1. Outline the chapter.

2. The rating of images belonging under different senses. Try to call up the images prescribed below, and rate each image according to the following scale:

_3. . . . The image is practically the same as a sensation, as bright, full, incisive, and, in short, possessed of genuine sensory quality_.

_2. . . . The image has a moderate degree of sensory quality_.

_1. . . . The image has only faint traces of sensory quality_.

_0. . . . No sensory image is called up, though there was a recall of the fact mentioned_.

Call up visual images of: a friend's face, a sun flower, a white house among trees, your own signature written in ink.

Call up auditory images of: the sound of your friend's voice, a familiar song, an automobile horn, the mewing of a cat.

Call up olfactory images of: the odor of coffee, of new-mown hay, of tar, of cheese.

Call up gustatory images of: sugar, salt, bitter, acid.

Call up cutaneous images of: the feel of velvet, a lump of ice, a pencil held against the tip of your nose, a pin p.r.i.c.king your finger.

Call up kinesthetic imagery of: lifting a heavy weight, reaching up to a high shelf, opening your mouth wide, kicking a ball.

Call up organic imagery of: feeling hungry, feeling thirsty, feeling nausea, feeling buoyant.

In case of which sense do you get the most lifelike imagery, and in case of which sense the least. By finding the average rating given to the images of each sense, you can arrange the senses in order, from the one in which your imagery rates highest to the one in which it rates lowest. It may be best to try more cases before reaching a final decision on this matter.

3. Verbal imagery. When you think of a word, do you have a visual, auditory, or kinesthetic image of it--or how does it come?

4. In reading, notice how much imagery of objects, persons, scenes, sounds, etc., occurs spontaneously.

5. a.n.a.lysis of a revery. Take any object as your starting point, and let your mind wander from that wherever it will for a minute.

{387} Then review and record the series of thoughts, and try to discover the linkages between them.

6. Free a.s.sociation experiment. Respond to each one of a list of disconnected words by saying the first word suggested by it. Use the following list: city, war, bird, potato, day, ocean, insect, mountain, tree, roof.

7. Controlled a.s.sociation, (a) Use the same list of stimulus words as above, but respond to each by a word meaning the _opposite_ or at least something contrasting, (b) Repeat, naming a _part_ of the object designated by each of these same words, (c) Repeat again, naming an _instance_ or variety of each of the objects named. Did you find wrong responses coming up, or did the mental set exclude them altogether?

8. Write on a sheet of paper ten pairs of one-place numbers, each pair in a little column with a line drawn below, as in addition or multiplication examples. See how long it takes you to _add_, and again how long it takes to _multiply_ all ten. Which task took the longer, and why? Did you notice any interference, such as thinking of a sum when you were "set" for products?

9. Free a.s.sociation test for students of psychology. Respond to each of the following stimulus words by the first word suggested by it of a psychological character:

conditioned objective gregarious delayed correlation fear negative end-brush mastery rat pyramidal submission stimulus semicircular feeling-tone subst.i.tute kinesthetic primary axon advantage tension synapse field blend autonomic quotient rod retention limit fovea nonsense apraxia saturated higher thalamus red-green paired organic complementary economy tendency after exploration preparatory basilar recency native fluctuation curve endocrine dot perseveration expressive Binet synesthesia James-Lange frontal facilitation flexion overlapping

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REFERENCES

On imagery, synesthesia, etc., see Gallon's _Inquiries into Human Faculty and Its Development_, 1883, pp. 57-112; and for more recent studies of imagery see G. H. Betts on _The Distribution and Function of Mental Imagery_, 1909, and Mabel R. Fernald on _The Diagnosis of Mental Imagery_, 1912.

On the diagnostic use of the a.s.sociation test, an extensive work is that of C. G. Jung, _Studies in Word-a.s.sociation_, translated by Eder, 1919.

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CHAPTER XVI

THE LAWS OF a.s.sOCIATION

AN ATTEMPT TO REDUCE THE LEARNING PROCESS TO ITS ELEMENTS

This is a very serious occasion. What we now have before us is one of the great outstanding problems of psychology, a problem that has come down through the ages, with succeeding generations of psychological thinkers contributing of their best to its solution; and our task is to attack this problem afresh in the light of modern knowledge of the facts of learning and memory. We wish to gather up the threads from the three preceding chapters, which have detailed many facts regarding learned reactions of all sorts, and see whether we cannot summarize our acc.u.mulated knowledge in the form of a few great laws. We wish also to relate our laws to what is known of the brain machinery.

