Chapter 6

Implicit memories

A memory revealed by direct memory testing usually manifest as priming effects in which current performance is guided or facilitated by previous experiences. Implicit memories are often accompanied by no conscious realization that one is, in fact, being influenced by specific past experiences. Recall is a direct memory test; so is the standard recognition test. We are often better at remembering that something is familiar than we are at remembering why it is familiar. This is why it's possible to have a sense of familiarity with no source memory ("I've seen her somewhere before, but I can't figure out where!"), and also why it's possible to be correct in judging familiarity but mistaken in judging source. There is remarkable similarity in implicit-memory performance by people at very different ages.

Repetition priming

A pattern of priming that occurs simply because a stimulus is presented a second time; processing is more efficient on the second presentation.

State-dependent learning

A phenomenon in which learning seems linked to the person' mental, emotional, or biological state during the learning. As a result of this linkage, the learning is most likely to show its effects when the person is again in that mental, emotional, or biological state. Ex: We should expect that divers who learn material while underwater should remember the material best if tested underwater; this will increase the chance that they'll be able to use the memory connections they established earlier. Likewise, the divers who learn on land should do best if tested on land. This is exactly what the data show.

Context reinstatement

A procedure in which someone is led to the same mental or emotional state he or she was in during some previous event; context reinstatement can often promote accurate recollection. The context has its effect only because it influences how the person thinks about the material to be remembered: its these thoughts, and the perspective the person has during learning, that really matter for memory, and not the physical environment.

Illusion of familiarity

A stimulus that is not familiar (i.e., you've not seen it recently) can also feel familiar. This sort of illusion of familiarity can be produced, for example, if the processing of a completely novel stimulus is more fluent than you expected--perhaps because the stimulus follows a pattern you've seen before, or because you've been unconsciously primed for the stimulus.

Word-stem completion

A task in which people are given the beginning of a word (e.g., "TOM") and must provide a word that starts with the letters provided. In some version of the task, only one solutions is possible, and so performance is measured by counting the number of words completed. In other versions of the task, several solutions are possible for each stem, and performance is assessed by determining which of the responses fulfill some other criterion.

Amnesia

A broad inability to remember events within a certain category, due in many cases to brain damage.

Korsakoff's syndrome

A clinical syndrome characterized primarily by dense anterograde amnesia. Korsakoff's syndrome is caused by damage to specific brain regions, and it is often precipitated by a form of malnutrition common among long-term alcoholics.

Remember/know distinction

A distinction between two experiences one can have in recalling a past event. If one "remembers" having encountered a stimulus before, then one usually can offer information about that encounter, including when, where, and how it occurred. If one merely "knows" that one has encountered a stimulus before, then one is likely to have a sense of familiarity with the stimulus but may have no idea when or where the stimulus was last encountered. fMRI scans show heightened activity in the hippocampus when people indicate that they "remember" a particular test item, suggesting that this brain structure is crucial for memory source. In contrast, "know" responses are associated with activity in a different area--the anterior parahippocampus, with the implication that this brain site is crucial for familiarity.

Direct memory testing

A form of memory testing in which people are asked explicitly to remember some previous event. Recall and standard recognition testing are both forms of direct memory testing. Often contrasted with indirect memory testing.

Indirect memory testing

A form of memory testing in which research participants are not told that their memories are being tested. Instead, they are tested in a fashion in which previous experiences can influence current behavior, often manifested as priming effects. In this form of testing, your current behavior is demonstrably influenced by a prior event, but you may be quite unaware of this. Examples of indirect tests include word-stem completion, the lexical-decision task, and tachistoscopic recognition.

Source memory

A form of memory that allows one to recollect the episode in which learning took place or the time and lace in which a particular stimulus was encountered.

Source confusion

A memory error in which one misremembers where a bit of information was learned or where a particular stimulus was last encountered.

Explicit memory

A memory revealed by direct memory testing and typically accompanied byt he conviction that one is remembering a specific prior episode. Performance on explicit-memory tasks is strongly age-dependent, with children and the elderly both outperformed by those in their middle years.

