Does having your phone nearby make you dumber? What "brain drain" got wrong

You have probably heard that the mere presence of your phone, face down and silent on the desk, makes you think less clearly. It is one of the most repeated findings about smartphones, and it sells a lot of products in our line of business. It has not held up well, and we would rather tell you that than lean on it.

The original claim

In 2017 a team led by Adrian Ward published a paper titled "Brain Drain". Nearly 800 people did tests of working memory and reasoning with their phone in one of three places: on the desk, in a pocket or bag, or in another room. All phones were on silent. The people whose phones were in another room scored best, and those with the phone on the desk scored worst. The authors concluded that just having your phone close by uses up some of your mental capacity. (Ward et al., 2017)

An earlier pair of experiments made a similar claim about conversations. When a mobile phone was lying in view while two strangers talked, they reported feeling less close and less connected than when a notebook was there. (Przybylski and Weinstein, 2013)

Both were widely reported. "Put your phone in another room" became standard advice.

What happened when others repeated the studies

Science works by repeating things, and here the repeats disagreed.

The thinking study. In 2022 two researchers ran a preregistered, direct repeat of Ward's second experiment. Where the phone was made no difference to performance on either task. (Ruiz Pardo and Minda, 2022)

The conversation study. A 2021 repeat with 356 people found no effect of a visible phone on closeness, trust or empathy between strangers. (Linares and Sellier, 2021)

The big picture. A 2024 meta-analysis pulled together 56 studies with more than 7,000 participants. Of the mental abilities examined, only one, working memory, showed a statistically reliable effect of a phone being present, and it was small. The author's conclusion was that the evidence gives limited support for an effect much smaller than first claimed. (Parry, 2024)

So the honest summary is this: a silent phone sitting near you might have a small effect on working memory. It probably does not noticeably lower your intelligence or ruin a conversation by lying on the table.

What does hold up

The thing that reliably causes trouble is not the phone being there. It is the phone being used.

In a randomised experiment, more than 300 people ate a restaurant meal with friends or family, with phones either out on the table or put away. The phones-out group felt more distracted and enjoyed the time with their companions less. In a second part of the study, people who had been using their phones during in-person time reported enjoying it less. (Dwyer, Kushlev and Dunn, 2018)

That is a less magical finding and a more useful one. The phone on the table is a problem because you will pick it up.

Why distance still helps

If presence alone does little, why does every guide, including ours, tell you to put the phone somewhere else?

Because of what distance does to use. A phone in your hand gets checked without a decision. A phone in the next room requires one: you have to stand up. Most of the time you do not bother.

There is modest evidence for this in everyday life. In a small trial, adults who kept their phones out of the bedroom for a week reported slight improvements in happiness and quality of life compared with a group who changed nothing. (Hughes and Burke, 2018) And in a large experiment on app limits, people cut their use of social apps by about 16% when given limits they could not dismiss on the spot. (Allcott, Gentzkow and Song, 2022)

Economists call arrangements like these commitment devices: choices you make in advance that raise the cost of doing the thing you are trying not to do. (Bryan, Karlan and Nelson, 2010)

What to do with this

• Do not feel bad about a phone in your bag. The idea that it is quietly draining you from in there is not well supported.
• Do move it when you want an hour of attention. Not because of invisible effects, but because you will not reach for what is not there.
• At meals, put it away, not face down. Face down on the table is still within reach.
• If the whole phone cannot go away, send the tempting part away. Most of us need the phone nearby for calls, maps or music. Locking the handful of apps that cause the problem gets you most of the benefit of distance and keeps the useful parts.

That last point is the idea behind products like ours. With moss, the phone stays in your pocket and the key to the distracting apps is a stone in another room. It is a way to get the "have to stand up" effect without giving up the phone. We make no claim that it raises your IQ. It makes one specific habit harder, and that is all it needs to do.

For more on which kinds of blocker have evidence behind them, read do app blockers work.