Certain physiological and motor reactions to disorganizing stimuli with special reference to their use as aids in the prediction of flying ability

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NORTHWESTERN UNIVERSITY

CERTAIN PHYSIOLOGICAL AND MOTOR REACTIONS TO DISORGANIZING STIMULI WITH SPECIAL REFERENCE TO THEIR USE AS AIDS IN THE PREDICTION OF FLYING ABILITY A DISSERTATION SUBMITTED TO THE GRADUATE SCHOOL IN PARTIAL FULFILLMENT OF THE REQUIREMENTS for the degree

DOCTOR OF PHILOSOPHY

SCHOOL OF EDUCATION

BY SOL LOUIS GARFIELD

EVANSTON, ILLINOIS JUNE, 1942

ProQuest Number: 10101431

All rights reserved INFORMATION TO ALL USERS The q u a lity o f this re p ro d u ctio n is d e p e n d e n t u p o n th e qua lity o f th e c o p y subm itted. In th e unlikely e v e n t th a t th e au th o r d id n o t send a c o m p le te m anuscript a n d th ere are missing pages, these will b e n o te d . Also, if m aterial had to b e re m o ve d , a n o te will in d ic a te th e d e letion .

uest, ProQuest 10101431 Published by ProQuest LLC (2016). C o p yrig h t o f th e Dissertation is held by th e Author. All rights reserved. This work is p ro te c te d against unauthorized co p y in g under Title 17, United States C o d e M icroform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106 - 1346

i

ACKN0W1XDGMENTS

The writer wishes to express his gratitude and thanks to several persons who aided him in carrying the following research through to completion.

First of all, the writer wishes to express

his gratitude to his examination committee in the School of Educa­ tion for allowing him to pursue the present research.

Secondly,

he desires to acknowledge his thanks to Professor A. R. Gilliland who suggested the study, and to Professor Paul A. Witty who cooperated in directing the study.

Special thanks are also due to

H. M. Wisely who worked with the present writer throughout the entire research project.

Finally, the writer is indebted to the

National Research Council, Division on the Selection and Training of Aircraft Pilots, for their consent to use the data from the Northwestern University Research Project for the present thesis.

482446

11

PREFACE

This dissertation represents a part of a larger research project being developed at Northwestern University to aid in the selection of pilots.

This project has been carried on for over a

year under the direction of A* R. Gilliland by means of several grants from the committee on Selection and Training of Aircraft Pilots of the National .Research Council.

Since the present disserta­

tion is so intimately connected with the entire project, a descrip­ tion of the rationale behind the entire program will enable the reader to understand better the research to be described in the following pages. After analyzing the abilities necessary for successful flying, we have come to the conclusion that certain of these abilities are extremely important.

Among the most important are:

good motor coordination, the ability to endure severe deprivation, and the aptitude for meeting disturbing situations with a minimum of disorganization.

We are convinced, that the successful pilot must in

some way combine these desirable attributes, and a survey of the literature appears to justify our convictions.

A non-successful

pilot, on the other hand, may possess one or more of these desired characteristics but be deficient in others.

For example, an indivi­

dual may have fine motor coordination and perform admirably on tests which measure this aptitude, but he may "lose his nerve11 or become disorganized when faced with a critical situation. be unable to utilize the abilities he possesses.

He would thus

Ill

It is for this reason that a variety of tests have been used in the total testing program, for attempts are made to test all of the basic abilities mentioned above,

ho one test will be satis­

factory for selecting individuals for training in aviation.

Attempts

must be made to get as complete a picture of the individual's capabilities as possible, otherwise the program will fail. lhat is presented in the following pages is merely the experimental situations and findings resulting from an attempt to appraise one particular aspect of the aviator — how he reacts to disorganizing stimuli.

This part of the program is not necessarily

the most important, but it is one which offers unusual avenues for research.

TABLE OF CONTENTS Chapter

Page

Acknowledgments .................... i Preface ......................................... li List of Tables ......... iv List of Illustrations .............................vi .................................

I.

The problem

II.

Apparatus and Experimental Design

1

1. The galvanic skin response as a measure of general bodily activity and internalarousal ....10 2. Subjects ............... 14 3. Situation I - The Falling Chair.............. 15 4. Situation II - Electric Shock .... 21 5. Situation III - Hand and arm sway with distraction............. 23 6. Situation IV - The Seashore Serial Discrimeter with distraction ....................... 25 III.

Treatment of Data 1. Measuresfrom the falling chair ........... 2. Measures from the administration of electric shock .............................. 3. Measures from the Seashore Swaymeter and Serial Discrimeter ................ 4. Treatment of the data in terms ofcodedscores .. 5. Eatings of flying success ...................

IV.

27 33 33 34 34

Results 1. Galvanic measures from the falling chair, Group I ............................... 37 2. Blood pressure records from thefallingchair ... 48 3. Reactions to electric shock................ 51 4. Results from the swaymeter................. 53 5. Results from the Seashore serialdiscrimeter .... 54

V.

Summary and Conclusions ..........................

Bibliography Appendix I Appendix II

...........................................

55 60

......................................... ............................

65 ■•• 77

iv

LIST OF TABLES Table

Page

I

Coefficients of Correlation between Various Measures from the Falling Chair and Flight Ratings, Group I ....................... ........ 57

II

Number of Student Pilots Exceeding the Critical Score on Log-Conductance Difference after the First Fall, Group I ............................

38

Correlations of three Measures from the Falling Chair with Each Other and with Flight Ratings, Group I ....................

59

III

IV

Beta Coefficients and Rounded Weight's for Three Measures from the Falling Chair,Group I ........... 40

V

Coefficients of Correlation between Various Measures from the Falling Chair and Flight Ratings, Groups I and II ........................................ 41

VI

Correlations of Three Measures from the Falling Chair with Each Other and with Flight Ratings, Groups I and II ........................................ 42

VII

Beta Coefficients and Rounded Weights for Three Measures from the Falling Chair, Groups I and II .... 43

VIII

Correlations of Three Measures from the Falling Chair with Each Other and with Flight Ratings, .................. Group 11

46

IX

Beta Coefficients for Three Measures from the Falling Chair, Group II ......................... 47

X

Correlations between Various Coefficients of Blood Pressure and Flight Ratings....... ............. 50

XI

Correlations between Two Measures of Recovery from Electric Shock and Flight Ratings,Group I ......... 52

XII

Coefficients of Correlation between Scores Secured from the Seashore Swaymeterand FlightRatings

XIII

XIV

Flight Ratings and Galvanic Measures from Falling Chair

53 65

Flight Ratings and Galvanic Measures from Falling Chair, Group II ................................ 66

V

Table

Page

XV

Flight Ratings and Coded "Galvanic Measures from Falling Chair, Group I ......................... 67

XVI

Flight Ratings and Coded Galvanic Measures from Falling Chair, Group II ........................ 68

XVII

Blood Pressure Coefficients from Falling Chair and. Their Coded Equivalents ..................

69

Blood Pressure Coefficients from Falling Chair and Their Coded Equivalents, Group II .....

70

Recoveiy Quotients and Coded Scores Secured from Electric Shock, Group I .......................

71

Scores on the Multi-Planar Hand and Arm Swaymeter, Group I ......................................

72

Scores on the Multi-Planar Hand and Arm Swaymeter, Group II ................................

7S

XXII

Scores on the Serial Discrimeter, Group I ........

74

XXIII

Table of Coded Values for Scores on all the Tests .. 7b

XVIII XIX XX XXI

vi

LIST OF ILLUSTRATIONS Figure

page

1.

Photograph of Falling Chair ................

16

2.

Photograph of Falling Chair after F a l l ............... 17

3.

Photograph of the Modified Darrow Behavior Research Resistance B o x ...................

18

4.

Diagram of Resistance Box Circuit..... .......... .. 19

5.

Photograph of Inductorium.....................

6•

Photograph of the Seashore Multi-PlanarSwaymeter..... 24

7.

