Dynamical evolutionary psychology: Individual decision rules and emergent social norms

A new theory integrating evolutionary and dynamical approaches is proposed. Following evolutionary models, psychological mechanisms are conceived as conditional decision rules designed to address fundamental problems confronted by human ancestors, with qualitatively different decision rules serving different problem domains and individual differences in decision rules as a function of adaptive and random variation. Following dynamical models, decision mechanisms within individuals are assumed to unfold in dynamic interplay with decision mechanisms of others in social networks. Decision mecha-nisms in different domains have different dynamic outcomes and lead to different sociospatial geome-tries. Three series of simulations examining trade-offs in cooperation and mating decisions illustrate how individual decision mechanisms and group dynamics mutually constrain one another, and offer insights about gene–culture interactions. Evolutionary psychology and dynamical systems theory have both been proposed as antidotes to the theoretical fragmentation that long characterized the field of psychology. Evolutionary psy-chologists have proposed that isolated psychological research top-ics such as aggression, taste aversion, language acquisition, mate selection, and spatial cognition can be connected to research on cultural anthropology, ecology, zoology, genetics, and physiology via principles of modern Darwinian theory (e.g., Buss, 1995; Kenrick, 1994; Lumsden & Wilson, 1981; Tooby & Cosmides, 1992). Dynamical systems theorists have searched for even more fundamental principles: general rules capable of linking informa-tion processing in the human brain with processes found in eco-nomic markets, biological ecosystems, and worldwide weathe