My primary aim in this chapter is not to provide a survey of the products of cognitive development research. Rather, the focus of the chapter is an examination of the succession of ways in which the study of cognitive development has been approached during the relatively brief period of its existence. Such an approach is based on the premise that an examination of this sort affords the greatest insight into the topic itself. The study of cognitive development, it can be claimed, has consisted of an overlapping historical succession of conceptualizations of (1) what it is that develops, (2) the process by means of which this development occurs, and (3) how the study of this development is best conducted. These conceptualizations have dictated both the questions that are selected for investigation and how the products of those investigations are understood. They have thus provided a series of "windows" through which the topic might be viewed, and it is only by examining these windows, or conceptual and methodological frameworks, themselves that one can gain a sense of how knowledge of cognitive development has progressed.
One thing a reader new to the field is likely to gain from this chapter is an appreciation of why the study of cognitive development has not yielded simple, straightforward answers to seemingly simple, straightforward, empirically researchable questions. For example, does basic memory capacity increase or remain constant as the individual develops? The reader should come to appreciate why such questions themselves, as well as their answers, turn out to be considerably more complex than they appear on the surface. Although the reader new to the field may be disillusioned to learn that the field lacks simple, easily