Inclusion of cultural variables in the study of human evolution is essential but introduces problems of vagueness, nonspecificity, and overgeneralization. Recognition of intracultural variation and conflict, and inclusion of ontogenetic processes such as individual learning are antidotal.

Men's interest in sex partners' status traits and commitment (investment thoughts) declines with number of sex partners and permissiveness of attitudes; women's investment thoughts do not seem to decline. Testosterone, dominance, sexual attractiveness, and number of sex partners are correlated in men but not in women. It is plausible that these sex differences are part of sexually dimorphic feedback systems. This type of feedback is consistent with both reciprocal and basal models of testosterone.

Sex differences in motivation and emotional reactions to casual sex suggest that the links to extraversion, constraint, impulsivity-sensation seeking, and sexual behavior differ for men and women. Because both testosterone and dominance, and dominance and number of sex partners appear to correlate in men but not in women, it is plausible that testosterone is involved in the creation and maintenance of these sex differences in linkage among the behavioral subsystems involved in sexuality and extraversion.

In their competition for higher-status men, women with higher socioeconomic status use indirect forms of aggression (ridicule and gossip) to derogate lower-status female competitors and the men who date them. Women's greater tendency to excuse their aggression is arguably a cultural enhancement of an evolutionarily based sex difference and not solely a cultural construction imposed by patriarchy.

Women with high sociosexual orientation inventory (SOI) scores may trade signs of willingness to invest for signs of ability to invest, instead of, or in addition to, genetic benefits. The target person's status traits affect women's judgments of sexual/physical attractiveness more than men's. An objective measure of a physical trait such as FA is therefore crucial in untangling the factors affecting women's judgments of attractiveness.

The Sociosexual Orientation Inventory (SOI) was not designed to illuminate the sexually dimorphic mental mechanisms posited by evolutionary theories. Its results are therefore open to competing interpretations. Measures designed to tap the thought processes surrounding sexual experience generate findings that are more compatible with evolutionary than with social structural theory.