Conditional and Alternative Reproductive Strategies: Individual Differences in Susceptibility to Rearing Experiences

Abstract

Contrasting explanations of variation in reproductive strategies emphasize nature (i.e., heritability) and nurture (i.e., environment). In this chapter it is argued that both may be correct, but not simply because, as so commonly assumed, nature and nurture interact to shape development. Rather, the proposition is advanced that there may be variation in susceptibility to rearing influence. Thus, in the case of some individuals, early vs. late maturation, promiscuous vs. committed sexuality, producing many vs. few offspring, and low- vs. high-investment parenting may reflect heritable proclivities (i.e., alternative reproductive strategies). In other individuals, however, environmental effects may account for observed differences in such features of development and behavior that define reproductive strategies (i.e., conditional strategies). After advancing this differential-susceptibility argument with respect to reproductive strategy, evidence is reviewed suggesting that highly negative infants may be most susceptible to rearing influence, at least with respect to the development of problem behavior, self control, and conscience, in order to illustrate the argument that individuals may vary in the degree to which their development is shaped by forces of nature and nurture.