The Multitasking Myth: What Doing Everything at Once Costs Your Team
The cost of doing everything at once
Most corporate teams treat the ability to juggle as a strength, and the evidence says it is costing them more than they realise. The inbox stays open during the meeting, chat pings land mid report, and the day ends with plenty of activity and not much finished.
The research is more nuanced than the headlines, which is good news for leaders. Some popular claims do not hold up under scrutiny. The core finding does: when attention switches, something is lost, and people feel it as stress.
The answer is not another productivity hack. It is a working rhythm that protects focus and builds in recovery. Two well known versions are the Pomodoro technique and the 90 minute work block, and they are not the same thing. Here is what the evidence says about each.
A hat tip to Thrive Global
This post was sparked by “9 Ways Multitasking is Killing Your Brain and Productivity, According to Neuroscientists”, written by Mayo Oshin and published on the Thrive Global community in 2018.
Thrive Global does valuable work keeping workplace wellbeing, burnout and sustainable performance on the agenda, and I have a lot of respect for it. Their article makes a strong case for doing one thing at a time. I have taken the idea in my own direction: I went back to the research, kept what holds up, trimmed what does not, and paired it with two working rhythms you can start using this week.
What the research shows, and what to leave out
Switching attention has a real cost, but some of the most repeated claims are weaker than they sound.
Start with what is solid. Sophie Leroy’s 2009 paper in Organizational Behavior and Human Decision Processes introduced the idea of attention residue: when we move from one task to another, part of our attention stays behind on the first, which makes it harder to perform on the second. If your people go from a report to a chat message to a meeting and back, they are carrying that residue all day.
Interruptions also change how people work. In a study of 48 participants, Mark, Gudith and Klocke (2008) found that people who were interrupted during email tasks finished in less time with no drop in quality, but reported significantly higher stress, frustration, time pressure and effort. The cost is not always slower work. It is faster, more strained work, which is exactly what burnout is built on.
There is practical evidence on email too. Kushlev and Dunn (2015) asked 124 adults to check email only three times a day for one week and as often as they liked for another. Daily stress was lower in the limited week (Cohen’s d = 0.37, a small to moderate effect). The authors are clear that this is not a cure all.
Now the claims to handle with care. The brain scan finding is real but often overstated. Loh and Kanai (2014), writing in PLOS ONE, scanned 75 healthy adults and found that heavier media multitasking was linked to less grey matter density in the anterior cingulate cortex. The authors state that the design “does not allow us to specify the direction of causality”, and that it is equally plausible that people with these brain differences multitask more. So “multitasking shrinks your brain” is not supported. “Is associated with” is.
The idea that heavy media multitaskers are worse at filtering distractions is also less settled than it once looked. After the influential 2009 study by Ophir, Nass and Wagner, Wiradhany and Nieuwenstein (2017) ran two replications and a meta analysis. Only five of 14 tests showed the predicted effect, only two held up under a stricter statistical check, and the overall association was no longer significant once small study bias was corrected for.
You may have seen figures such as “it takes 23 minutes to refocus after an interruption”. They are widely quoted, but I have not found them in the peer reviewed research, so I have not relied on them here. What the evidence does support is this: switching costs are real, stress is real, and the more dramatic brain claims need more research.
The Pomodoro technique: short bursts, planned recovery
Pomodoro gives you a simple structure for short bursts of focus, and the early evidence suggests that planned breaks beat improvised ones.
Developed by Francesco Cirillo, the technique works in rounds. You work on one task for 25 minutes with notifications off, then take a 5 minute break away from the screen. After four rounds you take a longer break of around 20 to 30 minutes. One full cycle of four rounds takes roughly 115 minutes: 100 minutes of focused work plus three short breaks.
The research is promising but small. Biwer and colleagues (2023), in the British Journal of Educational Psychology, compared 25 students using Pomodoro breaks with 35 taking breaks whenever they chose. The self regulated group studied for longer stretches, and that was linked to higher fatigue and lower concentration and motivation. Both groups reported similar mental effort and task completion.