Familiarity vs. source memory in learning

If specific brain areas (e.g., the rhinal cortex) are especially active during learning, then the stimulus is likely to seem familiar later on (and so that stimulus is likely to trigger a "know" response). In contrast, if other brain areas (e.g., the hippocampal region) are particularly active during learning, then there's a high probability that the person will offer a "remember" response to that stimulus when tested later on.

Familiarity

In some circumstances, the subjective feeling that one has encountered a stimulus before; in other circumstances, the objective fact that one has indeed encountered a stimulus before and is now in some way influenced by that encounter, whether or not one recalls that encounter or feels that the stimulus is familiar. False fame: This misattribution is possible only because the feeling of familiarity produced by these names was relatively vague, and so open to interpretation. The suggestion, then, is that implicit memories may leave people only with a borad sense that a stimulus is somehow distinctive--that it "rings a bell" or "strikes a chord." What happens after this depends on how they interpret that feeling. In both the illusion-of-truth and the false-fame experiments, participants are misinterpreting a sense of familiarity: They know that a name or a sentence is familiar, but they don't realize that this is because it was on the previous list. Instead, they falsely conclude that the name is familiar because it belongs to someone famous or that the sentence is familiar because they read it in some authoritative source. Noise experiment: The participants seemed not to realize at all that the previously presented sentences were, in fact, familiar. All they realized is that it was easier to perceive the sentences in one condition than it was in the other, and they mistakenly attributed this difference to differing noise levels. Here the implicit memory didn't at all change how participants felt about the sentences. Instead, the memory showed its influence by changing how the participantes felt about an entirely different stimulus--namely, the noise in which the sentences were embedded. Familiarity is more like a conclusion that you draw rather than a feeling triggered by a stimulus. Specifically, the evidence suggests that a stimulus will seem familiar whenever the following list of requirements is met: 1) You have encountered the stimulus before. 2) Because of that prior encounter (and the "practice" it afforded), you are now faser and more efficient in your processing of that stimulus, or processing fluency. 3) You detect that fluency, and this leads you to register the stimulus as somehow distinctive or special. 4) You reach a particular decision about that specialness--namely, that the stimulus has this distinctive quality because it is a stimulus you have met before in some prior episode. 5) You draw a conclusion about when and where you encountered the stimulus--in the experimenter's list of words, or yesterday in the newspaper, and so on.

Attribution

The step of explaining a feeling or event, usually by identifying the factors or the earlier event that is the cause of the current feeling or event. Ex: When you have a strong sense of familiarity, and you're willing to make an inference about where the familiarity came from. In other words, you attribute the familiarity to the earlier encounter, and thanks to this attribution, you will probably respond yes on the recognition test.

Recognition

The task of memory retrieval in which the items to be remembered are presented and the person must decide whether or not the item was encountered in some earlier circumstance. Thus, for example, one might be asked "Have you ever seen this person before?" or "Is this the poster you saw in the office yesterday?" Often contrasted with recall. Recognition follows the same rules as recall, and so is more likely if you formed the relevant connections during learning. Two-part theory of recognition: recognition sometimes depends on familiarity and sometimes on source memory. It is possible to have either one of these without the other. Ex of familiarity w/out source memory: On TV you see a familiar face (presumably of a famous person) but you are unable to say why the face is familiar. Here you cannot "place" the memory or identify the episode in which the face was last encountered. Ex of source memory w/out familiarity: Capgras syndrome

Recall

The task of memory retrieval in which the rememberer must come up with the desired materials, sometimes in response to a cue that names the context in which tese materials were earlier encountered ("Name the pictures you saw earlier"), sometimes in response to a question that requires the sought-after information ("Name a fruit" or "What is the state capital of California"). Often contrasted with recognition.

Encoding specificity

The tendency, when memorizing, to place in memory both the materials to be learned and also some amount of the context of those materials. As a result, these materials will be recognized as familiar, later on, only if the materials appear again in a similar context. In learning new material, you establish a memory that can be retrieved in a certain way, from a certain perspective. If the perspective changes--if, in particular, your understanding of the target information changes--then the original memory may not be retrieved. In light of this, we cannot speak of "good learning" (or "less good learning") in general. Instead, what counts as good learning may depend on later events.

