Smartphone Presence and Cognitive Performance: A Review

What the research actually says about phones and attention

The idea that a smartphone on your desk quietly drains your focus has become common advice. The claim is that the phone's mere presence uses limited cognitive resources, leaving less for the task in front of you. The evidence, however, is more complicated than the headline suggests.

This review breaks down five studies that tested phone presence against attention, memory and visual focus. They range from lab-based reaction-time tasks to a wearable eye-tracking study during dinner. Together, they suggest the problem is less about the phone being in the room and more about how much your mind reaches for it.

Studies at a glance

Does a phone in the room reduce attention?

The most direct test of the "mere presence" hypothesis comes from Skowronek and colleagues in 2023³. They had adults aged 20–34 complete a concentration and attention test both with and without a smartphone present. Performance was lower when the phone was in the room. The authors interpret this as support for the idea that a smartphone uses limited cognitive resources even when you are not using it³.

But a more recent study complicates that picture. Christodoulou and Roussos ran an experimental study in 2025 with young adults aged 18–25, randomly assigning them to a control group with no phone or an experimental group with a phone present¹. They measured attentional control using the Attention Network Test. Contrary to earlier work, the phone's presence did not significantly distract participants or impair attentional performance. Self-reported distraction and nomophobia, the fear of being without your phone, also showed no significant relationship with actual performance¹.

The two studies used different tasks and different age ranges, which may explain part of the disagreement. The honest reading is that phone presence alone is not a reliable attention killer for everyone.

Does phone presence affect memory?

Tanil and Yong tested memory rather than attention in a 2020 study of 119 undergraduates⁵. Participants completed a memory task with or without a smartphone present, and also filled in the Smartphone Addiction Scale. Those without phones had higher recall accuracy. The more striking finding was that phone conscious thought, how often participants thought about their phone, significantly predicted memory accuracy. In other words, the mental pull of the phone mattered more than its physical proximity⁵.

This fits with the attention residue research: when part of your mind is still on the phone, less is available for the task. You can read more about that mechanism in our piece on what attention residue is.

Does a phone always hurt performance?

Not always. Liu and colleagues tested attentional control using the Navon task, which requires switching attention between global and local levels of a stimulus⁴. They found that reaction times decreased, meaning participants responded faster, when a phone was nearby compared to when a mobile battery was nearby. Phone dependency was linked to more incorrect responses, but that effect was independent of phone presence. The authors suggest phone presence may have a positive influence on perceptual processing in this task, and that excluding phones from workplaces may not always be justified⁴.

This is a small, task-specific effect, not a licence to keep your phone glued to your hand. But it does show that the relationship between phone presence and performance is not uniformly negative.

What happens to your eyes when a phone is on the table?

Ladouce and Gillebert took the question out of the lab and into a meal². Using wearable eye-tracking and computer vision, they recorded gaze and body orientation while participants ate spaghetti with a phone either absent or placed on the left or right side of the tray. Phone placement shifted gaze toward its location throughout the meal. Without a phone, gaze centred normally; with a phone, participants fixated more on nearby objects and less on those opposite².

This study did not measure cognitive performance, but it captures something the lab tasks miss: a phone in view changes where your attention lands, moment by moment, even during a routine activity. That spatial pull is a form of distraction in its own right.

What the mixed findings mean

The five studies point in different directions because they measure different things. Attention, memory, reaction time and gaze are related but not identical. A phone might not impair one task while still pulling your eyes toward it during another.

Two patterns do emerge. First, phone dependency or addiction appears as a risk factor in several studies. Christodoulou and Roussos found smartphone addiction had a weak effect on errors among those performing with a phone present¹. Liu and colleagues found phone dependency led to more incorrect responses⁴. Tanil and Yong found phone conscious thought, not addiction score, predicted memory accuracy⁵. The common thread is that your relationship with the phone, how dependent you are and how often you think about it, matters more than whether it is physically nearby.

Second, the studies use short lab tasks. None of them tested deep work over hours, or the effect of notifications arriving mid-task. The practical question most people care about, whether a phone on the desk damages a two-hour writing session, is not directly answered by this evidence.

Practical steps that fit the evidence

The research does not support a blanket rule that any phone in the room ruins your focus. But it does support reducing both physical proximity and mental pull when you need to concentrate.

Put the phone out of sight, not just face down. The eye-tracking study shows that a visible phone shifts gaze toward it². Out of sight reduces that spatial pull. A lockable phone storage locker or a timed lock box can help if you want a physical barrier rather than willpower.

Reduce phone conscious thought. The memory study found that thinking about your phone predicted worse recall⁵. If you find yourself mentally checking for the phone, that is the signal to increase distance. A Kitchen Safe time-locking container locks the phone away for a set period, which removes the option to check it and, over time, the habit of reaching for it.

Watch for dependency, not just presence. Two studies linked phone dependency or addiction to more errors^1,4. If you feel anxious without the phone nearby, that is worth addressing directly. Our piece on what a dopamine detox is explains one common approach, and deleting social media apps covers a related lever.

Use time-boxing to create phone-free blocks. The research does not tell us the ideal block length, but a structured session with the phone elsewhere is a sensible starting point. The Pomodoro Technique is one option, and a visual timer can make the block feel concrete.

Do not overcorrect. One study found faster responses with a phone nearby⁴. If your work involves short, simple tasks and you are not phone-dependent, the phone's presence may not be your main problem. Spend your effort on the distractions that actually interrupt you, such as notifications. Our piece on batching notifications covers that.

Bottom line

The evidence that a phone's mere presence reliably impairs cognitive performance is moderate at best, and mixed. Some studies find an effect^3,5, others do not¹, and one finds a small benefit on a specific task⁴. The stronger, more consistent finding is that your relationship with the phone, how dependent you are and how often you think about it, predicts worse performance. Physical distance helps because it reduces both the visual pull and the mental checking. But the phone itself is not the whole story.