Stronger sexual impulses may explain why men cheat more than women

Previous research has shown that men are more likely than women to pursue romantic partners that are "off limits." However, until now, the explanation for this sex difference was largely unexplored.

One possible explanation for this effect is that men experience stronger sexual impulses than women do. A second possibility is that women have better self-control than men. The current study's results support the former explanation and provide new insight into humans' evolutionary origins.

"Overall, these studies suggest that men are more likely to give in to sexual temptations because they tend to have stronger sexual impulse strength than women do," says Natasha Tidwell, a doctoral student in the Department of Psychology at Texas A&M University, who authored the study. Paul Eastwick, assistant professor in the Department of Human Development and Family Sciences at The University of Texas at Austin, co-authored the study.

"But when people exercise self-control in a given situation, this sex difference in behavior is greatly reduced. It makes sense that self-control, which has relatively recent evolutionary origins compared to sexual impulses, would work similarly -- and as effectively -- for both men and women," Tidwell said.

Recently published in Personality and Social Psychology Bulletin, the study was composed of two separate experiments: the first, to determine how the sexes reacted to real-life sexual temptations in their past and, the second, to pick apart sexual impulses and self-control using a rapid-fire reaction time task.

In order to test their first hypothesis, researchers recruited 218 (70 male, 148 female) study participants from the United States.

Participants were first asked to recall and describe an attraction to an unavailable or incompatible member of the opposite sex. They then answered survey questions designed to measure strength of sexual impulse, attempts to intentionally control the sexual impulse, and resultant behaviors.

"When men reflected on their past sexual behavior, they reported experiencing relatively stronger impulses and acting on those impulses more than women did," says Tidwell.

However, men and women did not differ in the extent to which they exerted self-control.

"When men and women said they actually did exert self-control in sexual situations, impulse strength didn't predict how much either sex would actually engage in 'off-limits' sex," added Tidwell.

"Men have plenty of self-control -- just as much as women," says Eastwick. "However, if men fail to use self-control, their sexual impulses can be quite strong. This is often the situation when cheating occurs."

In order to measure the strength of sexual impulse relative to the strength of impulse control, the researchers recruited 600 undergraduate students (326 men, 274 women) to participate in a "Partner Selection Game."

Participants were very briefly shown images of opposite-sex individuals; the images were tagged either "good for you" or "bad for you." Participants were asked to accept or reject potential partners based on the computer-generated "good for you" or "bad for you" prompt. While they were shown photographs of both desirable and undesirable individuals, participants were instructed to make acceptance and rejection choices based on the computer-generated tags. In some trials, participants were asked to accept desirable and reject undesirable individuals; in other trials, participants were asked to go against their inclinations by rejecting desirable individuals and accepting undesirable individuals.

Men experienced a much stronger impulse to "accept" the desirable rather than the undesirable partners, and this impulse partially explained why men performed worse on the task than women did. However, this same procedure estimates people's ability to exert control over their responses, and men did not demonstrate a poorer ability to control their responses relative to women.