For people looking for ways to improve their cognitive performance, multitasking (performing two or more cognitively demanding tasks at the same time) seems like a great way to boost productivity. Why not write that work email while watching the news, so that you can get your work done and stay informed about the world in half the time it would take you to do the two things separately? Unfortunately, if you’re looking for such shortcuts, the science on multitasking is disappointing.

Multitasking and the brain

People who think they’re good at multitasking swear that they can really pay full attention to two conversations at once, or stay fully focused on two separate cognitively demanding tasks. But multiple psychological studies have shown that our brains can’t actually engage in two different, simultaneous activities—at least not the kind that require thoughtful attention. Instead, what we’re doing in such moments is very rapid “task switching.” We’re whip-sawing back and forth between the two tasks in a fraction of a second.

That might sound like a semantic difference. After all, who cares what it’s called, as long as you’re able to veer back and forth with such rapidity that it seems, for all intents and purposes, like you’re doing both things at once? But close study shows that even self-proclaimed multitasking experts are slower, more error-prone and less productive than those who focus on one task at a time. That may be because our brains are wired to tackle cognitive tasks by following certain protocols and adjusting our efforts to reflect progress already made.

As an example, let’s consider the writing of that work email, which under scrutiny turns out to be a very complex task. There are the technological steps to follow, such as opening the email reader, clicking the “Compose” button, entering the correct email address and typing up a subject line. Then there are the compositional aspects, such as including a good greeting and then making one’s points logically and with good flow and word choices. Remember that with every word that’s typed, the task changes slightly. You’re that much further into the message, and your word choices up to now have affected the tone and the logic, and thus the choices of wording that you must make as you continue to compose. Have you gotten your point across yet? Is it as clear as it could have been? Picture the process of writing the email as a map that keeps evolving as you work. When you multitask, you’re tearing yourself away from the map repeatedly, and each time you return to the task, you’ve got to reorient yourself to it, finding your place on the map. You might be good at that, and you might not feel like it costs you much time, but you are without doubt sacrificing micro-seconds to this unnecessary process of constant reorientation.

Should I avoid multitasking?

Yes and no. There’s absolutely nothing wrong with folding laundry while you watch TV, for example. What’s the worst that could happen? You might fold a little bit more slowly, but the idea of a “folding mistake” is laughable. Plus, for most people, folding laundry is such a common chore that it’s become automatic, and humans are quite good at performing multiple tasks that are bone-simple (That’s why it’s a common insult to say someone is incapable of walking and chewing gum at the same time).

There’s even a little evidence that multitasking is neuroprotective. An Alzheimer’s Association study found that women with three or more kids were 12% less likely to be diagnosed with dementia, possibly because during their child-rearing years the women had had to multitask constantly (But, while tantalizing, this idea is not borne out by any substantial body of research).

A 2016 study led by researchers at Purdue University found that the young people who were best at multitasking tested high for working memory, attention control, and fluid intelligence (problem-solving and abstract reasoning). But really, those findings serve less well as an argument for strategic multitasking than as an explanation as to why people with those attributes excelled at rapid task-switching. In other words, if those study subjects had been performing the same sets of tasks while focusing exclusively on one task at a time, their performance would presumably have been even better.

Since we know from considerable research that we’re less productive and more error-prone when we attempt to multitask, it makes sense to avoid the practice when the stakes of our performance are high. But there’s another reason to avoid multitasking, and that is that recent research suggests that multitasking changes our brains, diminishing our ability to focus. If our goal is improved concentration and focus, then training our brains not to pay full attention is directly counterproductive to our purposes. Multitasking is the opposite of mindfulness, the opposite of concentration.

What to do instead

There are a couple of reasons why you may be tempted to multitask or why you may already be a habitual multitasker. One is that you simply feel overwhelmed by the number of tasks before you and don’t feel like you have enough time to complete them all separately. The other is that you don’t have the attention span to stick to one task at a time. For people in this second category, focusing on just one thing can feel like torture.

If your problem is a sense of being overwhelmed, take stock of your workload and do what you can to clear your plate. Look for good, harmless opportunities to multitask (listening to a podcast while washing dishes, for example), and then map out your time as carefully as possible while allotting dedicated time to tasks that require full attention.

If your problem is an inability to focus, go ahead and continue going back and forth between your tasks, but try doing so at greater intervals of time instead of “simultaneously.” Set a timer, at first for just five minutes, then increasing to seven, then 10, and so on until you’ve worked your way up to 30 minutes. For that period of time, focus exclusively on one task. Then switch to the other task for the same amount of time. Once you’ve trained your brain to stay focused on one task for a solid chunk of time, you won’t want to go back to the more distracted method of working that we call multitasking.  

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