27. What has research shown about the relative abilities of elaborative rehearsal and maintenance rehearsal to form new long-term memories?
28. What is meant by "deep knowledge"?
29. What is the best way to develop deep knowledge?
30. What is the most effective studying strategy to use in your courses? (Note: In your answer, please describe the specific activities included in this strategy.)
31. What happens to the amount of stored information as it is transferred from the sensory store to the short-term store to the long-term store?
32. What reduces the amount of time and effort needed to elaboratively rehearse information in the short-term store?
33. What effect does this reduction of time and effort to elaboratively rehearse have on the amount of information transferred from the short-term store to the long-term store?
34. As you develop more and more knowledge about an academic area, what should happen with respect to the amount of time and effort needed to elaboratively rehearse new information in that area?

What is Long-Term Memory?

According to the cognitive approach, the long-term subsystem consists only of the long-term store. In other words, cognitive theorists do not include any components in this subsystem that further process information transferred from working memory. The long-term store can be described in terms of the same characteristics used to describe the sensory and short-term stores: the levels of awareness at which long-term memories are stored; the duration of long-term memories; the capacity of the long-term store; the encoding of long-term memories; and the causes of forgetting of long-term memories. The first characteristic will be discussed in this section. The other characteristics and the topic of forgetting from the long-term store will be discussed in Section 4-4.

Levels of Awareness of Long-Term Memories
We can think of the ability to attend to information stored in the memory system as involving a continuum from conscious, to preconscious, to unconscious (see Figure 6). By definition, only memory codes in the short-term store are at the conscious level. Therefore, memory codes in the long-term store are below the conscious level. As you probably know from your own experience, some long-term memories are relatively easy to retrieve (that is, to bring to the conscious level), such as the day and time of your favorite television show. These memory codes are stored at the preconscious[∂] level. On the other hand, other long-term memories are much more difficult, perhaps even impossible, to retrieve, such as the name of your second-grade teacher. These memory codes are stored at the unconscious[∂] level. In order to bring long-term memories to the conscious level, long-term memory codes must be attended to, which leads to their transfer to the short-term store. Unconscious long-term memory codes may not be able to enter the short-term store, but they still may be transferred to unconscious components of working memory, thereby affecting conscious cognitions, emotions, and behaviors. A long-term memory code stored at the preconscious level is called an explicit memory. For example, your conscious memory of what you were doing five minutes ago involves the activation of a preconscious long-term memory code. Or, the activation of a preconscious memory code about the meaning of the term "explicit memories" may allow you to answer a test question about explicit memories correctly. A long-term memory code stored at the unconscious level is called an implicit memory. For example, an implicit memory of the meaning of the term "implicit memories" may cause you to "guess" correctly when responding to a test item about the concept. Or an implicit memory of being frightened when you were an infant by a psychologist banging a hammer against a steel bar (Watson & Rayner, 1920) may cause you to avoid taking psychology courses in college.

Figure 6. Levels of Awareness & the Ease or Difficulty of
Attending to Mental Content at Each Level

The case of Henry M. can help us to understand better the distinction between explicit and implicit memories. As we saw in Section 4-2, it was very difficult for Henry to learn new information. Scoville and Milner (1957) provided some examples of Henry's amnesia:

Ten months ago [Henry's] family moved from their old house to a new one a few blocks away on the same street; he still has not learned the new address, though remembering the old one perfectly, nor can he be trusted to find his way home alone. Moreover, he does not know where objects in continual use are kept; for example, his mother still has to tell him where to find the lawn mower, even though he may have been using it only the day before. She also states that he will do the same jigsaw puzzles day after day without showing any practice effect and that he will read the same magazine over and over again without finding their contents familiar. This patient has even eaten luncheon in front of one of us [Brenda Milner] without being able to name, a mere half-hour later, a single item of food he had eaten; in fact, he could not remember having eaten luncheon at all. (p. 14)

Nevertheless, there are some things that he could learn and remember quite well. For example, he was tested often over many years in the same room at the Massachusetts Institute of Technology. When walking down the hall to the testing room, he would claim that he did not know where this room was, yet he would make the correct turns taking him to it. He seemed to know approximately where the room was, but he did not know that he knew this! This suggests that his amnesia was not complete. Although Henry did not have an explicit memory for the location of the testing room, he did have an implicit memory, which allowed him \to walk there. In general, Henry was unable to form new explicit memories, but he seemed able to form new implicit memories.

