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CHAPTER TWO

The Myth of Multitasking

There is time enough for everything in the

course of the day, if you do but one thing

at once; but there is not time enough in the

year, if you will do two things at a time.

LORD CHESTERFIELD

IT WAS AROUND NOON, AND THE AIRPORT CLUB LOUNGE WAS PACKED. Bad weather had delayed numerous flights, including mine. People were frantically trying to get in touch with their home offices as well as the clients they were scheduled to meet at their next destination. I could not help but notice the young man sitting across from me; he was talking very loudly into his headset and complaining about the flight delay. But what really caught my attention was how much he was interacting with the items around him. In addition to his headset conversation, he was scrolling through his personal digital assistant and checking his laptop screen, periodically typing a few keystrokes. He also was trying to read a story on the front page of the USA Today that was resting on a table next to him. As time went on, he appeared to cycle his attention easily among all the items. Surely, to the casual observer, this man was multitasking. I bet even the man himself believed he was multitasking—but he wasn’t. Why? Because the brain cannot multitask.

What Does Multitasking Mean?

Before we go any further, we need to define what the term multitasking means in this context. The original definition of multitasking came from the computer industry and referred to a microprocessor’s ability to carry out more than one task at a time. Obviously, humans can multitask in that they can simultaneously walk and talk, or ride a bicycle while pondering the beauty of nature, or knit while watching television. We are able to do these tasks concurrently because different parts of the brain are in command of each. Walking, riding a bicycle, and knitting are learned motor skills that are controlled primarily by a structure at the rear base of the brain called the cerebellum (see fig. 2.1). Talking, pondering, and watching television are cognitive operations, which we know are the main responsibility of the prefrontal cortex. As long as we perform tasks that call on two brain regions with separate responsibilities, we are able to carry them out successfully. But when we call on the same part of the brain to carry out two or more functions simultaneously, problems arise.

Figure 2.1: The prefrontal cortex deals with cognitive processing. The cerebellum controls motor movements, balance, and equilibrium.

Let’s demonstrate this notion with a simple but amusing motor skills activity. Sit in a chair, lift your right leg, and move it in clockwise circles for several seconds. Stop. Place your right foot back on the floor. Now extend your right arm and your right index finger. Use this finger to draw the number 8 continuously for several seconds. Stop. Now lift your right leg and move it in clockwise circles while at the same time drawing the number 8 with your right hand. How did you do? Did you lose control of either your leg or your hand movements?

What happened here? You were able to perform each of the movements separately. However, as soon as you tried to do them together, you were calling on the cerebellum to control two unrelated motor tasks simultaneously—a feat it cannot do. The neural signals got scrambled, and you lost control. Similar results will occur when the prefrontal cortex encounters the same predicament. Ever try to talk on the phone and write an email at the same time? Those cognitive activities are almost impossible to do together. For the purposes of this discussion, multitasking refers to calling on the same brain region to carry out more than one task simultaneously.

Survival Requires Focus

Remember, the brain’s main task is to keep its owner alive. Survival requires the ability to focus intently on incoming signals that could pose a threat to the individual. Those ancestors of ours who were unable to do so most likely ended up as some predator’s lunch; their genes never entered the gene pool. On the other hand, the individuals who were able to concentrate on a threat and find ways to avoid or defeat it were more apt to live long enough to find a mate and transmit that focusing ability to their offspring—and a few hundred millennia later, to us.

Torkel Klingberg, a cognitive neuroscientist at the Karolinska Institute in Sweden, has conducted experiments with brain scans that indicate that a certain region of the brain (known as the globus pallidus) is highly active when individuals are fending off distractions.¹ Think of this area as a nightclub bouncer, preventing irrelevant items from getting into the club called working memory. This makes sense. Focus equals survival. When a car is speeding toward you in the wrong lane and a head-on collision is imminent, you do not want your brain’s attention systems shifting suddenly to admiring the colorful flowers on the roadside trees or wondering whether the car needs a new set of tires.

In 2009, when Captain Chesley Sullenberger was piloting his disabled jet over the Hudson River with 155 passengers and crew on board, he knew that focus was his only hope. He didn’t even pray. “I imagine somebody in back was taking care of that for me,” he told Katie Couric of CBS News. “My focus was so intensely on landing, I thought of nothing else.” In the three minutes he had from the time the plane started its unrelenting descent until it hit water, Sullenberger screened out all external input and relied on his forty years of flying experience to guide the sixty-ton aircraft. After a bumpy landing on the water’s surface, he said to his copilot, “Well, that wasn’t as bad as I thought.”² Thanks to his focusing ability, not one life was lost.

