Phone Notifications and Focus: What a 2015 Lab Study Found

Your phone buzzes on the desk. You don't pick it up, don't even glance at the screen, and go right back to work. A 2015 lab experiment set out to test whether that moment alone, the notification itself, is enough to knock your attention off course.

What the researchers did

Cary Stothart, Ainsley Mitchum and Courtney Yehnert published their experiment in the Journal of Experimental Psychology: Human Perception and Performance in 2015. They brought 166 college students into the lab for a Sustained Attention to Response Task, a standard vigilance test in which numbers flash on a screen and you press a key for every one except 3. Participants worked through two blocks of 360 trials. In the second block only, the researchers sent four notifications, spaced 90 trials apart: a phone call for one group, a text message for another, while a control group's phones stayed silent throughout. None of the participants interacted with their phone to answer or check it; the notification simply arrived while the task went on.

What they found

• Notifications alone cost accuracy. From the first block to the second, the errors of both notification groups rose significantly more than the control group's, although nobody answered or checked a phone.
• The cost was about the size of using the phone. The authors describe the distraction as comparable in size to the drop in performance seen when people actively use a phone for calls or texts during a task, and Stothart's own summary compares it with the costs reported in studies of texting and driving.
• The text result needs caution. As Stothart's summary of the study notes, the text group started with fewer errors than the control group, and the two groups' error rates were similar in the second block, so the call result is the firmer of the two.
• The likely cause is a wandering mind, not the hand. The authors' explanation is that a short alert can prompt task-irrelevant thoughts, mind wandering, which is known to hurt performance on a task that needs continuous attention.

What the study can't tell you

This is one lab experiment with college students on an artificial task, pressing a key for every number but one, not real work, conversation or driving. How the effect plays out across a full day of actual notifications, arriving at random instead of on a fixed schedule, is a different question the study wasn't built to answer.

The text-message finding is also the shakier of the two, because that group started from a lower error rate than the control group. And the experiment is a single study from 2015; phones, apps and notification settings have all changed since, so it says nothing about whether today's tools for managing notifications change the picture.

What it means for your phone

The free fix is the most direct one: if a notification alone can cost you focus before you've even looked at it, fewer notifications is the first win. Turn off alerts for anything that isn't genuinely urgent before work that needs your attention, and let the phone sit face down or in another room entirely if a stretch of work can't afford any interruption.

For the rot apps that keep finding a way back onto your screen anyway, a Work, Focus or Reading session in Unrotten, started from Home's + button, locks them until the session ends, with a countdown on your Lock Screen and in the Dynamic Island, so a stray buzz can't turn into twenty minutes you didn't plan to spend. For more on training your attention back up, read our guides to attention span and to popcorn brain.