Employers and management gurus often speak of the benefits of multi-tasking but a new study by Dr Etienne Koechlin of the Ecole Normale Superieure in Paris suggests that the human brain might only be designed to do two tasks at once. The study used imaging techniques to monitor brain activity in 32 volunteers asked to perform a letter-matching test. When the volunteers completed one task at a time one side of a certain area of their frontal lobes lit up and when they completed two the frontal lobes divided the tasks between them. The brain was able to control switching between the two hemispheres when carrying out two tasks but people's accuracy went downhill quickly once a third was added. This research ties into earlier studies which showed that people find it easy to choose between two alternatives but much harder to deal with more than two.
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