Gloria Mark's research group at UC Irvine spent years shadowing office workers with stopwatches, and produced the most-quoted number in attention research: after an interruption, it takes about 23 minutes and 15 seconds to return fully to the original task. Her team also measured how often the interruptions come, and that number is the truly alarming one: for much of the day, knowledge workers switch what they're attending to every few minutes.
Why switching costs so much
Two mechanisms stack. First, the return path is indirect: interrupted people rarely go straight back, instead touching two or three other tasks on the way, each adding its own residue. Second is the residue itself, Sophie Leroy's term for the fraction of attention that stays with the previous task after a switch. Glance at your inbox "for one second" during hard work and you carry a little of every message you saw back into the work. The second was never a second.
Email is the biggest single source
Of all the channels pinging a professional, email interrupts most often and most legitimately: it's work-shaped, so checking it never feels like slacking. That's precisely what makes it expensive. An inbox monitored continuously converts the workday into confetti, with a 23-minute tax stapled to every glance.
The two changes that recover the most
You don't need a monastery. Two structural moves recapture most of the lost hours:
- Batch the batchable. Email in two to four fixed windows, closed in between. The full case, including what to do about urgency expectations.
- Cut notifications to a named-VIP list. A handful of senders may interrupt you; nobody else gets the privilege by default. Every notification you keep is an interruption you pre-approved.
A third multiplier: shrink what the email windows contain, so even the sanctioned switches are short. Pidgy pre-sorts a Gmail or Outlook inbox continuously, so a window opens onto five decisions instead of forty messages, and the day's total switching drops again. For where the recovered hours should go, see protecting deep work.
