Voluntary Isolation of Control in a Natural Muscle Group

Front matter

— Voluntary Isolation of Control in a Natural Muscle Group

A DISSERTATION

SUBMITTED TO THE FAcuULTY OF THE GRADUATE ScHoOL of ARTS AND LITERATURE IN CANDIDACY FOR THE DEGREE OF

Introduction

I. Statement of problem. 2. Description of apparatus. 3. Statement of method.

PAR ToL Experiments on thirty-two subjects to investigate The Process of Voluntary Isolation of Control of the Movement of the Ring Finger.

Series I Uninstructed movements. No distractions or limitations. Seven subjects.

I. VERTICAL MOVEMENTS. a. Preliminary statement. b. Right hand. (1) Introspective reports. (2) Summary of individual introspections. c. Left hand. (1) Preliminary statement. (2) Introspective reports. (d) Summary of left hand movement in vertical plane. 2. LATERAL MOVEMENTS. a. Preliminary statement. b. Right hand. (1) Introspective reports. (2) Summary of right hand lateral movements. c. General summary of Series I.

Series II Distractions and limitations.

Seven subjects. 1, THE BLINDFOLD. a. Purpose.

CONTENTS b. Introspective reports. c. Summary of results of blindfold.

2. BLINDFOLD, METRONOME AND COUNTING. a. Introspective reports. b. Summary of results of blindfold, metronome and counting.

3. BLINDFOLD, RECITING POETRY WITH METRONOME. a. Introspective reports. b. Summary of introspective reports.

4. READING PROSE. a. Introspective reports. b. Summary of results of reading prose.

Senes III The Pressure Curve. 1. Group I.—S1Ix SUBJECTS, THREE INSTRUCTED TO RELAX AND THREE TO CONTRACT. a. Object of the pressure test. b. Variation of pressure. c. Summary of individual reports.

2. Group II.—SrIx suBJECTSs. a. Right hand relaxed. b. Left hand contracted. c. Effect of rate on pressure and fatigue.

3. Group III.—Srx suBjects. a. Left hand contracted. b. Right hand relaxed. c. Methods compared.

Sertes IV Fingers unsupported. 1. Preliminary statement.

2. Introspective reports. 3. Summary of introspective reports.

General summary of Part I.

CONTENTS

PA belt

Interpretation of results. . Initial cue. . Control process. . Attention. . Inhibition.

KON Ho

CONCLUSION BIBLIOGRAPHY

Preface

I take this opportunity to express my keen sense of obligation to my many friends whose help has made it possible for me to write this paper. Especially to my teachers, Professor James Rowland Angell, Professor John B. Watson, now of Johns Hopkins University, Professor George B. Mead, and Professor Edward S. Ames, I owe much for their stimulating instruction and timely encouragement. Professor Harvey Carr gave me valuable suggestions as to the construction of apparatus.

I am also much indebted to my laboratory assistants, Mr. George H. Payne, Mr. Mark H. May, and Mr. George W. Middleton, who served in double capacity, as subjects, and, in the tests on the writer, as experimenters. To the students and teachers who gave so much of their time in serving as reagents in my experiments, I am particularly grateful.

My wife has given me great assistance in the reading, translating, and interpreting both German and French literature, treating of the problems discussed in the following pages.

INTRODUCTION

STATEMENT OF PROBLEM

The investigation recorded in this paper was begun in the fall of 1909 and was continued through the academic years of 1909- Ig11 and the summer of 1910. Publication of the results has been unfortunately delayed. It was hoped that by a long series of tests involving a careful examination of the voluntary control processes of the movement of the ring finger in both vertical and horizontal planes, and by a careful investigation of the inhibitory processes of the other fingers, some additional light might be cast both upon the problem of voluntary control of movement and upon the nature of the process of inhibition. The problem involved the determination of the mental antecedents of the movement, the mental concomitants which controlled it and the nature of the psychical processes involved in inhibition. The working out of these problems raised questions as to the nature of automatic action and imageless thought.

