Does Having Your Phone Nearby Hurt Your Studying?

There are really two questions hiding inside "is your phone hurting your studying?" The first is about using the phone: checking messages or scrolling while you are supposed to be learning. The second is about the phone just being there, face down on the desk, untouched.

Using a phone in class has the clearer evidence of harm; whether a silent phone on the desk matters is disputed.

1. Question 1: does using a device during class cost you points?

A study by Arnold Glass and Mengxue Kang, published in Educational Psychology in 2019, tested this inside a real college course rather than a lab.

How it worked: In a course taught in two sections, electronic devices (laptops, tablets, and phones) were allowed in half of the lectures and not in the other half. Because the same students experienced both conditions on different material, the researchers could compare each student with themselves.

What they found:

• Using a device for non-academic purposes during class did not lower scores on quiz questions asked during that same class. Students seemed to follow the lecture well enough in the moment.
• It did lower long-term retention of that lecture, which showed up as worse performance on the later unit exams and the final exam.
• Exam performance was worse than in the no-device condition both for students who reported using a device and for students who reported not using one in that class. The study does not say why the non-users were affected.

The lesson is uncomfortable but clear: divided attention can feel fine during the lecture and still cost you weeks later on the exam, when it is too late to notice.

2. Question 2: does a phone you are not using still drain your focus?

This idea is often called the "brain drain" effect, after a 2017 study by Ward and colleagues. In their second experiment, people kept their own phone either on the desk, in a pocket or bag, or outside the room, and the closer the phone, the worse they did on an attention-demanding task.

It became a widely shared finding. Later research has made the picture less certain.

A direct replication (2022). Researchers Ruiz Pardo and Minda at Western University in Canada ran a pre-registered replication of Ward's second experiment, published in Acta Psychologica. They used the same tasks and conditions, and added whether the phone was on or off, for six conditions in total. The result: the brain drain effect did not replicate. Phone location made no difference to performance on either task. The authors concluded that the mere presence of a phone may not be enough to affect cognitive performance.

A meta-analysis (2023). Böttger, Poschik, and Zierer at the University of Augsburg in Germany pooled 22 studies with 43 relevant effects, published in Behavioral Sciences. They found a significant overall negative effect of smartphone use and presence on memory, attention, and general cognitive performance. But they also found that not all areas were equally affected, that results varied a lot between studies, and that the country where a study was run was a key variable.

Note that the meta-analysis combined phone use and phone presence, so it does not settle the presence-only question on its own.

3. What the evidence supports, and how strongly

4. What to do about it

The safest strategy works regardless of how the presence debate ends.

Make using the phone harder than not using it. Put it in a bag or another room during focused study. Even if presence alone turns out not to matter, distance removes the easy temptation to check it, and checking is where the clearer evidence of harm is.

Treat class time as encoding time. The Glass and Kang results suggest that what you lose from distraction in class is not in-the-moment understanding but long-term memory. Keep devices out of non-academic use during lectures, even when the lecture feels easy.

Mind your surroundings. Non-users also scored lower in the classroom study, though it did not establish why, so sitting where you cannot see other screens is a small, free precaution.

Batch your checking. Decide in advance when you will look at messages, such as during a planned break, instead of whenever a notification arrives.

Do not rely on feeling focused. In the classroom study, students did fine on in-class questions and still lost points later. A better test is to quiz yourself on the material a few days afterward.

5. Key takeaways

• Using a device for non-academic purposes in class did not hurt same-day quiz scores but lowered later exam scores.
• Students who reported not using a device also scored lower on material from device-allowed lectures.
• The claim that an unused phone drains attention just by being present failed a direct replication.
• A meta-analysis found an overall negative link between smartphones and cognitive performance, with large variation across studies.
• Put the phone out of reach while studying and judge your focus by what you remember days later.