Rules of attraction

Can evolutionary psychology take the mystery out of how we meet and mate?

August 29, 2005|Julia M. Klein | Special to The Times

THREE years ago, Robert Kurzban spotted an advertisement for a service called HurryDate, offering an evening of three-minute meetings with 25 potential dates.

Kurzban was intrigued -- but not because he was looking for romance. As an evolutionary psychologist at the University of Pennsylvania, he thought speed dating could afford him a rare chance to study how people behave in real dating situations.

With the agreement of the company, Kurzban and a colleague surveyed the HurryDaters about a range of topics including religious background and their desire for children. Their fundamental questions: Did participants select the people most like themselves? Or did most of them prize similar traits -- such as appearance or high income -- and try to get the best deal they could in the mating market?

What the researchers discovered was that men and women chose their dates on the basis of "generally agreed upon mate values," the mating market hypothesis. Another finding: Both sexes relied mainly on physical attractiveness, largely disregarding factors such as income and social status.

"HurryDate participants are given three minutes in which to make their judgments," the psychologists wrote in a paper published in the May issue of the science journal Evolution and Human Behavior, "but they mostly could be made in three seconds."

The HurryDate research is one example of the everyday applications of evolutionary psychology, an interdisciplinary field that is influential and controversial. Other recent studies of human mating have explored issues such as the male preference for dating subordinates, why women have extramarital affairs and what trade-offs both sexes are willing to make in choosing partners.

Evolutionary psychology sees the mind as a set of evolved psychological mechanisms, or adaptations, that have promoted survival and reproduction. One branch of evolutionary psychology focuses on the distinct mating preferences and strategies of men and women. For example, because our male ancestors were easily able to sire numerous children at little cost to their fitness, the theory says, they were inclined to short-term mating with multiple partners. In choosing mates, they gravitated toward youth and physical attractiveness -- markers of fertility and health.

By contrast, females, for whom conception meant pregnancy and the need to care for a child, were more selective, searching for long-term commitments from males with the resources and willingness to invest in them and their offspring.


Theory's evolution

Support for this theory came from a landmark study by psychologist David M. Buss and colleagues in the 1980s, involving 37 cultures and 10,047 individuals. Buss, now professor of psychology at the University of Texas in Austin, found marked similarities across cultures, including a female preference for men with resources and status that persisted even when women had considerable resources of their own. Overall, women valued financial resources in a mate twice as much as men did.

"Up until that time, everyone believed that these things were very tethered to individual cultures and that cultures were infinitely variable," said Buss, whose more recent books have described the utility of jealousy and the universality of homicidal impulses.

Buss' survey continues to influence research on human mating. But some scientists and social scientists remain skeptical, saying evolutionary psychologists tend to neglect the role of learning and culture and to overemphasize genetics. Melvin Ember, an anthropologist and president of the Human Relations Area Files, a Yale-affiliated research organization, says that "focusing on universals" fails to explain either individual or cultural variation.

Jaak Panksepp, a neuroscientist at Falk Center for Molecular Therapeutics at Northwestern University, has chided evolutionary psychologists for ignoring recent neurological findings about human and mammalian brains.

Despite the objections, the field of evolutionary psychology is growing.

In recent years, Darwinian feminists and others have developed a more nuanced view of the complexities of female behavior. Women, it seems, aren't quite as monogamous as their partners might wish. They too sometimes pursue short-term mating strategies, though not everyone agrees on why.

Randy Thornhill, professor of biology at the University of New Mexico, said he has discovered that women, in an unconscious bid for better genes, will choose "extra-pair copulation" -- that is, have affairs -- with men who are more attractive (though perhaps less likely to commit) than their long-term mates. Other research indicates that women make different choices at different points in their menstrual cycle, opting for better-looking, more symmetrical and more masculine-appearing men when they are at their most fertile.

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