Toward an evolutionary history of female sociosexual variation.

Considerable progress has been made in behavioral genetics toward providing theoretical accounts of individual differences. One theoretical ask, however, has been largely neglected—that of constructing evolutionary accounts of behaviorally relevant genetic variance. We attempt to address this ask with respect to the genetic variance underlying sociosexuality, that is, the differences in the implicit prerequisites (in terms of time, attachment, commitment, etc.) to entering a sexual relationship. Specifically, we argue that genetic variance on this trait for females could have been maintained through frequency-dependent selection. In our evolutionary past, restricted females—those who require relatively more time, attachment, and commitment—could have benefited through paternal investment in their offspring. Unrestricted females—those who require relatively less time, attachment, and commitment—could have benefited through the quality of their mate's genes passed onto their sons. Moreover, the value of these alternate "strategies" could have been frequency-dependent. One prediction that follows from this evolutionary history is tested and supported in three studies. Those females genetically predisposed to be unrestricted are found to produce relatively more sons than females predisposed to be restricted. Additional predictions are offered and alternative accounts are discussed.