Previous experimenters have studied the growth of control in muscles over which normally we have little or no mastery, like the muscles of the external ear; or the methods of gaining new dexterities like type-writing with muscles over which we have a high degree of control. The present experiments differentiate themselves from both the preceding cases in dealing with the isolation of control over special muscles in a group which ordinarily contract together. Movement of the ring finger tends strongly to carry with it movement of the adjacent fingers. Our procedure, as will be seen, involves the suppression of the movement of these neighboring fingers and the development of the coordinations of the ring finger alone.

As the solution of our problem depended largely upon the introspective reports of the subjects who acted as reagents in the experiments, it was thought best to select persons who had had work in psychology. The persons serving as subjects were either instructors, graduate students in psychology, or senior college students that had taken one or more courses in the department. Twenty-two men and ten women were used and it may be said at once that no characteristic sex differences appear in the results.

In general outline the experiments fell into four series. In the first series, movement went on without any instruction as to method and without any limitation of the governing senses. Tests of the voluntary control of the fourth, or ring finger, of right and left hands were made for both vertical and lateral movements.

In the second series of experiments, movement was accompanied by a limiting or distracting process. This distracting process consisted in (1) the use of the blindfold; (2) counting aloud blindfolded; (3) reading aloud; (4) reciting a piece of poetry while blindfolded; and (5) attending to the tick of a metronome. The movement in each case was undirected as to method of control, but directed as to amplitude, and as to rate, when the metronome was used.

In the third series of experiments, tests of the pressure of the middle and little fingers were made. In this series the vertical movements only were used. One half of the subjects were instructed to relax and the others to hold the fingers rigid, while the fourth finger moved.

In Series I, II, and III, the hand was supported on a table, so it was thought best to test the control of the fingers without any support for the hand save the carpal joint. Therefore, in the fourth series, the forearm was placed in an arm-rest so that it was supported just above the carpal joint, thus leaving the hand free. The subjects were then instructed to relax the fingers.

DESCRIPTION OF APPARATUS

The tridimensional apparatus for registering finger movement was not suitable for the purpose of our investigation, so we devised one apparatus for registering finger movements in the vertical plane and another for registering movements in the horizontal plane. Two drums, 30 centimeters in length, were placed three meters apart on a long table and joined by a smoked paper belt; this enabled us to use more than six meters of kymograph paper without change, and provided space enough to register the movements of the fingers of six reagents. The progress of each subject was easily followed from day to day, and the records of the movements relative to one another could be seen at a glance. The two drums were rotated by means of a small electric motor and their rate was controlled by the use of a rheostat and a Pillsbury speed reducer, to which a belt running around each drum was attached. The registering apparatus was as follows: (Fig. I) a small wooden box (X), 25 cm. x 12 cm. x 12 cm., was

Ficure 1 placed on the carriage of the kymograph. In each end of this box were three rectangular holes, 15 mm. x 6 mm., through which ran three bars (1, 2, 3), 40 cm. xX 15 mm. x 6 mm., so adjusted that they could be easily moved back and forth in the horizontal plane; to these bars cords were attached and so directed by the use of pulleys that when the fingers were placed in thimbles (A, B, C) fastened to the other ends of the cords, any movement of the finger in the vertical plane pulled the bar in the horizontal plane. Weights attached by means of cords to the other ends of the bars pulled them back in place. Small holes, 3 mm. in diameter, were bored in the bars and in these were placed small pegs (a, b, c), tipped with fine wire, ground to a point, touching the smoked paper on the drum. These pegs registered the finger movements. Seconds were recorded by an electric time marker connected with a pendulum.

