Brainwork. David A. Sousa

Чтение книги онлайн.

СКАЧАТЬ 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 СКАЧАТЬ