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Thursday, October 15, 2009

Multi-tasking May Damage the Brain

We older adults tend to be awed at how young people today can multi-task. They seem to text message on cells phones, watch TV, listen to music, play a video or computer game, carrying on a conversation, and maybe even study their school lessons all simultaneously with apparent ease. Many adults, and even teachers, encourage multi-tasking because they think it is good stimulus for the brain and that learning how to multi-task is a useful skill. But I have already identified many research reports that show multi-tasking to impair formation of memory. Multi-tasking prevents the focused attention and reduction of distractions that are necessary for good memory.

Now there is a research report suggesting that the brain itself may be damaged by multi-tasking. Investigators at Stanford University gave questionnaires to their subjects to identify how much multi-tasking each person did. Nineteen subjects were "heavy multi-taskers" and 22 were "light multi-taskers." Comparison of how these two groups in thinking control tasks revealed that heavy media multi-taskers were more susceptible to interference from irrelevant environmental stimuli and from irrelevant representations in memory.In other words, they were more distractible. Then researchers tested the subjects for ability to filter relevant information from the environment and from their memories and to switch thinking tasks. A typical filtering test, for example, required subjects to detect changes in red triangles on a screen while ignoring blue triangles in the same pictures.

The heavy multi-taskers performed worse, even though their experience and presumed skill at multi-tasking should have made them more effective at these tasks. The heavy multi-taskers believed that they were good at multi-tasking, when in fact they were bad at every task that required multi-tasking.

It is not clear how much physical deterioration has occurred in brain from chronic multi-tasking. But at a minimum, multi-tasking is likely to reduce the brain's ability to develop concentration and thinking skills. Why do I suggest diminished thinking skills? Thinking is done with an orderly progression of items in working memory. Multi-tasking bombards working memory with scrambled and unfocused information and probably keeps the brain from learning how to optimize focus and orderly sequencing of thoughts through what I call the brain's "thought engine."

Source: Ophir, E., Nass, C. and Wagner, A. D. 2009. Cognitive control in media multitaskers. Procedings of the National Academy of Science. Aug. 24. doi: 10.1073/pnas0903620106


  1. So could this be backwards, would it be more likely that those who are distractible make better multi taskers? Is there research to show these same people when they stopped multitasking improved?

  2. Orlando asks insightful questions. I don't know if naturally distractible people make "better" multi-taskers. Studies on attention deficit people indicate they don't outgrow it, although it is theoretically possible that multi-taskers can learn to focus better, I don't know of any studies comparing their ability to focus before and after multi-tasking thinking styles.

    Bill Klemm

  3. lrueman3:45 PM

    Hi Dr. Bill,
    Some people just can't avoid multitasking at work. You are interrupted so many times (phone calls, colleages, subordinates, bosses,... And I think that memory is a critical tool at work.
    One thing I think someone can do at work is try to focus in just one thing or very few until the next interruption.
    Thank you very much for your blog. I read every post you write.

  4. When they first began to study working memory, a student was trained on memorizing strings of numbers. He became quite good at it, but his number memorization abilities didn't translate into actual working memory improvements. He just got better at memorizing numbers using tricks, but not letters, or spatial locations or anything else.

    However, real working memory improvements can be and were obtained using adaptive training.

    Maybe the same thing is valid in this case. The multi-taskers are not getting better at multi-tasking because they always multi-task on the same things (phone, driving, computer).

    Moreover, as they don't receive any indication of how well they are doing their multi-tasking, and training for improvement usually requires objective measurements.

    I really like this blog. I'll read it from now on


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