For recording movements in the horizontal plane, the following attachment was used in place of the box and bars described above: (Fig. IL)-a small box (4h,-1lo cm. x 10 ¢m.-x 20 cm;

Ficure II attached to the carriage of the kymograph, served as a support upon which to fasten a wooden block (Y), 2 cm. x 8 cm. x 10 cm., on which markers were fastened by means of screws (1, 2, 3) which served as pivots on which the markers moved. The pivots were at a distance of 20 cm. from the small end of the rods and 10 cm. from the ends to which the upright rods were attached at right angles. The horizontal rods (a, b, c), which served as markers, were made of wood, 2 cm. x 2 cm. x 30 cm., and tapered toward the ends in which were placed small wires, 8 cm. long, curved slightly toward the ends, which were ground to a point, so that they would mark readily on the drum. The upright rods worked on wooden pegs (4, 5, 6) as pivots running through the rods at a distance of 10 cm. from their upper ends and fastening them to the end of the box. These upright rods were made of wood, 2 cm. x 2 cm. x 40 cm., and to their lower ends thimbles (A, B, C) were attached and so adjusted as to fit the little, ring, and middle fingers when the hand lay flat on the table. The thimbles were 2 mm. above the surface of the table, so that the fingers did not touch the table during the lateral movement. This arrangement permitted the fingers and the markers to move in the same direction.

The apparatus used to record the pressure curve in Group I is shown in Figures IIIA, IIIB, and IV. T (Fig. IIIB) is a box,

Ficure III] A

I5 cm. x 30 cm. x 50 cm.; A and C are round pegs, I cm. in diameter, fastened in pistons of plaster of paris (B in Fig. IV), 5 cm. long and 2.5 cm. in diameter. The pistons worked in glass tubes, 10 cm. in length, and rested on coiled steel springs, 5 cm. long and 1.5 cm. in diameter. The glass tubes were fitted into tif:

[WR ]

Ficure III B holes bored half way through the bottom of the box, and made air-tight by the use of sealing wax; through the center of the base of each large glass tube a small glass tube C (Fig. IV) I cm. in diameter, was inserted; the small tube extended up into the large tube through the center of the steel spring 3 cm., and distance of 3 cm. below the bottom of the box to receive the rubber tube running to the tambours A and C (Fig. IIIB). The small tubes were made air-tight by means of sealing-wax. The pegs A and C (Fig. IIIB) extended 2 mm. above the top of the box. The pistons were made air-tight by the use of oil. In this series, Group I, a vertical drum (D) and a recording apparatus (a, b, c), attached to vertical bars controlled by weights were used, as shown in Fig. IIIB. In Groups II and III a horizontal drum was used.

STATEMENT OF METHOD

The subject sat on a laboratory stool at the end of a table, placed his little, ring, and middle fingers in the thimbles with aes J

Ficure 1V the palm of his hand laid flat on the table, and let his arm rest comfortably thereon. No directions were given in regard to the position of the other members of the body. The signal to move was given by means of a small electric bell. A few seconds before the signal to move, the signal “ready” was given.

The ring finger was selected first, because of the comparative ease with which apparatus could be adjusted to it, and because of its convenience for experimentation. In the second place, it usually has the least independent action of any of the fingers, hence would yield the best results for this experiment.

The subjects were tested daily for eighty seconds, and the tests were continued until the control process was practically perfect in each series. Conditions were kept as nearly constant as possible throughout the experiment. The test was given at the same hour each day. Any variation in the health or condition of the subject was noted.

We began the first series by requiring the reagent to move for one hundred seconds at each test; this was too long to secure the best results, as the fingers became so fatigued that control became impossible, so we reduced the time to eighty seconds. In the first series, we let each subject choose his own rate at first. We next tried various rates of 60, 70, 80, 90, and 100 movements per minute. The results are recorded below.

The objective side of the experiment consisted of a curve recorded, as already indicated, on the belt of smoked paper, passing over the two drums, by markers attached indirectly by means of cords, pulleys, and thimbles to the fingers. The time of the test and the position of the fingers during the same are accurately recorded. This method permits a careful study of the movement and control of each subject and his progress from imperfect to perfect control. The kymographic curves recorded by the six observers on the paper ran parallel to each other and each record was continued from day to day so that it was quite easy to follow the progress of the subjects.

