Do you watch TV while making plans with your partner? Do you write a WhatsApp during a work meeting? Most likely, you won’t be able to do either thing properly.
Multitasking, the seemingly admirable ability to do several things at once, was considered a triumph, a sign of greater productivity in the modern world, a way to make the most of every second of the day. However, the science is clear: multitasking, as we understand it, is not only impossible, it is also inefficient and could be detrimental to our cognitive abilities and our emotional state.
The Human Brain and the Illusion of Multitasking
In American culture, someone is sometimes ridiculed with the phrase “he can’t walk and chew gum at the same time” to indicate that he has limited intelligence. However, virtually everyone is capable of performing simple tasks like walking and chewing gum at the same time. Does this mean that we are all multitaskers?
Here’s the distinction. Multitasking is possible only if two conditions are met: that at least one of the tasks is so well-learned that it is automatic, meaning that it does not require concentration or thought to perform it—for example, walking or eating—and that each task involves different types of brain processing.
The myth of multitasking arises from a misunderstanding of how the brain works. The human brain is not designed to focus on more than one cognitive task at a time involving the same circuits.
The science is clear: multitasking, as we understand it, is not only impossible, it is also inefficient and could harm our cognitive abilities and emotional state.
“When we do two tasks at the same time, one or both, we’re going to do it badly,” says neurologist Marco Calabria, a professor at the Faculty of Health Sciences at the Open University of Catalonia and author of several studies on the brain’s ability to switch tasks. “If I’m talking to you on the phone and I start writing an email, I’ll either write a lot more or I’ll make mistakes, but if I focus on the task of writing, I won’t listen to you.”
The main reason is that the brain’s resources for controlling tasks are limited. When performing a task, our brain is constantly checking and monitoring whether we are performing it efficiently. “If you have to take a drink, the glass may weigh more than expected and you have to adjust the movement,” Calabria gives the example. These monitoring and correction processes are automatic, but “if we add more tasks to this monitoring system, we overload it, we take away resources.”
Switch tasks very quickly
There will be those who think that they can actually do two things at the same time. However, when it comes to two tasks that use the same part of the brain, for example language, only one of them is suitable. If we try, instead of doing these tasks simultaneously, we quickly switch from one to the other.
This process, called “task switching,” (task change), consumes a significant amount of mental energy and negatively affects performance. The part of the brain responsible for directing our attention from one task to another is the prefrontal cortex. This is the part where the executive functions of the brain reside, such as decision-making and attention.
Instead of performing these tasks simultaneously, we switch quickly from one to the other.
This constant change of focus generates what is called the “cost of switching.” Switching from one task to another is something we do in milliseconds, but there is a problem. Each task requires a different set of “instructions” and a different adaptation time. “If we have a task of a certain duration, but we switch from time to time to another, the level of efficiency decreases. When we return to the initial task, if it is writing an email, we will probably have to review the last lines to remember what we wanted to say,” Calabria explains.
Various studies have measured this loss of efficiency. According to a synthesis of studies by the American Psychological Association, multitasking can reduce productivity by up to 40%.
Do you still think you’re a multitasker? Research has shown that people who believe they’re good at multitasking and who do it frequently are actually the ones who have the most trouble switching between tasks. Not only were they less effective at switching tasks, but they also had difficulty filtering out irrelevant information and remembering what they were doing.
According to one study, driving and talking on the phone at the same time leads to more driving errors and less awareness of making them. Of course, it is much worse to drive and text on your cell phone, which increases the risk of accidents. Another study of students who used their cell phones while studying or in class found that they were less productive, retained less information, and got lower grades than students who did not use them.
If we have a task of a certain duration, but from time to time we switch to another, the level of efficiency decreases.
Marco Calabria
— neurologist
The emotional and cognitive cost of multitasking
Beyond the impact on efficiency, multitasking also has a cognitive cost. Different experiments have shown that performing several tasks at the same time activates the sympathetic nervous system (the one of action) and deactivates the parasympathetic nervous system (the one of relaxation). Other studies have found that, while cortisol levels, a measure of stress, did not increase, the stress, frustration and mental fatigue perceived by the participants did.
On the other hand, multitasking also interferes with memory consolidation. When we multitask, our brains have a harder time processing and storing information efficiently. A study published in Nature found that this feeling of having something “on the tip of our tongue”—those moments when we want to remember something and can’t—gets worse if we’re looking at two screens at the same time.
It’s precisely technology that has exacerbated the multitasking problem. From notifications on our phones to emails, everything pushes us to switch from one task to another, but even knowing that a task is pending can hurt us. A 2005 review of trials found that the mere presence of an unread email in your inbox can temporarily lower your IQ by up to 10 points—more than smoking marijuana or having a bad night’s sleep.
When we read something or listen to someone speak, it is a task that requires understanding, effort and concentration. Normally, after 20 minutes, your concentration level starts to drop and you start to get distracted.
Marco Calabria
— neurologist
How to escape multitasking
Instead of trying to multitask, experts recommend practicing “single-tasking” or mindfulness (mindfulness). But it also presents difficulties. “When we read something or listen to someone speak, it is a task that requires understanding, effort and concentration,” explains Marco Calabria. “Normally, after 20 minutes, your concentration level begins to drop and you start to get distracted.”
The solution proposed by Calabria is to perform a single task at a time, but taking breaks every 20 or 30 minutes, resting for five minutes. This technique known as pomodoro because it was popularized using a tomato-shaped timer can help us. “It’s good to disconnect the system for a few moments,” explains Marco Calabria. “We can’t spend hours and hours doing the same thing either.”
*Darío Pescador is editor and director of the Quo Magazine and author of the book the best of yourself Published by Oberon.
