The role of ontogenesis in human evolution and development

Chris Sinha

Abstract
Darwin's theory of evolution caused a revolutionary change in the concept of time. Evolution did not merely extend history backwards, it brought into being an entirely different order of time, in which different time-scales (durées) co-existed. Understanding the relations between time-scales - phylogenetic, ontogenetic, historical - was a major preoccupation of both biologists and psychologists. The best-known theory of this type was and is Haeckel's 'biogenetic law' of recapitulation. The metaphor of 'layers' of time - which, because of its association with palaeontology, is christened the 'palaeomorphic metaphor' - was central to the work even of those who, like the Soviet psychologist Vygotsky, rejected recapitulationism. Vygotsky's genetic psychology assumed the 'geological' stratification of 'lower' and 'higher' mental functions, corresponding respectively to biological and socio-cultural stages of evolution.

The mechanism proposed by Vygotsky for the development of 'higher' mental functions in the individual was internalization. However, this concept suffers from a logical problem, since it seeks to explain psychological processes in terms which presuppose those very processes. Vygotsky also emphasized the importance of tool-use in both the ontogeny and phylogeny of higher mental processes, drawing an analogy between tool-use and the use of conventional signs, including language. Again, however, this analogy is of limited usefulness, since neither tool-use nor cultural transmission is unique to humans.

An alternative account suggests rather that certain biological features of human infancy were selected, during the stages of human evolution post-dating the invention of tools, for their facilitative value in the process of what Vygotsky's colleague Leontiev called 'appropriation'. Infancy is then seen as a specific niche in which adaptive parameters are set by processes of individual appropriation, in the first instance, of canonical (socially standard) rules governing the use of tools and other artefacts. On this account, the biology of human infancy is a product of the co-evolution of culture and biology. Recent studies of infant cognition and social behaviour lend support to such an account. Infancy, on this account, played a crucial role in the 'socialization' of human biology.