Biology

It's important to remember that forgetting is important

It's important to remember tha...
It may be frustrating, but forgetting things plays an important part in memory
It may be frustrating, but forgetting things plays an important part in memory
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It may be frustrating, but forgetting things plays an important part in memory
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It may be frustrating, but forgetting things plays an important part in memory

If files on your computer suddenly vanished after a while, you'd be in line for a new one pretty quickly – and yet, that's basically what our brains do all the time. From misremembering facts in an exam that you spent all night cramming for, to losing the keys that were just in your hand a minute ago, forgetting is a frustrating experience. But a new paper suggests that when it comes to human memory, forgetting things may be just as important as remembering.

The new work is a review paper, taking a wider snapshot of the recent studies of the brain mechanisms involved in memory. But there are two sides to that coin: remembering (persistence) and forgetting (transience). Forgetting isn't just a failure to recall information, but an active process that helps the brain as a whole make decisions more efficiently.

"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," says Blake Richards, one of the paper's authors. "If you're trying to navigate the world and your brain is constantly bringing up multiple conflicting memories, that makes it harder for you to make an informed decision."

Rather than just holding onto everything like a sponge, the brain works better as an information filter. Unused or irrelevant fragments can be cleared away like running a disk cleanup on a computer, and we're left with the general gist of memories rather than every tiny detail. That's why you can remember your high school math teacher, but not every answer to every test you took.

Balancing persistence and transience helps us make better memory-based decisions in a few ways. Outdated information is let go in favor of what's more current, and generalizing the memories into core ideas allows us to apply them to more situations in the future.

As for how the brain actually does this, the researchers found a few mechanisms are at play. Synaptic connections between neurons can weaken or be eliminated over time, and as new neurons develop, they rewire the circuits in the hippocampus, overwriting existing memories. This could be particularly useful in a fast-paced environment, where new information is constantly flooding in and there's no point holding onto older details.

The review paper was published in the journal Neuron.

Source: Canadian Institute for Advanced Research

4 comments
Ralf Biernacki
I'm looking forward to the time when memory augmentation is available. So that, when I /need/ to know what answers I gave on that test 10 years ago, I can find out at a click. The recent life-logging craze is the first step towards that, but it is unworkable in the current guise, because retrieval is deal-breakingly clumsy. What's on my wishlist is an encrypted data-logger, internally hyperlinked for versatile retrieval (think TV Tropes :-P), intuitively easy to access for me, but also impossible to access for external parties---ideally a brain implant, needing my personal brain "signature" for decryption.
Bob
I remember when my sons were getting out of college and thought they had learned so much compared to Dad. They were insulted when I told them that their heads were still mostly empty. When they challenged me to prove it, I told them that if their heads were so full of knowledge where are they going to put the information they learn in the next 23 years? There must be empty space to save it. What about the years after that? Still more empty space needed to save it. I told them that older people are sometimes slow to remember because they have a much larger data base to sift through than a young person. They finally agreed that their heads must be mostly empty because they would need some place to put the next 60 years worth of learning. I really don't think that people really forget all that much. It is there but accessing it becomes more difficult. Have you ever driven down a road and thought this sure looks familiar and then remember that you really had been down this road 20 years ago and, yes, you do remember. The memory is still there.
Racqia Dvorak
The real problem is when your brain and your mind have different opinions about what is important to remember and what isn't.
Kwetla
@Racqia Mind: It sure would be useful to be able to remember all my bank details and card numbers off by heart Brain: Best I can do is all original 151 Pokemon and the levels they evolve at. How's that?