Another study showed that teens use different areas of their brains to perceive emotion.
When scientists at the McLean Hospital in Belmont, Mass., showed a group of teenagers and a group of adults pictures of faces, the adults correctly identified the emotion in the pictures as fear.
The teens' answers varied...and, because the scientists were watching the brain activity of the subjects through functional magnetic resonance imaging, the researchers could tell the teens were using the amygdala, a small region of the brain that's known for gut reactions, whereas the adults used the frontal cortex.
Here's where parents might wonder why on earth the brain would be programmed that way during adolescence. Casey, herself a mother to a 17-year-old boy, has spent a lot of time pondering that question, and has developed a theory of adaptation. When kids are young, parents act as their prefrontal cortex, she said. As teens venture out into the world, that has to change.
"The reason we think this is going on," she said, "is that you reach puberty and you need to go out and find a mate and other resources, and something's got to pull you out of your comfortable environment. It's a period of time where they need to learn how to be able to adapt to social pressures; to test the waters."