Imagine yourself in this experiment. You're asked to take a math test in an fMRI machine...and then you overhear the researchers insulting you. How your amygdala, the brain's anxiety trigger, will respond can be predicted by where you live
, found researchers at the University of Heidelberg. Rural types had very little amygdala activity; they seemed immune to stress. In small-town residents, the amygdala was moderately active. But in urban dwellers, it was frenzied
. One interpretation is that the city wires us for performance anxiety (and neuroses). More optimistically, that jumpy amygdala might help us deal better—or faster—in complex social situations
. It's the part of the brain that picks up on facial expressions and nuances
—judging, for instance, who's trustworthy or dangerous—and that's helpful when you regularly encounter hundreds of strangers. In other words, the social stress can be good stress
—it leads to street savvy.