Your email is open, the chat keeps pinging, and a document sits unfinished. You jump between them all day and end it busy, with little to show. Is switching the problem?
You’ll see the two side by side and why the last task stays in your head. You’ll learn what research measured and what one study shows. Then you’ll find out if multitasking is ever okay, and get four ways to stay on one task.
What is the difference between deep work and multitasking?
Deep work means one demanding task with your full attention. Multitasking at work means several tasks on the go and jumping between them.
Cal Newport, author of Deep Work (2016), describes deep work as professional activities done in “a state of distraction-free concentration.” These activities push your mental abilities to their limit.
At work, multitasking usually looks like this. Several tasks are open, and you jump between them: the email, the chat, back to the document. Below, I set it next to one deep work block, a fixed stretch of time for one task.
| One deep work block | Multitasking | |
|---|---|---|
| Tasks | One, with its goal written down | Several open at once |
| Attention | Stays on the one task | Jumps from task to task |
| New ideas and to-dos | Noted on a separate sheet for later | Followed the moment they come up |
| Phone, email, chat | Off or closed before you start | Open, answered as messages arrive |
| End of the day | A list of goals reached | Busy all day, little to show |
The left column is how one block works in my book. One goal on paper, and everything else waits. For the full picture, read about what deep work is.
What is attention residue?
Every jump in the right column leaves something behind. When you switch away from an unfinished task, part of your attention stays with it, and the next task suffers. The researcher Sophie Leroy calls this attention residue, meaning attention left over on the old task (2009).
Leroy tested this in two experiments, published in Organizational Behavior and Human Decision Processes. People had to stop thinking about one task to move their full attention to the next. Leaving an unfinished task was hard, and work on the next task suffered.
Just finishing the first task did not free people’s attention. Finishing it under time pressure did help. Then people could stop thinking about it.
So how often does this happen in a normal workday? And what does each switch cost? Researchers have measured both.
What does research say about task switching and productivity?
Research on task switching and productivity shows three things. People at work switch every few minutes, and each switch costs time. Interrupted work can also wait a long time before you return to it.
Each finding has names and years behind it:
- How often people switch: Gonzalez and Mark (2004) observed analysts, developers and managers. People spent about three minutes on a task before they switched.
- What a switch costs: Rubinstein, Meyer and Evans (2001) measured a time cost for switching between tasks. It grew with more complex rules.
- How long interrupted work waits: Gloria Mark gave Gallup a figure in 2006. Interrupted work was resumed after 23 minutes and 15 seconds on average.
Read the 23 minutes with care. They measure the time until people went back to the interrupted work. They do not measure how long it took to be fully focused again.
Either way, in a 45-minute block I can’t afford that kind of break. If other people keep breaking your focus, read about deep work when people keep interrupting you.
What does the Stanford study on multitasking show?
The research above measured single switches. The Stanford study looked at people instead. It compared heavy and light media multitaskers, meaning people who use many or few media at once.
The heavy ones were more easily distracted. The study did not test deep work.
Eyal Ophir, Clifford Nass and Anthony Wagner ran the study. They published “Cognitive control in media multitaskers” in PNAS (2009). They found three things:
- Heavy media multitaskers were more easily distracted by things around them that didn’t matter.
- They were also more easily distracted by things in their memory that didn’t matter.
- They did worse on a test of switching between tasks.
My reading: the people who multitask with media the most were not the best at switching.
As I read it, the study compares groups of people who multitask more or less with media. It does not compare a day of deep work with a day of multitasking.
Can anyone really do two things at once? Read about whether you can focus on two things at once.
Is multitasking ever okay?
Given what switching costs, my answer has two parts. Inside a block, no. Nothing runs alongside the task, not even music.
Between blocks, you switch tasks and match each one to your energy.
Music feels like it helps you focus. But it takes up mental space that you need for the task. My advice: skip it.
Music also means choosing it, hitting play and switching tracks. For me, every touch of the player pulls me out of flow. Flow is the state of being fully absorbed in the work.
If you can’t work without music, pick instrumental music with no singing that stays the same all the way through. Use one playlist on repeat. For more, read about deep work with music.
Between blocks, do demanding tasks when you have energy, and easier tasks when your energy fades. Wasting energy on an easy task is as inefficient as doing a hard task without energy.
How a Deep Work Block keeps you on one task
Whatever task you match to your energy, the block keeps you on it. It closes the other tasks before you start and gives new ones a place to wait.
Your phone is already off, as I described above. Four more tools do the rest:
- Close the other tasks: Close email, Slack and social media. Close every app and tab this task doesn’t need. Turn on Do Not Disturb.
- Write one block goal: Your protocol sheet is a blank sheet for goal and work steps. Write down the result you want.
- Park new tasks: Note them as a keyword on your thought sheet, a second sheet for new thoughts. Then go back to your task.
- Stuck? Stay in the task: Write the next mini step on the protocol sheet. If nothing works, switch to another part of the same task.
Every open app and every open tab is an open thought. To go further, learn how to avoid distractions during deep work and how to protect your blocks from Slack notifications.
After a few blocks, one task per block becomes routine. Then a 45-minute block gives you 45 minutes on one task, not 45 minutes of switching. See how it works →
FAQ
Can some people multitask without losing performance?
A few people can, at least in one setting. Watson and Strayer (2010) tested 200 people in a driving simulator with a demanding second task.
Of them, 2.5% showed no drop in performance. The vast majority got worse when multitasking.
Does multitasking damage your brain?
One brain study does not show that. In Loh and Kanai (2014), people who multitasked more with media had less dense gray matter in one brain region.
Gray matter is one kind of brain tissue. The authors say their study can’t show which causes which.
Is multitasking harder with ADHD?
One study says no. Gawrilow and colleagues (2011) compared 45 men with ADHD, a disorder of attention and activity, and 42 men without it.
The men with ADHD did not multitask worse. They felt better and more motivated when tasks were not mixed.