A sample Record Showing Changes in Log-Conductance and the Ensuing Physiological Recoveiy after Fall is Administered ..................................... 32

ZZ

CERTAIN PHYSIOLOGICAL AND MOTOR REACTIONS TO DISORGANIZING STIMULI WITH SPECIAL REFERENCE TO THEIR USE AS AIDS IN THE PREDICTION OF FLYING ABILITY

The Problem The ability to fly an airplane is made up of many different kinds of aptitudes and skills.

Some of the measures most frequently

mentioned by research workers in the psychology of aviation and aviation medicine have been:

reaction time, muscular coordination,

vision, equilibrium, ability to resist emotional stimuli, courage, and mental fitness.

It is thus observed that a great many capacities

or abilities are required of the person who is to become a good pilot. In order to devise tests of flying ability, one must attempt to sample as many of these capacities as possible or try in some way to appraise the total performance of the individual. (59)

It is for this reason

that the most successful programs have utilized a variety of tests and techniques. Since the aptitude for flying is made up of numerous abilities, no single test of a particular function will suffice as an instrument for selecting pilots.

This has been very clearly illus­

trated in the work of psychologists who have investigated this problem.

In the testing programs developed during the last war by

Stratton (59) and Henmon (52), no single test in their complete batteries correlated better than .3 with the criterion.

However,

since the different tests showed little correlation with each other, they could be combined into a battery which produced a fairly accep-

z table multiple coefficient of correlation. (32)

This is also a

rather common occurrence in other fields where aptitude tests are desired.

No single test qualifies for use by itself; hence, a

batteiy of four or five tests must be employed (31) (33).

Too much,

therefore, can not be expected from any test used alone, for it will be only partially successful in predicting flying ability.

If it is

combined with other tests, it may play an important role in contribu­ ting to the value of the total test batteiy. These preliminary statements have been thought worthwhile to orient the reader to the particular problem at hand.

The present

investigation is concerned with testing only one aspect, or a series of closely related aspects, of the total pattern of factors which go to make up "flying aptitude.11 It is not believed that the measurement of this aspect alone will solve the problem of pilot selection, but rather, that it will yield information about one aspect of flying ability which is important.

This particular aspect has been called

various names by different investigators.

The ability to resist

emotional stimuli, the ability to maintain self-control, the ability to act in an emergency — these are all parts of what we choose to call the ability to react successfully to disturbing and disorganizing stimuli.

This attribute has been mentioned again and again in the

literature as one of the basic characteristics of the successful flyer.

A brief survey of some of this literature may indicate clearly

the importance of this factor. Historical Survey and Related Literature The history of flying is a relatively short one, and, when

3

the first World War was under way, flying was still in its infancy. However, that war, as the present one, stimulated some study of the personal attributes and qualities which are important for successful flying.

As one studies this literature he finds that certain attri­

butes of the good flyer are stressed rather frequently.

One of these

is the ability of the aviator to meet disturbing situations calmly and efficiently. In a published report by Anderson (l) in 1918, the tempera­ ment of the aviator is especially stressed.

It is pointed out that

the flyer must be cool in emergencies and able to make quick and care­ ful decisions.

A study reported a year later in a French journal by

Binet (3) emphasized the fact that the aviator, above all, must guard against excitement, must always be calm and continually the master of himself.

Another French research (5) published, during the last war

reports certain experiments with flyers’ reactions to startle stimuli, e.g., the firing of a gun and. explosion of magnesium.

The experimen­

ters concluded that the best aviators were ’’calm men with nerves of steel.” Mepper (50), who helped devise tests for the selection of pilots in France during trie first World War, was among the first to emphasize the importance of reactions to emotion-provoking situations. He pointed out that the reactions of the pilot must not only be fast, but in addition, the effects of unforseen emotion must be short-lived. In order to evaluate this attribute, he measured the effect of a revolver shot on the subject’s respiration, hand tremor and vasomotor changes.

The excitable subjects gave more violent and longer-lasting

4

responses than the other subjects. Parsons (52) reported on characteristics which flight instructors agreed were essential for successful flying.

Coolness

under strain and dependability to do the correct thing at a critical moment were two of the five characteristics mentioned.

These

characteristics are essentially related to the type of reactions selected for special study in the present research.

The work of

American psychologists during the first World War also recognised the importance of adequate reaction to emotion-provoking stimuli. (52)(59) A measurement of this type of reaction was one of the best single measures utilized by Henmon (52). More recent reports also emphasize the importance of the individuals reactions to disturbing stimuli.

Gemelfi (29) (50), one

of the outstanding Italian workers in this field, has often stressed the importance of adequate resistance to emotional stimuli.

In his

analysis of the aptitudes required for successful flying, he lists the ability to offer adequate resistance to emotional stimulation as one of the five basic ones.

Jones (40), in a bulletin reporting the

factors comprising natural aptitude for flying, listed by the School of Aviation Medicine, mentions the importance of good control of perception, apprehension and volition under trying conditions. O'Reilly (51), in a Canadian journal, states that the pilot must be able to stand prolonged nervous strain and have sufficient ability to make correct decisions without loss of time at a critical moment. These observations are concurred in by Mashbum (49) who believes that the essential aspects of a military pilot are T1agile

5

exercise of intellect, unfailing will power, a high degree of reflex and kinesthetic development, perfect coordination, and above all complete control and guidance of his emotions.” Beaven (2), in commenting on a study by Longacres, points out that the tense or apprehensive individual usually does not learn to fly.

He is of the

opinion that this quality of an individual is instinctive and is based upon the primitive endowment of fear of falling combined with fear or distaste for loud noises.

Jensen (37) observes that a large group of

inadequate flyers are characterized by an inability to act in critical situations.

Tihen these pilots are thrown on their own resources in a

rather difficult situation, they become panic stricken or freeze on the controls.

Most of them have difficulty in finishing their

training. Other recent analyses of the aptitudes necessary for flying published in American journals also mention the importance of the ability to relax and the ability to resist emotional stimuli.

Further­

more, when attempts are made to weigh the various factors with regard to their importance as a means of selection, the abilities mentioned above are given considerable weight. (6)(39) It has thus been pointed out that various workers interested in the selection and training of aircraft pilots have emphasized the importance of the pilot’s ability to react adequately to disorganizing stimuli.

Some investigators have called it the ability to resist

emotional stimuli, others have labeled it the ability to act swiftly and correctly in a critical situation, while still others have spoken of the ability to maintain calm and equanimity in times of stress.

6

Some Investigators have merely commented upon the importance of this factor without attempting to do much about its measurement.

Others

have attempted to measure it in various ways. Some psychological and medical workers believe they can gain insight into the person1s ability to act in various situations by means of "personal interview and study of his family background." A method of examination by means of a personal interview has been reported by De Foney (21) (22) and Sutton(60).

The reports of this

method used with few additional tests indicated that the method had a great deal of promise.

It is essentially subjective in nature, how­

ever, and suffers somewhat from total reliance on the clinicianrs insight.

Khoades (54) also has reported a similar method. Another technique that has been rather commonly used was

to note the subjectTs reactions to a pistol shot or some similar disturbing stimulus.

The effect of the disturbing stimulus was judged

by comparing physiological measures under normal and. startle condi­ tions.

Examples of this kind of research are seen in the work of

Boyer (5), Nepper (50), and Henmon (52).

Other measurements taken

while a pistol was fired were hand tremor and reaction time.

Reaction

time during disturbance as compared with normal reaction time was utilized by some examiners as a measure of a person’s adaptability* Still other investigators, like Gemelli (28), attempted to appraise emotional reactions by measuring physiological responses to such stimuli as a name suddenly given or a memory recalled. Another method, used by the Army Air Corps to measure relaxation or tenseness of the subject, has been to hold the latter’s

7

arm outstretched in a supposedly relaxed maimer.

After a certain time

interval the support is withdrawn. If the extended arm falls to the subject’s side, he is considered relaxed\ if the arm remains out­ stretched, the person is judged to be tense.(36)(65) Some of the testing programs referred to above were not very successful, although a few have had some degree of promise.

Lack

of adequate controls, comparatively small samples, and a lack of statistical rigor, however, were some of the deficiencies in these earlier approaches.

Furthermore, several of these programs utilized

tests that were capable of measuring only relatively simple or super­ ficial segments of behavior.

