The Concept of Declarative Memory Explained
Declarative memory (sometimes called explicit memory) encompasses the acquisition, retention and retrieval of knowledge that can be consciously and intentionally recollected. Such knowledge includes memory for events (episodic memory Opens in new window) or facts (semantic memory Opens in new window).
According to Terr (1994), declarative memory is essentially a conscious record of learned information. It is the capability with which we consciously recall learned information. This involves thinking and attaching words to what has been learned and then remembered. The philosopher Gilbert Ryle (1949) called such knowledge Knowing that.
You know that biology is the study of living things, that there are 365 days in a year, that the capital of the United States is Washington, D.C., that an elephant is bigger than a flea.
You also know that your name is not Monty Python, that Earth is not flat, and that Mickey Mouse is not a real mouse.
A lot of the things we are taught in school are declarative knowledge, but you can acquire declarative knowledge through reading magazines and books, browsing the Web, visiting museums, talking to friends, walking around your neighborhood, peering through a microscope, and in a thousand other ways.
The defining characteristic of declarative knowledge is that it can be expressed. Usually it is expressed in words, but it can be expressed in other ways, including pictures and gestures. Declarative knowledge is also sometimes called explicit knowledge.
Cognitive psychologist Endel Tulving (1972) of the University of Toronto proposed that declarative memories be further subdivided into semantic and episodic memories.
- Semantic Memory
He defined semantic memory Opens in new window as “knowledge of the world.” It is “the kind of memory that makes it possible for humans or other organisms to acquire, store, and use information about the world in which they live” (Tulving & LePage, 2000, p. 213). Thus, an individual may know that the capital of France is Paris, but s/he may have no personal recollection of when, where or how s/he first learned this fact.
Although the term suggests some connection with language, that is a misnomer.
Animals with no linguistic skills nevertheless know a great deal about their surroundings. Wild rats, for example, know where food is to be found, how to get to their underground den, which rates they can dominate and which they must not challenge, and so on. And they know all these things even though they can’t speak or write a word.
- Episodic Memory
Tulving contrasted Semantic memory with Episodic memory, sometimes called autobiographical memory, which is the memory for our personally experienced events, the episodes of our lives. Episodic memory Opens in new window recognizes that “we can think of a person’s life as consisting of successive episodes” (Tulving, 1983, p. 19).
Distinction between Semantic and Episodic Memories
Both semantic and episodic memory may involve facts, even the same facts, but their significance is different.
While hiking in the mountains, you could be attacked by a mountain lion. When you recall facts related to that experience (the color of the animal, the name of the park where the attack occurred, the number of stitches you received), you are recalling things that you personally experienced, and you are drawing on episodic memories.
I may read a newspaper account of your experience. When I recall the color of the animal, the name of the park where the attack occurred, and the number of stitches you received, I am drawing on semantic memory.
Because much of the same kind of information can be stored in semantic and episodic memory, the distinction between them may seem arbitrary, even contrived.
But defenders of the distinction argue that whereas both deal with facts, episodic memory deals with facts that have a personal connection for the individual.
Your memory of the mountain lion attack is of a personal experience, for example, whereas my memory is of facts that hold no personal connection to me.
There is also a temporal distinction between these two kinds of memory. For you, the attack fits in a personal timeline—you probably remember how old you were, what year the attack took place, the season, that you were just about to go off to college, that your entry to college was delayed for a year while you recuperated, that you decided to change your major from wildlife biology to urban planning.
For me, the comparable memories (in the unlikely event that I recalled them) would be the name of the newspaper that carried the story, where I was when I read it, why I was in that particular place, and the like.
Episodic memory is said to be a late development in evolution, and some people believe that it is the one sort of memory that is not found in animals other than humans. (Tulving, 2001).