Neocortex: How Human Memory Works and How We Learn

I have been reading a book on how the brain functions, particularly the neocortex which we know as the two pinkish greyish hemispheres. It is a seriously technical and boring read, but that is why I bring the main points into this first post on explaining how our memory works. If you start to feel that this is tedious, just glance over the bold parts.

How the Neocortex and Human Memory Works

Sequential Patterns

Our memory works sequentially and in a hierarchy. We remember linear sequential patterns. A sequence is the basic building block of our memory, how we learn, and how we function as humans. A popular sequence, for example, is the alphabet. We can recite the alphabet from A to Z with very little effort because we memorized the sequence from the beginning to the end.

Related Article: Become a God for 79 Cents

But what if you were asked to recite the alphabet from Z to A? Computers have no problem doing this as they can process the alphabet backwards in a thousandth of a second.  But we humans would struggle, computing it sequentially. First, we would start to recite the alphabet until we get to, say, the last two or three letters, X Y Z. We would then be able to recite those backwards. Then we start from the beginning again and get to the next two or three in the list, U V W, then recite those backwards. Each time we are going through the sequential pattern in order to recite the alphabet backwards.

Neocortex Sequential Patterns

Neocortex Sequential Patterns

Pattern Hierarchy in the Neocortex

As for the hierarchical nature of memory, there are lower level patterns and higher level patterns which our neurons process instantaneously, without us even noticing. Take a sentence for example. At the very high end of the pattern hierarchy you will be able to judge whether the writer intended the statement to portray sarcasm, to be a comical remark, or whether the statement was meant to be rhetorical. You will be able to attach your personal feelings to the sentence based on what is written.

You go down the hierarchical ladder and you see grammatical patterns. You understand the colloquial nature of the text and your brain processes this so quickly that you don’t even have to stop and think.

Related Article: Photographic Memory (Phase 2: Holy Shit)

We go even further down the hierarchical ladder and your neocortex is able to guess what word you are reading without even finishing it completely. You just glance over the text and recognize the pattern of the letters. The word “letter” starts with a tall character and has two more tall t’s. It is short enough for your brain to guess that the most plausible word fitting the character pattern is the word “letter”. Your brain also looks for patterns in the text itself, such as contextual patterns.

Way at the bottom of the hierarchy the neocortex recognizes the letters themselves. This is a very rudimentary level and therefore we can say that, with the preconception that you are an American and you know the English alphabet, your neo-cortex recognizes individual letters at the speed of light, metaphorically. If you pass through a letter that has two slants like / and \, /\, your neocortex will almost instantly recognize it as the letter A, since there are no other candidates and enough of a pattern is present for the brain to guess.

In the same way, when you see someone writing like a douche, using $ for “S” and ! for “I”, like $H!T!, we can immediately see that the person intended to use “SHIT!”. This is called auto association, the ability to associate a pattern with a part of itself. We can recognize a pattern even if the entire pattern is not present.

A hierarchical pattern is basically a sequence of sequences of sequences etc…

Hierarchical Patterns = Recursion & Iteration (Where are the programmer geeks?)

In a 2002 paper that Noam Chomsky coauthored called “The Faculty of Language: What Is It, Who Has It, and How Did It Evolve?” he cited the attribute of “recursion” as accounting for the unique language faculty of the human species. Recursion, according to Chomsky, is the ability to put together small parts into a larger chunk, and then to use that chunk as a part in yet another structure, and to continue this process interactively. In this way we are able to build the elaborate structures of sentences and paragraphs from a limited set of words. This essentially describes what the neocortex does.

Related Article: Memory, a Torch Pass

Two excerpts from “How to Create a Mind: The Secret of Human Thought Revealed” that have a lot to do with how we experience learning and memorizing follows below:

The neocortex is, therefore, predicting what it expects to encounter. Envisaging the future is one of the primary reasons we have a neocortex. At the highest conceptual level, we are continually making predictions – who is going to walk through the door next, what someone is likely to say next, what we expect to see when we turn the corner, the likely results of our own actions, and so on. These predictions are constantly occurring at every level of the neocortex hierarchy. We often misrecognize people and things and words because our threshold for confirming an expected pattern is too low. (p59)

I believe I could pick out a picture of the woman with the baby carriage whom I saw earlier today from among a group of pictures of other women, despite the fact that I am unable to actually visualize her and cannot describe her much specifically. In this case my memory of her is a list of certain high-level features. These features do not have language or image labels attached to them, and they are not pixel images, so while I am able to think about her, I am unable to describe her. However, if I am presented with a picture of her, I can process the image, which results in the recognition of the same high-level features that were recognized the first time I saw her. I would be able to thereby determine that the features match and thus confidently pick out her picture.  (p66)

Here are some key points to draw from the top two paragraphs. The first paragraph reiterates the fact that our neocortex constantly guesses at blazing speeds what we are looking at or processing by using all of our five senses. The second paragraph basically states, HUMANS DO NOT HAVE PHOTOGRAPHIC MEMORY. DIGITAL CAMERAS DO. The closest to photographic memory that only some rare few humans get to is called eidetic imagery. It also points out that there is a difference between recognizing and recalling something. When you can’t recall a woman’s face from memory by drawing it out, but you can recognize it among a few pictures, that is called autoassociation, or being able to pull out a memory via some visual cue.

Last Point I Swear! Redundancy

Redundancy is the key to enforcing our pattern building, recognition, and recall. Let me also point out that humans have five senses and that we gather “data” from all five of them which allow our neocortex to build numerous patterns that point to the same reference. Take for example french fries. Your brain gathers data from the visual aspect, the crunching, the texture from the touch, the smell, and the amazing taste. The experience itself also enforces your pattern building to keep the fries in your memory.

Sources:

http://en.wikipedia.org/wiki/Autoassociative_memory

http://www.amazon.com/How-Create-Mind-Thought-Revealed/dp/0670025291

http://www.sciencemag.org/content/298/5598/1569.short

http://www.psychologytoday.com/articles/200603/the-truth-about-photographic-memory

Wondergressive: Experiments in Photographic Memory

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4 thoughts on “Neocortex: How Human Memory Works and How We Learn

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