Although many of these tests were

actually used in the selection of students for flight training, little was done in the way of following through the results on experimental groups.

In fact, it appears that many convictions of medical workers

were never put to experimental test.

In certain researches, for

example, It is shown that certain physical standards which were re­ quired of flyers actually correlated veiy little with flying ability (2)(55). This dissertation is an attempt to test certain selected attributes of an individual by more extensive techniques than have heretofore been employed.

It has been shown above that these attri­

butes are of significance in flying success.

The writer, therefore,

proposes to measure the reactions of student pilots to certain dis­ turbing and disorganizing stimuli in terms of certain physiological and motor responses.

Although somewhat similar work has been attempted

previously, it has been rather scattered and superficial.

The present

8

approach introduces certain new and rather different test situations, attempts are made to get as realistic ratings of flying ability as possible, and whenever possible, standard statistical techniques are utilized* As the result of this research, an attempt will be made to answer such questions as:

Are there characteristic differences in the

physiological reaction patterns of ^ood and poor pilots to disturbing stimuli?

Do good pilots recover more quickly from disorganizing

experiences than poor pilots?

Are poor pilots affected more in the

performance of a task when a strong distraction is introduced than are good pilots?

Do the different groups of student pilots react

differently to a sudden startle stimulus?

Attempts will be made not

only to test certain hypotheses, but to select measures which will be of practical significance in a test batteiy designed for the selection of aviators.

Again, it is necessary to point out that the particular

kind of behavior selected for special study in this investigation is only one of the many kinds of behavior which are important for success­ ful flying.

It is not assumed that it is the only important reaction

pattern or that its measurement will suffice alone as a means of predicting the ability to fly.

In fact, these measurements constitute

only a part, although an extremely important part, of a total battery of tests which are now being developed to aid in the selection of pilots.

5

APPARATUS MID EXPERIMENTAL DESIGN

The present research involves the measurement of both physiological and motor reactions.

In distinguishing these two types

of reactions, reference is made to the kind of measurement involved. In two of the four test situations to be described later in this chapter, only physiological measurements were taken.

In the other two

tests, the measurements involved either an actual record of work accomplished in a motor task, or a record of hand steadiness. Blood pressure and palmar skin resistance readings con­ stituted the physiological measures employed in the present under­ taking.

The use of blood pressure readings needs little justification.

The experimental literature both in the selection of aviators and in the psychology of emotions contains much research in which measures of blood pressure have been used (2) (15) (45) (55).

Several of the testing

programs mentioned in the preceeding chapter utilized measures of blood pressure in studying the effect of startle and emotion-provoking stimuli.

Because of its long history, and because various blood pres­

sure indices are utilized in the medical examination of aviators, It was deemed worthwhile including blood pressure as one of our measures. The use of palmar skin resistance records in the selection of pilots for flight training, however, is a much more infrequent occurrence, and perhaps needs somewhat more elaboration.

Only three

studies out of the 618 abstracted by Razran (55) for the Civil Aero­ nautics Administration mentioned the use of galvanic records of skin resistance as aids in the selection of pilots, and these studies did

10

not thoroughly explore the problem*

For example, one research utilized

galvanic records in studying emotional reactions to certain select words (7)*

Research by Darrow (8) (9), however, has demonstrated that

the electrical resistance of the skin is much more responsive to sensory stimuli than to ideational stimuli. The galvanic skin response as a. measure of general bodily: activity and internal arousal* A majority of the studies of the galvanic skin response .(G.S.R.)"^* have been interested in its physio­ logical basis, the stimuli which produce it, and the nconscious correlatesn which accompany it * At one time it was believed that the G.S.R. was a correlate of emotion (6£) or of conation (44). Whether the G.S.R* was an exclusive correlate of a specific mental state, however, was questioned by later investigators*

At one tune,

Landis (4S) stated that the G.S.R. was a phenomenon of considerable generality) in another report, however, he and Hunt (46) concluded that tension was the experience correlating best with the G.S.R. Darrow and Freeman (16) have pointed out "that situations favoring an increase in the subject's anticipation, alertness, or apprehension (including arousal from sleep), are likely to be attended

1.

Changes in the electrical properties of the skin as shown by any electrical measuring device have been called many names by workers interested in its functioning. Psycho-galvanic reflex, electrical phenomenon of the skin, palmar skin resistance, and galvanic skin response are a few of the more common names given to this particular phenomenon. Although we are concerned here with the skin resistance of the palmar areas, we shall use the expression, galvanic skin response (G.S.R.), as mentioned and defined by Landis (45) to denote this phenomenon.

11

by marked increase in conductance of the palm.”'1’ Startle and tension-producing stimuli appear to be the stimuli which produce the greatest changes in the G.S.R.

Since the G.S.R. is responsive to

this kind of stimulation, it is particularly applicable in this study. It is generally believed that the G.S.R. is a rather adequate index of sympathetic activity of the autonomic nervous system (44) (46) (66), although Darrow (15) and Freeman (25) hold that there is evidence which points to cortical control of such responses.

Ihether perfect agreement exists with regard to the

definite physiological basis of the G.S.R. need not concern us here* A considerable amount of research indicates that the G.S.R. is a worthwhile measure of general bodily reactivity. Freeman and Giffin point out the value of palmar skin resistance as an index of reactivity in the following manner: Those who work in the field of physiological reaction dynamics would now seem to have a choice clearly laid out. For study of how the central nervous system mobilizes energy under load one may accept a crude but fairly reliable indicator of rate of oxygen consumption where changes in- neuro­ muscular reactivity are often obscurely reflected, or he can substitute a more sensitive and specific index - the palmar skin resistance, but run the risk of faulty interpretation. This last diffi­ culty can be minimized much more than one is accustomed to think. (26, p.70)

1.

Palmar skin conductance is simply the reciprocal of the resis­ tance. The resistance readings are read in ohms while the conductance readings are treated in micromhos. Thus while a decrease in resistance would indicate a more aroused bodily state, an increase in conductance would lend itself to the same int erpretation.

12

The above writers state further that accurate measurements are possible only if adequate time is allowed for the subject to reach a thoroughly relaxed or ,!basaln state. In studying the effect of muscular tension upon palmar skin resistance, Freeman and Simpson came to the conclusion that the records of palmar skin resistance offered an unusually sensitive measure of bodily reactivity or preparation for overt behavior. The results of this experiment commend the palmar skin resistance as a sensitive and quantifiable index of the reactivity level or general excitation background involved in rein­ forcing, sustaining, and preparing for patterns of overt behavior. Although the palmar sweating responsible for changes in skin resistance is usually thought of as an autonomic function and hence beyond the control of voluntary increments in,tension or effort, there is abundant evidence of cortical control of such responses. (25, p.324-525) Darrow (15) and Darling and Darrow (17) corroborate the use of palmar skin resistance as a measure of general bodily reactiv­ ity.

Along with Freeman they suggest that it is probably the best

single indicator for such a measure.

It is superior in many

respects to such measures as blood pressure and action potentials, and correlates highly with basal metabolic rate at trbasaln levels. The precise explanations for this are not clearly known as yet, but one plausible explanation is offered by Darrow: The unique significance of palmar sweat secretion as an indicator of general bodily function may perhaps be in the fact that parasympathetic and sympathetic influence on the sweat glands do not cancel but in some fashion reinforce or supplement one another. (15, p.665) A recent report by Freeman and Pathman summarizes in

15

concise fashion the reasons for using palmar skin conductance as an index of the degree of general internal arousal produced by displacing stimulation. This measure (palmar skin conductance) is commended for the following reasons: (l) it is one of the most sensitive indices of increments in nervous activities obtainable in the intact organism; (2) it correlates well with the records of total oxygen consumption obtained under basal conditions; (5) it is markedly influenced by the activity of the autonomic nervous system and muscles; and (4) it shows a relatively high testretest reliability as compared with other physio­ logical measures of internal arousal, such as oxidative metabolism, (27, p.163) The research mentioned above appears to confirm these statements and to indicate that the G.S.R. is the most sensitive measure available for interpreting the extent of internal arousal of the organism.

