Life history, fundamental motives, and sexual competition

• Life history theory explains sex differences in sexual maturity and preferred ages in mates.
• Activating mating motives leads to showy displays in human males, as in other species.
• Variations in sex ratio and resources predictably alter sexual competition and marriage patterns.

When it comes to sexual competition, men and women play somewhat different games. To understand why, it helps to step back and consider our species in the context of elephants, pygmy shrews in Madagascar, and clownfish that change sex as they mature. From studying the wide range of vertebrate life histories, biological theorists have extracted a set of common principles that clarify many seemingly arbitrary variations in human mating behaviors. Application of life history theory to human beings has recently led to a number of interesting findings involving sex differences and similarities in mating and sexual competition across different developmental phases and ecological contexts.