What does “mere presence” actually mean in these studies?
It means the phone is physically nearby but not being used—no checking, no interaction. The key finding is that proximity and salience alone can reduce cognitive capacity on demanding tasks.

Why doesn’t turning a phone off reliably solve the problem?
In the lab experiment, powering phones off did not remove the performance drop when phones stayed nearby. The results support the idea that attention resources are still recruited when the device remains salient.

Which people are most likely to benefit from putting the phone away?
The evidence points most strongly to people with higher smartphone dependence. For them, separation produced the largest improvement in available working memory performance.

Are smartphones the only major distraction category?
No. In the education review, technology distractors were the largest category, but personal needs and the instructional environment also contributed. This implies effective prevention usually combines rules, tools, and habits.

Do phone bans always increase productivity at work?
Not necessarily. A field experiment found increased effort under bans, but output (completed interviews) did not consistently rise in parallel, showing that productivity depends on what actually constrains results in that job.