How does the Child Know? Origins of the Symbol in the Theories of Piaget and Werner*

Developmental psychologists assume that one cannot understand a psychological process without understanding the roots of that process. But this is a two-way affair, for the way in which a phenomenon is conceptualized guides the search for its precursors and early forms. Thus, in the case of language, if speech is seen as essential to language, we might look at babbling as a precursor for language; if, on the other hand, we consider conversation as central to language, we could well investigate early mother-child dialogue or the patterning of social play. If the symbolic function of language is stressed, we would look at nonverbal forms of symbolization. And if syntax is seen as central, we might claim, as Chomsky would, that language has no precursors, that it is an emergent function.†

However, assumptions about essential features of the end-product are only one type of determinant of the search for precursors. Perhaps even more critical are one's general assumptions about the nature of development. For example, is development to be conceptualized as gradual and continuous, or is there room for reorganization, transformations, discontinuity? What is the relationship among different functions — affect, motor activity, perception, and thought? In conceptualizing development, do we see