Immediately after each test, the subjects were asked to describe what took place in their minds from the giving of the signal to start until the close of the test. As the experiment progressed, our questions were made more searching, and so the introspective reports are more definite. The nature of the initial cue, the control factor in the moving finger and the other fingers, the focal point of attention, were searched for, and usually they were clearly and definitely given by the subjects in their introspective reports. A study of these introspections enabled the writer to determine their respective mental types. The immediate mental antecedents operative in initiating the movement, we term the “cue”. The mental concomitants of the movement, which seemed to guide the same, are termed “control processes”’.

PARI. I

SERIES ].—UNINSTRUCTED MoveMEnTs. No DisTRACTIONS OR LIMITATIONS—SEVEN SUBJECTS I. VERTICAL MOVEMENTS a. Preliminary statement

It is not our purpose to make an historical study of the various theories, of volition, but rather an introspective study of voluntary motor control under experimental conditions, checked by objective data. We have laid special emphasis upon a study of the initiatory cue of the movements made and the control process of the movement after it has been initiated. These processes vary according to the mental imagery of the different subjects, and also according to the degree of control acquired by each. Several of the subjects reported that the could vary the initiatory cue at will, by concentrating the attention upon the visual image of the movement to be made or upon the kinaesthetic image, or even upon the signal. But as a rule the mental type of each reagent determined his initiatory cue and his control process also.

The records of this series were made with the eyes of the subjects open and without any restrictions whatever. The reagent, having taken the position described in the previous section, was directed at a given signal to move his ring finger, with the metacarpo-phalangeal joint as a pivot, as high as he could without moving the other fingers. He was told to control his other fingers—that is, he was to keep the ring finger moving and the other fingers on the table. The records of the finger movements of the subjects were small at first and revealed many movements of the middle and little fingers. Practice rapidly lessened the number of these accessory movements in each test and increased the extent of movement of the ring finger. The series was continued until the latter movement was practically automatic, or until the control was substantially perfect. Even after the control had become perfect, fatigue, headache, nervousness, or worry on the part of the subject were followed by irregular reactions.

The curves at the beginning of the first series show an irregular record, both in extent and in rate. The height of the curves is small and irregular in all of these early records except two; two subjects moved rapidly from the first, but their control of the other fingers was slight. They desired to make a large movement and so did not emphasize control, and the result shows that the little finger and the middle finger move in rhythm with the ring finger. The other four reagents made smaller movements with the ring finger, but show better control of the other fingers.

Three of the subjects had a tendency to raise the hand from the table at the metacarpo-phalangeal joint; this placed the hand in a strained position, but enabled the reagent to make a more extended movement of the ring finger and gave him better control of the other fingers as he was enabled in this way to place them under more muscular tension. Two of the subjects broke up this habit after several weeks’ practice, but the other kept it for nearly four months.

Five of the subjects took a slightly leaning posture toward the hand that was active in the experiment. The whole organism was adjusted to this one activity. Sometimes the other hand would move as if it too were engaged in the work. Adjustment and tension of.the muscles were observed quite frequently in the non-acting hand. This fact emphasizes once more the law of excess discharge, the tendency of the motor impulse to be drained off into channels other than those immediately essential and especially those of an anatomically symmetrical kind. During the first set of tests one reagent kept time by nodding her head as she moved her finger and counted one, two, etc., with each stroke of the finger. She gained perfect control after a few days’ practice. The movement of the ring finger was not so extensive as that of the records of the other reagents, but her control of the other fingers was perfect after a few tests. Her speedy control was presumably due to the fact that she had had daily piano practice from childhood.

VOLUNTARY ISOLATION OF CONTROL II

The first and second phalangeal joints of the fingers of three of the subjects were loose, and so the curves representing their records do not show the actual movements that took place, while using the metacarpo-phalangeal joint as a pivot. This difficulty was overcome after considerable practice. Finally the subjects were able completely to relax the muscles and tendons controlling the movements of the fingers, and then the control of the fingers to be kept quiet was perfect, and the movement became practically automatic.