Furthermore, the reliability coefficients published

in the last mentioned study were in the neighborhood of .85 for the galvanic indices used.

For these reasons we have considered the

G.S.R. (of the palmar areas) as the most suitable measure for measuring physiological arousal to a disorganizing stimulus. Darrow (11)(13)(15), furthermore, believes that palmar skin conduc­ tance is an index of general preparatory and facilitative bodily processes mobilized to meet emergency situations. the response has functional significance.

In other words,

On the other hand,

Darrow has also pointed out that an unusually strong G.S.R. may be interpreted as excessive excitation In response to a displacing stimulus and may be indicative of a disorganized condition.

In

discussing how severe stimuli may disorganize activity, he states:

14

And since conditions of excessive excitation will often be attended also by very high palmar conductance it is clear that high conductance and good performance cannot be indiscriminately related. Obviously, there must be a limit to the extent to which marked palmar secretary activity may be associated with increased alertness and capacity for complex adaptive behavior. (15, p.85) Unusual amounts of physiological displacement to certain stimuli, therefore, appear to offer possibilities as indicators of internal disorganization.

It is this kind of a measure in which we

are interested for it is hypothesized that the poor aviator is the one who becomes disorganized when faced with a disturbing situation. Subjects.

The subjects used in this research were

primary and secondary flight students enrolled in the Civilian Pilot Training Program at Northwestern University.

These student pilots

represented two groups of pilots enrolled furing separate semesters. The first group was enrolled furing the second semester of the academic year, 1940-41, and the second group was in attendance during the first semester of the academic year, 1941-42.^ There were 47 students tested in the first group and 42 students in the second. These represent most of the flight students available for testing in the C.P.T. Program at Northwestern University during these two semesters. The tests selected for try-out and study were administered to the two groups of student flyers during the semester that they were pursuing their flight training at Northwestern.

The tests were

1. The two groups of student pilots will henceforth be known as Group I and Group II. For various reasons it was deemed worth­ while to treat the data separately as well as together.

15

usually given as two parts of a batteiy on separate days.

Through

the cooperation of E. L. Edmondson, coordinator of the flight program at Northwestern, unusual rapport was established with the subjects. Situation X - The Failing Chair. A specially constructed chair is used in which a chair seat with back is attached by an axle -|

(about five degrees in front of the center of gravity) to a frame. (Fig.I)

lShen the chair is released by a foot lever, it falls back­

ward approximately 90° (See Fig.II).

A spring attached to the back

starts the fall suddenly and a hydraulic door check first slows and finally stops the fall without a jar to the subject at the end of the fall. A standard Tycos aneroid sphygmomanometer was used for reading blood pressure.

G.S.R. readings were taken with a modified p I Darrow Behavior Research resistance box. (Fig.Ill and Fig.IV) Zinc electrodes (diameter 2 cm.) were attached to the left forearm and palm.

The active electrode, covered with a lg per cent solution of

zinc sulfate mixed in a kaolin base, was strapped to the left palm. The other electrode was attached to the forearm after the skin had been roughened by vigorous rubbing with Redux.

The Redux paste was

also used as the contact paste on this electrode. The subject was met outside of the experimental room by

I the experimenter and told that this part of the test was to be a study of his ability to relax.

After being instructed to relax as

1. The idea for using this type of equipment originally came from Blatz (4). 2, This box was designed by Emil Ranseen.

20

much as possible, the subject was blindfolded and conducted into the experimental room. given.

(A plausible explanation for the blindfold was

For a complete description of these instructions, see Appendix.)

The recording equipment was attached and straps placed across the subject's arms and legs.

Every effort was made to reduce any appre­

hension noticed in the subject.

He was told to relax as completely

as possible for approximately fifteen minutes. Galvanic skin resistance readings were taken continuously every 50 seconds. after each fall.

In addition, G.S.R. readings were taken 15 seconds Systolic and diastolic blood pressure were taken

after a period of three minutes, after a period of six minutes, and after each fall.

These measures constituted the measurements for

this test. After the subject had relaxed for ten minutes and the preliminary measurements were taken, the chair was suddenly released and the subject was thrown backwards in the chair without warning. He was immediately returned to the upright position and the necessary readings taken.

The subject was then informed that there would be

no additional falls and he was asked to relax once more.

After four

minutes had elapsed the subject was told he would be given another fall in a minute or two, but to continue his relaxation. later, a second fall was administered. the first fall was repeated.

Two minutes

The procedure which followed

Three minutes after the second fall, the

recording apparatus was turned off and the test completed.

The

subject was cautioned not to report anything about the experiment to any other member of the class.

21

Situation IT - Electric Shock. The apparatus used in measuring the reactions to electric shock was different for the two groups of subjects. *£•

(Fig.V)

We shall describe only the equipment for Group

The electrodes attached to the Modified Behavior

Research box mentioned above were connected in such a way that by throwing a double pole, double throw switch they could be put into connection with an inductorium.

The subject was told that he would

be given an electric shock which would be increased at regular inter­ vals of five seconds each.

He was strongly urged to accept as much

of the shock as he could withstand.

When the subject was unable to

stand any more shock he was told to say 11enough11 and the current would be turned off.

The experimenter carefully explained to the

subject that the shock was so controlled that no injury could occur. I The secondary coil of the inductorium was advanced one!i ] i half unit on a twelve unit scale every five seconds. The shock was administered by means of a knife switch for one second only during each five second interval,

Amount of shock was reported as the scale

j1. During the second semester of testing, a much more refined j apparatus for administering eleetric shock was made available by ! Dr. Jack W. Dunlap of the University of Rochester. This apparatus, I the electric stimulator, provides a rather precise means of j measuring the amount of shock which a person can endure. The I shock is received through two fingers immersed in two beakers | containing salt water. Attached to the beakers are two brass | i electrodes connected, to the electric stimulator. Amount of shock ji is increased by turning a dial at a constant rate. An unpublished. | j description of this apparatus has been prepared by Dr. Dunlap. I Because of mechanical difficulties, and also because the flying j schedule conflicted a great deal with our testing schedule, data on this apparatus were secured from only a few subjects. For this reason it was thought best to wait until more subjects had been given this test before writing up the results. These results will P be added later as an addendum to the present thesis.

25 .

unit at which the subject stated he could stand it no longer*

Gal­

vanic readings were taken immediately before the first shock and at one-half minute intervals for a period of three minutes after the final shock.

Basal G.S.R. readings were also available on each sub-

i ject for a five-minute period which proceeded the administration of the shock by fifteen minutes.

(During the latter period each subject

had been given a simple visual discrimination task.)

Physiological

displacement and recoveiy were available measures. Situation III - Hand and arm swav with distraction. A | series of six trials was given each subject on the Seashore Muitii planar Swaymeter. (Pig.VI)

This piece of equipment measures hand

| and arm sway in much the same way that the Miles Atoximeter and j similar apparatus measure body sway.

Its wheel recording arrangement -

ij

| i which consists of a driving wheel that will move in either direction ; ! and a driven wheel which moves in only one direction - makes possible ! accurate cumulative records of hand movement both in the vertical ! | and the horizontal planes.

Two fine ratchets on the driving wheel

! cause the driven wheel to move to the right and two ratchets attached to the frame prevent it from moving in the opposite direction.

Thus

i j

j!

measurements can be made for right and left, or up and down movements,

i j since two sets of wheels are employed. ! i

A brake locks the wheels in

ii

| position between trials. The task simply requires the subject to i jj hold a tiny pellet attached to the wheels and frame as steady as | possible. I

Each subject was given six trials of thirty seconds each.

ij

! During the third and sixth trials at twenty seconds from the beginning

25

of the trial, a sudden loud sound was made by dropping a pan behind the subject1s back.

The sound resembled a revolver shot and consti­

tuted the startle or distracting stimulus.

A record of normal hand

steadiness was then compared with distracted steadiness and the difference constituted the scores on this test.

Thus, not steadiness,

but changes in steadiness due to disturbance were measured. Situation IV - The Seashore serial discrimeter with 1 distraction. The Seashore serial discrimeter measures a relatively simple type of continuous discrimination reaction to visual stimuli. Four keys or levers are presented to the subject which control the movement of a circular disk.

