Media Multitasking and Forgetting: A Stanford Brain Study

Why do some people remember better than others, and why does a name or a detail sometimes slip away when you reach for it? A team at Stanford University went looking for the moment memory fails, and found that it often fails a second earlier, when attention drifts. They also found who drifts more: people who habitually juggle several media at once.

What the researchers did

The study, led by Kevin Madore with Anthony Wagner, was published in Nature in 2020. It enrolled 80 young adults aged 18 to 26 (average age 21.7), recruited through online advertisements at Stanford and in the surrounding community.

While each person did a series of memory tests, the team recorded two signs of where their attention was:

• Brain activity, with EEG. A rise in alpha waves over the back of the head is a known marker of attention turning away from the task.
• Pupil size. Pupils tend to narrow when alertness drops.

The memory tests asked people to recognize objects they had studied earlier, in three different ways. Separately, everyone did a 10-minute test of sustained attention, in which pictures of cities and mountains fade in and out on a screen and the task is to press a key for every city and hold back for the rare mountain. They also filled in questionnaires, including one on media multitasking: how many media a person typically uses at once in an hour of media use, such as watching TV while texting.

What they found

• Lapses come right before forgetting. When the brain and pupil signals showed attention drifting in the second before a memory cue, people were more likely to fail to remember something they had studied.
• Some people lapse more than others. Those with more lapses on the city and mountain test also did worse on the memory tests.
• Heavier media multitaskers lapsed more and remembered less. People who reported more media multitasking scored lower on all three memory tests and made more errors on the attention test. The correlations were moderate, around 0.3: a clear tendency, with plenty of overlap between people.
• Attention connects the two. In the statistical analysis, people's general tendency to lapse helped explain the link between their media multitasking and their memory.

The authors put it plainly: heavier media multitasking "is associated with a propensity to have attention lapses and forget."

What the study can't tell you

It can't say which came first. Nobody was asked to multitask more or less: the habit was measured with a questionnaire, at one point in time. Juggling media may train attention to drift, or people whose attention already drifts may be drawn to juggling media, or both. The authors themselves call for long-term studies to settle the direction.

The sample was also small and specific: 80 young adults near one university, tested in a lab. Media multitasking was self-reported, and people's reports of their own media use are often off. And memory for objects in a lab test isn't the same as remembering what a friend told you last week, though it's a reasonable stand-in.

What it means for your phone

You can't control every lapse, but you can stop setting up the conditions for them.

• One screen at a time. If the evening usually means a show, a feed and a group chat at once, try one of them, on its own, for a while.
• Be present when you reach for a memory. Lapses in the moment before remembering were what predicted forgetting. When you need to recall something, in an exam, a meeting or a conversation, put the phone out of sight first.
• Give attention long stretches. Single-tasking is a skill, and it grows with practice.

That's what a phone-free session in Unrotten is for: from Home's + button you start a Work, Focus or Reading session, and the apps you chose stay locked until it ends. For more on the restless feeling heavy multitasking leaves behind, read our guide to popcorn brain, and for focus in general, our guide to attention span.