Forgetfulness is a natural feature of the brain

2024 Author: Seth Attwood | [email protected]. Last modified: 2023-12-16 15:55

Most of us think that "perfect" memory is the ability to remember everything, but perhaps forgetfulness helps us navigate in a world that is constantly changing.

This opinion is expressed by two neuroscientists in a material published the other day in the journal Neuron. The rationale is that memory should not act like a VCR, but rather like a list of useful rules that help us make better decisions, says study co-author Blake Richards, a University of Toronto professor who studies theoretical connections between artificial intelligence and neuroscience. Therefore, our brain forgets outdated, irrelevant information, the one that can confuse us, or leads the wrong way.

We have yet to find the limits of how much information the human brain can store, and we can say for sure that there is more than enough space in it to remember everything. However, the brain actually wastes energy by making us forget, creating new neurons that "overwrite" old ones or weaken the connections between them. But why is this happening if it's not a lack of space?

First, forgetting old information can make us more effective. In a new article, Richards cites a 2016 study in which scientists trained mice to navigate a water maze. The researchers changed the obstacles and then gave some of the animals a medicine that helped them forget their original location. These mice found a new way out faster. Think about how many times you memorized the wrong name, and then you wanted to remove this information from memory and stop confusing it with the correct one.

Forgetting old information can also prevent us from over-generalizing one part of it. There are many parallels here with artificial intelligence and the way it is trained, Richards said. If you teach a computer to recognize faces by making it remember thousands of them, all it does is learn the details of specific faces. Then, when you show him a new face, the model doesn't really recognize him because she has never learned the general rules. Instead of learning that faces are usually oval and have two eyes, a nose and a mouth, the AI will find that some of these images have blue eyes, others have brown eyes, thicker lips in some places, and so on.

The human brain could also face a similar problem. Richards conducted a parcel with Borges' story "Remembrance Funes", in which man acquired the curse of perfect memory. In it, Funes recalls exquisite details, but "does not understand them, because all that he experiences is his individual experience." To remedy this situation, AI researchers use a technique called "regularization", with which they make the system forget some details until they figure out the basic information: what is a face, what is a dog, how is it different from a cat, etc.

The process by which it is determined what and how much information the brain should forget can be similar in humans and computers. Our brains tend to forget memories of things that happened (episodic memories) faster than general knowledge (semantic memories). In fact, episodic memories tend to fade pretty quickly anyway - knowing which shirt you wore six weeks ago is rarely helpful. There are many different factors here: how original the situation was, how much attention was paid to it, how much adrenaline was injected into the blood.“The principle of the brain is to forget everything except what is significant,” says Richards. Traumatic events such as an attack, for example, stay with us because the brain wants us to remember and avoid it, and this knowledge helps us to survive.

Ultimately, Richards says, we often assume that strong memories are good, but "in the end, our brains only do what is evolutionarily good for our survival." And in the case of memory, our brains were probably shaped by evolution to remember only what is appropriate for our survival. So maybe forgetfulness is just a feature of our brain, and not evidence of problems.