2- "may I have 30% of your attentionn please?"
Today it is possible to be productive, keep in constant contact with associates, and have fun at the same time. At least that is what ads for the latest digital gizmos claim. While writing an email to your boss or finishing a paper for your economics class, you can check for live updates on a tennis match halfway around the world or load songs into your portable media device. The boss expects you to prepare a sales report for tomorrow's meeting. No problem. You can do it and read a movie review at the same time. Or can you?
Multitasking, the popular term for this behavior, originally referred to the process by which computers appear to accomplish two or more tasks simultaneously. If computers can multitask with a single microprocessor, then certainly the much bigger human brain can train itself to do the same and enjoy the benefits of increased productivity. We humans are quite adept at letting our minds wander while performing a routine motor skill. We can do the dinner dishes while thinking about our next vacation, or chew gum while reading a newspaper. But psychologists ask this question: Do multitasking humans operate effectively and efficiently when they really need to concentrate?
The evidence suggests that the answer is no. One problem is interference, or what psychologists call the "Stroop effect." Back in the 1930s, the psychologist John Ridley Stroop showed there is a danger of error when the brain receives unexpected information while carrying out a routine task. To see what he found, try this experiment on yourself: As quickly as possible, say the name of each shape in Column 1 out loud. Then, do the same for Column 2. Then, do the same for Column 3.
If you are a good reader, most likely you completed the first column effortlessly, went a bit slower in the second column, and hesitated some. or even made an error, in the third column. Because you are much quicker at reading words out loud than naming shapes, you had difficulty ignoring the incorrect information that you read. Of course, this drill is a bit unnatural and designed to be confusing, but it shows that multitaskers are vulnerable to error and hesitation if they get interference from the wrong set of stimuli while switching between tasks. Imagine the damage a multitasking driver or air traffic controller could do if incorrect information intruded at the wrong time.
Research also suggests that switching between tasks significantly delays completion. If the two tasks are very routine and not too much alike— say, humming along to a new tune while diapering a squirming baby—the brain does not need to switch between the tasks because the two require different input channels. The humming requires listening and singing, whereas the diapering requires sight and the use of arm and hand muscles. But when a similar kind of attention is needed, the pace slows as the brain must switch back and forth between the two tasks.
In a study reported in the Journal of Experimental Psychology, Rubenstein, Meyer, and Evans measured the amount of time lost when people switch between tasks such as solving math problems and Identifying shapes. They discovered that as the tasks become less familiar, the area of the brain that mediates task switching and assigns mental resources takes longer to operate. Because each task requires a different set of rules, it seems the brain needs time to activate the appropriate set. With complex so tasks, the switching delays add up, making multitasking less efficient than concentrating on one task at a time. Other researchers report that the brain shows less, not more, neural activity when simultaneously attempting two complex tasks, even when a different area of the brain is used for each task. And less brain activity comes at a price. In one study, subjects were instructed to write a report and check their email. The multitaskers took one and a half times longer than those who completed one task before starting another.
This more leisurely work pace will no doubt appeal to many. But the problems with multitasking go beyond the lasue of time management. If switching takes time— perhaps a hatf-second or more—that could be long enough to distract a driver who is fiddling with a cell phone or scrolling through a complicated digital display on a car dashboard. Constant switching is also mentally stressful and may lead to a diminished capacity to remember facts and learn new skills. The brain simply may not get the time it needs to build and maintain neural connections and access memory.
All these negatives do not mean that you should never "whistle while you work" or sneak a peak at a ballgame while studying chemistry. But what about the boss who says "I need that website up by Friday and can you take my calls while I'm out" or the digital showoff who sits through a university lecture white text-messaging on a tiny cell phone screen and nodding to the beat of music piped into barely visible earphones? Remind them of this: The multitasking machinery of our digital world was most likely developed by very single-minded people focused intently on a single task.
