Everyone’s supposed to do it these days. Talk on the phone, read an e-mail, and clean up a file all at the same time. But new research suggests the human brain is not wired to do more than one thing at a time. And trying to multitask may actually impair your ability to get things done.


"With rare exceptions involving simple actions," says neuropsychologist Pierre Jolicoeur, who holds the Canada Research Chair in Experimental Cognitive Science, "nobody can perform two tasks perfectly at the same time."


In Jolicoeur’s lab at the Université de Montréal, subjects were asked to perform a simple task, like judging whether a sound is higher or lower than one that preceded it. The researcher then added a second task; for instance, indicating whether a letter on a screen is an X or an O.


The shorter the interval between the two tasks, Jolicoeur found, the longer it takes to accomplish the second.


"The critical moment is making the decision," explains Jolicoeur. "That’s the step that takes the longest.

"People do what’s called ‘fast switching’ between tasks. They may think they’re doing several things at once, but that’s just an illusion."

However, in normal daily situations — say, talking while writing a report — one of the activities will suffer. The crucial decision-making step is impaired, and the person either takes longer to finish or makes more mistakes.

The solution? Try to divide work into a series of small, simple tasks, Jolicoeur says, and focus on one at a time.For more info visit www.chairs.gc.ca.