To remember well, you have to efficiently retrieve a memory from your brain. But what if that memory comes with lots of baggage or clutter?
That’s what researchers believe is happening when healthy older adults try to recall information, but have a harder time doing it than younger people.
Aging comes with wisdom and knowledge, but it also means older adults — those between 60 and 85 years of age — process and store too much information in their brains, “creating cluttered memory” that comes entangled with no-longer-relevant facts, knowledge acquired years ago and lots of distractions, the authors of a review of studies wrote in the March issue of Trends in Cognitive Sciences.
This, in turn, can impair older people’s recall and appears to account for age differences seen in memory tests, they noted.
But this “overloaded” memory can also have some surprising benefits, said Tarek Amer, the lead author and a postdoctoral research fellow in the psychology department at Columbia University in New York.
“Clutter can be bad in certain situations, but there can be treasure in the clutter depending on the kind of tasks that you’re engaged in,” Amer told TODAY. “It really depends on the context.”
The disadvantages of cluttered memory
If the thing you want to remember is strongly bound to many irrelevant things that you have to sift through, it drags down memory performance.
Let’s say you have a favorite restaurant that changes locations. Younger people are better at scrubbing the previously relevant information — the old address — and updating it with the new one. It’s not that they erase memories, but younger brains are better at suppressing the old address when they’re trying to remember where the new restaurant location is, Amer said.
Older adults, meanwhile, might have a harder time deleting the old address. Their brains maintain strong access to it even though it’s no longer relevant.
“Those extra pieces of information might interfere with your ability to remember the target information,” or the new restaurant address, Amer noted. “They might remember the old location and all these extra memories that are associated with it that are not particularly relevant to the task at hand.”
Healthy aging also comes with a reduced ability to control attention, so older adults may be distracted by competing thoughts as they try to remember something. Therefore, their memories may contain irrelevant information that “passed through a ‘leaky’ attentional filter,” the authors wrote.
Another drawback for older adults is that they tend to depend too much on a lifetime of accumulated knowledge, which can increase memory errors.
“If you sometimes over-rely on this accumulated knowledge when you need to encode or remember new information, then that can provide a disadvantage,” Amer said.
The benefits of older memory
The new paper uses “enriched” memory as another way to describe how older adults remember.
All the extra diverse information and associations they carry can help them with tasks that require creativity and other open-ended tasks.
Decision-making benefits from an enriched memory, too. “We see that anecdotally all the time. Older adults tend to be in positions of power where they’re making important decisions,” Amer pointed out.
Think of pilots, doctors, country leaders and CEOs whose accumulated knowledge and wisdom are critical to their job performance.
How to keep your brain healthy as you get older
Robust evidence shows staying physically active is probably the best way to improve cognitive health as we age, Amer said. Exercise is associated with brain health, including better blood flow to regions that are involved in particularly demanding cognitive tasks, he added.
Regular exercise such as walking may slow brain aging by up to four years, a 2020 study found. Previous research showed it could be even more, 10 years on average, but it required moderate to heavy activity.
When researchers looked at the effect of exercise on thinking skills in people over 50, including memory, alertness and the ability to quickly process information, they found physical activity improved all of those skills. The key was 45-60 minutes of moderate to vigorous exercise per session “on as many days of the week as feasible.”
It pays to get started now: Cardiovascular fitness at one point in time can predict how well your memory may function in the future, experts have said.
Other important factors for a healthy memory include staying mentally active, being open to doing new things and putting yourself in intellectually engaging environments, Amer said. That could mean taking a photography class or learning to play a musical instrument.
“The point is essentially challenging yourself… physically or mentally,” he noted. “That is probably the best way to reduce clutter and be able to ignore irrelevant information that produces this clutter in memory.”