The Law of Exercise

Of one law of learning, we are perfectly sure. There is no doubt that the exercise of a reaction strengthens it, makes it more precise and more smooth-running, and gives it an advantage over alternative reactions which have not been exercised. Evidence for these statements began to appear as soon as we turned the corner into this part of our subject, and has acc.u.mulated ever since. This law is sometimes called the "law of habit", but might better be called the "law of improvement of a reaction through exercise", or, more briefly, the "law of exercise".

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The law of exercise is very broad in its scope, holding good of life generally and not alone of mental life. Exercise of a muscle develops the muscle, exercise of a gland develops the gland; and, in the same way, exercise of a mental reaction strengthens the machinery used in making that reaction.

Let us restate the law in terms of stimulus and response. _When a given stimulus arouses a certain response, the linkage between that stimulus and that response is improved by the exercise so obtained_, and thereafter the stimulus arouses the response more surely, more promptly, more strongly than before.

Under the law of exercise belong several _sub-laws_ already familiar to us.

1. The law of _frequency_ refers to the c.u.mulative effect of repeated exercise. The practice curve gives a picture of this sub-law, showing how improvement with repeated exercise of a performance is rapid at first and tapers off into the physiological limit, beyond which level more repet.i.tion cannot further improve the performance. The superiority of "s.p.a.ced study" over uns.p.a.ced means that exercise is more effective when rest periods intervene between the periods of exercise; as this is notoriously true of muscular exercise, it is not surprising to find it true of mental performances as well.

2. The law of _recency_ refers to the gradual weakening of the machinery for executing a reaction when no longer exercised; it is the general biological law of "atrophy through disuse" applied to the special case of learned reactions. As exercise improves the linkage between stimulus and response, so disuse allows the linkage to deteriorate. This law is pictured more completely and quant.i.tatively in the curve of forgetting.

Really, there are two laws of recency, the one being a {391} law of retention, the other a law of momentary warming up through exercise.

The law of retention, or of forgetting, is the same as atrophy through disuse. The warming-up effect, well seen in the muscle which is sluggish after a long rest but becomes lively and responsive after a bit of exercise, [Footnote: See p. 73.] appears also in the fact that a skilled act needs to be done a few times in quick succession before it reaches its highest efficiency, and in the fact of "primary memory", the lingering of a sensation or thought for a few moments after the stimulus that aroused it has ceased. Primary memory is not strictly memory, since it does not involve the recall of facts that have dropped out of mind, but just a new emphasis on facts that have not yet completely dropped out. Warming up is not a phenomenon of learning, but it is a form of recency, and is responsible for the very strong "recency value" that is sometimes a help in learning, [Footnote: See p. 345.] and sometimes a hindrance in recall.

[Footnote: See p. 356.]

3. The law of _intensity_ simply means that vigorous exercise strengthens a reaction more than weak exercise. This is to be expected, but the question is, in the case of mental performances, how to secure vigorous exercise. Well, by active recitation as compared with pa.s.sive reception, by close attention, by high level observation.

In active recitation, the memorizer strongly exercises the performance that he is trying to master, while in reading the lesson over and over he is giving less intense exercise to the same performance.

The Law of Effect

We come now to a law which has not so accepted a standing as the law of exercise, and which may perhaps be another sub-law under that general law. The "law of effect" may, however, be regarded simply as a generalized statement of {392} the facts of learning by trial and error. The cat, in learning the trick of escaping from a cage by turning the door-b.u.t.ton, makes and therefore exercises a variety of reactions; and you might expect, then, in accordance with the law of exercise, that all of these reactions would be more and more firmly linked to the cage-situation, instead of the successful reaction gradually getting the advantage and the unsuccessful being eliminated.

The law of effect, stated as objectively as possible, is simply that the successful or unsuccessful outcome or _effect_ of a reaction determines whether it shall become firmly linked with the stimulus, or detached from the stimulus and thus eliminated. _The linkage of a response to a stimulus is strengthened when the response is a success, and weakened when the response is a failure_.

Success here means reaching the goal of an awakened desire or _reaction-tendency_, and failure means being stopped or hindered from reaching the goal. Since success is satisfying and failure unpleasant, the law of effect is often stated in another form: a response that brings satisfaction is more and more firmly attached to the situation and reaction-tendency, while a response that brings pain or dissatisfaction is detached.

The law of effect is a statement of fact, but the question is whether it is an ultimate fact, or whether it can be explained as a special case of the law of exercise. Some have suggested that it is but a special case of the sub-law of frequency; they call attention to the fact that the successful response must be made at every trial, since the trial continues till success is attained, whereas no one unsuccessful response need be made at every trial; therefore in the long run the successful response must gain the frequency advantage.