The Real Dangers of Multitasking

From a Lecture Series Presented By Professor Indre Viskontas, Ph.D.

The popular misconception is that when we’re texting and driving or multitasking in some other way, we’re actually doubling up on our efficiency. The truth is that we’re not. We’re switching our attention between tasks—and every time we make a switch, we pay a price.

Image of man in car on phone multitasking

It’s So Easy To Multitask

Our lives have become so convenient, with email and world maps at our fingertips. You can drop down into virtually any city. And while catching a ride to a popular local restaurant, sign up for an exercise class, check international newspaper headlines, book a hotel room, and have a conference call with your boss.

It’s become so easy to do these things that many of us are prone to over-scheduling our lives, knowing that just because we’re not in the office that doesn’t mean that we can’t still accomplish work-related tasks. This bad habit leaves us breathless, putting us in a position in which we have to do more than one thing at the same time. We can’t just get lost in thought at a stoplight, so many of us—despite the fact that it’s illegal in many places—can’t resist the temptation of glancing at our smartphones as the seconds tick by interminably slowly.

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And yet, there are several studies that show that texting, checking email, or being otherwise engaged with our phones while driving renders us just as impaired as having had a few drinks. Depending on the study, texting has at least as big and sometimes a reportedly 4 times larger increase in accident risk than drinking 4 beers.

In one study, for example, drivers’ reaction times decreased by 13% if their blood alcohol level was at the legal limit and 21% if they were high on cannabis.

In one study, for example, drivers’ reaction times decreased by 13% if their blood alcohol level was at the legal limit and 21% if they were high on cannabis. Even during a hands-free call, reaction times decreased by 27%. Texting caused a decrease of 37% and making a call plummeted reaction times by 46%.

Well, you might think, driving is complicated. But surely I can walk and text. Not so, says a study published in the journal Gait & Posture showing that people who were texting while walking deviated off course 61% more often than those who weren’t texting. And another study showed that people talking on their cell phones while walking missed important cues in the environment—like a clown riding a unicycle.

So why is texting so disruptive to our ability to navigate either on 2 feet or 4 wheels? And why do we think it’s safe, despite the statistics indicating otherwise?

image of lady with baby trying to multitask
It’s a misconception that when we’re multitasking, we’re actually doing two things at once. But the truth is that we’re not.

Part of the answer is based on a popular misconception that when we’re texting and driving or multitasking in some other way, we’re actually doing two things at once—doubling up on our efficiency. But the truth is that we’re not. We’re switching our attention between tasks, and every time we make a switch, we pay a price.

And just like many of our cognitive biases, our memories, or the unconscious processes that shape our behavior, our intuition is not an accurate judge of how well we are switching between tasks.

Being Busy Is Not The Same As Being Productive

We’re often impressed by how much busy people can accomplish. And for many of us, the ability to squeeze more tasks into our day by doubling up on them is a source of pride, rather than shame.

But people who multitask more often—who consider themselves particularly good at it—are actually worse at it than the rest of us.

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In one study, researchers from Stanford University asked their student participants to report on their frequency of multitasking using different media. That is, how often do they report watching TV, texting, or listening to music while working on their computers? Based on those self-reports, the researchers divided the students into two groups—heavy multitaskers and light multitaskers.

Then, they tested these students on their ability to perform several cognitive tasks, including tests of task-switching ability. Common sense would predict that heavy multitaskers would show a benefit of practice on task switching since they spend so much time doing it.

The heavy multitaskers were actually worse at the task-switching tests than the light multitaskers. They were more easily distracted by irrelevant cues, and their ability to hold more than one thing in mind was worse than the students who were less likely to do 2 things at once.

But the authors instead found a paradox. The heavy multitaskers were actually worse at the task-switching tests than the light multitaskers. They were more easily distracted by irrelevant cues, and their ability to hold more than one thing in mind was worse than the students who were less likely to do 2 things at once.

The authors conclude that heavy multitaskers are less able to filter out distractions from the environment. They have more trouble ignoring intrusive memories and, most surprising of all, they are less able to suppress the interference from a rival task when asked to focus on a target one. That is, they are worse at switching between tasks.

And in another study, this one from the University of Utah, 70% of participants reported that they were above average at multitasking. But when asked to memorize a sequence of letters while also doing math problems, those who reported multitasking most often in real life performed the worst. The top 25% of performers were also the ones who reported multitasking only sparingly in daily life.

Image of Lady in office with many notes on her windows
Does multitasking lead to a greater susceptibility to distraction and a decrease in the ability to control your attention? Or are people who are more distractible more likely to spend time trying to do two things at once?

What we don’t know yet is whether this impairment is the chicken or the egg. Does multitasking lead to a greater susceptibility to distraction and a decrease in the ability to control your attention? Or are people who are more distractible more likely to spend time trying to do two things at once?