One hundred numbers ranging from one

to four are arranged around the edge of the disk and correspond to the four levers.

A wooden frame with a small aperture allows only

one number to be seen at a time.

By pressing the correct key, the

subject moves the disk and a new number appears at the aperture.

If

the subject presses an incorrect key, nothing will happen, for the disk revolves only if the correct key is pressed. The functioning of the apparatus is explained in the following way.

A simple weight driven escapement is released, one

point at a time, by pressing the appropriate one of four keys.

The

object is to make as many discrimination reactions as possible in a given period of time. of a weight.

1.

The revolving disk is under constant tension

Hhen the key is pressed it draws back an escapement

Since this piece of apparatus is now being used in the army, the writer was unable to photograph it.

26

lever which releases a steel peg and allows the disk to rotate 5,6 degrees in a clockwise direction until stopped by the next peg thus automatically presenting a new stimulus at the aperture*

Since

each lever moves separately and controls a single row of pegs, the right key must be pressed each time before the stimulus changes.

A

more complete description of this apparatus is found in the published report of Seashore. Two cycles of five trials each were given on the serial discrimeter.

(The steadiness test described above was administered

between the two cycles.)

On the third and fourth trial of each

cycle a veiy disagreeable jarring tone was passed through headphones to the subject’s ears*

This distraction tone was produced by

passing the current from two lj volt diy cells through an inductorium which had the secondary coil well advanced over the primary coil into a set of headphones with a resistance of 2,000 ohms.

Measures

of serial discrimination reaction under normal and distracting conditions were then computed.

The score on this test was the

difference between serial reactions under normal and distracting conditions.

27

TREATMENT OF DATA

Methods of treating the numerous measures derived from the first test situation constituted a major consideration.

Since

there 'were over forty galvanic readings for each subject on this test, attempts were made to secure a fruitful method, for treating the complex array of items.

No other test situation provided as

complicated a problem, for the other tests were relatively easy to score.

For this reason, much of the discussion will center around

the galvanic measurements secured from the falling chair. Measures from the falling chair. The measurements from this test were baaed on G.S.R. and blood pressure records taken during the twenty minute test period.

After certain preliminary

investigations, several measures were selected for use in this study.

The galvanic measurements which appeared to be worthy of

statistical analysis follow:

(1) changes in log-conductance as a

result of the first fall1; (2) changes in log-conductance as a result of the second fall; (3) the difference in the conductance readings taken immediately after the first and second falls; (4) the log conductance of the reading Just preceeding the first fall; and (5) a modified recoveiy quotient after the first fall.

1.

2.

Other

As has been pointed out previously, conductance scores are simply the reciprocals of resistance scores. Log-conductance scores are the logarithms of the conductance scores multiplied by 100. This recoveiy quotient is patterned after the one described by Freeman and Fathman (27), but differs in that an arbitrary time limit was set for the attaining of a basal level.

28

measures were devised but were discarded since they appeared to be of little value. Before discussing the measures mentioned above, it is worthwhile stating the considerations which prompted the use of conductance and log-conductance scores in the basic treatment of the data.

In the treatment of G.S.R. records there has been much dis­

cussion as to the most suitable type of measurement.

Hunt and Hunt

(54) and Landis and Hunt (46) are of the opinion that readings expressed in ohms (resistance) are as reliable and worthwhile as readings expressed in conductance or percentage units.

Other inves­

tigators, however, have taken exception to this point of view. Barrow (12) has insisted that conductance is a much more appropriate measure of galvanic changes since it takes into consideration changes relative to the pre-existing level of reactivity. (14) he advocates the use of log-conductance units.

In a later report His reasoning

here is that psychological activity may vary under certain conditions approximately as the logarithm of the concomitant physiological activity.

Wenger and Irwin (65) contend that Z scores provide a

better index of galvanic change than regular resistance levels on the grounds that small fluctuations are concealed at low resistance levels.

These latter accounts all emphasize the fact that small

changes at low levels of resistance may be as significant as large changes at high resistance levels.

For this reason they advocate

the use of measures other than resistance in ohms. In this present work the writer has found the recommenda­ tions of Darrow to be the most satisfactory • Either micromhos (the

29

unit of conductance) or log-conductance (the logarithms of conductance) have been used as the units of measurement.

Gross resistance scores

appear inadequate for, as has been stated, they do not take into consideration the level of the basal or pre-displacing reading.

As

Darrow (12) has pointed out, a change of 1000 ohms at a level of 10.000 ohms resistance is probably as significant as a change of 10.000 ohms at a resistance level of 100,000 ohms. In the first attempts to analyze the data, micromhos were employed as the basic unit of measurement.

Measures of displacement

were calculated in terms of the per cent change from the basal level to the level of arousal.^* Later, all the measures but one were changed into log-conductance units.

Instead of computing a percentage

of change, the difference between the log-conductance of the resting level and the aroused level was used.

This measure was found to be

somewhat more satisfactory because it gave a more symetrical distri­ bution.

Thus Darrow1s later view appears to have merit.

Further­

more, two recent articles by Schrek (58) and Schrek and Lipson (57) have shown that biological data are better represented by logarith­ mic distributions than by arithmetic distributions.

Their research

receives some substantiation from the present work.

The log-

conductance differences fell into a more continuous distribution than did the other units of measurement* The measures used in this study were selected after much

1.

B - A This can be expressed in terms of the formula, A , where B indicates the level of arousal and A indicates the resting level.

50

preliminary research*

Measures which other investigators have

recommended were utilized, as well as new measures which seemed to have some practicability.

As a result of these earlier analyses, the

following measures were used: 1. The difference in log-conductance between the level reached just before the disturbing stimulus was presented and the level immediately after. first and second falls.

This measure was computed for both the These measures give us an indication of how

much the person was aroused by the fall. E. The difference in micromhos between the levels reached immediately after the first and second falls.

That is, the reading

immediately following the first fall was subtracted from the reading follovring the second fall.

This measure was intended to give some

measure of the individual’s adaptability.

It was hypothesized that

those persons who showed as high or higher levels of reactivity on the second fall as on the first were those who could not adapt well to surprise situations. 5. The log-conductance of the reading just before the first fall was given was also utilized as a potential measure.

This

measure, taken after the subject had been relaxing for ten minutes, was believed to indicate the person's ability to relax.

Those

persons showing high conductance levels would be persons who were at a relatively high level of tension. 4, A recovery quotient patterned after the recoveiy quotient used by Freeman was also computed.

Because time of adminis­

tration is an important item in our test situations, we have not

31

followed the precise conditions for using Freeman’s formula.

We have

employed the reading just before the arousing stimulus is presented as a basal level.

This, of course, does not fulfil an important

condition set forth by Freeman for utilizing measures of physiological recovery, but practical demands necessitated certain changes.

Instead

of waiting until the subject reached a regular basal level, we allowed each subject to relax for a period of ten minutes before giving him a fall.

It was found that this amount of time is suf­

ficient to allow most people to reach a fairly relaxed state.

In

fact, an inspection of the individual records indicated that many of the subjects actually approached a true basal level in the time allotted.

For this reason we have computed measures of recovery.

1

The method of computing the recovery quotient is simple. The per cent of conductance change produced by the experimental stimulus is obtained from the conductance value fifteen seconds after the fall.

This is

1x1 terms of Fig. VII.

The per cent con-

I

ductance change following removal of stimulation was obtained by use of the conductance value four minutes after the fall.

Again in

B — C terms of Fig. VII, this procedure is — £— • The recoveiy quotient is computed by dividing conductance change following stimulation by conductance change caused by stimulation.

In terms ox a formula,

nn — P r„il ^ j[ recoveiy quotient beloYT 1.00 will indicate the degree ^ *“ B — A

1.

Freeman has since commented to the present writer that the procedure used here gives worthwhile measures of recovery. In a forthcoming article he discusses this matter at greater- length.

