Normal rate: about one drop per minute.
Chocolate placed in subject's hand: 1st minute 4 drops 2nd minute 3 drops 3rd minute 4 drops Subject smelled chocolate 5 drops Brought chocolate to lips but kept mouth closed. 9 drops Unless this method had been employed, we would not have known that the mere sight and touch of food had such a stimu- lating effect. The subject's own report is worthless, because the food might have inhibited swallowing, and his mouth would have filled with saliva, even though the fluid came at a normal rate. He probably would have told us that- his mouth watered. Some situations as we have experimentally determined do actually in- 32 PSYCHOLOGY hibit swallowing; then the mouth fills wiija. fluid, even though the stimulus actually produces glandular inhibition. In other words, it is quite clear that the presentation of the chocolate produced not only the overt response of reaching out for it and taking it towards the mouth, but at the same time produced implicit habit responses, which showed in the glandular reac- tion. It was only by means of the introduction of instru- mentation that we were able to bring this fact out. It is quite possible that all the glands of the body are subject to stimulus substitution.
B. METHODS EMPLOYED IN OBTAINING CONDITIONED MOTOR EEFLEXES.
Introduction. — In a similar way, Bechterew has shown that reaction in both striped and smooth muscles can be conditioned. These conditioned motor reflexes are quite common in daily life. We see them often in moving-picture tragedies; as, for example, when the villain displays a revolver and pulls the trigger, or strikes the unfortunate hero over the head with a black-jack, the mere sight of these acts makes many in the audience jump or withdraw exactly as though the sound were present, or the blow had fallen upon their own heads. In the laboratory the technic of the method is quite simple. Suppose we have our subject sit with a bare foot resting upon1 two metal electrodes. When the faradic stimulus (slight electric shock) is given, the foot is jerked up from the metal electrodes. We introduce some system for recording upon smoked paper the jerk of the foot, and for mark- ing on the record the moment the stimulus is given. The elec- tric shock will inevitably and invariably make the foot jump. The ringing of an electric bell, however, has no such effect. Now, if we sound the bell and stimulate the foot with the high fre- quency current simultaneously for a certain number of times (20 to 70 usually), we will find that the ringing of the bell alone will produce the upward jerk of the foot. Here, as before, there has been a substitution of stimulus: a sound which does not ordinarily call out the reflex soon comes to do so. Probably the simplest way to carry out conditioned reflex experiments is to .use the finger. In Fig. 2 we show the simple device employed.
PSYCHOLOGICAL METHODS 33 The palm of the hand is placed on one electrode, the middle finger upon the other. A little receiving tambour, having a cork saddle attached to it, is placed directly above the finger. At each upward fling of the finger, the tambour, attached to a writing lever, makes a mark upon a smoked drum. A somewhat more complicated recording system than is demanded in the present type of experiment is shown on page 37.
As may readily be seen, the finger can be more conveniently used for general laboratory purposes -than the foot. This technic SECONDARY OF INDUCTORIUM FIG. 2. — Method of recording finger movement and of giving faradic stimulation. A large electrode is placed under the hand, and a small electrode under the finger. When the key, in the experimenter's room, is pressed down by the operator the secondary cur- rent from the inductorium causes the finger to rise from the small electrode. A receiving tambour, to the face of which a saddle-shaped button has been shellacked, enables a graphic record to be made of such movements.
is now in general use, and can be used with children, with defec- tive individuals, as well as with normal adults. Our method for obtaining the reflex is somewhat as follows: In beginning work upon any new subject we first sound the bell alone to see if it will produce the reflex. We have never been able to get the reflex evoked by the bell alone prior to electrical stimulation. We next give the bell and shock simultaneously for about five trials, and then offer the bell alone. If the conditioned reflex does not appear, we next give five more stimulations with the bell and electric current simultaneously, and repeat this routine until the reflex appears. The conditioned reflex makes its appearance at first haltingly — that is, it will appear once and then disappear. Punishment is frequently resorted to. It may next appear twice\ in succession and again disappear. After a time it begins to appear regularly each time the bell is offered. In the best cases we 3 34 PSYCHOLOGY 34 PSYCHOLOGY get a conditioned reflex after about fourteen to thirty combined stimulations. In attempting to use this method one must be pre- pared to find certain subjects who do not readily show condi- tioned reflexes. Just what the reasons for this are cannot readily be stated at present. The method is really in its infancy.
