Types of memory

We learn our whole life, but do we know how we learn and memorize in the different types of memory that we have??

In order to understand how we learn and how we memorize so that we can remember later, we have to understand the ?????????? ???? ???????????????? that we have, where do we store what, and for how long.

The first classification of memories, done by how long do the memories reside in the memory, points those two types:

1. Short-Term memory

2. Long-Term memory

Having very intuitive names, it is not necessary to detail which one holds information for a short while and which one for a long while. And because the short-term memory contains no further classification and consists of the working memory, I will start with this one.

1. Short-Term memory

1.1.?????????????? ???????????? - is a short term memory holding only the most recent information related to the ongoing activity.

For example, working memory allows us to keep in mind a phone number during the time it takes to dial it.

Nowadays we are not dialing the phone numbers anymore because they are saved in our smartphones, we don't memorize routes because we use google maps, we don't memorize shopping lists because we go shopping with a digital list, in some cases created by the fridge itself. We don't memorize poems anymore, because young people impress the opposite gender with pictures on Instagram and not with poems and romance. And this is how, step by step and helped by the technology, our short-term memory became shorter.

George Miller, the founder of the cognitive psychology field, published in 1956 the article Psychological Review where he wrote about the magical number 7, as being the number of objects that the average human can hold in short-term memory. Of course, as in any other field, a deviation of plus-minus 2 is accepted. More recent research shows that nowadays our short-term memory shrank and holds only 5 items. If you are curious how long your short-term memory is test it using?this video.

In order to improve our working memory, we can make use of different memorization techniques like mnemonics and Loci methods. Those methods use our brain's ability developed over millions of years to memorize and recognize places and images. The main responsibility of our brain is to keep us alive, and not to make us happy, as many would desire. And due to this responsibility, for many millions of years remembering where the shelter was and identifying the poisonous plants was crucial for our survival. This is why, mnemonics, a method of memorization based on images (explanatory video) and Loci method based on locations (explanatory video) are very helpful when it comes to memorizing and improving short-term memory.

2. Long-Term memory

is further classified in:

?- explicit memory, contains the conscious memories that we have the intent and sometimes even force ourselves to record

- implicit memory, contains the unconscious memories that we record without being aware or with no intention of recording them

The explicit memory consists of:

2.1 ???????????????? ????????????

As the name suggests, episodic memory stores episodes of personal experience, events, unfolded episodes from our daily life together with their context: when, how, where, with whom happened.

Example of episodic memories: you remember what you had yesterday for breakfast, your task assigned by your boss, what Santa Claus brought you last Christmas.

The part of the brain that ?????????????? episodic memories is the ??????????????????????. This is situated in the reptilian brain (the oldest brain structure that we have) and this is involved in rapid learning, meaning here is recorded the information and held only for fast access but it will not remain here forever. ?The stored information will be then moved overnight during the REM sleep phase in the prefrontal cortex. ( Here is a link to a short video about the importance of sleep for learning and memorizing describing the architecture of sleep?)

Research has identified two brain regions that are critical for the retrieval of episodic memories:

- medial temporal lobe

- prefrontal cortex

The structures responsible for retrieval are affected by different factors like practice, individual experiences, and differences in genetic makeup. What makes episodic memory distinguish from other forms of memory is the retrieval of information regarding the spatial and temporal context in which the remembered event occurred. An individual with autonoetic (self-knowing) awareness is capable of traveling at will in subjective time by recollecting aspects of past experiences. The autonoetic consciousness is considered to be an evolutionarily advanced unique human capacity.

The duration of the storage largely depends on the attention that an individual gives to it: you might remember what suit you wore last week at the party but don't remember the name of the person that was introduced to you. The suit got your attention. It also depends on the level of emotion at the moment of recording. High levels of emotions, no matter if positive or negative, store the information with more details and for a longer time or even forever. Also, the memories stored under the high level of emotions: happiness or sadness, are retrieved with no effort and sometimes automatically based on triggers that were present in the environment at the time of recording. The smell of cinnamon and apples makes you immediately remember your grandmother and how you baked Christmas pies together.