We might see some hints in the traits of heavy multitaskers. That is, what else characterizes people who report multitasking often and who think they are particularly adept at it? Well, for one thing, they’re also more likely to be impulsive and to be labeled as sensation seekers—people who take more risks to get novel and intense experiences. So in my opinion, it might be true that people who have shorter attention spans, to begin with, gravitate toward multitasking.

But regardless of which way the arrow points, the increasing availability of multiple media at our fingertips is only going to make this problem worse. That is, the more people succumb to the growing temptations to multitask, the more likely we’re going to see adverse effects on their ability to focus on challenging tasks.

We Are Expected To Multitask

For many of us, the bigger issue is not just that we find it difficult to resist the temptation to entertain ourselves while we’re at a stoplight or walking along the street. The problem is the demand placed on us to always be available, to respond to emails and texts immediately, to fit a busy work schedule and family and friend time into a very short day—all this leaves with a few opportunities to spend a significant amount of time doing only one, focused thing.

man on beach multitasking
The problem is the demand placed on us to always be available, to respond to emails and texts immediately…

Multitasking, in the real world, isn’t just about listening to music while we work on a project. Instead, it’s what society demands of us, now that we’re so easily contacted and connected. So we can’t just avoid it altogether.

But too often we let all these demands distract us from important activities that require a maximum of focus, leaving a trail of unfinished projects and unfulfilled dreams in our wake.

Checking and responding to emails, making grocery lists, rearranging the living room are all things that I do when I’m unconsciously avoiding actually working. My husband can tell what kind of day I’ve had if he walks into a living room that he barely recognizes. It’s become a bit of a joke. And the more frequently we are distracted by a new email or an unfinished chore, the harder it is to resist the temptation.

I don’t like to use the term addiction to describe what’s happening here because addiction is complex and should, in my opinion, be reserved for situations involving drugs that create physical symptoms of withdrawal. But multitasking does resemble addiction in one way—the more we do it, the more we seem to be tempted to do it again.

Our brains are creatures of habits. If you do the same thing over and over, the networks of neurons that are involved in that task get strengthened and fire more efficiently. That means that the next time you do that thing, your brain’s activity will be slightly more fine-tuned. Like ski tracks on a hill, the more times the same path has been skied on, the deeper the ruts and the faster the track. But it’s also harder than to take a different track because now you need to overcome the rut.

Learn More: Can You Multitask Efficiently?

image of lady at work multitasking
…multitasking does resemble addiction in one way—the more we do it, the more we seem to be tempted to do it again

But by the same token, when you multitask, your brain doesn’t necessarily know which task is the important one.  It’ll gravitate toward the easy, more sculpted track. So if you’re doing two tasks, one of which is more ingrained, you’ll find your mind drifting back to that one rather than paving a new track. Checking email, which just requires the highly practiced task of reading, is easier than coming up with a genius new idea for a book.

The Mixing Cost

Even putting aside the decreased resources that we can spend on each task, every time we switch our attention from one task to another, we pay a price. Sometimes the price is small, and we can corral our attention back fairly easily. Often, in fact, we’re pretty quick at making the switch. But sometimes the cost is bigger than we think. Instead of a switch cost, we pay a price for mixing the two cognitive tasks—called a mixing cost.

The mixing cost is a measure of the extent to which the previous task intrudes into the current one.

The mixing cost is a measure of the extent to which the previous task intrudes into the current one. If you’re switching between checking email and preparing a presentation, the mixing cost can be pretty expensive, as you keep thinking about your emails—even though you should be thinking about your talk. And so we fall into a trap of wasting too much time, then having even less dedicated time to do the thing that we were supposed to be doing.

Which brings us to the question of whether training can improve multitasking ability. And the answer is yes—kind of. Though just multitasking itself might not do it, you need to have a strategy of how to get better at it. Usually, the strategy is to practice each task on its own before putting them together.

Brain imaging studies of this sort of multitask training show that the networks involved get more efficient—just as we would expect—rather than seeing a pattern in which new regions are recruited. We also see an increase in the speed of processing in the prefrontal cortex, underlining this increase in efficiency.

But multitasking the way most of us do it—alleviating the boring nature of one task, say driving, with a more stimulating bit of entertainment, say cell phone use—reduces our performance and our learning of the hard task. And there are some serious consequences to this kind of habit, as attested by the number of accidents caused by distracted drivers.

From the lecture series Brain Myths Exploded: Lessons from Neuroscience
Taught by Professor Indre Viskontas, Ph.D.

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1 Comment

  1. SO many managers need to read this article – It’s more productive for people to stay focused on task than to try and accomplish multiple things at once. There is an illusion that time is saved by doing two things at once; when in reality, the quality applied to doing one thing at one time ensures things are done right.

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