Safety experts advise against using a cell phone while driving because they want drivers to avoid distractions during cognitive activities. Talking on a cell phone requires significant cognitive resources. About 70 percent of a face-to-face conversation involves nonverbal communication, such as facial expressions, body gestures, posture, and degree of eye contact, all of which carry meaning. In the absence of these nonverbal cues—such as during a phone call—the brain has to work harder by analyzing the caller’s voice for tone, pitch, and pacing to determine the true meaning and intent of the caller’s words. This is not easy because even the best technology does not faithfully transmit all the characteristics of a person’s voice. Such diversion of attention resources—about 37 percent, according to the fMRI scans—significantly reduces the driver’s response time and ability to make quick decisions when the car in front suddenly brakes or another car unexpectedly changes lanes. Research studies conducted by David Strayer and his colleagues at the University of Utah and neuroscientist Marcel Just at Carnegie Mellon University have shown that the cognitive impairments that occur when using a cell phone while driving are as serious as those associated with driving while drunk.³ That’s scary. If you are thinking that hands-free or voice-activated cell phones are safer, you are mistaken. These studies showed that they made little difference in the driver’s level of distraction.

Does talking to someone in the car involve the same amount of distraction? No. Strayer’s research found that although talking with a passenger involves some diversion of attention, it is far less than the distraction of a phone conversation. In the car, you can hear all the characteristics of the passenger’s voice, and your eyes may catch direct or peripheral views of the speaker, helping you assess those important nonverbal signals. In short, it is a lot easier for your brain to determine the meaning and intent of the passenger’s words in the car than those of the caller on the phone. Furthermore, the passenger is an extra set of eyes to alert you to road hazards.

What about texting and driving? Well, let’s see. I am going to be driving a vehicle, a task that requires the full attention of my eyes and extensive coordination of my hands. Oh, and at the same time, I am going to be texting a message, a task that requires considerable attention from my eyes and intricate coordination of my fingers. Is there a problem with that? This combination is not only dangerous, it is insane!

The Costs of Tasking

If the man in the airport lounge is not multitasking, then what is he doing? When the brain has to attend to multiple items in working memory, one option is to shift its focus back and forth between two items at astonishing speeds. This is called alternate tasking. Or, the brain can shift its focus among more than two items, a process called sequential tasking. Figure 2.2 illustrates the two options.

Figure 2.2: The left diagram shows alternate tasking as the brain shifts its attention from A to B and back to A. The right diagram shows sequential tasking, with attention shifting from X to Y to Z and back to X.

The brain of our airport executive is probably using both methods. He is doing alternate tasking when, for example, his attention moves from the newspaper to the digital assistant and then to the paper again. If he were to get a phone call about a change in a meeting date, he would likely engage in sequential tasking. He would focus first on the caller’s message (X in fig. 2.2), turn to the digital assistant to send a text message to his office advising of the new date (Y), and then focus on his laptop to alter the dates in his slide presentation (Z). Then he could tell the caller that he made the necessary changes (back to X).

At this point, you might be thinking, “So what? Does it make any difference that multitasking is really alternate or sequential tasking? Isn’t the result the same—namely, that I can accomplish two tasks at about the same time?” Sorry, you may wish that to be true, but it is not.

Try this simple activity that demonstrates how alternate tasking causes cognitive problems. Get ready to count as quickly as you can from one to ten. Ready? Go! That probably took you about two seconds. Now get ready to recite the alphabet letters from A to J quickly. Ready? Go! That also took you around two seconds. If we put these two tasks together, one after the other, it would take you four seconds to complete. Instead, I would like you to interweave the two tasks as fast as you can, that is, A, 1, B, 2, and so on. Ready? Go! Now that likely took you fifteen to twenty seconds, and you may have made some errors. Your brain had to continually shift from the alphabet task to the counting task and back again. This constant shifting between or among items in working memory comes at a cognitive cost not only in time, but also in accuracy and attention. Figure 2.3 (page 28) helps explain why this is so.