So far we have discussed the motor conditioned reflex as it appears in the striped muscles of the hands, feet, legs. The un- striped and mixed striped and unstriped groups show conditioned reflexes as well. If a technic is developed for measuring the width of the pupil, a bright light may be used in place of an electrical stimulation. The bell is sounded at the same instant the bright light is flashed. The light causes the pupil to contract, and after the bell and light have appeared enough times together, the bell alone will produce the contraction. The respiratory mechanism can be very easily and readily made to show condi- tioned reflexes, as can the heart-beat.
Some General Characteristics of the Conditioned Reflex. — It is interesting at this point to treat) of certain characteristics of the reflex.
First, as regards the similarity and difference between the conditioned reflex and the primary reflex upon which it is grafted. However much they may differ so far as the cen- tral nervous pathway is concerned, the general and coarser motor features are closely similar. One watching the movements of a subject first beginning to show a conditioned reflex cannot tell whether he is being stimulated by the bell alone or by the bell and punishment combined. The conditioned motor reflex is usually sharp, quick and widespread, the whole body as a rule being brought into the reaction at first. Gradually the reflex becomes more circumscribed.
Second, as regards persistence of the reflex; after the reflex has once been thoroughly established it carries over from one day's experiments to the next for an indefinite 'period. Some- times a single punishment at the beginning of a day's work is necessary to cause the reflex to make its appearance. "We are not able to state over how long a period of time the unexercised reflex will persist. In one case we trained one subject thoroughly in PSYCHOLOGICAL METHODS 35 May to the bell, then did not test him again until October. The reflex did not appear on the first ringing of the bell, but after the first administration of the combined stimuli (at which the subject disrupted the apparatus although the induction shock was very weak) the conditioned reflex appeared regularly to the bell alone.
Third. We know that the conditioned motor reflex can be made to undergo reinforcement and inhibition by factors such as those described on page 171. A few examples of the role such factors play in the control of the reflex may be of interest. Take first the "fatigue" of the reflex. A well-trained subject will react regularly for an indefinite period of time to a stimulus given at an interval of four to five seconds. If now we give the stim- ulus, that is the bell, every two seconds for a short time, he may react for the first three times and then fail. If the interval is then lengthened, or a rest period introduced, the reflex will again appear. It will be seen later that we utilize this principle of fatigue in setting up differential reactions. Oftentimes before the conditioned reflex is thoroughly set up, it will after a time begin to decrease in amplitude. Whether the time is increased is not known. When the reflex is beginning to vanish it can be strengthened in a variety of ways, the most usual way being the introduction of the current, but it can be reinforced also by introducing simultaneously with the bell some other form of stimulation, such as contact or temperature.
Psychological Use of the Conditioned Reflex. — In the cases of the deaf and dumb, of infants and of some pathological subjects, language methods cannot be used. This, of course, is true with respect to the animal world also. Consequently we may say in general that the conditioned reflex method may prove of service wherever language cannot be depended upon (whether due to defect or not). In the second place, the conditioned reflex method may be used as a check upon the verbal report method to be described later. We may briefly illustrate some of the uses of the method as we have so far described it. Suppose we wish to determine the limits of spectral sensitivity in man, that is, how far out into the red and into the violet he can still react visually to ether waves. We start with any intermediate wave 36 PSYCHOLOGY 36 PSYCHOLOGY length and by use of the electric shock esfciblish a conditioned reflex. Each time the light appears the reflex occurs. We then increase the length of the wave rather sharply and if the reflex appears we again increase the wave length. We finally reach a point where the reflex breaks down, even when punish- ment is used to restore it—approximately at 760/*/*. This wave length represents the human being's spectral range at the red end. We then follow the same procedure with respect to the violet end (397^). In this way we determine the individual's range just as surely as if we had stimulated the subject with, monochromatic lights varying in wave lengths and asked him if he ' ' saw ' ' them. A use similar to this is possible in all the other sense fields, sound, cutaneous, smell, taste, etc. Even as we have discussed the method, it is also serviceable in the study of fatigue, adaptation and in the investigation of many other problems that lie in the borderland between physiology and psychology.
