By Caitlin Meredtih

Photo John Foxworth   Why do women have sex? According to David M. Buss, Ph.D., there are 237 separate reasons. For their recently released book, “Why Women Have Sex: Understanding Sexual Motivations From Adventure to Revenge (And Everything In Between),” he and co-author Cindy M. Meston, Ph.D., surveyed 1,000 women from around the world and were astonished by the sheer complexity of women’s sexual motivation.  In a recent interview, Buss said while all the predictable reasons women claim to have sex – attraction, love, pleasure – were listed, other “darker regions of human nature” also emerged. “Some women had sex to get revenge, to steal another’s boyfriend and a few even had sex in order to give someone else an STD.”

Like his three previous books on other aspects of the relationship between the sexes, “Why Women Have Sex” has received both national and international attention since it’s release in the fall of 2009. It is being translated into 13 languages. However, Buss’ research on the psychological differences between men and women were not always so well received.

In 1989, while working at the University of Michigan, Buss wrote a paper based on his 37-culture study of how women and men choose their mates. His conclusion that there are universally significant differences between what each gender is looking for — women value the potential for “resource acquisition” while men seek “enhanced reproductive capacity” – was met with criticism, hate mail, and even a suggestion by a fellow professor to suppress his findings. This hypothesis suggested that not only were there real, fundamental differences between the sexes, but that family and community were not the primary shapers of human behavior. Buss said this theory is now a staple of psychology 101.

 It was no accident that Buss’ study included 37 different cultures. Thinking at the time was that such mate selection differences were specific to U.S. and other Western cultures. According to evolutionary psychologists, an Inuit fisherman and a Wall Street banker share the same essential motivations regardless of culture or family of origin. Because of this belief, they test their hypotheses on multiple cultures, not always the case in social science research. “Evolutionary psychologists are held to a higher standard,” Buss said. “They implicitly assume universality.”

A common misperception about evolutionary psychologists is that since they describe human behavior as universal, they also believe human behavior is unchangeable, said Buss. Scandinavia, once the terrain of axe-wielding, invading Vikings that now has one of the lowest murder rates in the world, is one of many examples that refutes this notion.

Explaining humans in evolutionary terms can also lead to the false conclusion that evolutionary psychologists justify bad behavior, what Buss referred to as the “is-ought” problem. People believe that because the research explains the evolutionary motivations for human actions, the “is”, even in its darkest forms like murder, that the obvious conclusion is that it is inevitable or even beneficial, the “ought.” Universal claims about human beings’ capacity for negative behavior like infidelity and murder make people uncomfortable.

“Instead,” Buss said, “knowledge of our evolved psychology gives [us] a handle on how to turn on or off those competitive impulses.” In Buss’ research areas that involve crime and victims — murder, stalking and jealousy — this is especially important.

His findings that men are more likely to crave sexual variety  for evolutionary reasons, for instance, might lead some men to justify their extra-marital meanderings.  But Buss said many men have told him that knowing about the scientific basis for their wandering eye actually helps them stay more faithful because they understand it does not mean they do not love their wives.

Buss used Safeway grocery store as another example to explain how learning more about our evolved sexual differences can help us inhibit unwanted behaviors. In the late ’90s, the supermarket chain started a policy that required its salespeople to greet customers with a smile and eye contact. While the company’s intent was to improve customer service, the unintended consequence was increased sexual harassment of female workers by male customers.

Buss said this was a classic case of  “sexual over-perception bias.” His and others’ research has shown that men and women interpret the very same social acts in very different ways. What seemed like friendly smiles to the women, were taken as flirtatious overtures by the men, giving them permission to flirt back, sometimes to the point of sexual harassment. Conversely, women tend to feel more fearful and judge the same behaviors — like smiles — more negatively. A group of female workers finally sued and the policy was abandoned. If Safeway management had been more attuned to this evolved bias in men, Buss said, they could have predicted the effect the policy would have had.

Such policy implications were not always important to Buss. “Initially I was just interested in what makes people tick,” said Buss. “But now I’m more interested in using my research for positive change.”

Though his interest started with the why’s and how’s of mating, it soon led him down the path of jealousy, stalking and murder. As he got more interested in the criminal behaviors, however, he found that the consequences of his research touched the lives of people he knew.

Working on a college campus, where the American Society of Criminology estimates 25 percent of women are the victims of attempted or completed sexual assaults, it is hard to ignore the implications of his research on sexual victimization. Many of Buss’ female students have shared their stories of unwanted sexual attention, being stalked and raped.

In order to translate their findings into real-world interventions, Buss and Professor Joshua Duntley, a former student, used their research on common stalking triggers and patterns to create a Web site to help victims, http://stalkinghelp.org. Buss plans to launch a similar Web site to help victims, or potential victims, of sexual abuse.

Studying human’s capacity for murder, stalking and sexual obsession might create a cynical view of humanity, but Buss has a broader perspective. “We are a collection of behaviors,” Buss said. “Some are abhorrent and some are rosier.”

Buss believes that understanding the full spectrum of human behaviors, especially the darker ones, is essential to understanding the world.

“As you can probably tell, I’m not a fan of suppressing scientific truths,” Buss said. “Knowledge is almost always better than ignorance.”