Rules of attraction and evolutionary psychology
Evolutionary psychology sees the mind as a set of evolved psychological mechanisms, or adaptations, that have promoted survival and reproduction. One branch of evolutionary psychology focuses on the distinct mating preferences and strategies of men and women. For example, because our male ancestors were easily able to sire numerous children at little cost to their fitness, the theory says, they were inclined to short-term mating with multiple partners. In choosing mates, they gravitated toward youth and physical attractiveness — markers of fertility and health.
By contrast, females, for whom conception meant pregnancy and the need to care for a child, were more selective, searching for long-term commitments from males with the resources and willingness to invest in them and their offspring.