One run, one task: what every switch costs

One run, one task

An afternoon with an essay, a group chat and an inbox all open can feel busy and useful. You answer a message, write a sentence, check an email, write another sentence. A lot happens. Less of it is the essay than it feels like.

Each hop between tasks has a price. Psychologists call it the switch cost: the extra time and mistakes right after you change from one task to another.

What the research found

In 2001, Rubinstein, Meyer and Evans ran four experiments with young adults. People either repeated one task or swapped between two, such as sorting shapes by different rules or doing different kinds of sums. Switching cost time in every experiment. The cost grew when the rules were more complex, and it was bigger when switching into an unfamiliar task than into a familiar one. A cue saying which task came next made it smaller.

A 2003 review by Monsell pulled together many studies like these. Right after a switch, people are slower and usually make more mistakes. Time to prepare shrinks the cost but doesn’t remove it. Part of it seems to be the old task’s settings hanging on, and part is the time it takes to set up the new one.

These were short, simple tasks in a lab. Real work is messier, and the cost isn’t always on the clock. In a 2008 study by Mark and colleagues, 48 people, mostly university students, answered work emails. Those who were interrupted finished sooner, with the same quality, but felt more stress, frustration and time pressure. They seemed to make up for it by speeding up.

What about ADHD?

None of those studies were about ADHD. A 2018 review by Pievsky and McGrath pulled together 34 meta-analyses comparing people with and without ADHD on thinking tests. Shifting between rules or tasks showed a gap, but one of the smallest they found. In a small 2007 study by King and colleagues, 22 adults with ADHD were slower and less accurate overall than 22 without, yet the extra time each switch took wasn’t clearly bigger.

So switch costs look like something everyone pays. ADHD may add a little, but the evidence is mixed. There’s also a practical reason the idea suits ADHD (our view, not a research finding). Every switch is a small decision, and each decision is a moment for something else to catch your eye.

How to do it

Before a run, name the one thing it’s for. If another task comes to mind, write it down instead of doing it. Messages and other small jobs can share a run of their own later. If you need to change tasks, end the run and start a new one with a new name. You still switch, but between runs and on purpose.

Try this week

Pick one study session. Before each run, write the one task it’s for in a few words, such as ‘Essay: plan paragraph 2’. When a different task pops into your head, add it to a list and carry on. At the end of the session, count what you parked. Each one is a switch you didn’t make mid-run. If you followed a few anyway, that’s fine. Noticing them is the useful part.

Name the run, then see where it went

1. Signed in with the full layout, pick a subject under Subject (or add one with + new) and type the task in the What are you working on? box. Or, with the to-do list on, tap one of your My Day tasks above Start focus. That works without an account, and the task shows under the clock. Then press Start focus.
2. Another task comes to mind? With the to-do list on, press Park a thought for later below End session (or press N). Type it and press Enter. It’s saved to Tasks while the clock keeps going.
3. Decided to change task? Press End session, name the new task and start again. If your attention drifted off on its own, press I got distracted instead. Either way the run is kept and stays about one thing.

Signed in, Topics in the record shows where your time went. Pick a range such as 7d. Each subject shows its time, how many runs and its average run, roughly your attention span on it. If one subject’s runs are much shorter than the rest, it may be worth asking what pulls you away there. It’s a clue, not a grade. For single tasks, switch back to Chart and click a day’s bar. Runs on … lists each run with what it was for.

Guess, then see adds up a task’s runs by name, so one task per run keeps its answer honest.

Do heavy multitaskers get good at it?

Many people think juggling lots of things trains you to switch well. A small 2009 study by Ophir and colleagues found the opposite: people who used the most media at once did worse on a task-switching test. That result hasn’t held up well either. In 2017, Wiradhany and Nieuwenstein ran two new studies to check it (14 tests in all). Only five showed the expected effect. Pooling 39 results, they found a weak link with being easily distracted, which was no longer clear once they corrected for a known bias in small studies. So there’s no good sign that juggling trains you to switch well, and whether heavy multitaskers are worse at it is still open. Neither study was about ADHD.