One of the best-known areas of research in Evolutionary Psychology involves how men and women approach intimate sexual relationships differently. Perhaps the best-known studies purporting to demonstrate the nature of these two differing strategies are those done by David Buss and his colleagues. Their hypothesis holds that if males and females have conflicting agendas concerning mating behavior, the differences should appear in the ways males and females experience sexual jealousy.
These researchers found that women were consistently more upset by thoughts of their mates' emotional infidelity, while men showed more anxiety concerning their mates' sexual infidelity, as the hypothesis predicts.
These results are often cited as confirmation of the male parental investment-based model. They appear to reflect the differing interests the model predicts. A woman, according to the theory, would be more upset about her partner's emotional involvement with another woman, as that would threaten her vital interests more. According to the standard model, the worst-case scenario for a prehistoric woman in this evolutionary game would be to lose access to her man's resources and support. If he limits himself to a meaningless sexual dalliance with another woman (in modern terms, preferably a woman of a lower social class or a prostitute-whom he would be unlikely to marry), this would be far less threatening to her standard of living and that of her children. However, if he were to fall in love with another woman and leave, the woman's prospects (and those of her children) would plummet.