Factors in Retention
In the last two modules we have been concerned with the problems of reaming and the process by which behavior is acquired. We will now study the closely related phenomena of forgetting and retention.
LONG-TERM VERSUS SHORT-TEAM MEMORY
In recent years, evidence has been growing to support the idea of a two-stage memory process. The two stages are short- and long-term memory, sometimes called primary and secondary memory. We have all had experiences in which we ask someone for a phone number. We dial it and get a busy signal. If we try to redial it just a few seconds later, we usually have to ask for the number again. The number was stored in short-term memory and was quickly lost. If we wish to commit the number to long-term memory, we must either practice it or code it by some associations.
The fastest drop in retention occurs immediately after learning
Research on short term memory was conducted by Peterson and Peterson (1959). Items were presented for a brief period of time. Subjects were then asked to recall the items at intervals that varied from three to 18 seconds immediately after exposure. Results were dramatic. After three seconds, immediate recall was high, but after 18 seconds less than 10% of the subjects were able to recall the item.
According to one theory, the effects of short-term memory are due to neural traces in the brain resulting from presented stimuli (Hebb 1949). These traces quickly decay over time, making the item less available for immediate retrieval. The theory holds that in long-term memory, permanent traces are formed when stimuli are presented repeatedly.
Forgetting and retention are inverse concepts. Retention refers to the amount of original learning that is still effective, while forgetting refers to the amount lost. Figure 5 shows a typical retention curve.
F igure 5. Forgetting and retention compared
As the graph indicates, by far the greatest amount of forgetting takes place in the first few moments after learning. Thereafter, the curve levels off. The amount retained after 5 hours is only slightly greater than after 15 hours.
The form of the retention curve depends in part on what measure is used. The three most frequently used measures are recall, relearning, and recognition.
We find different retention rates depending on how we test for recall
In recall, the subject is asked to reproduce the original response in some form. In experimental work the subject often responds vocally or may even be asked to write his response in a blank. There is little prompting in recall testing. Often the student is simply instructed to remember as many items from a list as possible. As might be expected, a test of recall generally yields the lowest measure of retention.
Relearning is sometimes called the savings method. Using this method, the subject first learns some material and, after various lengths of time, relearns that same material to the same criterion level. The number of trials to relearn the material is always fewer than the number required to learn it the first time.
The formula for relearning expresses the percentage of practice time saved.
The relearning score = 100 x (original trials minus relearning trials) divided by original trials
For example: If it took ten trials to learn the material originally and only four trials to relearn it, the relearning score would equal 100 x (10-4)/10 = 60%
Relearning usually reveals more retention than recall because more stimulus conditions are present in both the original learning and the relearning. ,
Recognition is the type of retention measured by a multiple choice question. The learner is required to choose the correct alternative from among several. In an experimental situation, the subject would be required to point out the correct answer from among many.
With recognition measures, even weak retention is revealed. The presence of the correct response among the choices is a prompt for the correct choice. In addition, subjects (and students) can eliminate some incorrect choices on the basis of length, position, incorrect grammar, etc. This increases the chance of making the correct selection. Responses which were previously associated with stimuli similar to the test stimuli are more likely to be selected erroneously. The phenomenon of false recognition can be seen in the familiar feeling that one has been in a certain situation before. This feeling, called deja vue occurs when enough aspects of the immediate situation resemble a previous situation. We incorrectly identify the past with the present.
THE FORM OF THE RETENTION CURVE
Each of the three measures of retention yields different results.
If we used all three measures of the retention of a learning task, the results would typically resemble those shown in Figure 6, where Recognition is the top curve, relearning is next, and recall (on the bottom) shows the lowest amount of retention over time.
Figure 6. Retention curves for three measures of retention. The top curve is "recognition." The middle curve is "relearning. The bottom curve is that of "recall."
FACTORS AFFECTING RETENTION
Making material meaningful to the subject aids retention
1. Meaningfulness: An important factor in retention is the meaningfulness of the material. In experiments where material has been presented in prose form or where there is a "theme," retention is improved. .
Mediating associations are especially useful for long-term retention
2. Mediating Associations: A second variable is the use of mediation al elements. Memory experts have long advocated the use of associations and mnemonics in aiding recall.
An example of a well-known mnemonic device is the "On Old Olympus Towering Top, a Finn And German Viewed A Hop," used by medical students to memorize the names of the twelve cranial nerves. The student memorizes the verse and then uses the initial letters to prompt himself to say. "Olfactory, Optic, Culotte, Cochlear," and so on.
The assumption underlying the use of mediation is that if the learner is unable to recall the desired response, he might be able to recall the mediator, which in turn would act as a stimulus for the recall of the response.
