Explicit and Implicit Memory

in #science7 years ago (edited)

Picture

“It’s like riding a bicycle, you can’t unlearn it!”

Have you heard that before? For some reason, there are things that stick with us our whole life, which we don’t seem to forget. Other things, like your friend’s birthday, seem to slip your mind a lot faster. What’s the difference between these two memories?


Implicit Memory


When you learn an instrument, wake up 30 seconds before the alarm rings every day or get hungry at the sound of a metronome, that’s all connected to the implicit or procedural memory.

These memories are accessed without really thinking about it, your body just seems to do it. Associative and non-associative learning, which I talked about yesterday, is also a part of the implicit memory. @suesa
These memories are built through repetition. Did you ever hear of “muscle memory”? It’s basically that. Your muscles don’t remember, your brain does.

Did you ever have to think about how to walk? I’m sure most of you didn’t. It happens automatically, you don’t need to make a conscious effort, not like a child who is just learning to walk.


Explicit Memory


What did you have for dinner yesterday? When did Napoleon die? How many grains of sand are in the Sahara Desert? Did you know that Sahara already means desert so we’re calling this one “desert desert”?

While the implicit memory stores skills, habits, reflexes and similar, the explicit or declarative memory stores facts and events.

So if you forget your mother’s birthday, forget to bring out the trash on the correct day, don’t blame your whole brain. Just blame your explicit memory. That bitch has probably been ruining your life since you were born.


The Human Experiment


No good research without experiments, am I right? How about experiments on humans?

When someone had epileptic seizures, doctors used to cut out parts of the brain or separate the two hemispheres. In the case of patient H.M., they cut out a big chunk (the hippocampus, amygdala and the parahippocampal gyrus for those who want the details).

H.M. had been suffering from seizures since he was 10 which became worse after the age of 16. At 27, in 1953, it impacted his life so much that he agreed to an experimental surgery. Both he and his family had to sign off on this.

After they had cut out the beforementioned pieces of his brain, H.M. lost about 10 years of memories - and he couldn’t form new memories. You could talk to him and the moment he turned away, he had already forgotten you.

But!

He was able to train himself for a task.

The researchers gave H.M. a pencil and he had to draw a star but could only see his hand through a mirror. Drawing like this is really hard, but you can practice and become better at it. And H.M. did improve over time. In fact, he could still do it after three days without practicing.

He just didn’t remember that he had done this before, ever.

Removing these specific parts of his brain seemed to have removed his explicit memory, but his implicit memory was still working fine!

This is often the case with anterograde (= “directed forwards in time”) amnesia. Those who suffer it might not know what a violin is, but if they were able to play it before and you give it to them, they might still manage to play it.

H.M. died in 2008 after having experiments performed on him for most of his life.


The Animal Experiments


H.M. was only one point of data; proper research needs far more than that. But you can’t just go around and cut out people’s brains. There are laws against it.

Animals are a bit less protected, although the rules are still pretty strict. Researchers took two groups of mice (and rats). One with their brain intact, the other with the same regions removed that had been taken away in the case of H.M.

Then they threw (gently placed) them in a pool of water.

To quote the animal welfare officer: “Mice swim - but they don’t like it”.


Swimming Rat, By Jim Kenefick

Swimming is stress for a mouse. Even more so if it doesn’t know if it will ever get out. In this experiment, there was a platform placed inside the pool, just below the water surface. But the mice couldn’t see this. They had to swim around until they managed to find it.

This experiment was repeated in two ways:

  1. The mice were put in the pool in different spots
  2. The mice were always put in the pool from the same spot

In the first case, the normal mice needed less time to find the platform after several tries. They seemed to remember the position of the platform inside the pool. The mice with the brain surgery … they needed about the same time in every case. They didn’t remember.

But in the second version of the experiment, even the mice with brain surgery improved their times! It seemed like having to swim the same path over and over again is something controlled by the implicit memory. The mice probably didn’t consciously remember (but how are we supposed to find out, ask?), but their “muscle memory” lead them on the correct path.


Sources:

The Legacy of Patient H.M. for Neuroscience

Patient HM review – a botched lobotomy that changed science

Morris water maze

Declarative Memory: Definitions & Examples

Lecture “Bewusstes und Unbewusstes Lernen” by Uli Müller


Pictures taken from pixabay.com unless stated otherwise


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Please keep posting things like this i enjoyed reading it

I'm switching between fiction and science, depending on how much time I have and if the lectures I'm attending are interesting for steemit :P

Wow!!! 👏👏👏. I don't think I really have anything to bother about my implicit memory. I think I will have to spank my explicit memory now that I can pinpoint it is responsible for a lot of attrocities. Like forgetting answers when i want to write in the exam hall and forgetting some other things. Do you have an idea of how I can spank it? 😀😂

Poke your amygdala? 🤔

Implicit memory... this reminds me of a term I had heard previously, Overlearning. I wonder if an attempt at overlearning is actually an attempt to stuff something into implicit memory.

There are tricks leveraging so-called spatial memory where-by you associate new terms or random facts with spatial locations in a familiar but possibly imagined location which seems to help keep things in short term long enough to commit them to long term, but where was I going with this... something about memory... yeah, I could use a better one.

What a pretty picture at the start of the post. I have never been diagnosed but I'm pretty sure I have mild dyslexia. It takes me longer to get up to speed on a physical process than others but once I'm up to speed I overtake others. I believe from your post this many be the point where implicit memory takes over

Memories work in amazing ways. True that about unlearning how to ride a bicycle. Once learned it's for life. You may be rusty, but once you sat on that saddle and plant your feet on that pedal, next thing you are pedaling away. I felt sorry for HM. He had to endure so much but I believe the experiments provided profound results and insight into memory research. Thanks for sharing.

Yes I agree. I do feel sorry for HM however it does make me feel better about my life lol thats certainly a lesson to remember and hopefully one day we will have more efficient methods to research memory. Wish the both of you much success and thanks for sharing this informative post @suesa

@suesa I honestly had no idea that were even different kinds of "memory" - that was truly quite fascinating! Great share, thank you :)

Explaining scientific studies in this way makes it easier for people to learn. So your work should be clearer. Thanks for your studies

This answers my questions on your article two days ago :) I agree with the fact that, that bitch has been ruining my life since birth! :D

Thank you for yet again helping me make sense of my own being. Checking out @steemitadventure for the second time :)

Did I already promote him? Damn in that case I forgot to update my list...

Nooo :)

I clicked on him before commenting then commented. Then went back to his blog to admire more art then decided to follow him :D

I read a great longform article once about a woman who had no episodic memory (I can't find the article so I'm bound to get the details vaguely wrong).

She lived a perfectly normal life, even to the extent that she assumed people were "faking it" when they talked about stories from their past. And she was happy.

It was utterly fascinating (as are all such stories on memory and the brain). But also a good lesson I thought about how we don't necessarily need all of our past history - that it doesn't define us to the extent that we may think.

that's a good knowledge about Explicit and Implicit Memory.
thank you...@suesa

@RESTEEM####