Genes, interactions, and the development of behavior

Explaining how genes influence behavior is important to many branches of psychology, including development, behavior genetics, and evolutionary psychology. Presented here is a developmental model linking the immediate consequence of gene activity (transcription of messenger RNA molecules from DNA sequences) to behavior through multiple molecular, cellular, and physiological levels. The model provides a level of detail appropriate to theories of behavioral development that recognizes the molecular level of gene action, dispensing with the metaphorical use of such terms as blueprints, plans, or constraints that has obscured much previous discussion. Special attention is paid to the possible role of immediate-early genes in initiating developmental responses to experience, adding specificity to the claim that neither genes nor experience act alone to shape development. The question of how genes affect behavior has been a long-standing focus of both controversy and research within the behav-ioral and social sciences. It is most directly of concern to the study of behavioral development (Gottlieb, 1998; Wahlsten, 1999) but is also important for behavior genetics (McClearn, Plomin, Gora