For example, suppose you wished to learn an S-R pair like dog-plant. You could put the stimulus word on a flash card and its response on the back. Then you could use the method of anticipation to eventually learn the pair by rote. You could, however, use an alternate strategy. You could find a common association between the two words dog and plant such as house (dog-house, house-plant).
In an experiment by Toast (1967), one group of subjects learned a series of 12 word pairs. A second group of subjects was told only to find some common association between each of the two words. These tasks were followed by a test of immediate recall. The subjects were presented with the first member of each pair and asked to recall the second member. Initially the subjects in the rote-learning group were slightly superior to those in the association group. However, after a two-week interval, the association group showed almost no further loss while the rote group showed a typical loss in retention over time.
Some over learning increases short- and long-term retention dramatically
3. Overlearning: Overlearning results from practicing beyond the point when the material has been mastered. For example, suppose it takes a subject five trials to learn a list of items. If we now require him to complete five additional trials, we say that 100 percent overlearning has occurred. In a study by Krueger (1929), subjects were required to learn a list of nouns. One group reamed with 0 percent overleaming; in other words, they mastered the list, and then were given no more practice. Another group learned with 50 percent and a third with 100 percent additional practice trials beyond mastery.
The data in Figure 9 clearly indicate that greater overlearning leads to increased retention. However, the improvement in retention from 0 percent to 50 percent overlearning is much greater than the 50 percent to 100 Percent overlearning, indicating that a point was reached beyond which returns from the increased effort diminished.
SUMMARY OF FACTORS AFFECTING RETENTION:
It is interesting to note that almost all,"'memory systems" recommended by experts require you to (1) practice by reading or reciting beyond mastery (overlearning) (2) study the material in logical blocks which are related by a theme rather than in small disconnected pieces (increased meaningfulness), or (3) attempt to find as many associations or "reasons" to remember as possible (mediation). These recommendations are obviously in accord with the experimental data.
PROGRESS CHECK 1
Now test yourself without looking back.
1. Sam felt he had mastered the content of the assigned chapter in preparation for a test. But knowing the data on retention he went back and restudied the chapter with as much effort as he had used the first time. The resulting increase in retention that would be demonstrated on the test would be attributed to____________________________________
2. Students were given a paired-associate learning task on Monday. On Friday they were asked to relearn the task to the same level of mastery. The results are as follows:
Compute the percent savings.
3. A characteristic of short term memory is that:
a. forgetting is rapid.
b. interference effects are common.
c. false recognitions are decreased.
4. What factors below would affect the amount of retention?
a. meaningfulness of material
b. the use of mediational associations during original learning
c. the number of errors made before mastery
d. the number of practice trials given in the original learning task after mastery has
If the subject has forgotten 60% of what was known , what percentage has been retained?__________________________________________________
6. What do we call the method of measuring retention that asks the subject to write down all the items he remembers from a previous learning task?__________________________________
Overlearning results from practice beyond mastery. Which of
these are examples of behavior which is probably overlearned for
a. Knowing how to ride a bicycle
b. Knowing the multiplication
c. Knowing the rank of playing cards
d. (none of these)
Tom fell down 25 times before he learned to ride a unicycle 10 feet. Two weeks later he practiced again. This time he fell only 5 times before reaching his previous level of mastery. Use this formula to compute the percentage of savings.
Relearning score = (original minus relearning) divided by (original times 100).
The three most common ways used to measure retention are recall, relearning and recognition. Usually recall measure indicates the least amount retained while recognition measure indicates the highest. Indicate below the probable results for each curve.
All three of these factors have been shown to facilitate retention..
1 ) Meaningfulness
2) Use of mediation
It has long been stated by memory experts that the way to remember someone's name is to find an association between the name and some identifying personal characteristic such as his nose or eyes. Which of the three factors listed above would account for the resulting improved retention?
NOW TAKE PROGRESS CHECK 2
2) a, b, c
3) 25-5 x 100 = 80%
4) use of mediation
PROGRESS CHECK 2
1. Retention is the opposite of________________________
2. In recall, the subject is required to:
a. recognize the response.
b. relearn the response.
c. construct the response.
3. In overlearning we require the subject to:
a. practice beyond mastery.
b. first learn a guiding principle.
c. relearn a skill during the test for retention.
d. (none of these)
4. Suppose you took this same test two weeks from now and then again four weeks from now. Which is likely?
a. Both of your scores would be lower than today's score.
b. Your score two weeks from now and four weeks from now would not be much different.
c. Your score four weeks from now would be higher than two weeks from now.
d. (none of these)
5. Compute the savings in this task:
Mean Trials to
Criterion Original Learning
Mean Trials to
Criterion on Test Task
6. If you took all three measures (recall, recognition, and relearning) on the retention of a task, plot the expected results.
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