52

W *50

a.40

OSLO LOG-CONDUCTANCE

3ll0

aoo Ho

180

ITO 160 ISO 140

A « LE V E L

JU S T

BEFORE

ISO

B = LEVEL

FOLLOWING

lao

C = LEVEL

FOUR

FALL

FALL

MINUTES

AFTER

FALL

no 100

3

A

5

6

7

8

H

io

it

/a

/3

M

/jr

f6

TI ME IN M I N U T E S Fig. 7

A sample record showing changes in log-conductance and the ensuing physiological recovery after fall is administered.

33

to which recoveiy has advanced beyond this previous level.

This

measure thus gives us some indication of how well a person can recover from certain displacing stimuli. 5.

Blood pressure indices utilized were pulse pressure

divided by systolic pressures for each of the four separate readings. Extreme values at either end of the scale were considered poor. These indices gave somewhat better predictive indications than either systolic or diastolic blood pressure readings.

Studies by Beaven

(2) and Ickstadt (35) indicated that systolic or diastolic records alone did not distinguish successful from non-suecessful aviators. Measures from the administration of electric shock. The galvanic measures derived from this test situation were treated in much the same fashion as the measures from the chair.

Amount of

change due to shock and amount of physiological recoveiy were the measures selected.

In this test, two different measures of recovery

were computed since two different "basal’1 levels were available. Measures from the Seashore swavmeter and serial discrimeter. Measurements on these tests were relatively simple since each piece of apparatus provided its own readings.

Total amount of

arm and hand sway for each of six trials on the swaymeter was se­ cured.

The average of normal hand and arm movement was then sub­

tracted from the average movement which occurred when the startle stimulus was introduced and constituted the score.

Those indivi­

duals who showed the smallest differences would be the ones least affected by the external stimulus.

Again, it is well to point out

that we were not interested in steadiness per se, but in changes in

34

steadiness due to startle. Practically the same procedure was followed for inter­ preting the results secured from the serial discrimeter.

The read­

ings on the third and fourth trials of each cycle were subtracted from the readings on the first and second trials.

These differences

represented the scores on the test and indicated the effect of dis­ turbance on serial discrimination reactions. The treatment of the data in terms of coded scores. In the statistical treatment of the data all scores were converted into coded values ranging from one to nine or ten. instigated for several reasons:

This procedure was

(l) The average ratings from the

instructors at the flying field were easily converted into values from one to nine, (2) Iherry followed this procedure in an earlier analysis of part of the data; (3) The scores on the various tests differed, greatly in terms of units and size; (4) coded values are easier to work with in terms of multiple correlations and the weight­ ings of tests.

Thus scores from all tests were converted into coded

values and coefficients of correlation were computed between these coded values.

A completed table of coded values is given in the

appendix. Ratings of flying success. The ratings from the instruc­ tors in flying are usually given on a five point scale.

These

instructors were told to be as objective as possible and to rate the students on flying success only.

They were warned against being

unduly influenced by the personal attributes of the pilots.

The

ratings were then defined for them in the following manner.

A

35

rating of one represented a superior flyer; a rating of two a good flyer; an average pilot should be rated three; a pilot who was below average but not quite a ”wash-out” was to be given a rating of four; while a rating of five indicated a definitely poor flyer who was either a ^ash-out11 or a potential ”wash-out”. The instructors, some of whom were former Northwestern students, were unusually cooperative in their part of the task. Eatings on each subject were usually secured from at least two persons end sometimes more.

The ratings of the instructor and the

flight test inspector constituted the criterion with which the tests were compared. rating secured.

These ratings were averaged and a combined

Since this process of averaging gave plus or minus

scores, these scores were converted into coded values rangingfrom one to nine.

Since the ratings were not identical for both semesters

certain attempts were made to make them comparable.

For example, in

the ratings on the first group of subjects, there were no ratings of two plus.

Thus a rating of one was given a coded value of nine and

a rating of two was given a coded value of eight.

In the second

group, however, there were no combined ratings of one, but there were some ratings of two plus.

In order to equate the two groups,

therefore, a rating of two plus was given a coded value of nine, while a rating of two was again given a coded value of eight.

At­

tempts were thus made to provide comparability among the different sets of rating. The ratings used in this study are superior to the ratings used in many other studies.

First, the ability to fly is a definite

36

ability which can be observed in an actual situation.

It is not a

vague entity similar to the traits investigated in the study of personality.

Secondly, the instructors were unusually well acquain­

ted with their students,

-find, in the third place, the procedures

for rating the pilots were clearly and definitely explained to the instructors,

A reliability coefficient of .75 was secured between

the instructor's ratings and the flight inspector's ratings for 96 cases.

This is a rather high level of consistency for ratings.

57

RESULTS

The results of the experimentation will be presented separately for each test situation, and in certain cases, for each of the two groups of subjects as well as for both groups combined.

This

method of presentation will probably be the most practicable and will provide clear comparisons between the various tests. Galvanic measures from the falling chair: Group I,. Since many of the measures were originally derived from an analysis of Group I, the results from that group will be presented first.

Co­

efficients of correlation secured between measures from the falling chair and the ratings of the flight instructors are given in Table I. TABLE X COEFFICIENTS OF CORRELATION BETWEEN VARIOUS MEASURES FROM THE FALLING CHAIR AND FLIGHT RATINGS GROUP I, N = 46 Correlation with Flight ratings

Measures

Difference in Log-conductance —

first fall

.335

Difference in Log-conductance —

second fall

.437

Difference in Micromhos between first and second falls

.166

Log-conductance of basal reading

-.113

Recoveiy quotient — first fall

-.148

A recoveiy quotient for the second, fall was not submitted to statis­ tical treatment since inspection of the data revealed no relationship.

58

As Table I points out, three of the measures showed a positive correlation with ratings of flying success. Furthermore, the first two correlations give indications of significance.

The

correlation between the difference in log-conductance after the first fall and ratings of flying success is between the one per cent and five per cent level of probability according to Fisher’s test of

1 significance , while the correlation between the log-conductance difference after the second fall is significant at the one per cent level.

This latter statement implies that there is only one chance

in a hundred that a correlation of .457 could have arisen if there were no true correlation.

These figures would seem to indicate

that there is a positive relationship between the ability to resist becoming greatly aroused and flying success.

This relationship is

even better comprehended when the subjects are divided into three large groups and comparisons made.

As Table IX shows, of twelve

TABLE II HUMBER OF STUDENT PILOTS EXCEEDING THE CRITICAL SCORE ON LOG-CONDUCTANCE DIFFERENCE AFTER THE FIRST FALL GROUP I, N = 46 Sub-groups

No. of cases

No. exceeding the critical score

Poor pilots

12

8

Average pilots

20

11

Good pilots

14

1

subjects receiving the two lowest coded scores in terms of flying

1.

The reader is referred to Guilford (51, p.535-56) for a brief discussion of Fisher’s test for the significance of a correlation.

39

success, eight exceeded the critical score of thirty on the first fall.

Eleven out of tvrenty students receiving the next three coded

ratings exceeded this critical score, while onHy one out of the upper fourteen students secured a similar score.

Thus, degree of

arousal appeared to he unusually effective in distinguishing the very good and very poor flyers, hut less effective in distinguish­ ing the average pilots.

The other measures used alone were not as

effective in distinguishing the three groups, although there was an unmistakable trend for the superior pilots to show the smallest amount of arousal.

(See Appendix)

The next step was to tiy to find out how many of the galvanic measures should be utilized in terms of securing a com­ posite score for this test.

For this reason, inter-correlations

were computed for the three measures which correlated positively with the criterion.

These correlations are shown in Table III. TABLE III

CORRELATIONS OF THREE MEASURES FROM THE FALLING CHAIR WITH EACH OTHER AND WITH FLIGHT RATINGS GROUP I, N = 46 1.

2.

3.

1. Flying Rating 2. Difference in Log-conductance — first fall

.555

5. Difference in Log-conductance — second fall

.437

.377

4. Difference in Micromhos between first and second falls

.166

-.285

.125

40

On the basis of these intercorrelations beta coefficients were computed as suggested by Guilford (51, p.590-91).

These beta

values were then divided by the standard deviations of the respective variables to make them applicable to the original coded values, and were then rounded off to give a weighted value which would be easy to use.

These results are seen in Table IV.

