This is a short post about why we forget things so quickly aimed at the general public in conjunction with University of Otago’s Brain Health Research Center.

Memory systems of the brain, explained

“Ah where did I put my keys? I just had them!”
“Oh wait, what was her name again?”

Do these scenarios sound familiar? Don’t worry they happen to all of us from time to time. But why does this happen? Why do our brains remember some things but forget others? Well, there is three different but integrated memory systems in the brain.

Short-Term Memory

First there is the short-term memory system. You can think of this system as being akin to a conveyor belt. Information from the world comes in through our senses and unless it is picked up off the conveyor belt within about 18 seconds, it falls off the conveyor belt and can’t be retrieved again. Also similar to a conveyor belt, there is a limited amount of space on the belt for information. Many studies show this to be around 7 +/- 2 things but this can vary with what sort of information is being remembered. But then how do we remember anything? Well, if some sort of sensory information, like someone’s name, is taken off the conveyor belt and used in some way it goes to the working memory system.

Working Memory

The working memory system is similar to the short term memory system but is a more active process that involves your conscious attention. You can think of the working memory system like robots over the conveyor belt. If something on the conveyor belt is interesting or relevant to you, they will pick it up. They may pick things off the conveyor belt either automatically or because the manager (your conscious mind) told the robots to pick up that type of information. For example, if you alone in the woods on a dark, spooky night, the sound of sticks breaking in the distance will automatically be brought into your attention. If you are looking for your lost keys, the robots will pick up anything that looks like keys as you frantically run around your house looking for them and keeping the idea of keys and their importance in working memory. Keeping these robots running costs a lot of energy though so not everything will get picked up.

Long-Term Memory

But why can’t you just remember where the keys were in the first place? This is where the third memory system comes into play: Long-term memory. Long-term memory is the fantastic system that allows us to remember a seemingly infinite amount of information. This system can be imaged like information being picked up off the conveyor belt by the robots, put into a box, labeled with everything you think that new information is related to, and then stored on a shelf in a massive warehouse on shelves with like information. In order for information to go through this route it needs to be important and relevant to your consciousness. It also helps if the information is repeated over and over again. In the lost keys situation, you may put your keys in the same spot each day. However the one night you put them somewhere different your brain didn’t think much of it; their location just fell off the conveyor belt. When the morning comes, the information is long gone. As for people’s names, you may not be interested in them when they first introduce themselves and their name goes across the conveyor belt without being picked up. With both the keys misplaces and someone’s name, they both happen just one time. It could be the robots were too busy at the time and missed the key’s location or the person’s name the first time. Or finally, it could be the box just got lost among the shelves because there wasn’t enough labels on the box.

How to remember better

A tip to remembering things is to mindfully relate the new information to stuff you already know. It is also helpful if you can do it in a unique way such as with rhyming or alliteration or with physical attributes of the thing or person. All of which can act as memory cues. For example if you meet Dr. Bilkey for the first time you may link his name to Brain, BHRC, Blue eyes, and Bilkey-Silky-Silver hair. This way the working memory robot arms know the grab his name off the short-term memory conveyor belt because its important and to label it with relevant attributes so his name can easily be found in the long-term memory warehouse later.

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You can see the edited version in the BHRC’s newsletter here: http://www.otago.ac.nz/bhrc/otago373601.pdf

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This work by Blake Porter is licensed under a Creative Commons Attribution-Non Commercial-ShareAlike 4.0 International License

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