Shy people may be quiet, but there's a lot going on in their heads. When they encounter a frightening or unfamiliar situation--meeting someone new, for example--a brain region responsible for negative emotions goes into overdrive. But new research indicates that shy people may be more sensitive to all sorts of stimuli, not just frightening ones.
The findings come courtesy of brain scans of 13 extremely shy adolescents and 19 outgoing ones. Researchers, led by Amanda Guyer, a development psychologist at the National Institutes of Health in Bethesda, Maryland, placed each child in a functional magnetic resonance imaging machine and had them play games in which they could win or lose money. The study subjects--who were classified as either shy or outgoing based on psychological testing--were instructed to press a button as quickly as possible after being shown a signal. If they pressed the button in time, they won money, or at least prevented themselves from losing it.
Both groups performed similarly, and there was no difference in the activity of their amygdalas--the brain region that governs fear. Shy children, however, showed two to three times more activity in their striatum, which is associated with reward, than outgoing children, the team reports in the 14 June issue of the Journal of Neuroscience. "Up until now, people thought that [shyness] was mostly related to avoidance of social situations," says co-author and child psychiatrist Monique Ernst. "Here we showed that shy children have increased activity in the reward system of the brain as well."
Why this would be the case is still not clear. "One interpretation is that extremely shy children have an increased sensitivity to many types of stimuli--both frightening and rewarding," says Guyer. There are other possibilities as well, says Mauricio Delgado, a psychologist at Rutgers University in Newark, New Jersey. For example, increased activity in the striatum may help shy children cope with the anxiety of stressful situations, although not enough so to help them overcome their shyness.
These findings are also significant because they may help researchers understand why shy children develop psychiatric problems at an increased rate later in life, says Brian Knutson, a psychologist at Stanford University in Palo Alto, California. Because shy children appear to be more sensitive to winning and losing, they may experience emotions more strongly than others, putting them at risk for emotional disorders such as anxiety and depression. On the flip side, shy children may experience positive emotions such as success very strongly, helping them succeed, Knutson says.