Using a brain scanner, a team of scientists at Stanford University studied the brain activation as people with and without Williams syndrome looked at pictures of facial expressions: happy, neutral, or afraid.
Like a previous study, the scientists found that the amygdala in Williams syndrome was rather unmoved by the afraid faces. It's as though their brain did not register that those faces were something to feel nervous about, and might explain the hallmark social fearlessness of Williams syndrome.
But—and this was the new finding—the amygdala was highly activated when people with Williams syndrome looked at happy faces.
It was the other way around for the group without the syndrome: The amygdala turned on to fearful faces but not so much to happy ones.
This doesn't mean that people with Williams syndrome are frightened by happy faces, says Brian Haas, Ph.D., first author of the study. Instead, he says it reflects what's emotionally riveting for people.
"Happy facial expressions may be more rewarding for those with Williams syndrome," Haas says. "This may explain their increased drive and motivation to approach others and to socially interact."
This finding also fits with a broader picture of the amygdala that has been emerging recently. Rather than solely devoted to fear, the amygdala seems to deal with other strong emotions too, like sadness and happiness.
Haas says that the amygdala tunes into the things that are very relevant to us now and that can sway our feelings. So if you spot a snake, or watch a friend break into tears, the amygdala leaps to attention and points the brain's resources to these emotionally charged situations.
And for people with Williams syndrome, a happy face tugs powerfully on their attention. Haas hopes that this affinity for happy expressions may somehow be used to motivate or reinforce people with Williams syndrome when they are taught about what is socially appropriate. This could help those with the syndrome form closer social bonds with others, which often suffer due to their overly outgoing ways, he says.
Wednesday, June 17, 2009
Williams Syndrome and Social Fearlessness