Study: Multitasking Takes Up Time

Aug. 7, 2001 -- What else are you doing while reading this?

Researchers at the Federal Aviation Administration and the University of Michigan report that doing two or more things at once may decrease efficiency and actually take extra time switching from one task to another. In the most severe cases, it can even mean the difference between life and death.

"[People] get tired when they're trying to multitask," and in some cases a person could ultimately create more work for himself, according to one of the lead authors, David Meyer, of the university's psychology department.

In the study, four groups of young adults carried out a series of tasks and switched between different tasks, some complicated, such as solving math problems, and some more familiar, such as identifying geometric shapes.

The researchers found that time was lost in just switching from one task to another, and that time costs increased with the complexity of the tasks. The subjects got "up to speed" faster when they switched to tasks that were familiar.

The study was published this week in the August issue of the journal of the American Psychological Association.

Time Lost

When people, say, juggle browsing the Web and using other computer programs, or talk on the phone while driving, they are using their "executive control" processes in their brain, the researchers said. Those processes can be likened to the mental CEO, the part of the brain associated with establishing priorities among tasks and allocating resources to them.

"For each aspect of human performance — perceiving, thinking and acting — people have specific mental resources whose effective use requires supervision through executive mental control," said Meyer in materials provided with the report.

So called "multitasking" is becoming increasingly common because of cell phones and computers, the researchers point out, but it may just be adding wasted time and inefficiency to our days.

A mere half second of time lost to task switching can mean the difference between life and death for a driver using a cell phone, Meyer said.

Understanding executive mental control may help solve "fundamental problems associated with the design of equipment and human-computer interfaces for vehicle and aircraft operation, air traffic control and many other activities in which people must monitor and manipulate the environment through technologically advanced devices," Meyer said.

The authors say the research should make employers and employees think twice before implementing multitasking, and also change how they hire or train people, and help to formulate government regulations and standards.