Most guys would be okay if their girlfriend had an affair with another woman, according to a study in Personality and Individual Differences. But the same was not true for females in the same study. Most young women told the research team that if their partner had an affair with another guy – that would be a deal-breaker and they would end the relationships.
These results were just what two researchers had predicted would happen, based on their knowledge of evolution and sex, when they set out to interview undergraduates about their attitudes toward cheating.
According to the current theories of sexual evolution, men would be more threatened by their partners having physical sex with other men because the male evolutionary goal is to father children and to make sure which children are their biological offspring. Women would be more threatened by emotional cheating, because the female evolutionary goal is to find a partner that stays on a long-term basis and helps rear their children.
Dr. Mark Cloud and Dr. Jaime C. Confer, who are a father and daughter team, interviewed 324 males and 394 female undergraduates at two public universities in Pennsylvania. They asked them to imagine that they were in romantic, sexual relationships that had lasted three months or more, when they learned that one of three things happened. In the first scenario, their partner had a homosexual affair but now insists it is over and wants forgiveness. In the second scenario, it was the same thing except the affair was with a same-sex partner. In the third scenario, the partner had two affairs with same-sex partners and the number of times they had sex could be either once or twice for each partner.
The deal-breakers for females occurred when their partners had homosexual affairs or if they had sex twice with the same female partner. In these cases, over 60% of women said they would break off the relationship. Dr. Cloud said these scenarios indicate deep emotionality infidelity in that their partners have become bonded and are now receiving support and love from someone else. On the other hand, only 28% of males would break off the relationship if the infidelity occurred within a homosexual relationship and only 20% would break it off if she had sex twice with the same partner.
The research team noted that when men fantasize about sex, 97% think about having sex with two women at once. The idea of their partner having sex with another woman may feed that fantasy, or in an evolutionary way, open up the way to yet another sex partner. As one young man put it, “Can I join in?”
On the other hand, almost 40% of the males in the study would break it off if the girlfriend had sex with two partners more than twice. According to evolutionary theory, this kind of female behavior would make it harder for a man to determine if a child is his biological offspring.
Dr. Lisa Diamond and other researchers did not question the result of the study, but they did wonder about the wisdom of interpreting it along evolutionary theories. Dr. Diamond, in an interview with the New York Times, said young men are probably assuming that their girlfriends are doing a “Katy Perry” fling but young women might believe that their men are just born gay.
“This is a great example of the way in which it doesn’t make sense to test evolutionary psychology principles with contemporary college students,” she said, noting that the study shows only what modern young people think about sexual orientation.References
Confer, J., and Cloud, M. (2011). Sex differences in response to imagining a partner’s heterosexual or homosexual affair. Personality and Individual Differences, 50 (2), 129-134 DOI:
Jarrett, Christian. “Which is worse? Your Partner having A Homosexual or Heterosexual Affair?” The Research Digest, December 1, 2010.
“Men More Likely to Stick With Girlfriends Who Sleep With Other Women Than Other Men,” Science Daily, January 27, 2011.
Paul, Pamela. “Lipstick on Her Collar? Men Say OK,” The New York Times, February 25, 2011.
Shea, Christopher. “Sexuality, Twice As Nice?” The Wall Street Journal, December 18, 2010.