Multitasking is really a misnomer. What people actually do is work on one thing and then another with lots of frequent context shifting, which has been shown to reduce effectiveness.
Some scientists have let “being interrupted” stand in for multitasking in the experimental ecology, which may or may not be a useful design. But, anyway, these scientists discovered that if you had a control group doing a cognitive challenge without interruption and a group that gets interrupted, the latter does on average 20% worse on the cognitive challenge, which is the difference between a B- and an F.
The real experimental set up is slightly more complicated. Here’s Bob Sullivan, a journalist at NBC News, and Hugh Thompson, a computer scientist and entrepreneur (the authors of “The Plateau Effect: Getting From Stuck to Success,”) writing at the NYTimes.com on the real experiment:
To simulate the pull of an expected cellphone call or e-mail, we had subjects sit in a lab and perform a standard cognitive skill test. In the experiment, 136 subjects were asked to read a short passage and answer questions about it. There were three groups of subjects; one merely completed the test. The other two were told they “might be contacted for further instructions” at any moment via instant message.
During an initial test, the second and third groups were interrupted twice. Then a second test was administered, but this time, only the second group was interrupted. The third group awaited an interruption that never came. Let’s call the three groups Control, Interrupted and On High Alert.
As above, the so-called “Interrupted” did 20% worse than “Control”. The “On High Alert” folks, even though they don’t get interrupted, do worse than the people in “Control”. But the scientists kept administering new cognitive tasks and letting some work uninterrupted (“Control”) while telling the other two groups that there would be an interruption again but only actually interrupting “Interrupted” and leaving “On High Alert” uninterrupted.
As the tests were repeated, “Interrupted” got better — from 20% below Control to 14% below Control. And “On High Alert” starting doing better than that. The preferred interpretation:
Those who were warned of an interruption that never came improved by a whopping 43 percent, and even outperformed the control test takers who were left alone. This unexpected, counterintuitive finding requires further research, but Dr. Peer [the psychologist Eyal Peer at Carnegie Mellon, who along with Alessandro Acquisti, a professor of information technology, helped the authors do the experiment] thinks there’s a simple explanation: participants learned from their experience, and their brains adapted.
Somehow, it seems, they marshaled extra brain power to steel themselves against interruption, or perhaps the potential for interruptions served as a kind of deadline that helped them focus even better.
Yes, I’d bet that the expectation of an interruption helped produce greater cognitive resources to and focussed attention on the cognitive challenge.
Photo credit: phineasx at Flickr.com