Use of the Method for Determining Differential Sensi- tivity.— The method has a much wider range of applicability.
Res Fio. 3. — Showing system of making records, a, Marey tambour, connected with the receiving tambour from the finger (Fig. 2); b, electro-magnetic signal marker, connected with the key for giving the electrical shock; c, Marey tambour, connected with the pneumo- jtraph; d, signal marker connected with second's pendulum; e, double signal marker; one pointer moves when the negative stimulus (stimulus not to be reacted to) is given; second pointer moves only when the positive stimulus is given. The letters on the left refer as follows: R, the record of the finger reaction; F, faradic stimulation (punishment); Res, respiratory curve; T, time; N, negative stimulus; P, positive stimulus. A short schematic record of the ordinary curves obtained in the laboratory is shown. The eye should begin at the bottom and read up. The first record shows that the positive stimulus bell was given, that punishment was given simultaneously with it, and that the reflex occurred. The second record shows that the negative stimulus (a different bell) was given, that no punishment was given with it, and that the reflex appeared (conditioned, but undifferentiated reflex). Then followed eight stimulations with the negative bell to produce fatigue to the negative stimulus. After fatigue the positive bell was given, but witli no punishment; the reflex appeared. The negative bell was next given but no reflex appeared. The positive bell was again sounded and the reflex appeared (differentiation). It will be noticed that respiratory changes occur at every stimulation. There is a deep inspiration each time either of the bells is sounded, and also slowing in rate. When training is continued long enough, differentiation occurs in respiration. (See Fig. 4.) That is. in a short time only the positive bell can produce the changes shown in this drawing.
PSYCHOLOGICAL METHODS 37 We may employ it in some cases asi a substitute for the verbal report method. In order to use it in the place of the latter method, we have to arrange conditions so that the reflex will ap- pear when, for example, a red light is given, but not when a violet light is given; or when a tone of 256 d.v. is given, and not when one of 264 d.v. is given. By using the method in this way it becomes possible to state what the smallest difference in wave length between two lights must be in order to arouse differential reaction; the smallest vibration difference between two tones; the FIG. 4. — Perfect differentiation with one subject when the difference is 6 v.d.
FIG. 5. — Perfect differentiation with another subject when the difference is 3 v.d.
smallest difference in intensity between two tones of the same pitch or two lights of the same wave length. In other words, instead of asking the subject as we do in the verbal report method: Is this light brighter or dimmer than another light, or, Is this tone lower or higher* than that tonef — we use the condi- tioned reflex method. The technic is as follows: Suppose our prob- lem is to establish a conditioned reflex to -a tuning fork of a certain pitch (256 d.v.) and to a second fork of a different pitch (264 d.v.). We will call these two forks Fx (positive) and F2 (nega- tive). As in the method already described, we give the electric stimulus with Ft until the reflex appears. The recording system is 38 PSYCHOLOGY 38 PSYCHOLOGY shown in Fig. 3. After this is thoroughly established we throw in I<\, and the reflex, of course, will appear. We then continue stimulating with F2, but never introduce the electric stimulus coincidently with it. After five or ten stimulations in rapid succession with F2, the reflex to it will disappear. We then sud- denly throw in Fj and if the reflex does not appear we introduce punishment. After this procedure has been continued for some time we finally reach the desired stage where, without any elec- trical stimulus at all, the reflex will always appear with Fx but will not with F2. It now remains to see how fine we can make this difference. In order to test this we gradually decrease the vibration difference between Ft and F2. (Figs. 4 and 5 show a difference limen which was developed inxa very short time.)