Episodic memory tends to decline with age and is heavily influenced by chronic alcoholism and vitamin B1(Thiamin) deficiency. I am going to list the top 10 foods highest in Thiamin, hoping that you are going to find something to include regularly in your diet: lean pork chops, salmon, flax seeds, navy beans, green peas, tofu, brown rice, acorn squash, asparagus, mussels.

?????????????? is "the disease" when people fail to collect episodic memories.

2.2. Semantic memory

holds the permanent knowledge stored in?the cortex. This type of knowledge is general knowledge, mainly concepts and facts in other words semantic memories are what we know about the world and it is what we "exchange for money" in the so-called "making a living".

Examples of semantic memories: the language grammar rules, mathematical formulas, principles of physics, history, etc.

Another example to help differentiate between semantic and episodic memories: the knowledge that watermelons are round and big, green on the outside and red and sweet on the inside, is part of semantic memory whereas the knowledge about where and with whom you ate the last time a watermelon would be considered part of episodic memory.?To make the distinction between those types of memories, with only two words, semantic memory stores?facts?while episodic memory stores?episodes/events.

The information gathered over the day is transformed during the night, ?in the?REM (Rapid Eye Movement) sleep phase in semantic memories. The brain extracts the information, generalizes it, and integrates it into our vast library of knowledge. There are debates related to the location where this library is located in our brain, where the semantic memories are stored. The three suppositions are:

1. that the semantic memory share the same place with episodic memories in the medial temporal lobes
2. that the semantic memory resides in the temporal neocortex
3. some support the idea of having semantic memories distributed across all brain

?in the?REM (Rapid Eye Movement) sleep phase showed that retrieving the color of an object was associated with activation in the ventral temporal cortex whereas retrieving action-related information was associated with activation in the middle temporal and frontal cortex.

Storing semantic memories is a bit more tedious than storing episodic memories because, in the case of episodic memories, which are episodes from your life, the information enters through your senses. Semantic memories depend on contextual information and some knowledge is acquired directly and some indirectly through generalization.

For example: knowing that pear trees photosynthesize allows us to infer that lemon trees also photosynthesize.

How do we learn in semantic memory? Through repetition and association.

Through repetition, we activate repeatedly the neurons in the network created to hold that knowledge. You know the expression: if you don't use it you lose it, it stands also for the neural networks. What we don't use we forget. The history lesson about the formation of the roman empire under Augustus Emperor. You heard this information for sure, you have created a neural network to hold that information. But unless you are a history teacher that has repeated it frequently, you forgot it because you have not reactivated the neural network holding it, and with time this network "died".

Through association, we compare the new knowledge that we want to memorize with a similar concept or knowledge that we already have. When we associate things, at the neuron level, we activate 2 networks at the same time: the old existing network holding the information that we have and the new network that we create for holding the new knowledge. By making this analogy/association we create remembering cues, which will enable us to remember the new information more easily.

Can semantic memories be "forgotten"? Yes, it can. The syndrome is called "semantic dementia" and the disease causes gradual and selective atrophy of the temporal cortex.

The main characteristic of implicit memory is that it uses past experiences, like events from our episodic memory, to remember things without even thinking about them. The implicit memory consists of:

2.3.Procedural memory is a category of long-term memory and is responsible for knowing how to do things because it stores our repetitive, routine activities.

Example: tying shoes, playing piano, driving a car, or cycling.

Procedural memory is also known as subconscious memory or automatic memory because is also responsible for our habits. The workers on production lines use this type of memory at work. Once they have learned their work procedures, those are then triggered automatically from the procedural memory. Procedural memory is important in language development, it allows us to talk without thinking beforehand about all grammar and syntax rules.

For recording the information in the procedural memory the hippocampus is not involved anymore as in the case of the former memories (working, episodic and semantic) but the basal ganglia is now responsible. The basal ganglia is also part of the oldest reptilian brain (the oldest brain structure that we have) and it records ort habits. People having basal ganglia damage, cannot form new habits. Also, those having low willpower cannot form new habits.

For a good state of mind, it is important that our (your employees) daily work contains activities that involve semantic memory, in order to learn something new every day and to develop, but in the same manner, it is important to do activities involving procedural memory and the existing knowledge to experiencing the feeling of achievement, work done.