When I listen to my male friends talk about dating, it becomes clear that men and women take a different approach. My friend Harry sent me a JDate profile of a woman in whom he was interested. He has sent me many profiles, but this woman stood out. She was down to earth, warm, funny, and cute. She made of point of saying that all her pictures were new and, based on these pictures, to use Harry’s words; she was “beautiful in a plain way.” That’s how he describes a woman who wouldn’t turn every man’s head, just his own.

Harry spent an hour “conversating” (his word) with her by phone and found that she was everything she stated on her profile. He was excited to meet her and, indeed, she turned out to be just like her profile . . . and then some. She was overweight, which was not clear in her pictures and, to Harry, rendered her unattractive.

I’ve known Harry for over 25 years and have never found him to be shallow. But when I asked whether he would go out with her again, to see whether she would grow on him, he said absolutely not. He defended his decision, stating that he couldn’t help it; he was “wired” that way.

But we women are wired differently. If a guy seems like a mensch, has a good career, and an even better sense of humor, a woman can overlook the fact that he has “a few extra pounds.” Instead, a woman will focus on a guy’s beautiful eyes or his cute smile. His appearance or weight is not a deal breaker. Why the difference between the sexes?

To get some answers, I turned to the evolutionary psychologist David M. Buss, author of The Evolution of Desire: Strategies of Human Mating. Apparently, Buss believes that there is an evolutionary basis for Harry’s behavior. He reported on a 50-year cross-generational mating study that focused on the value that men and women place on different characteristics in a mate. In this study, the same 18 characteristics were measured at roughly one-decade intervals to determine whether mating preferences in the U.S. have changed over time. The results indicated that, in all cases, men rated physical attractiveness as more desirable in a potential mate than did women, who tended to see it as desirable, but not very important. Buss concluded: “Men’s greater preference for physically attractive mates is among the most consistently documented psychological sex differences” (p. 58).

But is this due to nature, nurture, or both? Harry’s claim that it’s his “nature” is not the full story. Buss added that the importance that people place on attractiveness is not “forever fixed in our genes.” Rather, research has shown that its importance has increased dramatically, corresponding with the rise in media depictions of attractive individuals. So, where nature left off, nurture has taken over. No surprise here.

What did surprise me, however, was the research that shows that men do not have an evolved preference for a particular amount of body fat. In short, not every man prefers a slim woman. Rather, men have a preference for whatever features are associated with status, which varies in predictable ways from culture to culture. In cultures where food is scarce, such the Bushmen of Australia, plumpness signals wealth, health, and adequate nutrition during development. In cultures where food is relatively abundant, however, such as the United States, the relationship between plumpness and status is reversed, and thinness is a sign of status. But Buss makes it clear that “such a preference does not require conscious calculation or awareness” (p. 56); it’s part of our “collective cultural unconscious.”

Finally, men have yet another evolutionary reason for their choices. Buss cited research that demonstrated that “dating someone who is physically attractive greatly increases a man’s status” (p. 60). Moreover, a man who dates an unattractive woman experiences a moderate decrease in status and reputation.

So, Harry was right. He can’t help himself. He’s a victim of the evolutionary forces of nature and nurture and, of course, so are women. But the difference is that, for women, the attractiveness of a man can “evolve” over time.