Layer 2 and a half? Memory

So far I’ve explain the brain in three super simple layers with each layer doing a different thing (remember it’s a model not a reality). What I didn’t mention was something fundamental to a lot of the work of the brain and that is memory – recalling stuff that has happened in the past to create experiences and responses in the present. It would be fair to say that the function of memory within the brain is complicated as the evolution of the brain happened at the same time as memory as they are part of the same system.

As luck would have it we also have a three stage model for memory (how about that) called the Atkinson-Shiffrin model or the multi-store model or modal model proposed int 1958.

Types of Memory Use

Declarative – conscious recall of information. Also called Explicit memory. Can be further divided into 1) semantic memory – information independent of context e.g., capital of England, or a colour being blue, and 2) episodic memory – information relating to a time and place e.g. a feeling of warmth, or it was early. Episodic memory is personal to the individual whilst semantic can be seen as shared factual.

Procedural – unconscious recall of information. Also called implicit memory. Gives the person the ability to do something with no effort like riding a bike or reading words (clever you).

Types of Memory Storage

Sensory register – where sensory information enters into memory for processing like information taken from your eyes when first seeing a picture (Iconic) or heard through the ears (Echoic). There isn’t anything for other senses like touch or smell but you get the idea that its where a stimulus is recorded.

Short-term or Primary or Active memory – short term storage of information to be processed immediately (seconds). You know when someone gives you a phone number to remember and they start saying it but by the end you can’t remember the first part – that’s short term memory. Only really good for storing 4 to 6 things at a time but this can be improved with practice (because everyone has the time to practice short term memory storage).

Working memory – memory that you have drawn down on to make a decision on like what you want to eat for the evening. Tends to be combined with short term memory like in a restaurant when the waiter gives you the specials you recall that you don’t like squid for some reason. Good for around a minute before new information needs to be drawn done. Also works with the third type of memory – long term memory.

In the Atkinson-Shiffrin memory model the short-term and working memory are seen as one. However it might be easier to see short-term and working as different as you can draw down working memory when you want.

Long-term memory – all the memory you have that is stored so is used in both declarative (explicit, thoughtful) memory and procedural (implicit, automatic) memory.

As with the model of the brain this is a simplification to aid understanding. In reality it’s a lot more complicated for example working member can result in longer term memory after you have worked something out like who the killer was in that film. Also long term memory degrades over time as it gets filtered and bundled together.

Emotional Memory – Powerful stuff but probably didn’t happen as you remember

A last thing on memory and that is the importance of emotion in memory. The limbic system components play a massive part in how memory is first processed and then stored. The more emotional the event the more likely it will be stored however that doesn’t mean it will be stored as a true recall of events but I’ll cover this off shortly.