Guide
Does a phone on the desk make you less sharp?
In 2017, a study made headlines: your own phone, just lying nearby, makes you worse at thinking. It became one of the most quoted findings about smartphones. Then other labs tried to repeat it.
In short. The 2017 “brain drain” study found that people had less mental capacity to spare when their own smartphone was nearby, even when they did not check it. Later research is mixed. A 2023 meta-analysis of 56 effects found a small cost to working memory only, smaller than first claimed; a 2024 meta-analysis of 33 studies found no effect at all. The phone on the desk probably costs less than you have heard. Picking it up costs more.
The original study
Adrian Ward and colleagues tested what they called the brain drain hypothesis: that your own phone, simply by being there, occupies part of your limited mental capacity and leaves less for the task in front of you. In two experiments, they found exactly that, even when people resisted the urge to check their phones. The cost was largest for the people most dependent on their phones. The paper appeared in the Journal of the Association for Consumer Research in 2017.
What happened next
| Study | What it found |
|---|---|
| Ward and colleagues, 2017, two experiments | Less available mental capacity with the phone nearby |
| Skowronek and colleagues, 2023, adults aged 20 to 34 | Lower scores on a concentration and attention test with a phone present |
| Parry, 2023, meta-analysis: 56 effects, 7,093 people | A small cost to working memory, and none for the other functions tested; small, uneven studies |
| Hartanto and colleagues, 2024, meta-analysis: 33 studies, 4,368 people | No effect on cognitive performance, whoever the people and however it was tested |
Meta-analyses pool many studies, so they are a better guide than any single one. Even so, the first one warns that the studies differ a lot in method and are often too small to detect a modest effect: the question is not closed.
What it means for your desk
- Moving the phone away does no harm. If it helps you to have it in a bag or another room, do it.
- Do not expect a miracle from that alone. In the 2024 meta-analysis, the authors saw little reason to think that keeping phones out of a workplace would by itself improve performance.
- The clearer costs are the interruptions, a buzz you have to decide about and a check that turns into ten minutes: what one buzz costs and why you keep checking your phone.
- In a meeting, it is also about the people. A phone on the table says something to the others: phones in meetings.
Does a ring cost attention too?
A ring on your finger is always there too, and nobody has tested whether that costs attention, so we claim nothing about it. What we design for is the clearer cost: picking up a phone for something small and staying. Lychnos Ring is being built to answer the small things in a line, buzz only for what you chose, and go quiet. It is in development and makes no health claims.
Sources, read 4 November 2026: Ward, Duke, Gneezy and Bos, brain drain: the mere presence of one’s own smartphone reduces available cognitive capacity, Journal of the Association for Consumer Research, 2017; Skowronek and colleagues, the mere presence of a smartphone reduces basal attentional performance, Scientific Reports, 2023; Parry, does the mere presence of a smartphone impact cognitive performance? A meta-analysis, Media Psychology, 2023; Hartanto and colleagues, the effect of mere presence of smartphone on cognitive functions: a four-level meta-analysis, Technology, Mind, and Behavior, 2024. Abstracts read through OpenAlex. General information.
Questions
Does having your phone nearby reduce your brainpower?
Probably much less than first claimed. A 2017 study found a cost; a meta-analysis of 56 effects found a small effect on working memory only, and another of 33 studies with 4,368 people found no effect on cognitive performance.
Should I keep my phone in another room while I work?
It does no harm, and it makes checking harder. But the evidence that the phone's mere presence lowers performance is weak; interruptions and checks are the clearer cost.