Under the Hood

Sixth Sense: Why The Brains Of Moderately Anxious People May Detect Danger Better Than Others

Anxious woman
People with anxiety are able to detect threats in different brain regions than those who are more laid back. jon hill, CC BY 2.0

It’s not uncommon for someone who’s running late, going on a first date, or speaking publicly to be ridden with anxiety. However, researchers in France suggest these feelings of apprehension and dread can actually have unexpected neurological benefits. Their recent study, published in the journal eLife, found anxious people’s brains react to threats in a different action-related region of their brains than those who are more laid back. This in turn allows them to fare better during a crisis.  

Specific regions of the human brain react to social threats quickly and automatically — within 200 milliseconds. Anxious individuals, however, tend to show increased sensitivity to these threats, as well as to negative emotions overall. Past studies have suggested anxiety could lead to an oversensitivity to threat signals, which in turn could impair how the brain processes threats. Rather than responding only when necessary, the anxious person remains in a state of permanent anxiousness, which impairs their ability to react quickly and causes them to be “frozen” in fear. The current study, however, found having anxiety actually allows these threat signals to reach the brain’s motor cortex more rapidly — triggering a fight-or-flight response.

For their study, lead author Marwa El Zein, of the French Institute of Health and Medical Research, and her colleagues measured electrical signals in 24 participants’ brains with an electroencephalogram (EEG). Each was asked to decide whether digitally altered faces expressed anger or fear — both expressions were meant to be perceived as threatening. While all faces showed the same expression, some had the eyes altered, so they were looking away from the camera. 

The results showed anxious people processed threats in regions of their brains responsible for action, while less anxious people processed them in their sensory circuits, which are responsible for facial recognition. The researchers found the direction of the people’s gaze in the images was key to enhancing participants’ sensitivity to their own emotions. When the gaze was directed at the camera, it produced a response in participants' brains far faster than when it was looking elsewhere.

"In a crowd, you will be most sensitive to an angry face looking toward you and will be less alert to an angry person looking somewhere else," El Zein said.

Although it should be obvious people are more likely to respond to something directed at them, the neurological reason for why this happened was poorly understood, until now. The researchers suggested this reaction to anger is an adaptive mechanism meant to help with survival. When humans evolved alongside dangerous predators, for example, this rapid reaction prevented injury or death.

A 2012 study supports this theory; anxiety, along with intelligence, coevolved as beneficial traits to enhance one’s chances of survival. Study author Dr. Jeremy Coplan said, “While excessive worry is generally seen as a negative trait and high intelligence as a positive one, worry may cause our species to avoid dangerous situations, regardless of how remote a possibility they may be.”

So, while anxious people may avoid taking risks, there’s a chance they’re the ones who will survive longer.

Sources: El Zein M, Wyart V, and Grezes J. Anxiety dissociates the adaptive functions of sensory and motor response enhancements to social threats. eLife. 2015.

Coplain JD, Hodulik S, Mathew SJ et al. The relationship between intelligence and anxiety: an association with subcortical white matter metabolism. Frontiers in Evolutionary Neuroscience. 2012.

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