Does a Switched-Off Phone Still Cost You Focus? A 2023 Study

Plenty of people work with their phone face down beside them and assume it costs nothing as long as they don't pick it up. Research on this "mere presence" effect has disagreed, and most earlier experiments used phones that were still switched on and could still receive messages. A 2023 experiment from Germany tested a phone that was switched off.

What the researchers did

Researchers at Paderborn University, J. Skowronek, A. Seifert and S. Lindberg, published the study in Scientific Reports in 2023. Because of the COVID-19 lockdown, the experiment ran over video calls in February and March 2021, with one to five students at a time sitting at their own desks at home.

Forty-nine students aged 20 to 34 volunteered. Seven were left out of the analysis, for example because they already knew the test, which left 42. Each was randomly assigned to one of two conditions, and everyone switched their phone off first. In one group, the phone lay face down on the desk in front of them, the screen hidden. In the other, they took it to another room.

Then everyone took the d2-R, a test of concentration widely used in German-speaking countries. It's a sheet of the letters d and p, each with one to four small marks, and the task is to cross out every d with exactly two marks: 14 rows, 20 seconds a row, 4 minutes and 40 seconds in all. Afterward, everyone filled in a short questionnaire on how dependent they felt on their smartphone.

What they found

• Lower attention scores with the phone on the desk. The test's attention score averaged 99.7 when the phone was on the desk and 109.0 when it was in another room, a difference close to what is conventionally called a large effect.
• The difference was speed. Students with the phone on the desk worked through fewer items (98.5 against 108.6 on the test's speed score).
• Accuracy didn't change. The two groups made errors at similar rates.
• Phone dependence made no difference. How dependent students said they were on their phones didn't change the effect.

The authors read this as a phone taking up some of the mind's limited capacity simply by being there, even switched off, and even on a simple task that earlier studies had found to be unaffected.

What the study can't tell you

This is one small study: 21 students per group, tested once, at home and over video. With groups that small, chance differences between the people in each group can matter, and the authors couldn't control the setting the way a laboratory can.

It also sits in a contested area. The authors themselves describe a replication that failed to find the original 2017 brain drain effect, and a 2024 meta-analysis of 56 studies found that a phone's mere presence reliably affected only working memory, and only a little. The test also lasted under five minutes, so it can't say what happens over an hour of work, or whether people stop noticing a phone that's always there.

What it means for your phone

Face down and switched off may not be far enough. When a task matters, put the phone in another room: at worst you lose an easy reach for it, and at best, as in this study, you get some attention back.

When the phone has to stay within reach, a Focus session in Unrotten, started from Home's + button, keeps the apps you chose locked until it ends, with a countdown on your Lock Screen. For a routine built on this and related research, read how to focus better, and to strengthen your attention over the coming weeks, how to improve your attention span.