A new emphasis has emerged in the literature on concepts and concept acquisition. There is now a strong focus on the role of theories and other explanatory belief systems in structuring concepts and conceptual change. A series of recent studies on adult concepts (e.g., Medin & Wattenmaker, 1987; Murphy and Medin, 1985; Rips, 1989) and a rediscovery of older work, such as Asch (1946), Luchins (1957), and Chapman and Chapman (1969), as well as developmental analyses (e.g., Carey, 1985; Keil, 1986, 1989; Wellman & Gelman, 1988), reveal the vital importance of theorylike beliefs in understanding concept structure and development. At roughly the same time, and for subtly related reasons, there has been a resurgence of interest in domain specificity of knowledge in cognitive development, with the consequence that researchers are now wondering whether the development of knowledge in different theoretical domains might influence concepts in ways that are unique to each domain. This chapter assesses how these two trends link up to help us understand the acquisition of word meaning.
Although the mapping between concept structure and semantic structure is certainly not one to one, as has been clearly illustrated by Clark (1983), neither are the relations random. I will argue that higher structural relations within and across concepts, as well as patterns of conceptual change, can have major and systematic influences on word meanings themselves. In this chapter I explore four aspects of concepts and conceptual change that may be particularly relevant to our understanding of semantic development: (a) interdomain differences, (b) causal beliefs versus atheoretical tabulations, (c) differentiation versus sharpening, and (d) the effects of a changing conceptual base on lexical induction.