Bair’ says that learning to make a voluntary movement is largely a matter of learning to relax. Relaxation is first learned by withdrawing the attention from the movement just effected. A voluntary attempt to relax will merely increase tension. Our experiments show that the inhibition of the movement of a member of a group is first learned by keeping the member rigid by muscular tension and secondly by drawing the attention from it. The latter is the method by which complete relaxation is acquired. The kind of material in the focus of attention, which. serves as initial cue and as control in the moving process is determined by the mental type of the reagent. We shall consider this more fully below, where we describe and analyze the introspections of the subjects that acted as reagents in our experiment.

In the following introspective accounts, tests of different chronological position in the series are presented in order that they may show a greater variety of conscious phenomena at the different stages of the problem. The experimenter rigorously avoided suggesting the special things reported. The terms used in the introspective accounts have their ordinary meaning. Kinaesthetic sensations are feelings of tension, movement, and the like, resident in the moving member and due to the latter’s movement. Kinaesthetic images? are memory images in which kinaesthetic sensations prevail. Auditory image and visual image are used in a similar manner. Visual-kinaesthetic, auditory-kinaesthetic and auditory-visual, indicate the fact that both elements were present, the more vivid element being placed first.

1 Psychological Review Vol. VIII, 1901, p. 470.

2 Whether these are pseudo-images, in reality sensations, need not be discussed. They were reported by the reagents as images and may so stand here.

b. Rrgut Hanp

(1) Introspective Reports Subject P.

First Trial—The initial cue was a visual-kinaesthetic image and visual and kinaesthetic perceptions were the control processes. Attention on extent of movement of ring finger. Attention oscillated. Saw little finger raised, attention was attracted to it, and then followed an irregular movement of ring finger. The latter became fatigued toward the close of the experiment, and the extent of movement became less, and the rate irregular. Motor control was lost after fatigue became great. Thought of record that he was making on the.drum.

Fiftieth trial—tThe initial cue was a visual image of the anticipated movement. Watched the members of the group. Attention was centered on control of all the fingers rather than on extent of movement. Paid, however, little attention to anything. Movement was practically automatic. Heard a locomotive whistle.

Subject B.

Fourth trial—Visual image of movement was the initial cue. Visual-kinaesthetic perception was the control process. Tried to concentrate attention on the ring finger and its movement. Little finger was drawn up by the weight which pulled the recorder back into position. Attention oscillated to the little finger. Middle finger moved next and drew attention to it. Was conscious of making a poor record which seemed to distract attention and cause embarrassment. Conscious of fatigue in little finger.

Siatieth trial—Had a vivid visual image of the movement before the finger began to move. Attention on regular movement of ring finger and control of the other fingers. Visual perception of the moving finger controlled its movement both as to extent and regularity. Conscious of good control.

Second trial.—Visual idea of the movement was the initial cue. Movement was controlled by visual perception of the ring finger. Attention on extent of movement of ring finger. Raised little finger once. This attracted attention to it in order to put it in position. No fatigue, but conscious of strain in arm.

Stxrtieth trial_—Visual-kinaesthetic ideational cue. Attention on extent and regularity of movement which was guided by muscular feeling in the ring figner. Some muscular strain in hand. Little finger moved slightly ; watched it to keep it down.

Subject G.

Eighth trial.—Kinaesthetic image of the movement was the initial cue. Attention on movement and on trying to keep the other fingers still. They both moved and attention was attracted to them. When attention was focused on putting little finger down on the table, the ring finger did not make its usual record. Was conscious of this at the time but unable to prevent it. Felt pain in the region of the scapula. Conscious of effort in the ring finger.

Fiftieth trial—Kinaesthetic image was the initial cue. Arm | ached at the beginning in making the adjustment. Attention was centered on keeping other fingers down and on trying to make a good record. Felt that she was making a good record and wondered why. Tried to relax arm. Kinaesthetic perception of the moving finger.

Subject M.

First trial—kKinaesthetic image of ring finger preceded the movement which was controlled by resident sensations. Tried to move ring finger. No thought of other fingers. Felt that ring finger would not move rightly.