Another example of this can be seen in a case study from a century ago (described in Sacks, 1995). One day in 1911, a neurologist by the name of Edouard Claparéde took his medical students on rounds. One of Claparéde's patients was a man with severe anterograde amnesia similar to Henry's. In order to demonstrate the man's memory disturbance, Claparéde placed a pin between his fingers and, when he reached for the patient's hand to shake it, he instead stuck the pin in the man's palm. Within a minute or two after this event, the man was unable to remember why his hand hurt: he had no episodic memory of the incident. The next day, however, the patient, although unable to recall the incident, refused to shake hands with Claparéde. This means that the patient must have formed an implicit memory of the incident. In fact, this patient’s reaction involved the classical conditioning of a fear response (the CS was the sight of Claparéde’s hand, the UCS was the pain caused by the pin, and the CR was the fear elicited by the sight of Claparéde’s hand). Classical conditioning often involves the formation of implicit memories.

In order for a person's long-term memory code (whether explicit or implicit) to affect his or her conscious cognitions, emotions, and behaviors, the person must experience a retrieval cue, which is a stimulus that activates a long-term memory code. If the memory code is an explicit one, the retrieval cue will cause a conscious memory to be retrieved. If the memory code is an implicit one, the retrieval cue will cause changes in conscious cognitions, emotions, and/or behaviors (as in the case of Claparéde’s patient) . Retrieval cues activate long-term memory codes because they are, in some way, associated with them. For example, if you want to retrieve explicit memories of the names of your friends in third grade, standing in your third-grade classroom or seeing a class picture from third grade might be adequate retrieval cues. In fact, these retrieval cues may bring back a flood of memories from that time period. Or perhaps, while eating waffles one day, you suddenly think of a friend from childhood. As you think more about this friend, you may remember the time you stayed overnight at his house and ate waffles for breakfast. In this example, the waffles were a retrieval cue because they were associated with this explicit memory of your childhood friend.

Smells and tastes seem to be especially good retrieval cues for explicit memories of life events from long ago. For example, Marcel Proust (1871–1922), the famous French novelist and essayist, described in a passage from his novel, In Search of Lost Time (À la Recherche du Temps Perdu), the recall of an intense and stirring childhood memory:

The other evening, having come in chilled, by the snow, and not being able to get warm, as I had started to read in my room under the lamp, my old cook offered to make tea, which I never drink. And chance had it that she brought me some slices of toast. I dipped the toast into my mouth and having the sensation against my palate of its sogginess permeated with the taste of tea, I felt a disturbance, scents of geraniums and orange trees, a feeling of extraordinary light, of happiness; I stayed motionless, fearing a single movement could interrupt what was happening in me, which I did not understand, but still concentrating on this taste of dunked bread, which seemed to produce such wonders, when suddenly the shaken partitions of my memory caved in, and it was the summers I spent in the country house I mentioned which burst into my consciousness, with their mornings, and drawing with them the procession, the nonstop charge of happy hours. Then I remembered: every day when I was dressed, I went down into the room of my grandfather, who had just awakened me and was drinking his tea. He used to dunk a rusk and give it to me. (quoted in Hilts, 1995, p. 77)

As an adult, the taste of toast dipped in tea served as a retrieval cue for a memory not recalled in many years — a memory of summers spent at a relative’s house. The memory's powerful impact was due to its vivid perceptual details and the strong emotions evoked. Most remembrances, however, are not so clear and striking. Retrieval cues (such as the several choices you read on a question from a multiple-choice test) are more likely to activate memories of general knowledge or fuzzy memories of past life events.

Another example of a retrieval cue involves the common experience of having to return to the place in which you recently had thought of something in order to remember what that thought was. For example, perhaps while you were in your bedroom one afternoon, you decided to drive to the grocery store and pick up a few things. You remembered that your car keys were in the kitchen and, so, you started to walk down the hallway towards the kitchen. Halfway there, however, you forgot why you were going to the kitchen. At that point, it is likely that you stopped, turned around, and returned to the bedroom. When you looked around the bedroom, you probably remembered suddenly that you had been walking to the kitchen to get your car keys. In this example, your bedroom served as a retrieval cue for the memory.

