Under stress, we all tend to seek comfort sometimes in not so healthy ways but a new study suggests that challenging experiences are as likely to promote good habits as they are to support bad ones.

In several different experiments, researchers led by Wendy Wood, a professor of psychology and business at the University of Southern California, found that under various types of stress, all types of habits got stronger not just the ones that cause trouble.

“When your willpower is low and you have little motivational energy, you are likely to fall back into old, bad habits of eating too much and not exercising — but only if those are, in fact, your habits,” says Wood. “Our novel finding is that people fall back into good habits in just the same way.” The study was published in the Journal of Personality and Social Psychology.

Stress depletes willpower; indeed, the brain is wired so that extreme stress actually shuts down the higher regions involved in long-term planning and thoughtful consideration. That’s because those functions are superfluous when survival is at stake. 

When under threat, the brain relies on faster, more primitive regions whose behavior is largely automatic under such circumstances. Automatic doesn’t mean built-in, however: many of our automatic behaviors, like riding a bike or eating french fries when feeling anxious, become automatic through repetition.

“People can’t make decisions easily when stressed, are low in willpower or feeling overwhelmed,” Wood says. “These pressures limit our capacity to make decisions.” The default in those cases is to engage in habitual behavior, so, she says, “When you are too tired to make a decision, you tend to just repeat what you usually do.” And it doesn’t matter what that habit is.

The new research involved various types of habits and stresses. In one experiment, 65 UCLA students were followed for 10 weeks and asked about their breakfast and news-reading habits. During the first few weeks, they recorded how often they ate foods that they considered healthy, such as cold cereal, hot cereal and health bars.

They also reported on their intake of what they labeled as unhealthy breakfast selections, including pastries, pancakes and French toast. In addition, they detailed whether they regularly read educational news sections like local and national news, or lighter fare like advice columns and comics.

The scientists gathered this data over several weeks, measuring how strong the students’ breakfast and news habits were at times when they weren’t facing stressful exams like midterms and finals. Later, they compared these choices with those made during exam periods.

And indeed, those who had strong habits — either healthy or unhealthy — engaged in those behaviors more when they felt stressed by exam periods. Whether it was eating French toast or health bars more regularly or reading news that they felt was important or a guilty pleasure, habitual behaviors increased under stress.

A second experiment involved 72 students at Duke University. This time, they were asked to specify goals they were hoping to achieve, such as improving grades or fitness. They also detailed particular behaviors they engaged in regularly to reach their goals, as well as behaviors that might get in the way.

For two of the four days of the study, they were randomly assigned to try to perform as much of their daily behavior as reasonably possible using their nondominant hand. This task tends to deplete self-control because it requires inhibiting a strong habit. Once again, this stressful experience increased habitual behavior  whether it worked toward or against the students’ goals.

Another experiment, this one including 164 UCLA students