TABLE IV BETA COEFFICIENTS AND BOUNDED WEIGHTS FOR THREE MEASURES FROM THE FALLING CHAIR GROUP I, N = 46

P

jSl

Difference in Log-conductance — first fall

.279

.146

1

Difference in Log-conductance — second fall

.506

.157

1

Difference in Micromhos between first and second falls

.207

.151

1

Measures

5 3 7 7 3

99 158 58

74 41 36 47 63 33 77 89 91 50 56 50 79 29

41 104 47 41 93 101 108 37 79 91 80 35

25 26 27 28 29 30 31 32 33 34 35 36 37 38 39

328 182 98 225 121 158 97 107 67 96 143 89 179 140 168

164 91 49 113 61 79 49 53 34 48 72 45 90 70 84

205 147 120 97 91 111 65 74 37 76 91 32 133 121 102

50 41 34 38 10 58 27

41

210

105

165

S3

r:

43 44 45 46 47

128 130 168 92 85

64 65 84 46 43

113 116 92 30 71

77 60 10

4 r; o c 4

112

66 68

0

41 127 16 21 71 10 0 0

0

26 73 21

0

67

8 0

9 7 8 8

7 9 6 0

o u

8

4 a V 9 9 6 6

7 7 9 5 7 9 7 4 n o

TABLE XXI SCORES AND CODED VALUES ON -THE I.:i£LTIPT,ANAR HAND AND APE S’.VATIETER

S 1 2

3 4 5 6 7

Total Scores On Normal Trials 241.0 98.0 219.0 182.0 160.5 132.0 101.0

10

99.5 131.5 105.5

11

122.0

12

117.0

8

9

13 14 18 16 17 18 19

Group Scores On Trials Nith Startle 120.5 49.0 109.5 91.0 80.25 6 6.0

50.5 49.75 65.75 52.75 61.0 58.5

202.0

101.0

59.25 115.75 69.0

20

118.5 231.5 138.0 176 154.0 146.0 52.0

21

110.0

22

93.5 145.0 104.0 94.5 265.5 88.5 96.5 112.5 146.5 118 129 167.5 117.0 78.0 190.0 103.0 111.5 151.0 140.0 139.5 85.0

23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

88.0

77.0 73 26 550 46.75 72.5 52.5 47.25 132.75 44.25 48.25 56. 25 73.25 59.0 64.5 83.75 53.5 39.0 95.0 51.5 55.75 75.5 70.0 69.75 42.5

II Average Scores On Normal Trials 154.5 78.0 145 165 93.5 106.5 82.5 72 95.5 55.5 54.5 102.5 127.5 74.5 155.0 56.5 141.0 91.5 112

50.0 168 77.0 89.5 97 54 174 58.0 119 85.0 80.0 67.5 116.5 85.0 91 59.5 131.5 66

93 72.0 107.0 102

55.5

N-42 Percent Change In Steadiness 28?, 59 32 81 16 61 63 44 45 5 24 75 26 25 33 -18 SO 18 48 92 205 64 23 34 14 31 31 146 51 9 65 80 1

55 52 39 27 66

- 4 52 46 33

Coded Score 7 5 7 3 8

5 5 6 6

9 8

4 7 8

7 9 5 8 6 2 0

4 8

3 8

7 7 0 6

9 4 3 9 5 5 6

7 4 9 5 6

7

74 TABLE XXII SCO RBI3 AID OODICD VALUES ON THE SERIAL DI3CTX.jN.72R Group I

N-40

A _________ B__________ G_______ D___________ E_____________ E-A Trials Trials Trial Trials " Trials Trial + 1 2 3 4 5 6 7 8 9 10 E-D 2

3 4 C O 7 8

9 10 11 12

13 14 15 16 17 18 19 20 21 22

23 25 26 27 28 29 31 32 33 34 35 36 38 39 41 43 44 45 46 47

77 73 73 33 103 106 67 70 83 70 68 100

71 94 83 84 85 110

76 87 86

97 95 102

90 88 86

95 87 93 75 89 98 83 91 92 91 84 87 108

118 83 90 94

82 79 72 96 91 113 70 73 97 93 73 116 75 109 74 93 93 117 93 97 98

110

110

100

96 105

88

76 74 22

94 117 66

73 93 84 79 115 74 105 87 90 88

103 82 39 90 91 93 96 75 98 98 93 97 95 95 94 93 103

88 86

96 91 96 97 80 99 101

93 101

98 96 96 96 111

81 81 65 100

87 116

89 78 76 100

103 86

77 119 99 132 81 87 107

97 92 81 122

100

101

38 75 113 72 108

95 73 116 76

101

111

120

99 131 84 87 107 105 90 127 91 124

102

100

102

106 94 127 118

68

74

86

38 84 122

90 94 92 112

98 102

82 93 100

33 109 100

78 99 101

96 104 97 92 89 96 112

88

126 70 75

91 93 33 1 00

94 94 100

117 97 108 93 96 99 94 107 98 85 98 106 99 100

95

88

126 95

92 132 108 99 119 119 109 109

100

90 122

118 100

113 128 109 109

109 144

110

110

101

104 105 107

96 99 ICC

104 105 116 106 87 105

112 100 86 101

107

119 109

111

111

110

105 108 107 108 125

120

101

113

122

89

88

105 103 83 127 87 124 95

100

106 104 104

101

94 94 84 123 91 130 84

102 110

102

113 10S 34 106 116 106 115 103 104 103 109 124

98 85 SO 116 92 131 81 89 109 96 86

130 87 126 96 96 84130 113 95 103 123 106 109 96 99

95 84 84 116 95 133 81 90

-10 11 mm

12

-34 9 5 7

111

106 87 133 85 127 97 98 89 132 99 qo 109

A

*T

21

18 - 8 18 -10

24 -21

- 5 - 8 4 29 10

120

- 5 25

109 106

-10 0J i

100

-30 - 5

103

100

101

11

105 104 106 90

100

-12

102

117 107 113

Coded Scooe 6

3 5 3 9 3 4 3 1

a 6 2 6 1

7 5 6

4 0

9 5 1 6

4 Q 5 3 6

108 106 94 107 ■114

14 16 o 13

112

10

0

101

1

0

101

101

101

109

23 3 - 7

100

102

-

109 123

104 126

-

2

o 3 3 4 -O

0

1

5 K

13

2

12

p

75

TABLE XXIII TABLE OF CODED VALUES FOR SCORES ON iLL THE TESTS 1. FLIGHT RATINGS GROUP I

GROUP II

Code 1

9

2

2- 54 5 5- 4 4&4— 5 -

8

7 6

5 4 5 2 1

2. L.C.DIFF.

2nd FALL

Code

Code

2

9

1 -- 6

9

0- 2

9

2

8

7--12 13--18 19--24 25--30 51--56 37--42 43--48 49--54 55--60

8

3- 5 - 8 9-11 12-14 15-17 18-20 21-25 24-26 27-29

8

7 6

5 4 5 2 1

5. L.C.of B

6

Code

7 6

5 4 5 2

200^211

1

212-222

0

9• B.P. COEFF. after 5 & 6 min.

