Illustration: Kieran Blakey

The Nuance

Why the Stressed Brain Falls Back on Old Habits

In an effort to save energy and cognitive resources, the stressed brain prioritizes old habits and routines over purposeful, deliberative action

Elemental
Published in
5 min readOct 15, 2020

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Distressed dogs tend to repeatedly lick their forelegs and paws. Happy and healthy dogs also do this, but stressed dogs do it more. In severe cases, they lick so frequently that they develop bald patches and skin ulcers.

Researchers have noticed similar anxiety-related behaviors in other animals — including humans. Many nervous or stressed-out people chew their nails, pick at their skin, or engage in other so-called body-focused repetitive behaviors (BFRBs) to the point of self-injury.

What explains BFRBs? The answer may be wrapped up in the way stress biases brain activity toward habitual thoughts and behaviors.

How stress encourages old habits

For a 2019 study in the journal Brain and Cognition, a team of Dutch researchers examined the brain’s response to stress. They found that as levels of the stress hormone cortisol increased following a threat or challenge, the activity in flexible, goal-directed brain systems tended to diminish. Meanwhile, activity in habit-related systems surged.

They concluded that in an effort to save energy and cognitive resources, the stressed brain prioritizes old habits and routines over purposeful, deliberative action. “Habits demand less cognitive effort, and thus become our default mode of behavior when stressed,” explains Tom Smeets, PhD, co-author of that study and a professor of social and behavioral sciences at Tilburg University in the Netherlands.

Other research teams have come to similar conclusions. A 2013 study in the Journal of Personality and Social Psychology found that stressful experiences are a drain on willpower and motivation. As a result, people fall into “automatic” and habitual…

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Markham Heid
Elemental

I’m a long-time contributor at TIME and other media orgs. I write mostly about health. I grew up in Michigan, but these days I live in southwest Germany.