Pornography studios might do well to take a tip from the Discovery Channel. According to a recent study, women are aroused by watching monkey sex. Sure, they're more aroused by watching human sex, but the loving habits of the bonobo are enough to bring out the primate in any civilized lady.
The study, conducted by Meredith Chivers of the Center for Addiction and Mental Health and J. Michael Bailey of Northwestern University, was published in the October issue of Biological Psychology. The researchers found that while straight men are only aroused by females of the human variety, straight women are equally aroused by all human sexual activity, including lesbian, heterosexual and homosexual male sex, and at least somewhat aroused by nonhuman sex.
Each subject involved in the report watched seven two-minute clips of sex: six scenes involving humans and one of bonobos. The subject constantly monitored and noted his or her subjective arousal. The subject was also affixed with a device that measured genital arousal–penis circumference for the men and vaginal pulse amplitude for the women.
All eighteen men were heterosexual and all reported subjective arousal only during the scenes with women. The objective data matched their reports: Images of our evolutionary ancestors do not make a man retrogress to Homo erectus. The eighteen heterosexual women reported greatest subjective arousal during the heterosexual scene, but their bodies reported they were less naturally selective.
Chivers said in a previous study she had shown a very low correlation between women's stated sexual interests and their sexual arousal patterns in the lab. The correlation was much higher for men, she said.
"There's the possibility that genital response for women is not necessarily imbued with meaning about her sexual interests," says Chivers. She also emphasized that her findings do not imply women harbor a latent desire for lesbian sex or bestiality.
While the women did not report their arousal in the subjective part of the study, Chivers said women are generally receptive to her findings about their objective responses.
"When I speak to women, there's sort of an intuitive 'Oh, yeah,'" she says.
Barbara Bartlik, a psychiatry professor at Cornell, said she was not alarmed by the women's response to the nonhuman stimuli.
"I don't know why this has surprised everybody that women get aroused watching humans and animals," she says. "Animals, because of the way they function in an uninhibited manner...can be very arousing to look at when they copulate."
However, Bartlik was surprised that the men did not have the same response as the women.
"I would wonder if the men weren't concerned about being labeled as homosexual or perverse by being interested in these things, and therefore their erections were inhibited," she said.
Chivers hopes to discover what specific aspect of a visual stimulus causes women to become aroused. Some experts believe mentally labeling an act as sexual arouses women. Others, including Chivers, believe innately recognized sexual features such as an erect penis, even out of their usual human context, stimulate women. She said she did not yet know how similar to humans an animal would need to be in order to elicit a sexual response from women.