Two cautions for the corporate setting. The participants were students, not people managing client calls and a full inbox, and the sample was small. So treat Pomodoro as a sensible experiment for your team rather than a proven prescription. The useful principle underneath is that the break is scheduled in advance, so it does not depend on anyone having the willpower to stop.
The 90 minute block: a guide only. Our Ultradian rythym does run in about 90 min blocks
The 90 minute block is a reasonable upper limit for a stretch of deep work, but the idea that your body runs on a fixed 90 minute clock is contested.
The idea traces back to sleep researcher Nathaniel Kleitman, who proposed a basic rest activity cycle of roughly 90 minutes (anywhere from 80 to 120) that continues through the waking day. Sleep cycles of that length are well established. Whether the same rhythm governs focus during the day is much less certain, and some researchers have argued that it does not.
The stronger support comes from studies of expert performance. Ericsson, Krampe and Tesch Romer (1993), in Psychological Review, studied elite violinists and found their practice sessions averaged about 80 minutes. The best players practised around 3.5 hours a day, and the authors noted little benefit from deliberate practice beyond four hours a day. They described optimal practice as a balance between effort and recovery, and the top players also slept longer and napped more than less accomplished players. That is evidence about musicians, not office teams, but it fits the same pattern: focused work in blocks, then genuine rest.
It also answers a question many people ask: the two methods are not the same length. Pomodoro’s longer break comes after four rounds, about 115 minutes in, while the 90 minute block is shorter. They are different tools with a shared principle.
Putting it to work in your team
The simplest way to use both methods is to run Pomodoro rounds inside one protected 90 minute block each day, and to change team habits so that block can survive.
Here is how I would start:
- Protect one 90 minute block a day for your most important work. Run it as three rounds of 25 minutes on and 5 minutes off, which adds up to exactly 90 minutes. This combination is my own practical adaptation, not a tested protocol, so treat it as an experiment.
- Check email at set times. The Kushlev and Dunn study used three checks a day, which is a sensible place to begin.
- Silence notifications during the block and set a status message so colleagues know when you will be back.
- Leaders, set the norm. Agree response times for messages, avoid pinging people during their blocks, and schedule meetings around them, not through them.
- Make the breaks real. Step away from the screen, move, and get some water or fresh air rather than switching to your phone.
- Review after two weeks. Ask the team what changed in their output and their stress, and adjust the block length to suit the work.
The point is not to be rigid. A client emergency will override any schedule. The goal is to make focus the default and interruption the exception.
Closing thoughts
Multitasking feels productive because it feels busy, and busy is easy to mistake for effective. The research does not support the most dramatic warnings, but it does support something quieter and more useful: switching has a cost, interruptions raise stress, and structured recovery helps.
Pick one block this week, try the rhythm, and notice what changes. Thank you again to Mayo Oshin and Thrive Global for the spark.
References
- Biwer, F. et al. (2023). Understanding effort regulation: Comparing ‘Pomodoro’ breaks and self regulated breaks. British Journal of Educational Psychology, 93(S2), 353 to 367. Wiley
- Ericsson, K. A., Krampe, R. T. and Tesch Romer, C. (1993). The role of deliberate practice in the acquisition of expert performance. Psychological Review, 100(3). Full text
- Kushlev, K. and Dunn, E. W. (2015). Checking email less frequently reduces stress. Computers in Human Behavior. Full text
- 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), 168 to 181. DOI
- Loh, K. K. and Kanai, R. (2014). Higher media multi tasking activity is associated with smaller gray matter density in the anterior cingulate cortex. PLOS ONE. Full text
- Mark, G., Gudith, D. and Klocke, U. (2008). The cost of interrupted work: more speed and stress. CHI conference proceedings. Full text
- Ophir, E., Nass, C. and Wagner, A. D. (2009). Cognitive control in media multitaskers. PNAS, 106, 15583 to 15587. PNAS
- Wiradhany, W. and Nieuwenstein, M. R. (2017). Cognitive control in media multitaskers: Two replication studies and a meta analysis. Attention, Perception, & Psychophysics. Springer
- Oshin, M. (2018). 9 ways multitasking is killing your brain and productivity, according to neuroscientists. Thrive Global community