With its expansive range and unprecedented potential for anonymity, 
the Internet gives voice to our deepest urges and most uninhibited thoughts. Inspired by the wealth of unfettered expression available online, neuroscientists Ogi Ogas and Sai Gaddam, who met as Ph.D. candidates at Boston University, began plumbing a few chosen search engines (including Dogpile and AOL) to create the world’s largest experiment in sexuality in 2009. Quietly tapping into a billion Web searches, they explored the private activities of more than 100 million men and women around the world. The result is the first large-scale scientific examination of human sexuality in more than half a century, since biologist Alfred Kinsey famously interviewed more than 18,000 middle-class Caucasians about their sexual behavior and published the Kinsey reports in 1948 and 1953.

Building on the work of Kinsey, neuroscientists have long made the case that male and female sexuality exist on different planes. But like Kinsey himself, they have been hampered by the dubious reliability of self-reports of sexual behavior and preferences as well as by small sample sizes. That is where the Internet comes in. By accessing raw data from Web searches and employing the help of Alexa—a company that measures Web traffic and publishes a list of the million most popular sites in the world—Ogas and Gaddam shine a light on hidden desire, a quirky realm of lust, fetish, and kink that, like the far side of the moon, has barely been glimpsed. Here is a sampling of their fascinating results, selected from their book, A Billion Wicked Thoughts.

LESSON ONE: Age is important, but youth is not the only attractor

The most influential male cue of all is chronological. Age dominates sexual searches, adult Web site content, and pornographic videos. On Dogpile, terms describing age are the most frequent type of adjective in sexual searches, appearing in one out of every six of them. When a man’s desire software evaluates a woman’s appearance, one of the most prominent criteria is age—and not just youth, either. Many sexual searches on Dogpile contain specific ages, such as “naked 25-year-olds” or “sexy 40-year-olds.” Though the popularity of adult women doesn’t quite reach that of teens, it is worth observing that more men search for 50-year-olds than search for 19-year-olds. There is a rather shocking number of searches for underage women, but you may be equally surprised to discover there is significant erotic interest in 60- and 70-year-olds. At one high-traffic porn site, the single most popular term users enter into the search engine is mom. On AOL, one out of four people who searched for sexually attractive mothers (MILFs) also searched for teens. Though the total number of granny searches amounts to less than 8 percent of the total youth searches, there are more sexual searches for grannies than for some common fetishes like spanking.

LESSON TWO: Men Are Trigger-Happy Hunters

On the Internet, male desire is a solitary affair. Men sit alone clicking on videos and images, rarely seeking to share their tastes and experiences with other men. Other men’s opinions about what is sexy are irrelevant or distracting. Men don’t require any information about a woman other than what they can see with their own eyes. They are also quite happy to masturbate alone in the airplane bathroom or at the back of the classroom—or in their office at the Pentagon.

THE LUST OF ELMER FUDD...
  Solitary, quick to arouse, goal-targeted, driven to hunt...and a little foolish. In other words, the male brain’s desire software is like Elmer Fudd. Fudd, the comic foil of Bugs Bunny in the Looney Tunes cartoons, is always on the hunt for a specific target: rabbits. Or as he says it, wabbits. Fudd is a solitary hunter. He is trigger-happy. The moment he sees a wabbit—or thinks he sees a wabbit—he squeezes the trigger.

Fudd is easily fooled by ducks dressed up as rabbits and other tricks played on him by Bugs Bunny. But even when Fudd shoots at a phony rabbit, he never gets discouraged. He reloads and gets back out there. Tomorrow is another day for the hunt. Another chance to bag a wabbit.

...DATES BACK 
TO CRO-MAGNON DAYS
  The male brain is designed to be more visually responsive to sexual stimuli than the female brain is. Male arousal itself relies on two structures located in the subcortex: the amygdala and the hypothalamus. These are tiny structures that operate without our conscious awareness. The amygdala is responsible for emotional responses. The hypothalamus is the engine of sexual arousal. In studies in which both men and women viewed pornography, the amygdala and the hypothalamus were activated more strongly in men. What you may have long suspected is true: Men’s brains are designed to objectify females.

This objectification of women extends deep into the mists of prehistory. The 
famous 26,000-year-old Venus of Willendorf statuette, hand-carved by a Cro-Magnon in Paleolithic Germany, features GG-cup breasts and a hippopotamal butt, but no face. The 40,000-year-old Venus of Hohle Fels boasts even more prodigious hips and mammaries—and titanic labia.

LESSON THREE: When nobody is watching, big is beautiful

Like youth, a woman’s body size appears to be an innate trigger of male arousal. Adjectives describing body size (such as chubby and thin) are the third-most-frequent category of adjectives appearing in Dogpile searches. Most of these searches are not seeking the slender bodies of cover models. For every search for a “skinny” girl, there are almost three searches for a “fat” girl. On the Web, many men are fans of BBW, which stands for Big, Beautiful Women. On the Alexa list, there are more than 504 adult sites explicitly dedicated to heavy ladies, and only 182 explicitly dedicated to skinny ones. The women on adult BBW sites have very large and round breasts, large and curvy hips, and large and round butts. Indeed, the overall impression is one of supersize visual cues of femininity. (Although the majority of women in mainstream porn are skinnier than average, toothpick-thin women are a rarity.)

Many sex scientists believe that women’s waist-to-hip ratios are a visual cue for men. Some research suggests that men around the world find a specific waist-to-hip ratio (0.7) to be most arousing. Even a particular part of the male brain associated with reward processing, the anterior cingulate gyrus, appears to be activated when a man views an ideal waist-to-hip ratio. However, hips and waist themselves rarely appear in sexual searches. If men prefer a low waist-to-hip ratio, this may be one reason why some men prefer heavy women, since many of the models featured in BBW porn have a low ratio due to their excessive hip size.

Large breasts are also extraordinarily popular in Internet porn, dominating images, stories, videos, and most international variations of animated erotica. Breasts, no matter what size, are the most popular body part in sexual searches in every country we looked at, including the United States, Russia, India, Germany, Japan, and Saudi Arabia.