Evolved Sexuality

An Interview with David M. Buss

It might sound like a lame excuse.

But if a man cheats on his wife, he might explain himself this way: “I couldn’t help it. My evolved psychological mechanisms made me have an affair.” And he’d be right.

Sort of.

David M. Buss, a psychologist at the University of Texas, has spent more than two decades studying sexual desire and behavior. And his research has led to one overarching observation: Across cultures, people’s mating strategies are universal.

Put in the most basic terms possible: Men and women are radically different when it comes to sex. Women seek mating partners with status and resources. Men seek partners who are physically attractive. Men are far more interested in casual sex than women are. All you need is love.

These conclusions conform to stereotypes of men and women and sex, but Buss’ work doesn’t merely describe behavior we’ve all seen. His book The Evolution of Desire (originally printed in 1994 and revised and expanded in 2003) proposes a unified theory of human mating.

As Buss writes in his book: “Sexual strategies are adaptive solutions to mating problems. Those in our evolutionary past who failed to mate successfully failed to become our ancestors. All of us descend from a long and unbroken line of ancestors who competed successfully for desirable mates, attracted mates who were reproductively valuable, retained mates long enough to reproduce, fended off interested rivals, and solved the problems that could have impeded reproductive success. We carry in us the sexual legacy of those success stories.”

Buss’ book answers a host of vexing human questions. The author listed a few in a recent interview: “Why would people be motivated to mate with the people that they’re motivated to mate with? Who are people fundamentally attracted to? Do … men and women differ profoundly in their mating preferences and their mating tactics and their mating strategies? Do mating strategies vary by context? The whole short-term [mating]/long-term [mating] distinction is critical. People don’t just marry for life, but they also engage in all sorts of mating.”

Across cultures, Buss found, mating behaviors are the same, and they all work toward the continuation of the genetic line. Women value status and resources because those give offspring the highest chance of survival. Men, on the other hand, seek women with certain physical features because they are outward signals of health and fertility. Men are more willing than women to have casual sex because that gives their genes the best chance to be passed on.

This straightforward explanation for human mating behavior, though, is problematic on several levels. And controversial.

“A Volatile Mix”

Sexuality, evolution, and sex differences are all politically charged subjects, Buss said, and in putting them together “you get a very volatile mix. … The bottom line is it that it [the findings] contradicted widely held beliefs at the time.”

For one thing, Buss’ work provides a scientific theory explaining – and perhaps providing excuses for – all sorts of behaviors that most people frown upon, from infidelity to the male fixation on mate appearance to, possibly, rape.

Second, Buss’ theory undercuts some of the things we want to believe about our sexual relationships. “One likes to believe that someone values you or loves you for who you are, your personal qualities,” he said. “And so … things like, from a male perspective, the notion that females place an importance on a man’s position, status, and resources, that can be a little bothersome. Or conversely, from a woman’s perspective, the fact that men value physical appearance so highly in their mate selection … .

“There is a kind of harsh reality that resources and physical appearance do matter. And those sorts of findings contradict our romantic visions of how we would like mating to be.”

In a scientific context, Buss said, his findings and theories applied the relatively new field of evolutionary psychology to human mating. “There was a belief in the social sciences that men and women were identical in their underlying psychology except by virtue of how they were socialized by parents or the culture,” Buss said. His research, on the other hand, suggested that this “blank slate” theory of human psychology was incorrect, and that there are dramatic and universal sex differences.

Through evolution, Buss said, “humans come into the world equipped with psychological adaptations that emerge at relevant times during development.” For example, infants have a suckling reflex, Buss said, while six-month-old children have a fear of strangers. And when puberty hits, mating adaptations kick in.

For many people, an evolutionary explanation for mating behavior will make intuitive sense. Buss’ book is geared to the general reader, and his language, points, and analogies are clear. But Buss said that his findings were surprising.

“These things are often common sense or intuitive in hindsight,” he said. But “before I did the cross-cultural study, I went around to different professors in psychology and sociology and anthropology, and I asked them to make a prediction about whether the sex differences that I found [in the United States] would be local to our culture or to Western cultures or to capitalist cultures, or whether they would be universal, and almost every single professor predicted that they would not be universal.” And they were wrong.

Other surprises in the research, Buss said, included the universal emphasis placed on love in mating. “I was taught that love was a kind of Western invention by some white European poet a couple hundred years ago,” he said. He added that he also hadn’t anticipated “the ubiquity of sexual conflict” in mating behaviors around the world.

Can Behavior Be Changed?

Buss was first attracted to mating as a research topic in the early 1980s, he said. He was trained as a personality psychologist and started research into sexuality on the side. People obviously talk a great deal about sex and relationships, he said, yet the scientific understanding of mating was inadequate.

“There weren’t really any good theories of mating, and the theories of mating that existed were very simplistic,” Buss said. “There were things like, well, people look for people who resemble their opposite-sex parent. You have that kind of Freudian conception. Then you have, well, people look for similarity. Or, no, … people look for opposites.

“But these aren’t really well-grounded theories … . I realized that there was a vast field out there, a domain that was theoretically extremely important, given its proximity to the engine of the evolutionary process, and also important in everyone’s day-to-day lives, but that the field really hadn’t studied it.”

He started with research in the United States and in 1984 gave a lecture on his early findings. American Scientist invited him to write an article on the topic, and the response to that 1985 piece allowed him to expand his inquiries to cultures around the world. That led to the key finding – against expectations – that mating behaviors are indeed universal. That, in turn, laid the groundwork for Buss’ conclusion that sexual selection – a theory first espoused by Darwin – had forged human mating behavior over millions of years.

Buss said that he felt strongly about sharing his work with the general public, not just scientists. “I’m a firm believer that scientists should not remain cloistered in their laboratories writing for the 37 other people in the world who are doing similar kinds of work,” he said. “Ultimately, I am and other professors are public servants … . I teach at a state univers
ity. … I’ve received grant funding from the federal government, from other foundations, so ultimately, it’s the people – including taxpayers – who support the work. So why shouldn’t they be the beneficiaries of access to knowledge about the work?”

Mating is obviously a topic of intense interest to most people, and Buss’ work generates as many questions as it answers. Perhaps most importantly: Can these mating behaviors be changed?

Just because behaviors that a society deems unacceptable or undesirable are deeply ingrained through evolution doesn’t mean that we have to accept them, Buss said.

“You can deactivate certain psychological mechanisms,” he said. “For example, in the realm of sexual conflict, things like sexual coercion, sexual harassment, we know that … male psychology is sensitive to the cost of doing those sorts of things. So ratcheting up the costs of behaviors that we don’t like or find abhorrent will lower their incidence. And I think it has.

“I think it would be extraordinarily difficult to eliminate the underlying psychological mechanisms that generate the behavior, but you can curtail the expression of those mechanisms in behavior by raising the cost of those things.”

Other tendencies, though, might be impossible to reduce, such as the male preference for physically attractive women. That inclination stems from the “wealth of information that physical appearance provides about a woman’s underlying health status and fertility status,” Buss said.

As for the man who could use evolutionary psychology as an excuse for philandering, Buss said that knowledge about the roots of mating patterns can be a tool to alter behavior. “Some men tell me that reading my book has helped them to remain more faithful to their wives,” he said, “because what happens is they find themselves attracted to other women, and the fact is men and women are attracted to other individuals even if they’re in happy relationships. … They realize it doesn’t mean that they don’t love their wives or girlfriends. They say, ‘Oh, that’s my evolved desire for sexual variety talking.’ And that helps them to keep that in a proper perspective.”

This article originally appeared, in slightly different form, in the River Cities’ Reader.