Multitasking feels efficient. You’re answering an email while on a call, glancing at a message while drafting a proposal, keeping four things moving at once.
The research is fairly consistent that you aren’t doing four things at once. You’re doing one thing at a time and switching between them very quickly — and every switch costs you something you don’t notice paying.
What the research actually shows
We switch; we don’t multitask. Psychologists including David Meyer at the University of Michigan spent years measuring what happens when people alternate between tasks. The consistent finding is that switching carries a cost: time lost reorienting to the new task, and more errors. The cost is small per switch and large across a day.
Almost nobody is the exception. In 2010, Jason Watson and David Strayer at the University of Utah tested people driving in a simulator while doing a demanding phone task. About 2.5% of participants showed no drop in performance on either. They called them “supertaskers.” The other 97.5% got measurably worse at both.
Which means that if you believe you’re good at multitasking, the odds are very heavily against it.
Heavy multitaskers get worse at focusing, not better. Researchers at Stanford — Eyal Ophir, Clifford Nass and Anthony Wagner — published a study in 2009 comparing people who habitually juggled lots of media with people who didn’t. The heavy multitaskers were worse at filtering out irrelevant information. Nass later described them as being drawn to whatever was most distracting.
The intuitive assumption is that practice makes you better at juggling. The evidence suggests the opposite.
Getting back takes a while. Gloria Mark at the University of California, Irvine, has studied interruptions in real workplaces for years. Her work found that after being interrupted, people took on average over twenty minutes to return to the task they’d been doing — frequently working on other things in between.
And a caution about the brain claims. You’ll see it said that multitasking shrinks your brain. That comes from a 2014 study that found heavy media multitaskers had lower grey matter density in one region. It was a small study, and it showed an association, not a cause — it’s equally possible that people with that brain structure are more drawn to multitasking. Interesting, and nowhere near settled.
Why owners suffer most
An employee can often close the door. A business owner is the answer to everyone’s question.
The team comes to you. The clients come to you. The suppliers come to you. And each of those is a switch, arriving at a moment you didn’t choose, pulling you out of whatever you were thinking about.
This is structural, not a discipline problem. An owner who is the bottleneck for every decision will be interrupted constantly regardless of how focused they’d like to be, and the fragmentation is a symptom of how the business is organised.
Which is also why so many owners do their real thinking at eleven at night. It’s the only time nobody is switching them.
What actually helps
Protect one block a day. Ninety minutes, notifications off, door closed if you have one, and nothing but the one thing that matters most. Put it in the calendar, or it won’t survive the day.
Batch the small things. Email, messages and calls in two or three windows rather than continuously. Answering everything instantly feels responsive. It mostly just means everything gets your worst attention.
Tell people when you’re reachable. “I’m focused until eleven — message me then” sounds unresponsive and works remarkably well. Most things that feel urgent turn out to be comfortably able to wait ninety minutes.
Turn off everything that isn’t essential. Every notification is an invitation to switch. Most of them are invitations you’d decline if anyone asked.
And fix the structure. If you’re interrupted constantly because every decision comes to you, the long-term answer isn’t better focus. It’s giving people the authority to decide without you.
Stop hiring for it
One practical change most owners never think of.
Look at your job adverts. Many of them say “must be able to multitask” or “comfortable juggling competing priorities.”
That phrase describes a working environment that the research says makes people less effective. It also attracts people who’ve learned to cope with chaos rather than people who’ve learned to prevent it.
Try instead: “able to prioritise, finish what they start, and say clearly when something has to wait.” That describes the person you actually want, and it tells candidates something honest about how you’d like your business to run.
The short version
You’re almost certainly not in the 2.5%. Switching costs you time and accuracy on every change, and it gets worse with habit rather than better.
Protect one block a day, batch the rest, and look honestly at whether the interruptions are a focus problem or a symptom of everything routing through you. For most owners it’s the second.