Lexical-decision task

A test in which participants are shown strings of letters and must indicate, as quickly as possible, whether each string of letters is a word in English or not. It is supposed that people perform this task by "looking up" these strings in their "mental dictionary." Lexical decisions are appreciably quicker if the persona has recently seen the test word; that is lexical decision shows a pattern of repetition priming. This priming is observed even when participants have no recollection for having encountered the stimulus words before. At a sufficient delay, the direct memory test is likely tos how that the participants have completely forgotten the words presented earlier; their recognition performance is essentially random.

Activity in the hippocampus

Activity in the hippocampus is presumably helping to create the memory connections we have been discussing all along, and it is these connection that promote source memory: The connections like a memory item to other thoughts that help identify the episode (the source) in which that item was encountered, and this allows you to recall when and where you saw (or heard) that item. In regards to familiarity, effortful encoding , with attention to paid relationships, is not crucial. Instead, sheer exposure to a stimulus, or rote rehearsal, seems to be enough. Thus, evidence does not imply that the hippocampus is the "seat" of memory in the brain because damage to the hippocampus does not disrupt already-established memories. (Hippocampus dammage is associated with anterograde amnesia, not retrograde.) Instead, the hippocampus plays its main role in memory acquisition.

Double dissociation

An argument used by researchers to prove that two processes or two structures are truly distinct. To make this argument, one must show that each of the processes or structures can be disrupted without in any way interfering with one another. Thus, it's possible to interfere with explicit memory while sparing implicit, and that it's also possible to disrupt implicit memory while sparing explicit. (Refer to p. 194.)

Illusion of truth

An effect of implicit memory in which claims that are familiar end up seeming more plausible. This is extremely relevant in the political arena and in advertising.

Processing fluency

An improvement in the speed or ease of processing that results from prior practice in using those same processing steps. Thus, when we say these tasks are influenced by implicit memory, we're simply acknowledging the fact that once a stimulus has been perceived it will be easier to perceive the next time around. People are sensitive to the degree of processing fluency. That is, people know when they have perceived easily and when they have perceived only by expending more effort. THey likewise know when a sequence of thoughts was particularly fluent and when the sequence was labored. This sense of specialness ("that rings a bell") is caused by ease in processing brought on by fluency, which in turn was created by practice. Once the stimulus has changed, however, your well-practiced steps of perceiving don't run as smoothly as they have int he past, and so the perception is less fluent than it had been. This lack of fluency is detected and gives you the "something is new" feeling, but then the attribution step fails.

Anterograde amnesia

An inability to remember experiences that occurred after the event that triggered the memory disruption. Often contrasted with retrograde amnesia. Used to be described as a "disconnection syndrome;" the idea was that the problem was lodged in the connection between working memory and long-term memory, so that patients were unable to move information form working memory into long-term storage. This is why new memories could not be established... or so they thought. Ex: H.M. Patients suffering form anterograde amnesia can remember events from before the amnesia's start, suggesting that there is nothing wrong with their long-term memories. The patients also seem to have interactive working memories. These patients seem completely incapable of recalling episodes or events, or no explicit memory. On the other hand, these patients do learn and do remember; they seem to have intact implicit memories.

Retrograde amnesia

An inability to remember experiences that occurred before the event that triggered the memory disruption. Often contrasted with anterograde amnesia.

Objective familiarity

When you've seen something recently, but it does not feel familiar. In these cases, you detect the fluency and attribute it to some other source ("The noise is soft" rather than "The sentence is familiar," or "That melody is lovely" rather than "The melody is familiar"). In other words, you go through all steps 1-3, but not 4 & 5: you do not attribute fluency to a specific prior event, and os you do not experience a sense of familiarity.

Memory without awareness

With tachistoscopic testing, performance is considerably improved if participants have recently viewed the test word, and again this benefit does not depend on conscious recollection. Here too, participants are being influenced by a specific past experience that they seem (consciously) not to remember at all--a pattern that some researchers refer to as "memory without awareness."