Cognitive researchers study the mental processes that allow us to perform various tasks. In trying to understand how we perform tasks involving memory, researchers have identified and described three fundamental mental processes: encoding, storing, and retrieving (for discussions of basic memory processes, see Baddely, Eysenck, & Anderson, 2009; Willingham, 2004). Encoding occurs when information is translated into a form that can be processed mentally. In other words, encoding is “a special way of paying attention to ongoing events” so that this information can be placed into the memory system (Schacter, 1996, p. 42). It is similar to librarians classifying new books before placing them on a library shelf. Just as librarians encode new books in order assign numbers to them that will allow library patrons to easily locate the books they need, we encode information (we “label” it in various ways) before placing the information into memory. For example, how might we encode the words in the following list?
dog car dance job mouse book can plant lamp sun
What is the first thing you would do to memorize this list? You may be thinking something like, “I would read it!” But what does reading involve? It might involve something like the following:
- You first have to detect the visual stimuli (light) coming from the page, which involves activation of the sensory receptors (rods and cones) in the retinas of your eyes. The processing of the visual stimuli begins in the retina: the activity of various receptors are facilitated or inhibited by the activity of other receptors.
- This processed information then is transmitted through the optic nerve to the thalamus deep in the brain, where it is further processed before being sent to structures in the limbic system and the occipital lobes of the cerebral cortex, where more sophisticated processing occurs.
- From the occipital lobes, the information is sent to the temporal and parietal lobes for processing that is important for recognizing the words as words.
- From these areas, the information is sent to auditory areas in the temporal lobes of the cerebral cortex that are associated with sound perception, and then to language areas in various parts of the brain, where the sounds are translated into meaningful words, phrases, and sentences.
In this way, the squiggly lines on the page are transformed from light information into complex meanings in a fraction of a second. Each transformation involves a different kind of encoding. With respect to verbal information, memory researchers distinguish three kinds of encoding:
- Structural encoding. This involves translating the visual information from written words into its physical structure. In short, various characteristics of the visual input, such as the number of letters in a word or whether the word was written in upper- or lower-case letters, are encoded.
- Phonemic encoding. This involves translating the visual input from written words into sounds. For example, phonemic encoding of the words in the list presented above would allow us to state that the words rhyme with bog, bar, chance, etc.
- Semantic encoding. This involves translating the visual information from written words into their meanings (for example, being able to define them or to form a mental image of the objects they refer to). After semantically encoding the words in the above list, we would remember that they are synonyms (words or phrases that mean exactly or nearly the same thing as other words or phrases) of canine, automobile, rhythmic movement of the body, etc.
A memory code for information is formed when that information has been encoded in some manner. For example, when semantically encoding words in a list, you might form memory codes that consist of visual images of the objects, situations, or activities to which the words are referring, or dictionary definitions of the words, or a short story that uses the words, etc.
Once new information is encoded, it is stored. Storage of encoded information occurs when it is maintained (held) in memory for some period of time. This period of time is anywhere from a fraction of a second to years. The mental “location” in which the encoded information is held is referred to as a memory store. For example, long-term memories would be held in the long-term memory store. Memory as a whole often is described in terms of interacting subsystems (e.g., short-term memory interacting with long-term memory), each with its own memory store (see Section 5-6 for a discussion of this).
In order for encoded and stored information to affect our cognitions, emotions, and behaviors, it must be possible to access it — to get it out of storage. Retrieval of stored information occurs when it is activated in such a way that it can influence other mental events and behaviors. For example, when studying for an essay test, you are trying to encode the information in order to put it into the long-term memory store. Later, when you take the test, you’ll need to retrieve this stored information. As you already know, retrieving this information can be very difficult. For instance, you will not be able to retrieve the information well if you did not attend to it carefully when studying. In this case, you may not have encoded the information well enough to store it for more than a few seconds, so that no information is left to retrieve. In the case of Jimmie — the man described in the previous section who was unable to form new memories — his brain damage made it impossible for him to store information for more than about 20 seconds, regardless of how he encoded it. And for the rest of us, even if we encode new information well enough to lead to its long-term storage, we still may find it very difficult to retrieve it. For example, we all have had trouble with retrieving words that are on the “tip-of-the-tongue.” In general, forgetting occurs when information is:
- experienced but not encoded (if it is not encoded, then it cannot be stored);
- encoded but not stored (for instance, when we say that something we were told “went in one ear and out the other,” we mean that, although the information may have been phonemically encoded, it was not stored);
- encoded and stored, but cannot be retrieved (which may happen, for instance, if you haven’t thought about the information in a long time).
Thus, forgetting may occur because of problems with any one or more of the three mental processes involved in memory — encoding, storing, and retrieving.
Study Questions for Section 5-5
- In your own words, how would you define encoding?
- What is an example of structural encoding not mentioned in the text?
- What us an example of phonemic encoding not mentioned in the text?
- What is an example of semantic encoding not mentioned in the text?
- How are structural, phonemic, and semantic encoding similar to and different from each other?
- What is a memory code? (In your answer, please give some examples of memory codes.)
- In your own words, how would you define the storing of information in memory?
- What is a memory store?
- In your own words, how would you define the retrieving of information from memory?
- If information is not encoded, can it still be stored? Why or why not?
- If information is not stored, can it still be retrieved? Why or why not?
- What can cause forgetting?
Baddely, A., Eysenck, M. W., & Anderson, M. (2009). Memory. New York: Psychology Press.
Schacter, D. L. (1996). Searching for memory: The brain, the mind, and the past. New York: BasicBooks.
Willingham, D. T. (2004). Cognition: The thinking animal (2nd ed.). Upper Saddle River, NJ: Pearson.