant to everyday communication skills, and it is of theoretical interest because it lies at the interface of language, cognition, and social skills. It therefore brings to the fore issues surrounding the uneven cognitive profile frequently observed in WS. In particular, how the development of figurative language fares in WS is considered, given the apparent strengths in language and social skills whereas the overall IQ indicates moderate levels of learning disability. The methods described are more general, however, and could be applied to a variety of neurodevelopmental disorders