6

5 4 3 2 1

5 4 5 2 1 0

Code

Code

9

23-24

9

8

21-22

8

7

19-20 17-18 15-16 13-14

6

5 4 3 2 1 0

11-12

9-10 7-8 5-6

, . B.■X* * COEFF. after 1 st & 2 nd falls

10

Code 47--49 44-46 50-52 41-43 55-55 38-40 56-58 55-57 59-61 52-54 62-64 29-31 65-67 26-28 68-70

Code

6

5 4 5 2 1 0

8

9

-54-28 *27-21 -20-14 -13- 7 -6- 0 1- 7 8-14 15-21 22-28 29-55

8

7 6

5 4 3 2 1 0

. Comp.Chair Betas of Gr.I- & II Code 50-54 45-49 40-44 35-59 30-34 25-29 20-24 15-19 10-14

Y 6

5 4 5 2 1

9 8

7 6

5 4 3 2 1

0

11. SHOCK R.Q.I

Code

12,• shock R.C.II

o o

40-42 37-39 43-45 34-36 46-48 31-35 49-51 28-30 52-54 25-27 55-57 22-24 58-60

Code 7

6

4. DIFF.IN LilCRO. 1st & 2nd F.

7

6

7. Comp.Chair Betas of Gr.I

90--99% 80--89% 70--79% 60--69% 50--59% 40--49% 50--59% 20-29% -19% 10- 9% 0-

9 8

7

. R. Q. st fall

1

104-115 116-127 128-139 140-151 152-165 164-175 176-187 188-199

1st FALL

Code t 25* 5- 4** 4 4- 5 -

5. L.C.DIFF

8

7 6

5 4 5 2 1

265-289 9 256-262 8 209-235 7 182-208 6 155-181 5 128-154 4 101-127 3 74-100 2 47- 75 1 20- 46 0

164-181 146-165 128-145 110-127 92-109 74- 91 56-75 38- 55 20- 57 2- 19

9 8

7 6

5 4 5 2 1 0

TABLE X X I H ( continued)

13. PER CENT CHANGE IN STEADINESS

14. DIFFERENCES ON THE SERIAL DISCR.

Code 0

13 26 59 52 65 78 91 104 117

- 12 - 25 - 58 - 51 - 64 - 77 - 90 - 103 - 116 - 129

9 8

7 6

5 4

3 2 1 0

Code -29 - -55 - -28 -15 - - 2 1 - 8 - -14 1 - 7 -22

-

-

0

-

7 14 21 28 -

6

13

9

8 7 6

5 4 5

20

2

27 34

1 0

APPENDIX II

77 DIRECTIONS FOR FALL

(Outside experimental room) ^_F?cpei^imenter A . “Are you (Name)? Let's see, I believe you are in he primaiy flight class. Were you in class the other day when the general purpose and. plan of these tests were explained? (Answers fit the reply from S.) "We have two tests that are to be given today. In this first part we are merely trying to see how well you can relax. It has been found that many poor pilots are very tense most of the time, and we are attempting to work out some definite relationships. "Besides measuring your general muscular relaxation curve during the rest period of 15 minutes, we are going to record measure­ ments of blood pressure, Of course you will have your eyes covered because it has been found that a person relaxes very little if he keeps his eyes open. "We have had to crowd our equipment for both the first and second tests of our experiment into this one room. Due to this fact I am going to place this mask over your face before we enter the room because the surprise in seeing the equipment for the second test is part of the test. This second test is not connected in any way with the first relaxation period. "During this first part I want you to let yourself relax just as much as you can— just try to be loose and limp all over.11 (Subject and Experimenter enter room) "Just step this way— that's it— • Now then, turn around. Here is the chair. That's right just sit back in it. The chair is a little high because we have built some of our recording equipment beneath it. "Let's see, I believe recording equipment can be to place the regular blood for your physical exams."

you should roll up both sleeves so our connected. Now, on your arm we are going pressure cuff— the same kind you have had (Connect in.)

Experimenter B. "And on this arm we will measure skin tension. I will clean off just a little spot here." (Start rubbing forearm with Redux.) "This probably feels as if I'm rubbing with sandpaper but really its just a towel." Experimenter B. "Is this strap too tight? We don't want to bind your arm. Now, open up your left hand please and we will attach the rest of the equipment. Is this strap too tight?" Experimenter A. "Now then just put your hands in your lap, and I'm going to place this wiggleometer strap across your leg 511 arm*

78

— ^^Grimenter A. "These devices will measure any gross muscular movement "that you might make— not that we want you to remain rigid or>stiffdduring the time, but any large movements do affect the relax­ ation records and must be taken into consideration.1' Experimenter A. "Now remember, you are to just nlet go" and rest. It would be all right if you could even go to sleep. If your head feels droopy donTt hesitate to drop it forward, and if at any time you feel cramped or uncomfortable feel free to change your position as much as the equipment allows. This part will last about 15 minutes and we won't say anything more until it is over. O.K., lets go." After the first fall, the subject is told that the fall is part of the experiment. Experimenter B then says, "You won't receive any more falls. Now see how quickly you can relax again.” Four minutes after the first fall experimenter B says, "we are going to give you another fall in a minute or so, but just keep on relaxing until the fall." Two minutes later the second fall is given. One of the experimenters then says, "All right, thats all of the falls— just relax for a minute or two and we are through.

79 DIRECTIONS FOR ADMINISTERING ELECTRIC SHOCK

(At the beginning of the test period.) ’’For the first few minutes of this test we want you to tiy to relax as much as you can. The equip­ ment which is being attached to your arm is the same equipment we used in the other test. Nothing will be said for the next few minutes, so relax as much as you can. (Before administering shock.) The next part of the test is rather severe. We want to see how much electric shock you can stand. What we are interested in measuring is the ’ability to take it.’ The only way we can do this without causing you any physical harm is by using this kind of electric shock. Although the shock may be uncomfortable, it positively cannot hurt you in any way. The apparatus is constructed in such a way that the amperage is kept at a very low level. The shock will come through the electrodes attached to your arm. The first few shocks will be very mild but later ones will increase in severity. They will come at Intervals of five seconds and will last but one second each. We shall continue to increase the amount of shock until you say you can stand it no longer. As soon as you say this, the current will be stopped. Try to take as much shock as you positively can. All right, we are ready to begin. (After shock.) There will be no more elctric shock. Just try to relax for the next few minutes and the test will be all over•

60

DIRECTIONS FOR THE MULTI-PLANAR HAND AND ARM SffJffiMEEER

"This Is a test of hand and arm sway. In this test of hand and arm sway all you do is to take this piece of metal between your fore­ finger and your thumb like this, and bring it to a position that makes the threads form a right angle here. (Demonstrate) After you have the hand in position and I say go, I will release the brake and the equipment will measure any movement of your hand. During the trial which will last 30 seconds, just try to keep your hand as steady as possible. Don't worry about the angle— in other words if you move your hand this way (demonstrate right movement). Don't try to move back (demonstrate) because you will just double your movement record. Do you understand? All right, ready, go. (After third trial)

Now let's try it some more without the noise."

81

DIRECTIONS lOR THE SERIAL DISCRIMETER

nThis is a test of* ho?/ well you can make certain kinds of reactions. As you can see there are four levers which you are to press down with your fingers— one finger for each lever. These levers control the movement of the numbers which appear at this opening. When number one appears you are to press the first lever down; when number two appears you are to press the second lever down, etc. Only the appropriate lever will allow the number to move and a new number to appear. Notice that when number four appears at the opening only pushing the fourth lever will cause a new number to appear. If you press any of the other three levers the number remains at the opening. You are to be given five trials of one minute each on this test. As soon as you press the correct key, a new number will appear and you will press the appropriate key for that number. You will con­ tinue to do this until I tell you to stop. Try to work as rapidly and accurately as you can. Your score on this test will be the number of times you have selected, the correct lever. Have you any questions? All right, go. (Trials 3, 4, 8 and 9.) Now we are going to place these headphones over your ears. At certain times you will hear a jarring noise. Try not to pay any attention to this noise but work as efficiently as you can. You will do the same thing you have done in the preceeding trial Ready, go,n

SOL LOUIS GARFIELD

Born: January 8, 1918, Chicago, Illinois

Education: B.S., Northwestern University, 1938; M.A., 1939, Ph.D., 1942. Publications: "The Reading Interests of Negro High School Students", with William G. Brink and Paul Witty. Educational Administration and Supervision. XXVI (Nov., 1940) pp 607-613. "A Comparison of the Vocational Interests of Negro and White High School Students", with William G. Brink and Paul Witty. Journal of Educational Psychology, XXXII (Feb., 1S41) pp 124-132. "Interests of High School Students in Motion Pictures and the Radio", with William G, Brink and Paul Witty. Journal of Educational Psychology, XXXII (Mar., 1941) pp 176-184. "Teachers Reactions to Certain Aspects of In-service Education", with C. A. Vieber. Educational Administration and Supervision, XXVIII (Sept., 1942) pp 463-468. "Trends in Discussions of Intelligence: Race Differences,"with Paul Witty. Journal of Educational Psychology, XXXIII (Nov.,1942) pp 584-594.