Mind: Paying a Mental Price Due to Task Switching

For better or worse, the consumption of media, as varied as e-mail and TV, has exploded. In 2008, people consumed three times as much information each day as they did in 1960. And they are constantly shifting their attention.

Until 15 years ago, scientists thought the brain stopped developing after childhood. Now they understand that its neural networks continue to develop, influenced by things like learning skills.

In a test created by Mr. Ophir and his colleagues, subjects at a computer were briefly shown an image of red rectangles. Then they saw a similar image and were asked whether any of the rectangles had moved. It was a simple task until the addition of a twist: blue rectangles were added, and the subjects were told to ignore them.

The multitaskers then did a significantly worse job than the non-multitaskers at recognizing whether red rectangles had changed position. In other words, they had trouble filtering out the blue ones — the irrelevant information.

So, too, the multitaskers took longer than non-multitaskers to switch among tasks, like differentiating vowels from consonants and then odd from even numbers. The multitaskers were shown to be less efficient at juggling problems.

Other tests at Stanford, an important center for research in this fast-growing field, showed multitaskers tended to search for new information rather than accept a reward for putting older, more valuable information to work.

Preliminary research shows some people can more easily juggle multiple information streams. These “supertaskers” represent less than 3 percent of the population, according to scientists at the University of Utah.

Other research shows computer use has neurological advantages. In imaging studies, Dr. Small observed that Internet users showed greater brain activity than nonusers, suggesting they were growing their neural circuitry.

For much more, see Hooked on Gadgets, and Paying a Mental Price by Matt Richtel, June 6, 2010, at nytimes.com.