Psychology Part 38

Unintentional Learning

What we have been examining is intentional memorizing, with the "will to learn" strongly in the game. The a.s.sertion has sometimes been made that the will to learn is necessary if any learning is to be accomplished. We must look into this matter, for it has an important bearing on the whole question of the process of learning.

There is a famous incident that occurred in a Swiss psychological laboratory, when a foreign student was supposed to be memorizing a list of nonsense syllables. After the list had been pa.s.sed before him many times without his giving the expected signal that he was ready to recite, the experimenter remarked that he seemed to be having trouble in memorizing the syllables. "Oh! I didn't understand that I was to learn them", he said, and it was found that, in fact, he had made almost no progress towards learning the list. He had been observing the separate syllables, with no effort to connect them into a series.

Another incident: subjects were put repeatedly through a "color naming test", which consisted of five colors repeated in irregular order, the object being to name the one hundred bits of color as rapidly as possible. After the subjects had been through this test over two hundred times, you would think they could recite it from memory; but not {347} at all! They had very little memory of the order of the bits of color. Their efforts had been wholly concentrated upon naming the bits as seen, and not in connecting them into a series that could be remembered.

The experiment described a few pages back on "paired a.s.sociates" is another case in point. The subjects memorized the pairs, but made no effort to connect the pairs in order, and consequently were not able later to remember the order of the pairs.

Many somewhat similar experiments have been performed, with the object of measuring the reliability of the testimony of eye-witnesses; and it has been found that testimony is very unreliable except for facts that were specifically noted at the time. Enact a little scene before a cla.s.s of students who do not suspect that their memory of the affair is later to be tested, and you will find that their memory for many facts that were before their eyes is hazy, absent, or positively false.

These facts all emphasize the importance of the will to learn. But let us consider another line of facts. An event occurs before our eyes, and we do notice certain facts about it, not with any intention of remembering them later, but simply because they arouse our interest; later, we recall such facts with great clearness and certainty. Or, we hear a tune time after time, and gradually come to be able to sing it ourselves, without ever having attempted to memorize it. Practically all that the child learns in the first few years of his life, he learns without any "will to learn".

What is the difference between the case where the will to learn is necessary, and the case where it is unnecessary? The difference is that in the one case we observe facts for the purpose of committing them to memory, and in the other case we observe the facts without any such intention. In both cases we remember what we have definitely observed, {348} and fail to remember what we have not observed.

Sometimes, to be sure, it is not so much observation as doing that is operative. We may make a certain reaction with the object of learning it so as to make it later, or we may make the reaction for some other reason; but in either case we learn it.

What is essential, then, is not the will to learn, but the doing and observing. The will to learn is sometimes important, as a directive tendency, to steer doing and observing into channels relevant to the particular memory task that we need to perform. But committing to memory seems not to be any special form of activity; rather, it consists of reactions that also occur without any view to future remembering. Not only do we learn _by_ doing and observing, but doing and observing _are_ learning.

Retention

We come now to the second of our four main problems, and ask how we retain, or carry around inside of us, what we have learned. The answer is, not by any process or activity. Retention is a resting state, in which a learned reaction remains until the stimulus arrives that can arouse it again. We carry around with us, not the reaction, but the machinery for making the reaction.

Consider, for example, the retention of motor skill. A boy who has learned to turn a handspring does not have to keep doing it all the time in order to retain it. He may keep himself in better form by reviewing the performance occasionally, but he retains the skill even while eating and sleeping. The same can be said of the retention of the multiplication table, or of a poem, or of knowledge of any kind.

The machinery that is retained consists very largely in brain connections. Connections formed in the process of {349} learning remain behind in a resting condition till again aroused to activity by some appropriate stimulus.

But the machinery developed in the process of learning is subject to the wasting effects of time. It is subject to the law of "atrophy through disuse". Just as a muscle, brought by exercise into the pink of condition, and then left long inactive, grows weak and small, so it is with the brain connections formed in learning. With prolongation of the condition of rest, the machinery is less and less able to function, till finally all retention of a once-learned reaction may be lost.

But _is_ anything once learned ever completely forgotten and lost?

