The Truth Behind Women's Brains PART 2

[Juan and Yenan]

The Truth Behind Women's Brains
20/20's Elizabeth Vargas Looks at the Chemical Changes That Occur Through Life That Change How Men and Women Think

Girls' Brains More Advanced at Puberty
To further illustrate how a teen's changing brain chemistry often molds their behavior, Dr. Brizendine invited ABC's 20/20 to listen as she spoke to students at the Marin School outside San Francisco. Girls, she explained, mature faster than boys, and girls' brains are as much as two years ahead during puberty.

In fact, neuro-imaging shows that, early on, the typical teen girl has a stronger connection between the areas of the brain that control impulse -- the amygdala -- and judgment -- the prefrontal cortex.

It may not be until late adolescence or their early 20s that boys' brains catch up to their girl peers.

"To know that they're smarter than us by two years -- it's a gap, it really is," said John Bessolo, one of the students in Dr. Brizendine's high school group. "They are the superior beings of the brain."

But when it comes to sex, boys take the lead -- or least their brains do.

Dr. Brizendine explains that the male amygdala, which also controls sexual thought, is twice as large as that of females. Fueled by testosterone, it triggers the typical teenage male brain to think about sex every 52 seconds, compared to a few times a day for teen girls.

"When I hang out with my guy friends, it's really odd to think that every, like, whatever seconds, they're thinking about sex," said high school student Sara Johnson. "And that you can't stop them from thinking about that."


Are Girls Really More Emotional?
When it comes to emotions, Dr. Brizedine says girls have their own area that's twice as large as boys' -- the hippocampus, which is the seat of emotional memory. The female brain uses many centers in both hemispheres that activate in response to faces, voices and expressions. Men, however, use only one side of their brain.

Dr. Brizendine asked the teens to come up with questions they always wanted to ask the opposite sex. Teen girls, she explained, physically receive pleasure through the simple act of gossiping.

John posed the first question to the girls: "Why do you go to the bathroom in groups?"

"Girls are close to each other, and we like to do things together," responded Kelly Ericson, another member of the class. "It's more, 'I have to go pee. Oh, you have to go pee too? Let's go together.'"

Dr. Brizendine had a scientific explanation for this increased camaraderie in girls.

"Actually, there is a hormone that gets released when girls are, sort of more intimate with each other -- in terms of talking and fixing each other's hair and doing stuff. That's called oxytocin. It's a hormone that's released in the brain that's kind of a "feel good" hormone."

The hormone oxytocin gives a surge of pleasure, the same rush a drug addict gets from taking cocaine or heroin.