Explicit Memory
Episodic Memory
Episodic or autobiographical memory lets you remember events that you personally experienced at a specific time and place, such as the name of someone, and the date and place of some public event. Its most distinctive feature is that you see yourself as an actor in your own events.
You thus memorize not only the events themselves, but also the entire context surrounding them. The emotional charges you experienced at the time of the events will condition the quality of your memorization of the episode. Episodic memory is the kind most often affected by various forms of amnesia.
Semantic Memory
Semantic memory stores general knowledge, like the meaning of words, names of locations, people’s customs, and the function of all kinds of things, including their color and odor. This knowledge base can be accessed quickly and easily.
Semantic memory is the residue of experiences stored in episodic memory. It focuses on common features of various episodes and extracts them from their context. Over time, a gradual transition takes place from episodic to semantic memory. The sensitivity to particular events is reduced so that the information takes on a more generalized format.
The understanding of our personal experiences is necessary, due to the concepts and knowledge stored in our semantic memory. Thus, both types of memory interact constantly.
Semantic memory also includes our memory of the rules and concepts that let us construct a mental representation of the world without direct contact. Its content is abstract and relational and is associated with the meaning of words.
People with Alzheimer’s symptoms often lose the ability to distinguish fine categories, such as species of animals or types of objects. Over time, this extends to more general categories. When seeing a spaniel, they may say, “that is a dog”. Later, they may just say “that is an animal”.
