News Release
April 15, 2003
For Immediate Release
Contact: Brian Weaver
(202) 783.2077 ext. 3022
bweaver@psychologicalscience.org
Report Shows that Task Switching Impairs Reaction Time
Imagine yourself driving home: You're talking on your cell phone, planning dinner. You decide to stop by the fish market to pick up some salmon. You alternate between steering, braking, watching traffic, following the conversation, thinking about dinner wines, and looking for the turnoff for the fish store. And you probably have the radio on, too. Of course, none of these activities is especially difficult. But the combination could be deadly because managing that combination goes beyond our cognitive skills and habits.
In an article published in the April issue of Current Directions in Psychological Science, Gordon D. Logan of Vanderbilt University said our "executive processes" are the cognitive controls behind our ability to move between these kinds of tasks.
Executive control is studied in a variety of ways, including looking at our ability to monitor, control, and coordinate tasks. Logan reported that researchers have begun to revisit the task-switching procedure, originally developed in 1927, to study people's ability to change from one task to another.
"Task-switching procedures allow researchers to compare performance when subjects alternate between tasks with performance when they repeat tasks - for example," Logan wrote, "switching between talking on the cell phone and paying attention to the road versus doing either one alone."
Research shows that an individual's reaction time is longer when tasks alternate rather than when they are repeated. This difference is the switch cost. (You can demonstrate switch costs by saying the alphabet out loud as quickly as possible, and then repeat it silently as quickly as possible. Then say the alphabet again, alternating between saying the letters aloud and silently. The alternation should be much harder and take longer than the repetitions.)
Logan wrote that executive control "is the next step in the cumulative investigation of cognition … Research on executive control promises to complete the picture and answer the remaining questions" about cognition and our abilities to determine action.
For more information, contact Logan at gordon.logan@vanderbilt.edu or visit the APS Media Center at www.psychologicalscience.org/media. Current Directions in Psychological Science is a journal of the American Psychological Society and contains concise reviews spanning all of scientific psychology and its applications. The American Psychological Society's mission focuses on the advancement of research and science-based psychology in the public interest.