Member-only story
The Nuance
Does Multitasking Really Tire Out My Brain?
Scientists disagree over whether certain mental tasks are more fatiguing than others
Every week, the Nuance will go beyond the basics, offering a deep and researched look at the latest science and expert insights on a buzzed-about health topic.
We’re all familiar with the sensation of mental fatigue. Your mind feels sluggish and bleary, like it’s gone soft around the edges. You also feel a little cranky and sleepy, and making decisions, even minor ones, is a struggle.
The longer you go without sleep and food, the more likely you are to experience this sort of mental lethargy. No surprise there. But comb through the research on cognitive fatigue and you’ll find a mountain of studies that suggest there are certain mental tasks that seem to drain our brains faster than others.
“Multitasking is a myth.”
Some of the most robust evidence suggests that multitasking is particularly fatiguing. A 2009 study in Brain Research found that people who spent two hours engaged in a multitasking challenge gradually made more errors and had slower reaction times, which the authors attributed to mental tiredness.
“Multitasking is a myth,” says Daniel Levitin, professor emeritus of psychology at Canada’s McGill University and author of The Organized Mind: Thinking Straight in the Age of Information Overload. According to Levitin, the human brain can concentrate on only one thing at a time, so when you ask your mind to manage several cognitive tasks at once, “all the switching is neurobiologically expensive and will tire you out.”
Making decisions is another chore the brain finds especially taxing, Levitin says, which may help explain why sorting through your inbox can be such a slog. He reels off all the decisions involved in checking email: “Do I read this now or later? Do I respond now or later? Do I forward this to someone? Do I need to get more information before I can answer?” If your day involves heavy doses of both multitasking and decision-making, it’s no wonder you feel mentally exhausted by the end of it.
