Introduction

The defining characteristic of the human species is its culture-bearing capacity whereby very similar biological organisms develop and sustain extraordinarily diverse behavioral repertoires. Research on human behavior, then, must necessarily concern itself with the scope and significance of this diversity and the process of its development in childhood. However, contemporary psychological research often assumes instead a homogeneity of repertoire and of underlying psychological function - coupled with a concomitant assimilation of the psychological to the biological - and neglects the process of culture acquisition. Theories and methods developed from such a perspective neither incline their proponents to developmentally oriented comparative research nor provide a set of concepts and tools adequate to undertake it.

The reality of cultural diversity requires us to adopt a comparative perspective from the beginning as part of a coherent effort to account for the actual range of human psychological functioning and the process of its formation. Such a coherent effort demands more than simply testing whether our local findings generalize to other cultures or looking for a specific, naturally occurring equivalent for some odd manipulation we cannot perform within our own culture for one reason or another. Rather, it requires taking seriously the proposal that the human developmental process is designed to support diversity in behavioral outcome and that psychological research programs must take account of this from the outset if they are to produce adequate methods and theories.