Kenrick puts it in evolutionary perspective. Like us, he says, our ancestors were probably designed to make some estimation of the possible pool of alternatives and some estimation of their own worth relative to the possibilities.

The catch is they just didn't see that many people, and certainly not many beautiful people. They lived in a little village of maybe 30. Even if you counted distant third cousins, our ancestors might have been exposed to a grand total of 500 people in their lifetime. And among those 500, some were old, some were young, but very few were very attractive.

Today anyone who turns on the TV or looks at a magazine can easily see 500 beautiful people in an hour, certainly in an evening. "My pool includes the people I see in my everyday life," explains Kenrick. "I don't consciously think that the people I see through movies, TV and magazines are artificial. Still, seeing Juliette Binoche all the time registers in my brain."

Our minds have not caught up. They haven't evolved to correct for MTV. "Our research suggests that our brains don't discount the women on the cover of Cosmo even when subjects know these women are models. Subjects judge an average attractive woman as less desirable as a date after just having seen models," Kenrick says.

Part of the problem is we're built to selectively remember the really beautiful. They stand out. "That's what you're drawn to," says Kenrick. "It feels good on the brain." And any stimulus that's vivid becomes readily available to memory, encouraging you to overestimate the true frequency of beautiful women out there.

So the women men count as possibilities are not real possibilities for most of them. That leads to a lot of guys sitting at home alone with their fantasies of unobtainable supermodels, stuck in a secret, sorry state that makes them unable to access real love for real women. Or, as Kenrick finds, a lot of guys on college campuses whining, "There are no attractive women to date." Under a constant barrage of media images of beautiful women, these guys have an expectation of attractiveness that is unusually high—and that makes the real people around them, in whom they might really be interested, seem lackluster, even if they are quite good-looking.

The idea that beauty could make so many men so miserable has acquired hard-nosed mathematical proof. In the world of abstract logic, marriage is looked on as a basic matching problem with statistical underpinnings in game theory. Logic says that everybody wants to do as well as they possibly can in selecting a life partner. And when people apply varied criteria for choosing a mate, everybody ends up with a partner with whom they are more or less satisfied. Not everybody gets his or her No. 1 choice, but everybody winds up reasonably content.

But the world has changed since mathematicians first tackled the matching of people with mates in the early 1960s. Films, television and magazines have not only given beauty a commanding presence in our lives but have also helped standardize our vision of attractiveness. Enter Guido Caldarelli, Ph.D., of the University of Rome, and Andrea Capocci, Ph.D., of the University of Fribourg in Switzerland. Once they introduced into their mating equations what they call the "Vogue factor"—a measure of the influence of beauty—they found that people become dissatisfied with their sexual partners.

"When the concept of 'most beautiful' people in the world tends to be the same for everyone, it becomes more and more difficult to make more people happy," say the researchers. The same few beautiful people top everyone's list of desired partners—clearly an impossibility—and no one comes close to being matched with any of their choices. So people become unhappy with their partner possibilities.

Alas, it's not simply a theoretical issue. Sociologist Satoshi Kanazawa, Ph.D., finds that real-life consequences of the contrast effect exist, such as divorce. The contrast effect not only undermines marriages; it then keeps men single—and miserable.

Kanazawa, assistant professor of sociology at Indiana University of Pennsylvania, wondered: "If men found themselves being less attracted to their mates after being exposed to eight or 16 pictures in a half-hour experiment, what would be the effect if that happened day in, day out, for 20 years?" It immediately occurred to him that high school and college teachers would be prime candidates for a study; they are constantly surrounded by young women in their reproductive prime. The only other occupation he could think of where the overwhelming majority of people men come in contact with are young women, was Hollywood movie directors, as well as producers and actors—a group not known for their stable marriages. But there was not an available body of data on them like there was on teachers, from a general population survey.

What Kanazawa found was summed up in the title of his report published last year in Evolution and Human Behavior: "Teaching May Be Hazardous to Your Marriage." Men are generally less likely to be currently divorced or separated than women, and overall teachers are particularly unlikely to be divorced or separated. But being a male teacher or professor wiped out that advantage. And not just any male teacher is at risk. Male kindergarten and grade school teachers were contentedly monogamous. "There appears to be something about male teachers who come in daily contact with teenaged women that increases the likelihood of being currently divorced or separated," Kanazawa says. He adds that these men remain unmarried because any adult women they might meet and date after their divorce would pale in comparison to the pretty young things constantly around them.

"Most real-life divorces happen because one or the other spouse is dissatisfied with their mate," says Kanazawa. "The contrast effect can explain why men might unconsciously become dissatisfied. They don't know why they suddenly find their middle-aged wives not appealing anymore; their exposure to young women might be a reason."

It would be blissfully easy to point a finger and claim that such infatuation with the young and the beautiful is the fault of the media and its barrage of nubile bodies. But it would also be incorrect. They're just giving us what we are naturally interested in.

All the evidence indicates that we are wired to respond to beauty. It's more than a matter of mere aesthetics; beauty is nature's shorthand for healthy and fertile, for reproductive capacity, a visible cue that a woman has the kind of prime partner potential that will bestow good genes on future generations. One of the prime elements of beauty, for example, is symmetry of body features. Research suggests that symmetrical people are physically and psychologically healthier than their less symmetrical counterparts.