UCSF neuroscientists have found that by training on attention tests, people young and old can improve brain performance and multitasking skills.
Anyone who tries to perform two tasks at once is likely to do worse on both. Why that is so at the neurological level has largely been terra incognita. But research now is starting to reveal the impact of multitasking on short-term memory and attention.
Adam Gazzaley, MD, PhD, associate professor of neurology, physiology and psychiatry, and researchers at the UCSF Neuroscience Imaging Center use EEG, MRI and other non-invasive tools to study cognitive processes while people try their best on drills that test short-term memory.
In one early study, images of either faces or natural scenes pop up on a computer screen in random order, each for about a second. Participants are instructed to focus on one type of image — their target image — and ignore the other type. Soon afterward, they are shown either a face or a scene and asked to press a button if this is their target image.
The task challenges participants’ visual attention and memory in the face of distractions and multitasking. The “wrong” image is essentially a visual distraction from the task at hand.
The studies have revealed specific brain processing abilities that decline with age and compromise short-term, or “working” memory — a capacity that underlies performance on a range of cognitive abilities.
About one-third of seniors do as well as the average 20-year-old, Gazzaley found. But most perform considerably less well. Many researchers have hypothesized what brain functions account for the differences. Gazzaley’s lab has sorted through the possible explanations using the brain imaging measurements.
Changes in blood flow to different brain regions show that, compared to younger people, the visual perception parts of the brain in most older people get stuck on the wrong images. This, Gazzaley said, overburdens short-term memory and explains poorer performance.
“Older people tend to ‘overprocess’ distracting stimuli, and they are also slower to recover their focus after an interruption when multitasking,” he said. “There seems to be a stickiness in their brain’s ability to switch back to the main task.”
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