The limits of multitasking

by Kevin Rafferty

Special To The Japan Times

My earliest memories are of my mother — as no doubt for many people. She was always busy bustling about the house, cooking meals, baking, washing up, scrubbing the floor, cutting and re-sewing dresses so that they could be worn by younger sisters, making sure that we were doing our homework, wiping a tear as she hauled clothes from the copper hurt by the rheumatoid arthritis that would cripple her. She was also doing at least two things at once. We would probably call it multitasking; she called it life.

Of course, these days technology is transforming our lives, removing drudgery and making the exchange of information and ideas in an instant a commonplace thing all around the world, from Hong Kong to Honolulu, Tokyo to Timbuktu and back again, no problem.

One simple problem is beginning to loom large: Can the wiring in our human brains keep up with the speed of the computer-inspired gadgets?

In Asia, it’s common to see car drivers smoking and animatedly using their mobile telephones as they drive. Children, who may have kicked a ball or played tag going to school in my day, now listen to music and text while they bicycle across busy roads. People on commuter trains, when they are not sleeping, play furious hand-held electronic games while listening to music and talking to friends.

That’s nothing of course to the multitasking that computers can do. Or what we can do with the help of computers. We can network with Facebook, send and receive e-mails, write an article, send a multimillion dollar proposal round the world, watch YouTube, and talk to colleagues, all more or less simultaneously. But two recent items suggest that multitasking may not be a good deal. In modern jargon, it may be an ask too far.

In the United Kingdom the transport authorities increased the fine for using a mobile telephone while driving your car or even when stopped at traffic lights to £100 plus three penalty points on your license. That, of course, is a government decision that using a mobile while driving is potentially dangerous.

More interesting is a study from three researchers at Stanford University in the U.S., suggesting that chronic multitasking could be bad for you even when you are not multitasking. Priceconomics, the self-styled “price guide for everything,” drew attention to the work of Eyal Ophir, Clifford Nass and Anthony Wagner, which suggests that multitasking can become dangerous to your ability to perform regular tasks.

The three researchers recruited students at Stanford and identified them as either heavy or light media multitaskers depending on how often they used multiple streams of information, such as texting, e-mail, doing online research, watching YouTube or listening to music at the same time. They set the students various tasks.

In the first experiment they tested ability to filter out distractions when given a task. This is akin to the cocktail party test, where we learn to concentrate of the chatter that involves us and shut out the rest as ambient noise. The students were asked to check whether a rectangle changed orientation or to identify a particular series of letters, while being distracted and instructed to ignore the distracting elements.

Those students who did not regularly multitask had both higher accuracy and a faster response time.

Next, the students’ memories were tested. After seeing several series of letters flash on a computer screen, they were shown a single letter and asked whether that letter had been on a specified previous screen. In this test the light multitaskers did slightly better than the heavy ones.

But the most striking conclusion was the number of false alarms by the heavy multitaskers as the task got more complicated. The researchers reported that the multitaskers “were more susceptible to interference from items that seemed familiar, and this problem increased as the memory load increased.”

Finally the students were asked to perform a combination of the two previous tasks designed to test their ability to switch between tasks. They alternated irregularly between performing the same task multiple times and switching back and forth between the two.

You might expect that people used to switching between, for example, e-mails and Facebook would be used to smoothly moving between tasks. But the results showed that the hardened multitaskers did worse: They were easily distracted and worse at switching between tasks.

As the researchers put it, frequent multitaskers “have greater difficulty filtering out irrelevant stimuli from their environment, (are) less likely to ignore irrelevant representations in memory, and are less effective in suppressing the activation of irrelevant task sets.”

So the British and other governments may be right to ban the driver who is using his or her mobile on the move. Companies might also ask about the dangers of information overload leading to loss of productivity. Some psychology professors claim that possibly 10 percent of the population may be good at multitasking — or be supertaskers — so the chances are you will not be.

Other research has also demonstrated the pressures of doing different tasks at once. A study several years ago by the Institute of Psychiatry at the University of London found that “workers distracted by e-mail and phone calls suffer a fall in IQ more than twice that found in marijuana smokers.”

One of the “breakthrough ideas” of Harvard Business Review in 2007 was Linda Stone’s idea of “continuous partial attention,” which seems to sum up the use of gadgets and the electronic age in which we are “constantly scanning for opportunities and staying on top of contacts, events, and activities in an effort to miss nothing.”

The risk of missing nothing is that you do nothing well. One of the golden rules of psychiatrists and experts in productivity is OHIO — meaning only handle it once, take something on and see it through to fruition. An American study claimed that the loss of productivity from constant switching in multitasking and not completing anything well was as much as $650 billion a year.

Some studies have shown that workers switch between different tasks, such as looking at e-mails, doing research, talking on the telephone and talking to colleagues in the office, about every three minutes. Switching between tasks may cause a 40 percent loss in productivity.

There is still some argument about how many tasks is too many. A French study in 2010 found that the human brain can handle two complicated tasks at once using the two lobes that divide the tasks equally. But if you add a third task the risk is that the frontal cortex gets overwhelmed.

There is of course the famous jibe against a leading U.S. politician that he could not both walk and chew gum. Human brains can handle routine or mechanical tasks simultaneously, such as walking and talking or chewing gum, or listening to music while cooking, but the moment you add a complication, such as the pot boiling, things risk getting messy and you have to concentrate on one task or risk losing everything.

Kevin Rafferty is a professor at the Institute for Academic Initiatives at Osaka University.