The cost of switching tasks, and how to switch less

Every time you switch from one task to another, you pay a small cost. It takes a moment to remember where you were and what you were doing, and part of your mind stays behind on the last task for a while. The researcher Sophie Leroy called that leftover attention residue. One switch is cheap. Forty a day, most of them to check a message, add up to a working day where nothing gets your full attention.

The fix is not heroic willpower. It is two habits: switch less often, by batching email and chat into set times, and switch more cleanly, by closing the loop on a task (or writing down where you left it) before you move on. This post explains why switching costs what it does, and how to do both.

What happens in your head when you switch

Psychologists have studied task switching in the lab for decades, and the basic finding is consistent: when people switch between two tasks, they are slower and make more mistakes than when they stick with one, even when they know the switch is coming. Your mind has to drop one set of rules and goals and load another, and that takes time.

This is why what feels like multitasking is mostly fast switching. Writing an email while half-listening to a meeting means flicking your attention back and forth, and both get worse. Most people feel productive while doing it, which makes it easy to underrate the cost.

In real work the cost is probably bigger than in a lab, because real tasks are bigger. Getting back into a complex spreadsheet, a piece of code or a difficult paragraph means rebuilding a picture you were holding in your head, and that can take minutes, not moments.

Attention residue

Sophie Leroy, an organizational researcher, gave the leftover part a name in a paper published in 2009. In her studies, people who moved on from a task they hadn't finished kept thinking about it, and they did worse on the next task than people who had finished the first one before moving on. Some of their attention was still back on the unfinished work.

It is worth being careful with this. The studies were done with short tasks in controlled settings, and nobody can tell you how many minutes a particular switch will cost you. But the idea matches most people's experience. You close the chat window, but the question someone asked is still running in the back of your mind while you try to write.

A later study by Leroy and a colleague pointed to a simple remedy: when people were interrupted, writing a brief plan for how they would pick the task up again seemed to reduce the residue and help them focus on the interruption. That idea comes up again below, because it is the easiest thing in this post to start doing today.

Why a quick check is never quick

Checking chat or email in the middle of a task feels harmless. It takes ten seconds. The trouble is what comes with those ten seconds.

• It rarely stays one check. One message leads to a reply, and the reply leads to the next unread thread.
• It opens new loops. You see a question you can't answer now, or a problem you can't fix yet. Now it sits in your head beside the work you came back to, which is attention residue in its purest form.
• It happens a lot. A ten-second check every ten minutes is six switches an hour, each with its own small restart.
• It feels like a rest, but it isn't. Your eyes stay on the screen and your mind stays busy. A real break, like standing up or looking out of the window, does more for you in the same time.

None of this means messages don't matter. It means the time you read them matters.

Batch email and chat

Batching means handling messages in a few set slots instead of whenever they arrive. A rhythm that suits many desk jobs looks like this:

1. Pick your slots. For example, first thing after your morning plan, before lunch, mid-afternoon and before you finish. If your role needs faster replies, check at the end of each focused block instead, perhaps every hour.
2. Close the apps between slots. Not minimized, closed. If the mail app isn't open, its badge and its banners can't pull you in.
3. Turn off what you can. Mute chat notifications from channels that are not about you, and turn off sounds and badges for mail. Cutting Mac notifications down walks through each setting.
4. Tell people. A line in your chat status or email signature ("I check messages a few times a day; call me if it's urgent") changes what colleagues expect, and gives them a route for the rare real emergency.

A Focus on your Mac can enforce the quiet between slots: allow a few people and apps, silence the rest, and put it on a schedule. Focus modes on Mac covers the setup.

Close the loop before you switch

You can't avoid every switch. Meetings start, colleagues need answers, the day has edges. What you can do is make each switch cleaner.

Stop at a natural break

Where you can, switch at the end of a unit of work: the end of a section, a finished function, a sent reply. A finished piece leaves far less behind than one abandoned in the middle of a thought.

Write a ready-to-resume note

If you have to stop in the middle, take thirty seconds to write two lines before you go: where you are, and what the very next step is. "Halfway through the pricing section; next, check the numbers in the second table." Put it at the top of the document, in a sticky note or in a comment. It tells your mind the task is parked safely, and it makes the restart much faster.

Keep a capture list

Stray thoughts are switches too. When something pops into your head mid-task ("must reply to Sam", "book the dentist"), write it on a list and go back to work. A list in Reminders or a note in Notes works fine. The thought is safe, and you deal with it at your next batching slot.

Leave space between big switches

Moving straight from one demanding task into another, or into a meeting, carries the most residue. A few minutes between them helps: stand up, refill your water, look across the room. It gives the last task time to settle before the next one starts.

A nudge when a check becomes a stay

The hardest switches to catch are the ones that were meant to be short. If you use Notchpals with Bolt in your crew, its scrolling check is built for this. Spend 20 minutes in a row in one of the chat, news, video or gaming apps on its list, and Bolt comes down from the notch about it.

BoltScroll loop detected. Exit condition: you. Please run it.

The list is fixed and leaves out web browsers, so a long afternoon on a news site in a browser tab goes unnoticed. For more on catching that kind of drift, see doomscrolling at work.

To protect a block of work rather than catch a slip, start a 25 or 50 minute focus session from the Notchpals menu bar. Until it ends, the crew keeps its own interruptions to the few that can't wait: apart from Bolt, only a battery close to empty or a meeting about to start gets through.