Fans of Fifty Shades of Grey have declared the book so steamy that they recommend women wear pantyliners while reading it. The film version premieres this weekend, and devotees who have already broken records in pre-sale tickets might expect the big-screen experience to be even hotter than the book. But science suggests that they can leave their pantyliners at home.
Regardless of whether director Sam Taylor-Johnson created a titillating film, researchers have found that women don't enjoy watching sex as much as they do reading about it — which means Christian Grey probably won't satisfy on the silver screen quite like he did on their Kindles.
"There's overwhelming evidence that women prefer erotica to be textual rather than visual," says Ogi Ogas, a neuroscientist and co-author of A Billion Wicked Thoughts, in which he analyzes billions of web searches and millions of erotic sites to quantify what people truly desire. He found that women make just 1 out of every 50 purchases on porn websites, but that they buy 9 out of every 10 romance novels.
There's a scientific reason women prefer to read about sex rather than see it. Historically, men have had a biological imperative to impregnate as many women as possible, so that they have the highest chance of passing on their genes. "For a man, all he needs to know is whether the woman is healthy and fertile. You can judge that visually," says Ogas. This has been demonstrated by a body of research which shows that men are more easily aroused by visual stimuli.
By contrast, consider the biological imperatives for women, who have a limited number of opportunities to bear children and, accordingly, must use caution when picking a mate. Determining whether the man can and will take care of their children and whether he will make a good partner long-term are crucial. This has become so ingrained in our romantic ideals that even after birth control became ubiquitous and women were allowed to see sex as a means of pleasure, the fantasy persists. Even if they aren't planning on having children or are attracted to other women, Ogas says brain scans show that women need more than a hot picture to be psychologically aroused — even if they are physically. So the fantasy of learning about a man's true nature became the center of almost all erotic literature (not to mention classic literature as well, from Jane Eyre to Gone With the Wind.)
"What is he thinking? Will he be here for the long haul? These are not questions you can get immediate answers to," says Ogas. "That's why a 200-page book is so much better suited to this fantasy than a video clip. It perfectly replicates that puzzle."
While the most popular porn site for women only receives about 50,000 visitors per month (compared to the tens of millions of male visitors to top porn sites like XVideos, YouPorn, and RedTube), millions of women buy erotic novels. Fifty Shades alone has sold over 100 million copies. And many women visit fan-fiction websites where they share and discuss erotic fantasies surrounding their favorite novels, like Fifty Shades of Grey—which itself started out as Twilight fanfiction.
Some sociologists have argued that women have been taught not to seek out visual porn, or that there's a dearth of female-friendly porn videos that focus more on plot. But Ogas says there are plenty of female directors making "feminism-friendly" visual pornography with a narrative — it just doesn't get clicks. "If women wanted to see that kind of porn, they would seek it out," says Ogas. "Huge numbers of men are routinely looking for things that weren't culturally indoctrinated in them — things you would never talk about with friends — when they're online in the privacy of their own homes. Not true for women."
In short, women's browsing habits suggest they like to leave certain things to the imagination — and their imaginations are a lot more detailed that those of their male counterparts. In a seminal study conducted at a California university in 1990 and published in the Journal of Sex Research, psychologists found that men's fantasies revolved around the physical aspects of the sex, whereas women liked to focus on details.
"Women pay more attention to setting and circumstance," says Catherine Salmon, an evolutionary psychologist who studies pornography. "They're also a lot more likely to fantasize about someone they know — a current partner, a past partner, someone they would like to be a future partner, or a celebrity."
But unlike what you might find on PornHub, Fifty Shades does still have a romantic plot. "This isn't the porn version of Fifty Shades. It's still going to be a romance, albeit a kinky one, and women will enjoy that part," Salmon says. After all, they have long flocked to so-called chick-flicks. Even the most visually stimulating movies aimed at heterosexual women, like Channing Tatum's Magic Mike, fulfill the romantic fantasy. "If Channing Tatum had turned out to be an a-hole in that movie, women would not have liked it."
Still, Fifty Shades fans have long imagined themselves in Anastasia's heels. Seeing that fantasy translated to the screen will likely be more enjoyable for the boyfriends dragged to this film than the female fans themselves.
"I suspect that if women were fans of the book — if they found it pleasurable — the movie will be a bit of a disappointment," says Ogas.
Don't worry. The book will still be there when you get home.
Malerie Marder for TIME