"It might be important"

It might. The phone is where the school rings and where the hospital texts. A look at it is a look at whether you're needed.

But think about what actually arrives. In a day, the phone offers you a delivery, a group chat, a headline, three emails you didn't want, a like, an update from an app you forgot you had, and, once in a long while, something that can't wait. The glance during a story isn't a check for the thing that can't wait. It's a check of everything, in the hope that one of them is interesting, and the thing that can't wait is almost never what's there.

There's a simpler test. The things that genuinely can't wait ten minutes announce themselves. They ring, and keep ringing, or they come from a number that only calls when it matters. Everything else can wait ten minutes, which is about how long it takes for the person talking to you to finish. If you're waiting on a specific call, a hospital, a builder, a child's lift home, say so at the start. Then the look at the phone when it rings is an announced exception and not a glance.

What one interruption does is worth knowing. Jessa Reed, Kathy Hirsh-Pasek and Roberta Michnick Golinkoff had thirty-eight mothers each teach their two-year-old two new words, one at a time. During one of the two teaching periods, the mother's phone rang and she took the call. The children learned the word from the uninterrupted teaching. They didn't learn the word from the interrupted one, even though the mothers said the word just as many times in each. The number of words didn't change. The thread did.

It's a small study of one narrow thing, and I wouldn't build much on it alone. But it makes a point that's easy to miss. A break in a conversation isn't a pause after which everything resumes. It's a cut, and the thing being built on the other side of it doesn't always survive.

So the important message is real, and it's rare, and the glance is the habit of checking for it ninety-nine times when it isn't there. The one time it is, it will ring.