In Brief

Men in committed relationships tend to have lower testosterone levels than those who are single, according to a study in the October issue of the Journal of Personality and Social Psychology (Vol. 91, No. 4). However, men in relationships who report cheating on their partners--or even who just say they'd consider it--have levels about as high as single men, notes Steve Gangestad, PhD, one of the study's authors and a psychology professor at the University of New Mexico.

"They are really in some sense not taken off the market," says Gangestad. "They are still interested in other women, and they are still high in testosterone. They are still engaged in the mating effort."

Past research suggests that elevated testosterone aids men in their efforts to attract mates by increasing their confidence and aggressiveness toward competing men, he adds.

Gangestad and his colleagues collected the saliva of 176 undergraduate students and then asked them to complete a questionnaire assessing their current relationship status and attitudes toward cheating. Some of the students were asked whether they'd consider cheating and others were asked whether they'd cheated in the past.

The single men, including people who would consider cheating and those who said they never would, had equally high levels of testosterone. The men in relationships who would not consider cheating, however, showed low testosterone compared with the relationship-bound men who would.

The results suggest that testosterone levels change in response to social conditions, and that the hormone helps men meet the perceived challenges of their environment, Gangestad says. While elevated testosterone levels help men find mates, lower levels may promote affiliative and nurturing behavior, he notes. In fact, lower levels of the androgen are associated with increased responsiveness to infant cries, past research shows.

"Testosterone facilitates competition with other men for partners...but it may interfere with other kinds of tasks, such as parenting," Gangestad notes.

--S. Dingfelder