Do married men and women use the same tactics when dealing with a potential extrapair copulation (EPC) partner? Or are the preferred tactics of men and women gender-specific? Two psychologists, Susan Hughes and Marissa Harrison, wanted to find out. They also wanted to test some of the predictions of evolutionary psychology. So, they ran a study asking people who were looking to cheat on their spouse if they would admit, or had admitted to their potential EPC partner, that they were already in a committed relationship.

Evolutionary theory predicts that it would make sense for a man to try to conceal, from an EPC partner, the fact that he is already in a committed relationship (married or otherwise). A previously committed man is likely to have limited time to spend time with an EPC and, unless he is very rich, limited ability to provide her with resources. Since women have an evolved preference for men who can provide resources and thereby contribute to the raising of any children she might have (Buss, 1994), a previously committed man is not as desirable as a partner as a man who is unattached, all other things being equal. If a female lover were to produce a child, she would have to bear enormous costs and she would not typically be able to count on her married (or otherwise committed) lover for help. It’s, of course, a situation—the abandoned lover—that has been described so often that it has become a cliché. Any man seeking a lover would know this and therefore would have an incentive to conceal the fact that he is in a committed relationship from a potential EPC partner.

The situation is not the same for a woman. The fact that she is already in a committed relationship might well enhance her appeal. Men tend to seek sexual encounters that are cost- and commitment-free, a fact that is as often documented as it is decried. A woman who is willing to provide sex without needing time or resources from the man might well be seen as an ideal candidate lover. After all, such a woman gives him an opportunity to increase his reproductive success—his fitness—without his incurring any costs in money or effort. If a woman in a committed relationship wants a lover but worries that he might be afraid of entanglement, it makes sense for her to reveal her status. Perhaps he is married or otherwise attached; letting him know where she stands could relieve him from the fear of being trapped into an unwanted commitment.

The results of the study tend to confirm the predictions of evolutionary theory. Hughes and Harrison found that women seeking EPC partners were more likely than men to reveal that they were already in a committed relationship. This held true whether they were asked what they had already done in reality, or what they would do, hypothetically, if given the opportunity.

To us bloggers, these results indicate that men and women have an intuitive sense of tendencies and preferences that have been built into the human genome and psychology over the long years of human and perhaps pre-human evolution. These intuitions don’t compel us to behave in any particular way, but they do nudge us in certain directions, even when we aren’t aware of these voices from the past. Evolutionary psychologists seem to take particular delight in rescuing some of these tendencies from obscurity.