The concept of retrieval cue helps to explain why using elaborative rehearsal to encode information in the short-term store is the best strategy for creating easily accessible and stable long-term memories. When we elaboratively encode information, a memory code is created that can be activated by a larger number of retrieval cues because elaborative rehearsal creates a number of links to information already stored in the long-term subsystem. Furthermore, the greater the number of possible retrieval cues, the more likely it becomes that the memory will be retrieved often, which creates a stronger and more durable memory code. For example, if you encoded the name of the behaviorist, "John Watson" in terms of his later career as an advertising executive (see here), you may be unable to answer a test question asking you to "name the famous behaviorist who studied the conditioning of fear in Little Albert." A memory code created through the use of elaborative rehearsal, however, probably would allow you to answer this question easily since a larger number of retrieval cues (such as this test question) would activate the memory code associated with John Watson.

Retrieval cues may also explain déjà vu experiences, in which people have the uncanny feeling that they have already experienced in the past the situation in which they find themselves currently. The cognitive theory of déjà vu states that stimuli in the current situation are acting as a retrieval cue for a memory of a different, but still similar, situation from the past. For example, when looking out at a classroom of faces, teachers sometimes feel as if they are reliving a previous experience. It is likely, however, that the current situation is activating a long-term memory code of a past experience in which they were looking out at a classroom full of faces, especially if that experience occurred in the same classroom. (A comedian once stated that he was suffering from two memory problems — amnesia and déjà vu—at the same time. He said, “I feel as if I’ve forgotten this before.”)

There is evidence that mental states can serve as retrieval cues. For example, state-dependent memory is said to occur when people are better able to retrieve information learned while in a particular mental state (such as a state of consciousness or a mood state) when they are again in that same mental state. For example, if you study for your test while drinking a few beers, you may do better on the test if you have a few beers while taking it. Before you put this strategy into action, however, you should be aware that you will do much better on the test if you are sober both while studying for the test and while taking the test. Nonetheless, some research on state-dependent memory suggests that, if you are slightly intoxicated while studying, then you may do a bit better if you are slightly intoxicated while taking the test.

A mood is a stable (lasts for at least several days) and pervasive (occurs in most situations) emotional state. For example, in order to be diagnosed with a mood disorder, such as major depression, a person must experience the emotion of depression (severe sadness) every day for most of the day over at least a two-week period. A person who becomes depressed for a day after receiving a low grade on a chemistry test is experiencing a change in emotions, but not changes in moods. Some research on state-dependent memory suggests that the mood you are in while learning material may serve as a retrieval cue when you later are asked to remember this information. For example, if you learn a word list while depressed, then you may retrieve more of this information if you are depressed than if you are in a neutral or a happy mood. Thus, if you study for a test while depressed and anxious, you may do better on the test if you are depressed and anxious while taking it. Again, you probably will perform best if you are happy and energetic both while studying for the test and while taking the test.

A concept related to but distinct from state-dependent memory is the mood-congruence effect. The mood-congruence effect is an increased tendency to recall life events consistent with one's present mood relative to life events inconsistent with that mood. For example, when you are happy, you are more likely to recall positive experiences from your past (such as the time you found a twenty-dollar bill) than you are to recall negative experiences (such as the time you lost a twenty-dollar bill). In other words, research on the mood-congruence effect suggests that your present mood state may serve as a retrieval cue for long-term memories formed when you were in the same mood state. The mood-congruence effect implies that it may not be a good idea to trust the negative memories of a depressed, anxious, or distressed person: such a person would be expected to more easily recall negative than positive long-term memories. If you have known this person for a long time, you may be amazed at how many positive memories he or she seems to be forgetting. There is no need to worry, however. As soon as the person's mood improves, there should be an increase in the number of positive memories retrieved.

Furthermore, when you are feeling anxious and depressed, you are likely to remember past events as being more negative than than you remember them at other times:

Researchers have documented ... that people tend naturally to reconstruct the past in terms of their present circumstances, exaggerating the degree of earlier misfortune and trauma if they currently are feeling bad, minimizing it if they are feeling good. Findings from various studies — of Gulf War veterans, car accident victims, witnesses to school shootings, international peacekeepers — are remarkably consistent in this regard. They show that individuals with more severe symptoms of anxiety and depression remember a traumatic event as being worse when they are asked about it a second time many months, or even years, after the first. Those with fewer symptoms, however, tended to recall the event as less harrowing than they had previously described it. (Sommers & Satel, 2005, p. 155)

In other words, ..... This is somewhat different than the mood-congruence effect, though related to it.

Study Questions