Heavy Media Multitaskers and Distraction: The 2009 Stanford Study

If you watch TV while texting while scrolling, are you training your brain to handle distraction, or making it worse at it? In 2009, three researchers at Stanford University put that question to the test, and the answer surprised them.

What the researchers did

The study, by Eyal Ophir, Clifford Nass and Anthony Wagner, was published in the Proceedings of the National Academy of Sciences. It started with a questionnaire: 262 Stanford students reported how many hours a week they spent with 12 kinds of media, from print, TV and online video to music, games, calls, instant messages, texts, email and the web, and what else they used at the same time. From their answers, the researchers built a media multitasking index: roughly, how many media a person juggles at once in a typical hour of media use.

They then invited students from the two ends of the range, heavy media multitaskers and light ones, to the lab. Groups of 15 to 22 students on each side took computer tests of cognitive control:

• Filtering. An array of rectangles flashed twice, and the task was to say whether one of the two red ones had changed its angle in between, while ignoring up to six blue ones.
• Holding context. Respond to a target pair of letters, A followed by X, with distracting letters in between to ignore.
• Updating memory. Say whether each letter matched the one two or three back.
• Switching. Classify a number as odd or even, or a letter as a vowel or a consonant, depending on a cue that changed from trial to trial.
• Stopping. Hold back a response when a tone sounded.

What they found

• Distractors got in. As blue rectangles were added, the heavy multitaskers did worse; the light multitaskers weren't affected at all. With distracting letters, the heavy multitaskers were 77 milliseconds slower to respond.
• Memory got cluttered. Moving from the two-back to the three-back task cost heavy multitaskers more, and their false alarms rose more, as if letters that no longer mattered were still in mind.
• Switching was slower. The surprise: heavy multitaskers, who switch all day, were worse at it. Their cost for switching between tasks was 167 milliseconds larger, which the authors put down to trouble shutting out the task they had just left.
• Not more impulsive. On the stopping test the two groups didn't differ, so the heavy multitaskers weren't simply less in control of their responses.

The authors' reading was that heavy media multitaskers take in more of everything, relevant or not. As they put it, the heavy multitaskers may be "distracted by the multiple streams of media they are consuming," or the light multitaskers may simply be better at directing their attention when distractions arrive. They also noted it might be "a difference in orientation rather than a deficit."

What the study can't tell you

Which came first. Nobody was assigned to multitask more or less. The study compared people with different habits, so it can't say whether juggling media changes attention or whether people who are already easily distracted juggle more media. The authors raised both possibilities.

How general it is. The lab groups were small, made up of Stanford students, and chosen from the extremes of the range, which can make differences look larger than they are across most people.

Whether it holds up. Later work has been mixed. In 2017, two researchers at the University of Groningen repeated the tests: only five of their 14 showed the effect, and only two held up in a stricter analysis. Their meta-analysis of 39 results found a weak link between media multitasking and distractibility that disappeared after correcting for small studies. A 2018 review co-written by Wagner concluded that heavier media multitaskers do tend to do worse in several areas, though many studies find no difference, and that the links most often involve sustaining attention on a goal over time.

What it means for your phone

The strongest version of the 2009 finding may not survive, but its practical lesson is cheap to follow: if your attention lets more in, let less in.

• One stream at a time. Watch the show or scroll the feed, not both.
• Cut what reaches you. Notifications you don't need are distractions you'll have to filter. Turn them off, or batch them.
• Switch less. Every switch between tasks has a cost, and in this study the heavy multitaskers paid more of it.

For stretches that need your full attention, Unrotten has phone-free sessions: from Home's + button, a Work, Focus or Reading session keeps the apps you chose locked until it ends. For what the wider research says about restless attention, read our guide to popcorn brain, and for focus in general, attention span.