April 11, 2011 -- Is multitasking getting harder with age? A new study suggests that older brains behave differently when it comes to switching between two tasks.
Researchers found that older people have a more difficult time multitasking not because they have to devote more attention to a secondary task, but because their brains have a harder time disengaging from the secondary task and going back to the original one.
The study used functional magnetic resonance imaging (fMRI) to analyze brain activity in 20 people over age 60 while they performed a multitasking exercise. Then, researchers compared their results to a similar experiment with 20 younger adults.
They found that older adults had more difficulty recognizing a nature scene that had been previously shown to them when they were interrupted to perform another task, which involved stating the gender and approximate age of a face shown to them before the nature scene.
Researchers say the brain imaging showed that the older participants initially reacted to the new task in a similar manner as the younger group. But there the similarities ended.
"Unlike younger individuals, older adults failed to both disengage from the interruption and re-establish functional connections associated with the disrupted memory network," write Wesley C. Clapp of the University of California, San Francisco, and colleagues in the Proceedings of the National Academy of Sciences.
Researchers say the results suggest that multitasking causes a bigger working memory disruption in older adults because of this inability to switch between tasks efficiently.