Brains of outgoing people react more positively to happy faces than those of shy individuals, study shows

It doesn't matter whether people are shy or outgoing, their brains react the same way to something scary - call it a universal human trait of self-preservation.

But Stanford researchers have discovered that people's brains are more likely to react to something positive - such as a happy face - if they are upbeat and outgoing rather than serious and shy.

"We think this is a nice example of the way the brain supports both universal human traits or characteristics, and variations that make one person different from the other,'' said John Gabrieli, associate professor of psychology. ''We don't know to what extent this is a cause or a consequence of your view of the world."

The findings are published in the journal Science on June 21 in an article titled "Amygdala Response to Happy Faces as a Function of Extraversion."

The research focuses on the amygdala, a pea-sized area of the brain associated with emotion and memory that is found in the middle of the head behind the eyes.

According to Turhan Canli, the paper's lead author who is currently an assistant psychology professor at State University of New York-Stony Brook, previous research on the amygdala using functional magnetic resonance imaging (fMRI) has mostly focused on recording negative emotions.

For example, work has been done on fear conditioning with animals where a neutral stimulus is paired with a negative experience such as an electric foot shock. "The animal will learn very quickly to avoid that kind of stimulus, or it will respond to it with fear," said Canli, a former Stanford postdoctoral student. "That makes evolutionary sense - when bad things happen you don't want to have to encounter them more than once."

In addition to being associated with emotional learning and memory, the amygdala activates or ''lights up'' in fMRI scans wh
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Contact: Lisa Trei
lisatrei@stanford.edu
650-725-0224
Stanford University
20-Jun-2002