Sexual Chemistry: What Men and Women Prefer When Searching for a Partner

It's a dance as old as human race. At cocktail lounges and church socials, during office coffee breaks and dinner parties - and most blatantly, perhaps, in the personal ads - men and women perform an elaborate ritual of advertisement and assessment that precedes an essential part of nearly every life: mating.

It all may seem very modern, but a new group of researchers argues that love is part of a universal human behavior with roots stretching back to dawn of humankind. These scientists, who call themselves evolutionary psychologist, contend that, in stark contrast to the image of brute cavemen dragging their mates by hair, our ancestors engaged in a sophisticated mating dance of sexual intrigue, shrewd strategizing and savvy negotiating that has left its stamp on human psychology. Indeed, this ancient legacy influences everything from sexual attraction to infidelity and jealousy.

Scientists have long known that people typically choose mates who closely resemble themselves in build and intelligence, But a survey of more than 10,000 people in 37 cultures on six continents, conducted by psychologist David Buss, reveals that men value physical attractiveness and youth in a mate more that women do; women are more concerned with a prospective mate's ambition, status and wealth.

These mating preferences evolved in response to the biological challenges faced by men and women in producing children - the definition of success in evolutionary terms. American evolutionary biologist Robert Trives points out that females invest far more time and energy in reproduction and child rearing than do males. Human infants require more nurturing than any animal on earth. Because of that' women have evolved a psychology that is concerned with a father's to help out with this enormous - with his clout, protection and resources.

"Women size up a man's finances even when they may not have to"

So powerful is this legacy that nowadays women size up a man's finances even when they may not have to. In a recent study, female medical students, though anticipating financial success, were most interested in men whose earning capacity was equal to or greater than their own.

For men, on the other hand, reproductive success depends on the fertility of their mates. Thus, males have evolved a mind-set that homes in on visual signs of a woman's health and youth. Modern man's sense of beauty- clear skin, bright eyes and youthful appearance - is the legacy of aeons spent diagnosing the health and fertility of potential mates.

This concern swith women's reproductive health also helps explain why men value curvaceous figures. Research by Devendra Singh of the University of Texas at Austin reveals that people consists judge of waist to hips. The ideal proportion - the hips roughly a third larger than the waist - reflects a hormonal balance that results in women's storing fat on their hips as opposed to their waists, a condition that correlates with higher fertility and resistance to disease. Today's obession with being slim has not changed this equation, Singh found. While the winning Miss America has become 30 percent thinner over the past several decades, her waist-to-hip ratio has remained relatively consistent.

Men and women also display different mating psychologies when they are just playing around as opposed to searching for life long partner. Women looking for "short-term" mates prefer attractive men, according to a survey by Buss and his colleague David Schmitt. On the other hand, another study found that while men also value attractiveness in the short term, they usually settle for less attractive mates playing the field.

Indeed, throughout human evolution, men have often pursued a dual mating strategy. Their most successful tactic was to find a healthy, fertile, long-term mate. But it also didn't hurt to take advantage of any low-risk opportunity to sire as many children as possible outside the relationship.