Long term memory has a large capacity and contains memories that are decades old, in addition to memories that arrives several minutes ago. Atkinson & Shifrrin proposed that information in LTM is encoded semantically, ie: in terms of its meaning. Memories in LTM are relatively permanent and are not likely to be lost.
The accuracy of LTM is influence by a number of factors. Some of the important factors among them are:
a) Context
b) Explicit vs implicit measure of memory
c) Mood
d) Expertise
1. Effect of context: encoding specificity ( bedrooms, knives, kitchen)
Encoding specificity principle, states that recalling of the material is better if the retrieval context is like the encoding context. In context forgetting occurs when the 2 contexts do not match. Context is not limited to physical location and it includes other cues present during encoding and recall, such as speakers voice or our mood etc.
Our explanation for some of the inconsistence of context is outstanding hypothesis which propose that context can be completely outshine (ie: not helpful or covers up) when other better cues are present. In other words when the material to be recalled is been well learned, then the memory cues from that material should be strong enough to outshine the relatively weak context cues and when the material is not been learned, then context cues can be help trigger memory. In the short context should be especially important when you have not yet mastered the material.
2. Explicit Vs implicit measures of memory
Explicit memory measures requires a participant to remember information. The most common explicit measures are recall a recognition. In contrast an implicit memory measure requires the participants to perform a task ( ie: to do something). Implicit memory show the effect of previous experience that creep out in our ongoing behavior when we are not making a conscious effort to recall the past. One of the critical distinction between explicit and implicit memory measures is that explicit tasks requires conscious recollection of previous experience in the contrast implicit memory tasks do not require conscious recollection of previous experience.
1. Research of Amnesic patient.
Elizabeth Warrinnton and Lawrence Wieiskrantz (1970) conducted an experiment in which they compared the performance of normal individuals with 4 Amnesic patients on explicit and implicit memory task. Among 4 Amnesic patients 3 had Kossakoffs Syndrome associated with sever alcoholism which involve brain damage and Amnesia and one temporal lobe was surgically removed. The researches produced a list of English words to both the groups and were asked to recall in one test and were asked to recognize in another memory test. The result revealed that the amnesic patient performed very poorly in both the explicit memory test.
In the next stories both the groups were presented with 2 implicit memory tests. In one task they were presented word guessing games. (ie: word were presented in jumbled manner and they had to make meaningful word out of it (mutilated words). In the 2nd task, participants were presented with 1st few letters and they were instructed to produce the 1st word that came to their mind (word stem test). The results of these tests were very astonishing in which the amnesic patients performed identical to normal participants. Both the groups correctly identified 45% of mutilated words and 65% of word stem test.
Note: this research of Warinton and Lawrence is a good example of a concept called dissolution. (dissolution occurs when a variable has large effect on one king of test but little or no effect on another kind of test. It also discuss when variable has one kind of effect if measured by test A and an opposite effect if measured with test B.
2. Research with normal adults.
Some researches on normal adults have showed that people score higher in an explicit test when they have processed the stimuli semantically rather than perceptually where as on implicit memory test they may score higher when material is processed perceptually than semantically.
Mary Susan Weldon and Henry Roediger (1987) examined the phenomena of pictures superiorly effect (pictures are usually remembered better than words) for both explicit and implicit memory. They showed the students slide containing typed word of concrete objects or simple black on white drawing. Lather they were asked to recall (explicit test) and to complete word fragment (implicit test) (eg; EI_P_ _N_). They were given 5 min for recall task and were asked to recall in any other they wish. For word completion task they were given 20 sec. for each item. Results showed that explicit memory measures showed the usual picture superiority effect. (ie: participants recalled more of items originally seen as pictures rather than words however for implicit memory test the result were Vise Versa).
3. Mood
Memory is influenced by whether the emotional tone of the material matches your current mood. It is also affected by the match of us mood between encoding time and retrieval time.
Memory for word differing in Emotion:
In a typical study conducted by few psychologists, people were asked to learn a list which had pleasant, unpleasant and neutral words. Then their recall was tested a delay of several minute and later after several months. The results showed that pleasant items were recalled better than the negative items and neutral items particularly when then delay was long.
This research explains the effect of Pollyanna principle which states that unpleasant items are usually processed more efficiently and accurately then less pleasant items.
Mood congruence:
Mood congruence means that memory is better when the material to be learned is congruent with a person’s mood. Thus a person who is in pleasant mood will learn material better than unpleasant material.
Blancy (1986) in his research proved that depressed people tend to recall more negative materials where as a people who are more normal tend to recall more positive material.
Mood state dependence:
According to mood state dependence, our recall when we are in a particular mood depends partly on our mood when we originally learned the material. Here the emotional nature of the material doesn’t matter instead memory depends upon whether the mood during encoding is matching with the mood during recalling.
4. Expertise
Expertise is the 4th factor which dramatically influences long term memory. This is because:
1) Experts posses a well organized, carefully learned known structure.
2) Experts have more vivid visual images for the items they must recall.
3) Experts are more likely to recognize the material they must recall, forming meaningful chunks that group related material together.
4) Experts rehearse in different fashion.
5) Experts are better at reconstructing missing portions of information from material that is partially remembered.
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