Imagine: You’re on your way home from work after a long, stressful day. Your hand is on the wheel and your foot on the petal, but your mind’s still back at the office. Stacks of paperwork, loads of emails, frustrated coworkers, angry boss. The next thing you know, you’re just centimeters away from ramming into the car in front of you. Luckily, you exited your trance just in time to slam on the breaks. ‘That could have been bad,’ you think to yourself.

When we’re stressed, we’re often not ourselves. We’re frustrated, distracted versions instead, who don’t recognize potential dangers very well, says a new study “Stress attenuates the flexible updating of aversive value” conducted by NYU psychology researchers, which is published in the latest edition of Proceedings of the National Academy of Sciences. Despite the conventional view that says stress enhances our abilities to pick up on and handle threats, this research team found that stress actually diminishes our abilities to detect and handle new dangers.

“Our study shows that when we are under stress, we pay less attention to changes in the environment, potentially putting us at increased risk for ignoring new sources of threat. As a result, stress can reduce the flexibility of our responses to threats by impairing how well we track and update predictions of potentially dangerous circumstances,” explains Candace Raio, lead author of the study and postdoctoral researcher at New York University.

To make these discoveries, the research team from NYU—which was joined by Jian Li, a scientist at Peking University—conducted a series of experiments centered around the idea of “Pavlovian threat-conditioning.” They first had their subjects look at different images on a computer screen, while they administered a mild electric wrist shock every now and then. So some images were paired with these shocks (threat cues), while others were not (safe cues).

Then, half of the subjects endured a lab test designed to elevate stress hormones (alpha-amylase and cortisol), where they put their arm in a freezing ice bath. And finally, all of the participants were brought back together to repeat the first procedure—only this time, the cue outcomes were switched. So the images that were previously paired with shocks now were not, as the researchers were curious to see how they’d anticipate the cues and analyze their physiological arousal responses.

The research team found that the stress group (or the individuals who endured the ice baths) were less likely to change their responses to the new threatening images or the ones paired with shocks the second time around, thereby indicating that stress impaired the participants’ abilities to detect new threats. Or more specifically: stressed subjects showed a diminished physiological response to the new threat cue, which suggests that they failed to perceive the new threat as threatening.

So the next time you’re really stressed, it will do you well to think about this diminished response to stresses. Doing so could mean the difference between getting safely home, having close calls like the scenario mentioned above, or even winding up in a dangerous accident. Remember: it’s better to be safe than sorry.

Source: NYU “Stress Diminishes Our Capacity to Sense New Dangers.” NeuroscienceNews. NeuroscienceNews, 2 October 2017. <>.

Original Research: Abstract for “Stress attenuates the flexible updating of aversive value” by Candace M. Raio, Catherine A. Hartley, Temidayo A. Orederu, Jian Li, and Elizabeth A. Phelps in PNAS. Published online October 2 2017 doi:10.1073/pnas.1702565114