ObservatoryIf you’ve read anything about focus in the last decade, you’ve met the number: it takes 23 minutes to get back on task after an interruption. It appears in productivity books, LinkedIn posts and app marketing, usually with no source, sometimes with the wrong one.
The number is real, but it’s narrower than the way it’s used. Here is where it comes from.
Where “23 minutes” comes from
The figure is from research by Gloria Mark at the University of California, Irvine. In a 2008 study, Mark, Daniela Gudith and Ulrich Klocke ran an experiment in which people did an email-answering task while being interrupted, and measured how the interruptions changed their work. Mark has summarised the resulting resumption figure in interviews as roughly 23 minutes (the precise value reported was 23 minutes and 15 seconds) to return to the original task after being pulled off it. The paper itself is “The Cost of Interrupted Work: More Speed and Stress”, presented at CHI 2008.
Two details matter when you read that number:
- It was measured in an office-style task with external interruptions, not on people checking their own phones at will. The interruptions were imposed by the researchers.
- People compensated by working faster. The interrupted participants finished in about the same time as the uninterrupted group, but reported more stress, more frustration and more time pressure. The cost showed up in how it felt, not only in the clock.
So “23 minutes” is best read as the time it took a group of people to return to the original task after being interrupted in a lab-like setting, not a law about your brain.
What we can say with more confidence
Across the interruption literature, a few findings are consistent enough to act on:
- Resuming is a cost in itself. Coming back to a task means reconstructing where you were. Sophie Leroy’s work on attention residue found that part of your attention stays with the previous task after you switch, and performance on the new one suffers.
- Self-interruptions are common. Later observational work by Mark and colleagues found people interrupt themselves nearly as often as they’re interrupted by others. A phone check is a self-interruption.
- The recovery time varies a lot. It depends on what you were doing, how far in you were, and what the interruption was. A quick glance at a notification is not the same as a ten-minute scroll.
What this means for your next phone check
The honest takeaway isn’t “every glance costs you 23 minutes”. It’s that every interruption has a resumption cost you don’t feel while it’s happening, and the only way to know your own number is to measure it.
That is why Observatory records a drift every time you leave the app during a session, and shows the length of it rather than adding it to your focus time. After a few weeks you can see your own figures: how often you drift, how long each drift runs, and which hours or days are worse. Your own numbers will be more useful than any average from a study.
Sources
- Mark, G., Gudith, D., & Klocke, U. (2008). The Cost of Interrupted Work: More Speed and Stress. CHI 2008. PDF
- Leroy, S. (2009). Why is it so hard to do my work? The challenge of attention residue when switching between work tasks. Organizational Behavior and Human Decision Processes, 109(2). Abstract
Observatory is a calm focus timer for iPhone that only counts real focus. Drifts and pauses are tracked, never added. How it measures focus.
