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Illustration of a pencil eraser erasing lines from a drawing of a brain.
Illustration by Vanda Marasan

Some Forgetfulness? It’s a Good Thing

Researchers discover that our brain erases certain memories for a reason

It’s a common complaint that as we age we become more absent-minded. But a certain amount of forgetting plays a vital role in how our memory functions, according to new research from U of T and the Hospital for Sick Children.

“The goal of memory is to optimize decision-making,” says Blake Richards, a professor of biological sciences at U of T Scarborough. “So it’s important that the brain forgets irrelevant details and instead focuses on the stuff that’s going to help make decisions in the real world.”

Neurobiological research into memory has tended to focus on the cellular mechanisms involved in how the brain stores information, known as persistence. Much less attention has been paid to the mechanisms involved in forgetting, known as transience. Scientists have thought that an inability to remember comes down to a failure of the process to store or recall information.

This new research, by Richards and Paul Frankland, a U of T professor and a scientist at SickKids, shows that, in fact, some cell activities promote memory loss and are distinct from those involved in storing information.

Why would our brain want us to forget? One reason, says Richards, is that, in a rapidly changing world, old information becomes outdated. “If your brain is constantly bringing up multiple memories with conflicting information, this makes it harder to make an informed decision.”

Another reason is that to make generalizations based on large amounts of information, it helps to forget some of the details. This allows us to focus on the knowledge that’s essential to making the right decision.

“We tend to idealize the person who can ace a trivia game, but the point of memory is not being able to remember who won the Stanley Cup in 1972,” he says. “The point of memory is to make you an intelligent person who can make good decisions, given the circumstances.”

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  1. One Response to “ Some Forgetfulness? It’s a Good Thing ”

  2. gail Crossin Desnoyers says:

    If I follow the logic about memory loss and decisions, we should all be making better decisions as we age. Is there any evidence for this? My mother at 103 and I both comment that we remember the silliest things from the distant past that were not even important then but can't remember important things now.