Put the phone in another room, but for the right reason
The famous 'brain drain' study did not replicate cleanly. The habit is still worth keeping.
Do this
Leave the phone outside the room during focused work and during conversations. Judge it by whether you finish things and whether people feel heard, rather than by a claimed cognitive effect.
Why it works
The original finding - that the mere presence of a phone reduces available cognitive capacity even when it is off - was widely publicised. Subsequent replication attempts have produced mixed and often null results. What does hold up is that notifications and pickups interrupt, and interruptions cost measurable time and accuracy.
Where it fails
The interesting version of the claim is the one that has not replicated. The version that survives is mundane: a device you check pulls attention. Do not over-explain a sensible habit with a shaky study.
How you’ll know
Count pickups for a day using the phone's own screen time tool. Most people are wrong about their number by a wide margin.