Your anxious, jittery friend might be the perfect person to have with you in a crisis. The same fraught, jumpy relationship with the world that stresses out anxious folks may also give them a sixth sense for danger, a kind of neurotic Spidey-sense.
French researchers have found that anxious people process threats using a different part of the brain than more relaxed folks. Whereas a "low anxious" Big Lebowski-type personality will process threats in the same brain circuits used for facial recognition, Woody Allen-types process them in the part of the brain responsible for action. This suggests that anxiety may actually offer an evolutionary advantage, but one which is a little too sensitive for the modern world we live in today.
These results come from tests that gauged subjects’ reactions to scared or angry people. The study tested how people respond to gaze direction and facial displays of emotion, specifically, "anger paired with direct gaze, and fear paired with averted gaze." Reactions were gauged by measuring electrical activity in the brain.
Subjects were found to respond much faster (by 200 milliseconds) to an angry person looking right at them, than if that angry person was looking elsewhere. This is a rather obvious threat, for which we have a hardwired, fast-acting response. The other trigger combo is a person with a scared expression, looking elsewhere, which can signify an external threat. "The response of the brain regions that control action was greater in volunteers with higher levels of anxiety, which highlights the role of anxiety in reacting rapidly to social threats in the environment," says the study.
The result is that high-anxious individuals, who encode threats in their motor cortex instead of in the face-processing part of the brain, have a "tendency to interpret ambiguous stimuli as threatening." The study concludes that "evolutionary pressure might have shaped the human brain to prioritize threat signals in parallel in sensory and motor systems." This mechanism, which is great for quickly assessing threats even while you’re not paying any attention, "could increase perceptual sensitivity to other features of the sensory environment."
These results won’t stop anxious people from worrying about every little thing, but at least they’ll know that, should real danger present itself, they’ll be running to safety while everyone else is still scratching their heads.