Researchers at the University of Michigan found that productivity dropped as much as 40 percent when subjects tried to do two or more things at once. The switching exacts other costs too--mistakes and burnout. One of the study's authors, David Meyer, asserts bluntly that quality work and multitasking are incompatible.
Brian Bailey and Joseph Konstan of the University of Minnesota discovered that sleeve-tugging peripheral tasks triggered twice the number of errors and jacked up levels of annoyance to anywhere between 31 percent and 106 percent. Their interrupted test workers also took 3 percent to 27 percent more time to complete the reading, counting or math problems. In fact, the harder the interrupted task, the harder it was to get back on track.