“Our results suggest that older adults might have heightened distractibility,” said study co-author Lilian Azer, a graduate student from the University of California, Riverside.
For the study, the researchers assessed the interaction between physical exertion — such as driving a car or carrying in the groceries — and short-term memory performance when distractors were also in play and when they weren’t.
“Action and cognition, which interact often in daily life, are sensitive to the effects of aging,” Azer said in a university news release.
“Our study found that in comparison to younger adults, older adults are less likely to ignore distractors in their surroundings when simultaneously engaging in a cognitive task and an effortful physical task. Ignoring task-irrelevant items declines with age and this decline is greater when simultaneously performing a physical task — a frequent occurrence in daily life,” she explained.
The study team recruited 19 adults aged 65 to 86 and then enrolled another 31 younger adults, ranging from 18 to 28 years old.
All participants were asked to grip a hand dynamometer at either 5% or 30% of their strength while they also did a short-term memory task.
A visual gauge provided real-time feedback on the exerted grip force, a type of grip similar to what would be used for walking up a stairwell, driving, or carrying a grocery bag.
Nearby was a memory array of small blue and red orientation bars. Study participants needed to focus on the red bars, whereas the blue bars were distractors similar to how a vibrant billboard, a car honking or an unrelated conversation might serve as a distraction.
During an exercise designed to not have distractions, participants were shown three red bars momentarily and later asked to recall the bars’ orientation.
In the distracted version of the exercise, they were shown five blue bars and instructed to only remember the orientation of the red bars.
“We found that under high physical effort, older adults were less likely to both ignore the distracting information and focus on the task-relevant information,” Azer said.
As people grow older, they may experience mental ("cognitive") changes that can include worse short-term memory, slower speed of processing information and heightened distractibility, said study co-author Weiwei Zhang, an associate professor of psychology at UC Riverside.
“Understanding how cognitive and physical actions interact can help us be more aware of how distracting information in our environment may impair our working memory,” Zhang added.
Effortful mental or physical activities are essential for our everyday functioning, Azer said. While driving, people tend to hold the steering wheel with about 30% of their maximum physical strength. When carrying shopping bags, they tend to use about 20% of their maximum physical strength.
“As we engage in these physical activities, very often we simultaneously engage in cognitive tasks where distractors — a billboard or a car sales commercial on the radio — may be present,” Azer said. “Inhibitory control may suffer during these concurrent tasks, making it more difficult, especially for older adults, to ignore the distractors and focus on task-relevant information.”
It's important to minimize distractions since it’s rare to perform a task in complete isolation, Azer said.
“If this is not possible, we need to be aware that the effortful physical task may impair our ability to both perform a working memory task and successfully ignore surrounding distracting information,” Azer said.
The study results were published online recently in Psychology and Aging.
The study was supported by grants from the U.S. National Institute of Mental Health, National Institute on Aging and National Institute of Neurological Disorders and Stroke.
The U.S. Department of Health and Human Services has more on aging.
SOURCE: University of California, Riverside, news release, May 10, 2023