This type of memory allows us to generate the necessary concepts to understand the world.
Memory is a psychological concept in which we usually think as if it were a single thing: the act of remembering what we had for dinner yesterday seems to have the same nature as remembering which is the capital of Egypt or what the steps of a choreography are like that we have been practicing. However, from the perspective of Psychology this is not the case, since there are different types of memory.
For example, part of memory is not made up of concepts, but of emotions and patterns and movements. However, within the type of memory composed of verbalizable aspects of knowledge, which is called declarative memory, there is also a subdivision. On the one hand there is the episodic memory, which is one that contains memories about narrative information from our past experiences (such as what happened to us yesterday when we went to buy bread), and on the other we find semantic memory, on which we will focus. in this article.
What is semantic memory?
In short, semantic memory is one that contains all the information related to the concepts thanks to which we understand the world and ourselves. That is, it is something like the storehouse of concepts about everything we know: the name of the countries, the characteristics of mammals, the history of the region in which we live, etc.
In other words, semantic memory makes it possible for us to understand the environment in which we find ourselves and also ourselves, since it allows us to reflect on our personal characteristics.
Although being a type of declarative memory it is composed of concepts, unlike episodic memory this does not follow a narrative progression. The fact that Africa is a continent has nothing to do with an experience with a beginning, development and ending, it is enough to know the term “Africa” and link it to a territory that we have been able to see on a map and that exists beyond that map, not just as part of an anecdote from our private lives.
The information that semantic memory contains can be understood as a pyramid of concepts; Some of them are very general and are made up of other concepts, which in turn are made up of others, until reaching units of information that are very basic and not very significant because they are too specific.
Thus, it is a mental capacity that is expressed consciously and often voluntarily, for example, when we need to access relevant information to correctly answer an exam question (something that does not happen with emotional memory, or not to the same extent).
Semantic memory functions
All types of memory are of crucial importance and complement each other, but the case of semantic memory is special since thanks to it we are able to create the concepts necessary to develop language and to become capable of thinking in such a way. abstract.
If non-declarative memory is useful when it comes to directing our behavior based on our learning and episodic memory allows us to understand the concrete context in which we live and what specific situations we have gone through, semantics is what generates all those ideas that we need to build beliefs, expectations, goals, etc.
Thus, this type of memory is closely linked to the ability to use language, which is nothing more than a system of symbols with an abstract meaning not linked to a specific place and time.
Parts of the brain involved
The differentiation between semantic memory and other types of memory is not simply theoretical: it is materially embodied in the brain.
For example, emotional memory is closely related to the activity carried out by a part of the brain called the amygdala, while episodic memory is related to another structure called the hippocampus and the cerebral cortex.
Regarding semantic memory, it also depends in part on the hippocampus, but to a lesser extent than episodic memory. It is believed that, compared to the episodic, the importance of the general activity of the cerebral cortex is greater.
As each type of memory has several brain structures more oriented to it than the others, this means that certain neurological pathologies also affect some more than the rest.
In the case of semantic memory, it seems to be especially vulnerable to lesions in the prefrontal cortex, although alterations in the hippocampus also affect it greatly, as occurs with episodic memory .
However, in practice, many pathologies that wear down our ability to remember concepts damage several areas of the brain at the same time. This is what happens for example with dementias ; practically all of them play against this type of mental capacity, since they kill many neurons distributed throughout almost the entire brain (although more in some areas than in others).