Seeing notifications from social media apps seems to throw us off course for several seconds – even if we don’t open them.

Hippolyte Fournier at Lumière University Lyon 2 in France has long been interested in understanding attention and how social media affects it. “I feel impacted when I receive a notification from a social media app while I’m working,” he says.

To learn more, Fournier and his colleagues asked 180 university students to complete a psychology test known as a Stroop task on a smartphone-sized screen. This measures how quickly someone can name the colour of a series of printed words that spell different colours, such as the word “purple” written in green.

While the students carried out the task, social media notifications popped up, which they couldn’t open. Some were led to believe the alerts were their own, synced from their smartphones, while others weren’t. A third group saw blurred alerts that couldn’t be read.