A Note on the Scope of Developmental Behaviour Genetics

Abstract

The behaviour genetic decomposition of individual differences has been presented as being irrelevant to the study of human behavioural ontogeny. This introduces two problems. First, the analysis of systematic differences constitutes the basis for most statistical models used in the social sciences. If, generally speaking, this type of analysis is uninformative regarding development, how then can one empirically investigate human development? Second, behaviour genetic analyses are the only way to arrive at meaningful statements regarding the contributions of heredity and environment to human development. If results thus obtained are irrelevant, it is impossible to say anything on the subject of heredity, environment, and human ontogeny that is both meaningful and informative. It is argued that developmental behaviour genetics should not be viewed as a theory of development, but rather as a method of testing certain well-defined hypotheses regarding the contributions of genetic and environmental influences to human development. Individual differences assessed at any point in time reflect developmental processes prior to that time-gene-environment models are in a very basic sense inherently developmental... (Loehlin, 1975, p.41). Obviously the finding of innate differences in behaviour does not illuminate the development of that behaviour in any way (Johnston, 1988, p. 623).