Evolutionists pick up one one-night stands.

Men and women approach one-night stands altogether differently, the result of millions of years of sexual evolution, according to a recent study This sexual divide hinges on the question of what men and women look for in a mate. It turns out that men leave their standards behind when scouting for a casual liaison, while women consistently maintain theirs.

"From an evolutionary perspective, mating is the most important game around; the more you understand it, the better you'll be at succeeding - or at not being dissatisfied or horrified with what the opposite sex does, says Douglas T. Kenrick, a psychologist at Arizona State University in Tempe. Kenrick and his colleagues researched the differences between men and women's criteria for a mate in the gamut of relationships from onetime sexual encounters through marriage.

The psychologists asked 327 college students to state their criteria for 24 traits, such as intelligence, status, and emotional stability, The students also evaluated themselves on the same traits. Unlike most previous efforts, the study synthesizes two often disparate theoretical approaches: social psychology and evolutionary psychology (SN: 10/12/91, p.232). Combining the two helps reveal the deep-rooted reasons for different mating behavior between men and women, says Kenrick.

The gap between the sexes appeared greatest when students were asked to consider a one-night stand, the study found. In addition, men's standards for a mate correlated less closely with their self-appraisals than did women's, particularly for casual relationships. But when it came to the question of marriage, the differences faded away, with both men and women desiring agreeable, attractive, and emotionally stable mates. The study appears in the June JOURNAL OF PERSONALITY AND SOCIAL PSYCHOLOGY.

Both social and evolutionary psychologists view relationships as a kind of market exchange in which each person seeks the best possible deal, leading to partners of about equal assets coupling up. Social exchange theory, however, emphasizes the role of culture in setting the value of a trait, such as beauty, wealth, or kindness. Social psychologists downplay innate differences between the sexes, emphasizing the impact of socialization on sexual behavior.

Evolutionary psychologists, in contrast, view differences in sexual behavior as a basic aspect of human nature that is shaped by evolution. Therefore, traits that appeal to the opposite sex and help one compete for a mate - such as social dominance in men and physical attractiveness in women -- have been favored and passed down. Evolutionary theorists point out that, to our ancestors, social dominance signified the ability to compete well and provide for offspring, while attractiveness and youth indicated the health needed to bear children.

To test evolutionary theory, Kenrick's group reasoned that men and women would differ most when considering a casual liaison. Men would be relatively indiscriminate, given the chance to "enhance their genetic interest with no resource investment," notes Kenrick. Women, who could end up paying a high price for a rash mating session, were expected to be selective.

The study incorporated an important assumption of social psychology - that individuals perceive the costs and benefits of sexual behavior differently depending on the type of relationship pursued. It also applied social psychologists' awareness that men and women take mating seriously.

Many social psychologists continue to hold evolutionary psychology at arm's length because they consider humans' behavioral past outside the purview of present-day experience. But, says Kenrick, "We should not research human mating behavior without asking about its evolutionary significance -just as we ask about all other animals."