The soft ping or buzz on your phone that lets you know a new message has arrived is hard to ignore. But it can mean trouble when it’s time to concentrate on a task, according to a new study that will be published in the June issue of the journal Computers in Human Behavior. 

The study found that whenever we receive a message notification, it interrupts our concentration for 7 seconds. It turns out that the type of information that we see in the notification also matters. The more personally relevant the notification, the larger the distraction.

“This interruption likely arises from several mechanisms, such as [a notification’s] perceptual prominence, the conditioning acquired through repeated exposure, and the possible social significance,” Hippolyte Fournier, a postdoctoral fellow at the University of Lausanne in Switzerland and the study’s first author, told CNET.

While 7 seconds may not seem like much, we get a lot of notifications throughout the day, and those seconds can add up. 

“We observed that both the volume of notifications and how often individuals check their smartphones were linked to greater disruption,” Fournier said. “This pattern suggests that the fragmented nature of smartphone use, rather than simply total usage duration, may be a key factor in understanding how digital technologies influence attentional processes.”

Attention hijack

The study used a Stroop task, a test that measures how quickly you can process information and how well you can focus. Colored words flash across a screen for the test. The font of each word is one color, but the text of the word is a different color. So the word “blue” might be written in green font.

You have to identify the font color and ignore the color that the word spells out. It’s a lot harder than it sounds. You can take the test yourself using this YouTube video. 

The researchers recruited 180 university students for the study. The students were randomly split up into three groups. All students received a Stroop task, and notifications popped up on the screen as they completed the test. But the researchers slightly changed the experiment for each group.

The researchers told the first group that the screen was mirroring their personal phones, so the students thought they were seeing their real notifications.

The second group saw pop-ups on the screen that looked like real social media notifications, but the group knew they were false. This helped the researchers test how learned habits impact attention, without personal relevance. 

The third group saw only blurry notifications, with illegible text. The researchers used this test to determine how the visual distraction of an unexpected pop-up affected the group’s attention. 

The notifications slowed students’ ability to process information by about 7 seconds across all three groups. But for students who thought they were getting real notifications, the delay was more pronounced. 

“Although it is well documented that notifications can automatically attract attention, far less is understood about the cognitive processes that drive this attentional capture and the reasons why some people may be more susceptible than others,” Fournier said. “Our objective was to gain a better understanding of both the underlying mechanisms and the individual differences that could account for this variability in sensitivity.”

Brain delay

In the US, 90% of all people own a smartphone, according to Pew Research, and a Harmony Healthcare IT study found that we spend over 5 hours a day using them. But how long we spend on our phones may not matter as much as how often we check our notifications.

“In a lab study designed to mimic real-life notification exposure, we found that the frequency of notifications and checking habits mattered more than total screen time,” Fabian Ringeval, another of the paper’s authors, wrote in a LinkedIn post. “The more often we interact with our phones, the more vulnerable our attention becomes to interruption.” 

Anna Lembke, a psychiatry professor at Stanford, told CNET that the study mirrors what she sees clinically and in research literature, “namely that the level of engagement — for example how many notifications a person gets and how quickly they respond to notifications — is as big a predictor, or an even bigger predictor, of harmful, problematic use than time spent.”

Researchers found that study participants received about 100 notifications per day. So the notifications we get on our phones could be slowing down our cognitive abilities through near-constant distraction. 

“In everyday situations that require continuous attention — like driving or learning — even short slowdowns can add up,” Ringeval wrote. “Our findings suggest that improving digital well-being may be less about ‘using our phones less’ and more about reducing unnecessary interruptions.”

Lembke said it’s fair to worry about how smartphone notifications impact our attention, “which is why platforms for minors should silence notifications by default and make it difficult to re-activate notifications without parental consent, and why adults should electively turn off notifications to improve concentration and well-being, with rare exceptions for safety reasons.”