Last week I gave a talk on Personality and Sexuality. One question that cropped up was - "How do I know if my partner is cheating on me?" By chance the next morning there was a newspaper article attributing uncommitted sex, one-night stands, and acts of infidelity to genetics.
Individuals who have frequent sex with multiple partners are psychologically different from those who have frequent sex with single partner (Simpson & Gangestad, 1991). This sociosexual difference places individuals in two groups
- Unrestricted sociosexual types, have a higher number of sexual partners, and one night stands. They have a permissive attitude to casual and uncommitted sex.
- Restricted sociosexual types, require greater closeness and commitment before sex with their romantic partner.
Genetics plays an important role in sociosexuality
Genes evolve to enhance survival of the species. From an evolutionary viewpoint females reproduce with a mate who will invest in their offspring and produce offspring with an advantaged genetic makeup. Female socio-sexual orientation exists because males vary in the quality of their genes.
- Unrestricted type females benefit from passing the genes of men with greater reproductive success to their own offspring. To induce males to invest in their offspring they frequently engage in pretense and deceit, traits that are strongly associated with unrestricted sociosexuality.
- Restricted type females benefit from caring males who limit reproductive efforts to the females own offspring.
- Male sociosexuality evolved through competition. Males who do not succeed with an unrestricted socio-sexual orientation become Restricted.
How do you know your partner's sociosexuality?
Lynda Boothroyd showed that observers were able to identify restricted vs. unrestricted individuals from cues in thier faces. My audience successfully differentiated the Restricted and Unrestricted pairs from the same picture. Test yourself.
What does this mean for a relationship?
- Restricted socio-sexual personalities are more willing to remain in an unsatisfactory marriage. They are less likely to be drawn out of such a relationship by attractive alternate partners.
- For Unrestricted individuals long term stability in the relationship depends on the extent to which the partner is highly attractive and possesses high social visibility. Decisions to continue or terminate a relationship depend more on changes in the partners physical attractiveness and social status.
However, personality is not all in the genes. Genes contribute to the biological aspect of personality - temperament. Personality also has an acquired aspect - character. When fully developed, character defines the mature personality.
How do I know if my partner is cheating on me?
To return to the question. Asking the question indicates there are already boundaries being overstepped. It indicates an erosion of trust - a core component in any long-term relationship. That is what needs to be addressed.
Jeffry A Simpson, Steven W Gangestad. Personality and sexuality: empirical relations and an integrative theoretical model. In: Sexuality in close relationships. Kathleen McKinney, Susan Sprecher Editors. Lawrence Erlbaum Associates. New Jersey. 1991:71-92.
