As we age, we seem to get worse at ignoring irrelevant stimuli. It's what makes restaurant conversations challenging—having to converse while also shutting out surrounding chatter. New research bears out the aging brain's distractibility but also suggests that training may help us tune out interference.
Scientists at Brown University recruited seniors and twentysomethings for a visual experiment. Presented with a sequence of letters and numbers, participants were asked to report back only the numbers—all the while disregarding a series of meaningless dots. Sometimes the dots moved randomly, but other times they traveled in a clear direction, making them harder to ignore.
Older participants ended up accidentally learning the dots' patterns, based on the accuracy of their answers when asked which way the dots were moving, whereas young adults seemed able to suppress that information and focus on the numbers, the researchers reported last November in Current Biology.
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In a separate study published in Neuron, scientists at the University of California, San Francisco, showed they could train aging brains to become less distractible. Their regimen helped aging rats as well as older people. The researchers played three different sounds and rewarded trainees for identifying a target tone while ignoring distracter frequencies. As the subjects improved, the task grew more challenging—the distracting tone became harder to discriminate from the target.
After the training, both rats and people made fewer distraction-related errors in tests of attention and memory. Electrophysiological brain recordings showed their neural responses to distracters also mellowed out.
Previous brain-training approaches tried to fix distractibility by improving focus, but those efforts failed. “‘Focus’ and ‘ignore’ are not two sides of the same coin,” explains senior author Adam Gazzaley. “If you consider neural measures of focusing, older people look like 20-year-olds. The deficit is specific for ignoring distractions.”
