The first experiment in the most intensive study on sex since the days of Alfred Kinsey took place in the summer of 2009 over a bowl of spaghetti. Ogi Ogas, a Boston Ph.D. student, had run into a neighbor couple in the lobby of his apartment complex as they were picking up their mail. He didn't know them well but figured it was worth a shot: Ogas asked if they might "help" with a study he was conducting—a massive survey about sex. The couple laughed nervously. But they were intrigued. Forty-eight hours later, the three men sat sandwiched on a red vinyl couch, sharing pasta, red wine, and a marathon session of gay porn. A giant silk-screen of Sophia Loren hung in the background; the couple's pug nuzzled at the trio's feet. They would remain in this position for five hours.
It wasn't an orgy, nor was it typical entertainment for Ogas, a 40-year-old computational neuroscientist (who has a girlfriend). But while Ogas's fellow doctoral students were busy writing computer code, he and his buddy Sai Gaddam simply couldn't stop talking about sex. Specifically, how the brain decides what turns us on. "Nobody in our field had taken a shot at sexual desire—and most of our colleagues thought we were insane to do it," Ogas says. "But the same neural principles that apply to our higher cognitive functions apply to sexual behavior, too."
And so began the "world's largest experiment" in human sexuality, as the first-time authors call it in their new book, A Billion Wicked Thoughts. Analyzing the results of a billion anonymous Web searches, Ogas and Gaddam claim to have determined the sexual behavior of more than 100 million people.
Anything anyone can possibly imagine is supposed to be available in online porn. But that doesn't mean it's those niche kinks that most people are searching for. In fact, the most popular erotic searches are relatively conventional, with just 20 interests accounting for 80 percent of all searches. The most popular? "Youth."
The authors say men are wired to view women's anatomy as objects. A computer engineer would say the male brain is like an "OR gate"—a machine turned on by any single stimulus. "It doesn't take much to trigger male arousal," Ogas says. Breasts, women kissing, a news photo of a woman's bottom—they pretty much all do the trick.
To figure out, that is. A woman's sexual brain chemistry is far more complex than a man's—chock-full of wires that require multiple stimuli to get turned on. A chiseled face or six-pack abs simply won't do it for most women: they need to be emotionally turned on, too. Complicated, but oh-so-alluring.
The number of men in the U.S. and Canada who accessed online porn in 2008.
The bra size that attracted the most men in an experiment conducted in a French nightclub.
3 to 1
The rate at which men look for overweight women compared with underweight women in Web searches.