Not answering your phone might be nearly as distracting as picking it up. Even if you wait to read a text or look at a notification, the act of knowing they're there is enough to place strain on your memory and disrupt your performance on a task, according to a new study by Florida State University researchers in the Journal of Experimental Psychology.

The study asked 212 university students to complete a basic computer task to measure their attention. Some of them received either text messages or phone calls during the task. They hadn’t been given any instructions about silencing their ringers or avoiding checking their phones prior to the task. (Later, students who did read their messages during the task or who had their cell phones off were excluded from the results, for a total of 166 participants.)

The students who received phone notifications during the study performed worse on the sustained attention task than students who didn’t hear their phone go off, even if the student didn’t actually pick up the call. The researchers hypothesize that the decrease in attention was due to “the tendency for cellular notifications to prompt task-irrelevant thoughts, or mind wandering, which persist beyond the duration of the notifications themselves.” The effect was similar to those seen in studies of distracted and not-distracted driving.

If just the act of noticing your phone is ringing and making a mental note to check it later makes you significantly worse at the task at hand, it indicates that driving with a cell phone—even if you don’t take any calls—might be more dangerous than previously thought. As a phone-addicted Millennial, I’ll testify that the brain power it takes to resist the compulsive urge to check my phone can sap a lot of my attention. Moreover, if phones are this distracting, wearing an Apple watch that vibrates against your skin every time you get a text may not be the best path to focus. Push notifications are ruining the world.

[h/t: The Science of Us]