CHAPTER VI

ACQUIRING MOTOR CONTROL

Main points of the chapter. 1. Acquiring motor control is important in gymnastic and shop activities, in dancing, in musical technique, and in the pronunciation of a foreign language.

2. Psychological experiments upon motor control furnish few suggestions concerning methods of instruction, because they have ordinarily been conducted upon uninstructed learning.

3. There is a great mass of empirical discussion concerning the best methods of instruction to be used.

4. Practically the only point upon which there is agreement is the necessity of good form. There is often radical disagreement as to what good form is in any given case.

5. Studies in the anatomy and operation of the vocal apparatus in producing sound have led to an exaggerated emphasis upon instruction concerning the vocal movements in learning to sing and in learning to pronounce a foreign language.

Motor control important in various activities. As stated in the preceding chapter, the acquisition of motor skill is the principal type of learning involved in gymnastic exercises, in dancing, in shop activities, in some laboratory exercises, in mastering certain forms of musical technique, and in the pronunciation of a foreign language. Typical examples in gymnastics are learning to swing Indian clubs, to fence, and to do the kip on the horizontal bar. In the laboratory and shop, learning to bend and blow glass, to dissect animals, to manipulate pie crust, to file iron, and to plane wood are examples. Acquiring skill in fingering in playing the piano or violin and learning to say ich or böse in German are examples from musical technique and the pronunciation of a foreign language respectively.

Questions of method involved. In determining the best methods to be used in learning most economically and effectively to make the correct movements in these various activities the following special questions arise:

I. Are there certain best methods of performing a given act, to which the learner's attention should be directed?

2. (a) How useful are verbal directions or instructions concerning how to make the movements? (b) How useful is imitation?

3. Should the learner's attention be centered on the movement or on its objective result?

4. To what extent is it necessary to depend upon the method of trial and accidental success?

5. To what extent is it profitable to give separate attention to the learning of the elementary movements which constitute a complex act?

Experimental investigations have given little assistance. These questions could easily be experimentally investigated in psychological laboratories, because the conditions of learning in the case of motor skill are relatively easy to determine and control. A scientific experimental investigation in any case aims to simplify, control, and modify in certain definite ways the conditions which determine a given event or series of events, and to measure exactly the effects of the modifications. In some types of learning (for example, in the case of acquiring skill in reflective thinking or in expression, or in acquiring habits of enjoyment) the processes of learning and the determining conditions are so complex that it is a difficult problem to control and measure them experimentally; but in the case of certain relatively simple acts of motor skill the experimental investigations are easily conducted, and a number have been made. Unfortunately, however, most of these have concerned undirected or uninstructed learning; that is, the learner has been left largely to himself to acquire skill in the act under investigation. Consequently, little

light has been thrown upon the relative efficiency of various forms of instruction in modifying the learner's progress.

Learning to juggle balls a typical example of experimentation. A good example of the investigation of learning to perform a complex act is E. J. Swift's work on the tossing and catching of balls. Five persons, technically known as "subjects," practiced for a good many days, and the results of the practice were definitely measured. Each subject juggled two balls; that is, he tried to keep both going with one hand, catching and throwing one while the other was in the air. There were three principal aspects or elements in the acquisition of skill in the performance: namely, (a) acquisition of general control in throwing; (b) sureness in catching; (c) use of some special method of throwing so as to avoid collisions.

If we consider Swift's experiment in terms of the general questions raised above on page 99, we may note the following points:

1. Better methods of throwing and catching important. There are certainly better if not best methods of throwing and catching. For example, to avoid collisions, it is better to give the balls a circular motion, so that they go up on one line and come down on another. Moreover, of the possible circular motions it is better to use one from right to left instead of one in which the balls are thrown up at arm's length and take such a circular course as to fall close to the body. Hence a subject who hit upon the right-to-left or left-to-right circular movement early in the experiment made rapid progress. Likewise, in catching, it is better to let the ball fall into the palm held horizontally in front of the body than to catch it "with the hand high in the air and the palm forward and almost perpendicular," as was done by one of the subjects, with the result that he made relatively little improvement during the month that he used this second method.

2. Verbal directions help in this case. The possibility of profiting by verbal instructions, supplemented perhaps

by imitation, seems perfectly evident in a case like this. Hence Swift makes the following statement:

We see in this the value of suggesting good ways of doing things while the learning is still in its early stages. If the learner goes on [without instruction], he will finally develop a plan of his own, but only after a good deal of wandering, and even then it may not be the best. (10: 182)

3. Attention sometimes on movement, sometimes on result. In some cases it would seem that the learner's attention might with advantage be centered on the movement, and in other cases on the objective result. For example, in the case of the poor method of catching described above, the substitution of the better method would seem to involve centering the attention on the movement or position of the hand. This does not mean that the subject would look at his hand, but its position would be kept clearly in mind in modifying the method. On the other hand, in the adoption of the right-toleft circular method of throwing, attention would almost certainly be centered on the objective result, namely, the path followed by the ball.

4. Trial and accidental success used in finer adjustments. After full allowance is made for the possibilities of verbal instruction and imitation in assisting the learner to use the best methods, there remains a very large rôle to be played by the method of trial and accidental success. This becomes evident in the case of tossing and catching balls when attention is called to the large part played by the fingers and wrist in skillful juggling. The finer adjustments made by these parts do not come clearly to mind at any stage in the learning, yet they are most important in catching and throwing the ball skillfully.

5. Separate training on elements not valuable here. There can be little question concerning the desirability or undesirability of giving separate training on each of the

elements which constitute the complex act in this case. By omitting catching for the time being, it would be possible to give separate attention to throwing, and vice versa; but it is doubtful whether anyone would advocate this. To be sure, efficiency in the act as a whole depends to a large extent upon efficiency in each part of the act. Hence an individual might throw well but his total efficiency remain low because he caught poorly. But since his catching is always to follow upon his throwing, it would seem best to strive to improve his catching in connection with the throwing instead of separately. Here the sequence is so intimate, or so certain, that separate mastery of one of the elements would seem to be uneconomical. There may be cases, however, which we shall discuss later, in which separate attention to the elements of a complex movement may seem to be justified.

Other investigations illustrating trial and error. — In order to bring out more clearly the part played by the method of trial and accidental success in adult learning we shall study briefly two other examples from experimental psychology. The first is an experiment conducted by J. H. Bair on learning to move the ears, and the second is W. F. Dearborn's description of the acquisition of skill in mirror writing.

Learning to move the ears a good example. - Learning to move the ears is for most adults an almost entirely novel feat. It is learned by securing separate control of certain movements of the ears which may occur when certain general movements of the head muscles are made, including raising the brows. That is, the movement which it is desired to control is first made as a part of a general diffuse movement of the neighboring muscles, and gradually by a process of selection and elimination comes to be made by itself. The same process of selection from a more diffuse movement occurs in learning to alternate the ears, in learning to raise the brows without moving (or innervating) the ears, and in learning to raise one brow independently of the other.