The standard narrative of human sexual evolution says: men provide women with goods and services in exchange for women’s sexual fidelity. But is that really true or relevant today? Christopher Ryan, the co-author of Sex at Dawn with Cacilda Jethá, takes a deeper look and has quite a few bones to pick with this idea.

Christopher Ryan: Are we designed to be sexual omnivores? Ryan explains that our sexual patterns are an outgrowth of agricultural models—which accounts for only about five percent of human history. For the other 95 percent, human sexuality was “a way of establishing and maintaining the complex flexible social systems, networks, that our ancestors were very good at.” In hunter-gatherer societies, there were overlapping sexual relationships between members of a community—a more fluid system than the Victorian model we’re wedded to today. In fact, several contemporary societies around the world argue against the sexual myth we’ve built up, too.

“My hope is that a more accurate updated understanding of human sexuality will lead us to have greater tolerance for ourselves, for each other, greater respect for unconventional relationship configurations like same-sex marriage or polyamorous unions, and that we’ll finally put to rest the idea that men have some innate instinctive right to monitor and control women’s sexual behavior,” Ryan says. “And we’ll see that it’s not only gay people that have to come out of the closet: we all have closets we have to come out of.”

Below, read up on some more lines of research that suggest out-of-the-box ideas about our sexuality.

1. Question: Is bisexuality a sexual orientation, something that’s temporary or an outgrowth of the sexual fluidity we all exhibit?
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   Research: In a 2008 study, Lisa M. Diamond of the University of Utah presented the results of a decade-long assessment of nearly 70 women who identified as lesbian, bisexual, or sexually unlabelable. Five times over the course of the study, the women detailed their sexual identities, attractions, behaviors, and their social and familial relationships.
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   Results: Based on Diamond’s findings, bisexuality is not a “transitional stage that women adopt ‘on the way’ to lesbian identification” or an “experimental phase” for heterosexuals. Her results, instead, supported that, “Bisexuality may best be interpreted as a stable pattern of attraction to both sexes in which the specific balance of same-sex to other-sex desires necessarily varies according to interpersonal and situational factors,” she writes.
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2. Question: Which comes first—desire or arousal?
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   Research: In a study from 2004, described in this New York Times article, Ellen Laan, Stephanie Both and Mark Spiering of the University of Amsterdam examined participants’ physical responses to sexual images.
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   Results: The research indicates that we respond physically to highly sexual visuals before our mind even engages with them. In other words, desire doesn’t precede arousal—it’s the other way around. And we aren’t even aware it’s happening.
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3. Question: Do men and women respond differently to sexual images?
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   Research: The same New York Times article describes an Emory University study that tracked participants’ eye movements and brain activity while they looked at sexually explicit photos.
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   Results: Men and women didn’t have the same reactions, but they might not be the ones you’d expect. Men looked at the faces in the photographs much more than women did, and everyone quickly flipped past close-ups of genitalia. Brain activity was gender-dependent: in particular, men had a lot more activity in the amygdala than women did.
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4. Question: Does geography influence the body types we idealize and are attracted to?
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   Research: There’s a lot written about the effects of culture and media on the bodily standards we uphold. But the International Body Project, a survey of 7,434 people worldwide, aimed to investigate whether there were more base-level factors motivating our ideal body types, too.
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   Results: The researchers found that places with low socioeconomic status tended to value heavier female body types, while places with high socioeconomic status tended to favor thinner bodies—possibly because body fat acts as an indicator of status when resources are scarce. And the effect of media shouldn’t be underestimated: “Our results show that body dissatisfaction and desire for thinness is commonplace in high-SES settings across world regions, highlighting the need for international attention to this problem,” the researchers write.
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5. Question: Do men and women have different sex drives?
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   Research: A recent New York Times Magazine article describes a University of Wisconsin, Madison “meta-analysis” of more than 800 studies of our sexual habits conducted over 15 years.
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   Results: The researchers found that “the evidence for an inborn disparity in sexual motivation is debatable,” the Times Magazine piece reports. The study “suggests that the very statistics evolutionary psychologists use to prove innate difference — like number of sexual partners or rates of masturbation — are heavily influenced by culture. All scientists really know is that the disparity in desire exists, at least after a relationship has lasted a while.” Women’s desire does decrease, but not as a matter of course—as a result of monogamy in particular.

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