How uncertainty builds anxiety

Alfred Hitchcock observed that “there is no terror in the explosion, only in the anticipation of it.” A common way to build suspense in a movie scene is for the audience to know that something bad is going to happen, but not when it will happen. But how does uncertainty act to increase our anxiety?

in a recent article In the diary Computational psychiatryResearchers from the Department of Psychology at the University of California, Davis, take a deeper look at what drives fear.

Not knowing when something will happen can cause anxiety, but until now we had no idea why, said Drew Fox, associate professor of psychology at UC Davis. The first step in addressing this problem is to be more precise about how we define uncertainty, he said.

Fox and graduate student Dan Holley realized that when something bad is anticipated to happen, depending on how the scenario is set up, there can be big differences in the perception of danger at different times, even if the probability of it happens The bad thing that happens is the same.

For example, if there is a ten-second countdown for an electric shock, the risk rate is low until the countdown ends. But if the shock could occur at any time during those ten seconds, the hazard rate should increase, they calculated.

“If you know something is going to happen, as time goes by, the hazard rate increases because you know it didn’t happen before,” Fox said. “The hazard rate will always be higher if you don’t know when it’s going to happen.”

The risk rate increases over time

Holley and Fox, working with professor Erie Boorman and graduate student Erica Varga, set up an experiment to test their idea. Volunteers received a small cash incentive (one cent per second) to stay in a virtual environment but you could also suffer a slight electric shock at some point unless they chose to leave first.

They found that, as expected, the risk rate, rather than the actual probability of being shocked, generates anxiety.

“At each experimental time point, the threat hazard rate corresponded almost perfectly to our participants’ behavior, while the momentary threat probabilities had no predictive value,” Holley said. He volunteers They also reported feeling significantly more anxious in the environment with a higher risk rate.

Our brains likely evolved to track rising rates of danger, Holley said.

“Imagine a gazelle in the Serengeti,” he said. “As a matter of survival, you might keep your head down and graze a little more, but the trade-off is that you’re a little more likely to be attacked by a lion.”

The more the gazelle grazes, the more the danger rate increases.

“Something in his mind must be tracking the danger rate and guiding his behavior accordingly,” Holley said.

By examining the concept of uncertainty in anxiety-provoking situations, researchers hope to better understand the mechanisms behind fear and anxiety, including ways to treat the millions of people who suffer from extreme anxiety disorders.