Busy eyes can make ears go temporarily deaf

There’s only so much brainpower to go around, and when the eyes hog it all, the ears suffer.

When challenged with a tough visual task, people are less likely to perceive a tone, scientists report in the Dec. 9 Journal of Neuroscience. The results help explain what parents of screen-obsessed teenagers already know. 

For the study, people heard a tone while searching for a letter on a computer screen. When the letter was easy to find, participants were pretty good at identifying a tone. But when the search got harder, people were less likely to report hearing the sound, a phenomenon called inattentional deafness.  

Neural responses to the tone were blunted when people worked on a hard visual task, but not when the visual task was easy, researchers found. By showing that a demanding visual job can siphon resources away from hearing, the results suggest that perceptual overload can jump between senses.