In the spring of 1978, a professor at Florida State University gave the students in his seminar on experimental social psychology an unusual assignment. For the next few weeks, they were to approach undergraduates of the opposite sex and compliment them: “I’ve been noticing you around campus lately and find you very attractive.” Then they would ask one of the following questions:
(a) “Would you go out with me tonight?”
(b) “Would you come over to my apartment tonight?”
(c) “Would you go to bed with me tonight?
Roughly equal numbers of men and women on the FSU campus accepted invitations for dates from strangers: in response to question (a), 50 percent of men and 56 percent of women said yes. However, the responses to (b) revealed a dramatic split, which followed gender lines in exactly the manner the professor had predicted: while 69 percent of men were willing to meet a female stranger at her apartment, only 6 percent of women would meet a male at his. And while 75 percent of the male students approached said they were game for casual sex, not one female did.
The professor, whose name was Russell D. Clark III, never recounted how many actual hookups (or hurt feelings) resulted from the experiment. He did, however, develop a novel approach to analyze his data. Clark argued that men and women reacted differently to being propositioned in part because they had evolved differently. Contemporary attitudes toward sex were not the product of social norms; they constituted adaptations. Nature selected swagger in men and prudishness in women over eons, just as it favored gazelles with limbs quick enough to flee predators and birds with beaks sharp enough to break seeds: such traits increased the fitness of our ancestors, their ability to survive and reproduce themselves.
The first colleagues to whom Clark sent his article dismissed it. “This paper should be rejected without possibility of being submitted to any scholarly journal,” one peer reviewer wrote. “If Cosmopolitan won’t print it…then Penthouse Forum might.” Clark had given up on finding a publisher when, in 1980, he met Elaine Hatfield, a psychology professor at the University of Hawaii who shared his research agenda and convinced him that it was worth fighting for. In the spring of 1982, Clark and Hatfield repeated the FSU study and obtained almost identical results. Still, fellow scientists were skeptical. “Who cares what the result is to such a silly question,” read one rejection letter the pair received in 1984. “I mean, who cares other than Redbook, Mademoiselle, Glamour, or Self—all of which would cream their jeans to get hold of this study.”
It wasn’t until July 1988 that the Journal of Psychology & Human Sexuality accepted Clark and Hatfield’s article. When it appeared in 1989, “Gender Differences in Receptivity to Sexual Offers” passed mostly unnoticed. Among the few of their colleagues who did take note, some pointed out that it used evolution to excuse chauvinistic behaviors. “The devil (or Darwin) made me do it,” joked one feminist critic. But Clark and Hatfield would have the last laugh: their claim that the insights of evolutionary biology could be used to cast light on the human mind and human behavior became the first principle of a new field that took off in the 1990s. Dubbed “evolutionary psychology” (“ev psych” or “EP” for short), it has gained an ever-stronger hold on the popular imagination.