[2] Men tend to have higher SOI scores and be more unrestricted than women across a variety of cultures.
This may be because gay men have more potential partners who prefer short-term, casual sexual encounters.
[6] Individuals who are sociosexually unrestricted tend to score higher on openness to experience,[7] and be more extraverted,[8] less agreeable,[8] lower on honesty-humility,[9] more erotophilic,[10] more impulsive,[11] more likely to take risks,[11] more likely to have an avoidant attachment style,[12] less likely to have a secure attachment style,[13] and score higher on the dark triad traits (i.e. narcissism, Machiavellianism, psychopathy).
[18] Individuals with an intrinsic religious orientation (i.e., religion as an end) tend to be sociosexually restricted, while those with an extrinsic religious orientation (i.e., religion as a means to achieve non-religious goals) tend to be unrestricted.
[22][23] Unrestricted individuals place more importance on partners' physical attractiveness and sex appeal, while restricted individuals place more weight on characteristics indicative of good personal and parenting qualities (e.g., kind, responsible, faithful).
[31] In regions that suffer from a high prevalence of infectious diseases, both men and women report lower levels of sociosexuality, as the costs of an incautious lifestyle (i.e., being unrestricted) may outweigh the benefits.
[33] This may be explained by the generalized Trivers-Willard hypothesis, which states that parents who possess any heritable trait that increases males' reproductive success above females' will have more sons, and will have more daughters if they possess traits that increase females' reproductive success above males'.
Thus, women should be more selective and restricted in order to have children with partners possessing good genes and resources, who can provide for potential offspring.
High sex ratios (more men) are associated with lower SOI scores (more restricted sociosexual orientation), as men must satisfy women's preference for long-term monogamous relationships if they are to effectively compete for the limited number of women.
[37] Strategic pluralism suggests that women evolved to evaluate men on two dimensions: their potential to be a good provider for offspring and their degree of genetic quality.
In demanding environments where biparental care was critical to infant survival, women should have valued good parenting qualities more, leading men to adopt a more restricted sociosexuality and invest more in their offspring to help ensure their children survive.