Some say no, being strongly impressed by cases of recovery of memories that were thought to be altogether gone. Childhood experiences that were supposed to be completely forgotten, and that could not at first be recalled at all, have sometimes been recovered after a long and devious search. Sometimes a hypnotized person remembers facts that he could not get at in the waking state. Persons in a fever have been known to speak a language heard in childhood, but so long disused as to be completely inaccessible in the normal state. Such facts have been generalized into the extravagant statement that nothing once known is ever forgotten. For it is an extravagant statement. It would mean that all the lessons you had ever learned could still be recited, if only the right stimulus could be found to arouse them; it would mean that all the lectures you ever heard (and attended to) are still retained, that all the stories you ever read are still retained, that all the faces you ever noticed are still retained, that all the scenes and happenings that ever got your attention could still be revived if only the right means were taken to revive them. There is no evidence for any such extreme view.

The modern, scientific study of this matter began with {350} recognizing the fact that there are _degrees of retention_, ranging all the way from one hundred per cent, to zero, and with the invention of methods of measuring retention. Suppose you have memorized a list of twenty numbers some time ago, and kept a record of the time you then took to learn it; since when you have not thought of it again.

[Ill.u.s.tration: Fig. 53.--(From Ebbinghaus.) The curve of forgetting.

The curve sinks at first rapidly, and then slowly, from the 100 per cent line towards the zero line, 100 per cent. here meaning perfect retention, and 0 no retention.]

On attempting now to recite it, you make no headway and are inclined to think you have entirely forgotten it. But, finding the list again, you _relearn_ it, and probably find that your time for relearning is less than the original learning time--unless the lapse of time has run into months. Now consider--if no time at all were needed for relearning, because the list could be recited easily without, your retention would be one hundred per cent. If, on the contrary, it took you just as long now to relearn as it did originally to learn, the retention would be zero. If it takes you now two-thirds as long to relearn as it originally took to learn, then {351} one-third of the work originally done on the list does not have to be done over, and _this saving is the measure of retention_.

By the use of this method, the curve of retention, or curve of forgetting, as it is also called, has been determined. It is a curve that first goes down steeply, and then more and more gradually, till it approximates to zero; which means that the loss of what has been learned proceeds rapidly at first and then more and more slowly.

The curve of forgetting can be determined by other methods besides the saving method--by the recall method or by the recognition method; and data obtained by these methods are given in the adjoining tables. It will be seen that the different methods agree in showing a curve that falls off more rapidly at first than later. More is lost in the first hour than in the second hour, and more in the first week than in the second week. Few of the experiments have been continued long enough to bring the curve actually to the zero line, but it has come very close to that line in tests conducted after an interval of two to four months.

PER CENT. OF WORDS RECOGNIZED AT DIFFERENT INTERVALS AFTER BEING SEEN (From Strong)

Interval between Per cent. recognized with exposure and test certainty and correctness

15 secs. 84

5 min. 73

15 min. 62

30 min. 58

1 hour 56

2 hours 50

4 hours 47

8 hours 40

12 hours 38

1 day 29

2 days 24

4 days 19

7 days 10

The subject read a list of 20 disconnected words once through, giving careful attention to each word. Immediately at the close of the reading he performed an example in mental arithmetic, to prevent his reviewing the list of words mentally. After an interval, he was shown these {352} twenty words mixed with twenty others, and had to pick out those he surely recognized as having been shown before.

Many lists were used, for testing after the different intervals.

Five adult subjects took part in the experiment, and in all 15 lists were used with each interval; the per cents. given in the table are the averages for the 15 lists.

THE PER CENT. OF ERROR IN RECALLING DETAILS OF A PICTURE AFTER DIFFERENT INTERVALS OF TIME (From Dallenbach)

Time of test Per cent, of error Per cent of error in spontaneous in answering recall questions regarding the picture

Immediately after exposure 10 14

After 5 days 14 18

After 15 days 18 20

After 46 days 22 22

The picture was placed in the subject's hands, and he examined it for one minute, at the end of which time he wrote down as complete a description of the picture as possible, and then answered a set of sixty questions covering all the features of the picture. After five days he was retested in the same way, and again after fifteen days, etc. In one respect this is not a typical memory experiment, since the test after five days would revive the subject's memory of the picture and slacken the progress of forgetting. The experiment corresponds more closely to the conditions of ordinary life, when we do recall a scene at intervals; or it corresponds to the conditions surrounding the eye-witness of a crime, who must testify regarding it, time after time, before police, lawyers and juries. However, the subjects in this experiment realized at the time that they were to be examined later, and studied the picture more carefully than the eye-witness of a crime would study the event occurring before his eyes; so that the per cent. of error was smaller here than can be expected in the courtroom.

It must be understood that this cla.s.sical curve of forgetting only holds good, strictly, for material that has _barely_ been learned.