A two-second glance at your phone does not cost two seconds

The number everyone quotes

Researchers who followed information workers and timed their task-switching found it took an average of roughly 23 minutes to return to an original task after being interrupted. The figure is widely shared, usually stripped of its context.

So here is the context. It is an average from observing real workplaces, not a controlled constant. For a simple, well-rehearsed task you resume in seconds. For difficult creative work it can be considerably worse. Treat 23 minutes as an order of magnitude, not a personal prediction.

Why re-entry is the expensive part

When you are deep in something, you are holding a structure in mind: where you are, what you just decided, what you ruled out, what comes next. None of that is written down. An interruption does not pause that structure — it lets it decay, and rebuilding it is effortful work that produces nothing visible.

This is why the cost feels invisible. You can see the eight seconds you spent reading the message. You cannot see the twenty minutes of degraded work that followed, because it looks exactly like working.

The finding that removes the usual excuse

The common defence is: I have good self-control, I leave notifications on and simply do not check them. An experiment tested precisely that. Participants doing an attention task were interrupted by notifications they did not view or respond to. Their error rate rose anyway.

The cost is not paid at the moment you decide whether to check. It is paid the instant the alert arrives, before any decision exists. Discipline is applied too late to help.

What follows from this

If the cost lands before your willpower can act, the only intervention that works is not receiving the alert. That means silencing categories of notification rather than resolving to resist them — a one-time change instead of a decision you have to win repeatedly.

• Turn off notifications for any app that has never sent you something genuinely urgent. Most people can do three in ninety seconds.
• Before you stop mid-task, spend ten seconds writing the exact next step. It buys back most of the re-entry cost.
• Batch the things you do need to see, so you pay re-entry once rather than nine times.

One thing the research also found

In a follow-up study, interrupted workers did compensate: they worked faster to finish on time. But they reported significantly more stress, frustration and effort to do it. So the real cost is split — partly time, partly strain. If your interrupted days leave you exhausted despite finishing everything, that is not imagination.