Fiftieth trial—vVisual-kinaesthetic imaginal cue. Visual-kinaesthetic perception of ring finger controlled the movement. Attention on moving more slowly than usual and also on extent. Just let the finger “go itself’. Had no difficulty in keeping the other fingers from moving. Did not keep attention on the finger all the time toward the close of the test. Movement was practically automatic.

Subject K.

First trial—Visual image preceded the movement which was controlled by visual perception of ring finger. Attention was focused on the movement of ring finger, but it oscillated to middle finger and to little finger. Felt fatigue in forearm.

Thirtieth trial_—Visual image initiated the movement. Attention on extent of movement and on the perfect control of the other fingers. Had a visual image of the record as it would appear on the drum. Conscious of perfect control.

(2) Summary of Individual Introspections The introspections reported by the reagents show that attention was generally focused upon the idea of the extent of movement of the ring finger. The subjects as a rule emphasized extent of movement too much, and consequently they were unable completely to inhibit the movements of the middle and little fingers.

M. reported that he could control his movement better when he moved the finger rapidly—at the rate of sixty or seventy times per minute. He reported also that this gave him better control of the other fingers. This report is confirmed by a study of the curve recorded on the kymograph.

P., on the other hand, moved deliberately and soon gained complete control of his fingers. In the first four or five tests, he reported that he had difficulty in getting definite resident sensations in the moving finger, and the record shows a corresponding irregularity in the movements of the ring finger and inability to inhibit the movements of the other fingers. After a few tests he focused his attention with regularity on extent of movement, and was able to disregard the other fingers. He said that he had no thought of them. When attention was focused completely upon the movement of the ring finger, its record was even and regular and the infibition of the other fingers was complete.

G. was ambitious from the start to make a large movement. Her attention was focused on extent of movement rather than on voluntary control. It took many trials to eliminate the movements of her other fingers. This was due in part to the size of the thimble which was too large for her ring finger and so slipped at times, thus causing the other fingers to move.

During the first set of this series G. reported that while her attention was focused on extent of movement, the latter was controlled by a visual perception of it. Whenever her other fingers were drawn up by force of the weights or moved in the effort to move the ring finger, if attention was attracted to the little finger or the middle finger, it was after the movement had taken place. Sometimes, one of the other fingers would be pulled up gradually by the weights without any knowledge on the part of the subject of the position of the finger; but in the effort to move the ring finger or in the effort to make sure that the other finger was down, the latter moved and then attention was directed to it. Quite frequently the record shows that the other fingers moved without the knowledge of the subject.

G. reported muscular fatigue and strain in the muscles of the forearm just below the elbow and in the muscles of the arm in the region of the scapula, whenever the test was continued longer than eighty seconds. She reported also sensations of strain in tendons of fingers and hand. When her attention was strongly focused on the movement of the finger of the right hand, she reported a twitching of the muscles in the left forearm. Extent of movement was judged by the tendinous strain in the moving finger. :

S. was able to make a large movement from the first; this was largely due, as we have said above, to the shape of his hand and fingers. When the palm of his hand was placed flat on the table, the tips of his fingers, when in their normal position, were not touching the table. This fact made it more difficult for him to control his other fingers, when he was moving his ring finger, because his joints are loose and permit the fingers to bend back readily at the phalangeal joints. It took him a long time to overcome this.

His control process was a visual image of the curve that he was making on the drum by the movement of the ring finger. A visual image of the record guided his movements both as to extent and regularity. Only once during Series I, which was continued for two months and a half, did this subject report kinaesthetic perception—the feeling of the moving finger—as the process which guided his movement. His movement finally became semi-automatic and his control perfect for several days at a time and then a day would come in which he could not inhibit the movements of the other fingers. This could usually be accounted for by overwork—mental or physical. He always reported attention attracted to the other fingers after their movement. He frequently reported strain in the tendons of the back of the hand and in the moving fingers. Toward the close of this series his movement was so nearly automatic that he gave little attention to the fingers, and so reported only very vague visual images of his movement.