And guys won't be surprised to learn that women are much choosier about partners than they are.
"Just because people say they're looking for a particular set of characteristics in a mate, someone like themselves, doesn't mean that is what they'll end up choosing," Peter M. Todd, of the cognitive science program at Indiana University, Bloomington, said in a telephone interview.
Researchers led by Todd report in Tuesday's edition of Proceedings of the National Academy of Sciences that their study found humans were similar to most other mammals, "following Darwin's principle of choosy females and competitive males, even if humans say something different."
Their study involved 26 men and 20 women in Munich, Germany.
Participants ranged in age from 26 to their early 40s and took part in "speed dating," short meetings of three to seven minutes in which people chat, then move on to meet another dater. Afterward, participants check off the people they'd like to meet again, and dates can be arranged between pairs who select one another.
Speed dating let researchers look at a lot of mate choices in a short time, Todd said.
In the study, participants were asked before the session to fill out a questionnaire about what they were looking for in a mate, listing such categories as wealth and status, family commitment, physical appearance, healthiness and attractiveness.
After the session, the researchers compared what the participants said they were looking for with the people they actually chose to ask for another date.
Men's choices did not reflect their stated preferences, the researchers concluded. Instead, men appeared to base their decisions mostly on the women's physical attractiveness.
The men also appeared to be much less choosy. Men tended to select nearly every woman above a certain minimum attractiveness threshold, Todd said.
Women's actual choices, like men's, did not reflect their stated preferences, but they made more discriminating choices, the researchers found.
The scientists said women were aware of the importance of their own attractiveness to men, and adjusted their expectations to select the more desirable guys.
"Women made offers to men who had overall qualities that were on a par with the women's self-rated attractiveness. They didn't greatly overshoot their attractiveness," Todd said, "because part of the goal for women is to choose men who would stay with them"
But, he added, "they didn't go lower. They knew what they could get and aimed for that level."
So, it turns out, the women's attractiveness influenced the choices of the men and the women.