Are Our Sexual Brains From the Stone Age?

Aug. 27 -- Men aren't the only ones with cheating hearts, and scientists do not believe that there is any such thing as a battle of the sexes either, according to a new book that takes a scientific look at sex.

In her new book, Sex: A Natural History, science reporter Joann Rodgers debunks some previous sexual theories, as she explores the biology and psychology of what drives our sexual behavior, from why we find Hollywood star Brad Pitt attractive, to why we sometimes cheat on our mates.

The findings: Sex is a lot more scientific than you might think. Though often influenced by culture, Rodgers found that human sexual behavior, including flirting and courtship, is also determined by biology — and certain rituals are the same now as they were in the era of cavemen.

"A lot of sexual behavior — including what we're attracted to — is hardwired into our brains," Rodgers said. "A lot of it is conditioned by the way evolution formed our brains. Basically, our sexual brains are from the stone age."

The Mating Dance

Culture also plays a role, which leads to variation in sexual behavior among various people and varying ideals of beauty. But there are basic similarities that remain the same.

"Certain kinds of behavior are so universal that they appear to be biologically programmed," Rodgers said. "There is a mating dance."

When scientists studied flirting couples at a hotel bar, they saw some of the same things again and again — gestures that are part of our "brain chemistry," Rodgers said.

A couple that was "connecting" would look into each other's eyes. When they sat down together, the man would lean forward, thrusting out his chest, while the woman would start twirling her hair.

"The man makes the first touch, say pretending to brush something off the woman's blouse," Rogers said. The hands would eventually touch each other, and eventually, the couple heads off to one of the rooms, researchers found.

No Battle of the Sexes