Forget It. It’s Good for You.
Clearing out our memories to make way for new ones.
Paula Span is a typical doting grandmother. She is with her 3-year-old granddaughter, Bartola, about once a week, and together they sing, and read, and play at the park, and go to the beach.
But precious as that time is, Ms. Span, who writes about aging for The Times, understands a reality that nags at many grandparents like her: Bartola, she wrote, “will remember virtually none of it.”
And so it begins, the lifelong journey of doing, absorbing and forgetting. Bartola’s memory will become stronger and many more experiences will stick, but then many others will fall away. She will eventually reach that stage where she can recall a particularly good (or bad) moment from 30 years earlier, but will not recall what she had for breakfast.
That is not a bad thing. Researchers say that forgetting things clears out space in our brains for new information that is more important. Think of it as a desk that is too cluttered to find what you need.
“We’re inundated with so much information every day, and much of that information is turned into memories in the brain,” Ronald Davis, a neurobiologist in Jupiter, Florida, told The Times. “We simply cannot deal with all of it.”
Some researchers say that forgetting helps clear space for creative thinking.
How forgetting happens is a subject of fascination for scientists. A study from a team at Nagoya University in Japan suggests a role for cells called melanin-concentrating hormone neurons, which are most active during the R.E.M. sleep stage. “The neurons may be clearing up memory resources for the next day,” said Akihiro Yamanaka, who led the team.
Other studies have suggested other forces are at play. “As we learn, and as other animals learn throughout the day, various forgetting mechanisms may always be slowly eroding memory,” Dr. Davis said.
Some aspects of memory loss stubbornly defy explanation. Such is the case with the condition known as transient global amnesia, a lapse where the brain simply seems to stop recording. It is temporary but terrifying.
The Times’s Jane Brody believes she may have suffered such an episode two years ago. Somewhere in a 30-minute memory gap, she apparently fell off her bicycle, walked it home, and walked to the hospital with her son to deal with a cut on her chin.
“Lacking any residual symptoms, I was — and still am — most disturbed by the fact that I have no idea why or how I fell and thus no way to avoid it in the future,” she wrote.
Whatever the causes of such later-life lapses, they are surely different from what goes on in the mind of a 3-year-old like Bartola. Children that age are working with a clean slate — one that self-erases constantly.
“Young children form memories early,” Patricia Bauer, a cognitive developmental psychologist at Emory University in Atlanta, told The Times. “But they forget them so quickly, more quickly than adults.”
Cognitive scientists have strategies for helping children hang on to memories you want them to keep: prompting them to talk repeatedly about the details of the day, or putting together photos from an adventure. But Ms. Span knows there are limits to what can be saved, and she is O.K. with that, as long as Bartola can hold on to the big picture.
“I do want her to remember me, not specific events so much as my presence,” she wrote. “I want her to know that I helped care for her, comfort her and celebrate her. That I was there, a part of her life, and loved her ferociously.”