Figure 2.3: The solid line shows an increase in working memory processing for the assignment. As soon as attention shifts to the phone call, indicated by the dotted line, memory resources devoted to the assignment drop as memory resources are used to begin processing information from the caller.

Say you are in your office, working intently on your computer to complete an important assignment for the CEO. The rise in the solid line in figure 2.3 shows how your working memory is devoting its full resources to processing the assignment. Recall that working memory has a limited capacity. Your cell phone rings. The caller ID indicates that your spouse is at the other end. You think, “Hmmm, I’d better answer it.” As soon as you do, attention resources shift from your assignment to the phone call. Signals from the emotional brain facilitate this shift because, after all, the caller is your spouse, and there may be emotional consequences later for not answering the call. Notice in figure 2.3 how the solid line (resources associated with your assignment) drops rapidly, while the dotted line—representing the resources dedicated to the phone call—rises quickly. When the call ends, working memory has pushed out much of what you were working on for the assignment to make room for the items discussed in your spouse’s call. Returning to your assignment, you realize that you do not remember much of what you were working on at the time of the call, and you think, “OK, where was I?”

This dramatic loss of attention occurs every time you switch your focus to another source of information, such as answering a phone call or an email. Researchers call this the task switch cost, and these costs add up. Often, working memory gets fatigued from this constant shifting and pays less attention to new information—another reason why too much information paralyzes working memory. Brain scans confirm how easily nonrelevant stimuli, such as the spouse’s phone call, can disrupt our concentration. Using fMRI, researcher Katherine Moore and her colleagues at the University of Michigan found that irrelevant cues introduced when a person was concentrating on relevant information literally hijacked the attention systems, causing resources to be diverted to processing the unrelated items.⁴ Amazingly, these constant interruptions can have a lasting effect on our brainpower.

Attempts at Multitasking Can Dumb You Down

Research studies at the Institute of Psychiatry of King’s College London, led by Glenn Wilson, looked at the mental concentration levels of 1,100 office workers.⁵ They found that excessive use of technology actually reduced workers’ intelligence. Individuals who were distracted by incoming phone calls or emails had an astounding ten-point drop in their IQ—more than twice that found in studies of the impact of marijuana use on intelligence. Participants who had a lack of discipline in handling emails had the largest IQ loss. Many workers had an almost addictive compulsion to reply to each new message, resulting in constant changes in focus and the eventual fatigue of the prefrontal cortex. Their attempts at being more productive were, in reality, seriously undermining their productivity. Curiously, 90 percent of the participants agreed that it was rude to receive and handle messages during office meetings or face-to-face conversations. Nonetheless, about a third of them said that this had become an acceptable practice because they believed their supervisors interpreted their behavior as a sign of diligence and efficiency.

Attempts at Multitasking Adversely Affect Long-Term Memory

There is growing research evidence that consistent attempts at multitasking affect our brain’s ability to encode information into long-term memory. Psychologist Karin Foerde and her colleagues at the University of California, Los Angeles used fMRI scans to observe the brains of participants as they were learning and trying to remember numerous tasks.⁶ One group learned their tasks without distractions, whereas the other group had their learning interrupted with distracting beeps—not unlike those we hear from cell phones or arriving emails. Later, the researchers asked both groups to recall what they had learned. The undistracted group was able to recall significantly more of what they learned than the distracted group, an indication that distractions interfere with learning and memory. Looking at brain scans while both groups were engaged in learning revealed that the part of the brain responsible for encoding long-term memories (the hippocampus) was active in the undistracted group but inactive in the distracted group. The researchers concluded that attempts at multitasking change the way we learn and diminish what we remember.

Attempts at Multitasking Hinder Working Memory in Older People

One of the more disturbing research findings on how multitasking might affect the brain comes from a study comparing how the working memories of older and younger individuals respond to interruptions in their work. Wesley Clapp, Adam Gazzaley, and their colleagues, neurologists at the University of California, San Francisco, found that attempts at multitasking took a significantly greater toll on the working memory of the older participants (ages sixty to eighty) than the younger ones (in their twenties and thirties).⁷ Their study examined how long it took the participants to remember and refocus on a task after a brief interruption. Older participants found it much more difficult to disengage from the interruption and reestablish contact with their original task. This may partially explain why older folks can walk to the refrigerator and then stand at the door trying to remember what they were going to get or go to the supermarket for bread and come back with twenty other items but not bread.