Multitasking - bad for the brain?

From the random samples section of the Aug. 28 issue of Science, reporting unsettling news from one of the first-ever studies of chronic multitaskers:

A team headed by psychologist Eyal Ophir compared 19 "heavy media multitaskers" (HMMs), identified by questionnaires on media use, with 22 "light media multitaskers" (LMMs). They tested how well the subjects could filter relevant information from the environment, filter relevant information in their memories, and quickly switch cognitive tasks. One filtering test, for example, required viewers to note changes in red rectangles while ignoring blue rectangles in the same pictures.

HMMs did worse than LMMs across the board. Surprisingly, says co-author Clifford Nass, "they're bad at every cognitive control task necessary for multitasking." Nass, a sociologist, says the study has "disturbing" implications in an age when more and more people are simultaneously working on computers, listening to music, surfing the Web, and texting or talking on a phone. Also troubling, he notes, is that "people who chronically multitask believe they're good at it." The findings are reported this week in the Proceedings of the National Academy of Sciences.

The team hopes to investigate whether multitasking really scrambles brains or whether people with poor filtering and attentional abilities are more attracted to it to begin with. Psychologist Anthony Wagner suspects that media multitasking offers instant rewards that reinforce "exploratory" behavior at the expense of the ability to concentrate on a particular task.