Mating fast and slow? Sociosexual orientations are not reflective of life history trajectories

Abstract

Within evolutionary psychology, a dominant assumption is that adaptive variation in fast versus slow life history strategies centrally includes variation in sociosexual orientations. Fast reproductive strategies—prioritizing current reproduction and high number of low-quality offspring—are purportedly facilitated by short-term, uncommitted sexual relationships with multiple partners and investing little in resulting offspring (a high mating effort, low parental effort strategy). Slow strategies—of producing few, high-quality offspring—purportedly entails having few lifetime sexual partners and forming long-term, committed pair-bonds in which both parents invest heavily in offspring (a high parental effort, low mating effort strategy). Notably, proposals for individual variation in human life history strategies are inspired by cross-species evidence on covariation of traits related to reproduction and longevity. However, examination of evidence across mammals, birds, and primates reveals that variations in mating versus parental effort are not central to the interspecies dimensions of fast-slow strategies. Variations in pair-bonding and biparental care likewise do not map onto the fast-slow continuum or offspring quantity versus quality dimension. Indeed, in human foraging groups, male provisioning appears to increase offspring quantity. For several reasons, sex with multiple partners does not promote women's fertility rate. Alternative selection pressures are more likely to have led to adaptive variation in human mating strategies.