The True Cost of Multi-tasking

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My view last week “off the grid”

I spent last week “off the grid” on an island in Lake Michigan.  No internet, no email, no cell phones. It was different, interesting, and strange. I was actually glad to get back to the grid. But the experience made me think. The major difference for me was that I stopped “multi-tasking”.

Task switching, not multi-tasking –  A while ago I wrote a post about multi-tasking, and the research at Stanford that shows that even younger people aren’t good at multi-tasking.  But the term multi-tasking is actually a misnomer. People can’t actually do more than one task at a time. Instead we switch tasks. So the term that is used in the research is “task switching”.

Task switching is “expensive” – There has been a lot of research on task switching. Here’s what we know from the research:

• It takes more time to get tasks completed if you switch between them than if you do them one at a time.
• You make more errors when you switch than if you do one task at a time.
• If the tasks are complex then these time and error penalties increase.
• Each task switch might waste only 1/10th of a second, but if you do a lot of switching in a day it can add up to a loss of 40% of your productivity.
• Task switching involves several parts of your brain: Brain scans during task switching show activity in four major areas: the pre-frontal cortex is involved in shifting and focusing your attention, and selecting which task to do when. The posterior parietal lobe activates rules for each task you switch to, the anterior cingulate gyrus monitors errors, and the pre-motor cortex is preparing for you to move in some way.

Meyer, D. E., Evans, J. E., Lauber, E. J., Gmeindl, L., Rubinstein, J., Junck, L., & Koeppe, R. A. (1998). The role of dorsolateral prefrontal cortex for executive cognitive processes in task switching. Journal of Cognitive Neuroscience, 1998, Vol. 10.