Other Objective Methods. — The conditioned reflex methods have been looked upon as the only objective methods in psy- chology. This is not true when we consider psychological methods in a broad way. All methods used in reaction time experiments and in experiments on "memory" and association are purely objective methods: much of the testing work, the work in experi- mental pedagogy and in business psychology, has been done with the aid of objective methods.
III. VERBAL REPORT METHODS.
Introduction. — The methods so far discussed have dealt with th<- integrated motor and glandular behavior of individuals other th;m ourselves. The methods have been largely developed by and have come into prominence through the study of animal behavior and infant human subjects. Indeed, in these fields we must depend largely upon such methods, since the observation of the happenings in their own bodies and the verbal reports of the same are impossible in the case of animals, or very imperfect in the case of 'abnormal individuals. Man is above all an animal which reacts most often and most complexly with speech reac- tions. The notion has somehow gained ground that objective psychology does not deal with speech reactions. This, of course, is a mistake. It would be foolish and one-sided to an ab-' surd degree to neglect man's! vocal behavior. Often the sole PSYCHOLOGICAL METHODS 39 observable reaction in man is speech. In other words, his ad- justments to situations are made more frequently by speech than through action of the remaining motor mechanisms. We shall in a later chapter develop our notion of the implicit and explicit language adjustments. We wish here mainly to show the use of speech reactions as a part of general psycho- logical methods. As an illustration of the use of the verbal report method in an actual experiment we may glance for a moment at the tests on sensitivity to warmth and cold on a given area of the skin. We first mark off a small area and go over it with a warm and a cold cylinder: we say to the subject, ' ' Tell us each time the cold cylinder is applied and each time the warm cylinder is applied. ' ' If the area touched is sensitive to cold he responds with the word "cold," and similarly when the warm cylinder is applied with the word "warm." The verbal report or response is put down in our records of the results of the ex- periment and is used exactly as the conditioned reflex responses would be used had we adopted that form of experimentation in our test.
Is There a Verbal Report Method Distinct from Other Observable Methods? — Up to the present time psychologists have employed the verbal report method in a somewhat different sense from that used here. Without entering into' this bitterly contested and controversial field, we can briefly outline- the posi- tion of this text in regard to it. The question: Can I make the same observations upon myself that I make on other individuals 1 brings home the difficulties. The answer is, of course, "yes," but it will be remembered that on page 13 we stated that all we can observe in another individual is his behavior, and we defined behavior as the integrated responses of muscles and glands. The question now becomes simpler: Can I observe the move- ments of my own muscles and glands and their integration? For example, that I am writing, that my face is flushed, etc.? Who would deny it?
At this point we diverge for a moment to correct a miscon- ception which has arisen with reference to objective psychology. The misconception lies in the fact that a good many psychol- 40 PSYCHOLOGY ogists have misunderstood the behaviorist's position. They insist that he is only observing the individual movements of the muscles and glands; that he is interested in the muscles and glands in exactly the same way the physiologist is interested in them. This is not the whole statement. The behaviorist is interested in inte- grations and total activities of the individual. At one moment we ask the question: What is the indiyidual doing? We observe that he is typewriting, searching for a lost pocket-book or "react- ing" to an emotional stimulus. If the latter happens to be true and we are interested in the way his emotional life as a whole hangs together, we may go on to show why the individual reacts in an emotional way to this particular stimulus. We may show how his fear reactions to certain situations arose in his infancy and how they have affected his whole personality and 'more highly organized habit activities. To illustrate this we may give a hypothetical example: Through some injury (or other emotional happening) in youth, occasioned by a rapidly moving mechanical toy, the individual cannot be induced to enter an automobile or motor boat or to ride in a train if it can possibly be avoided. In the occupations and activities of individuals we do not stop as a rule to reduce the total activity to muscle twitches. We can do it if necessary and we do do it at times when it becomes necessary to study the various part reactions. Surely objective psychology can study brick-laying, house build- ing, playing games, marriage or emotional activity without being accused of reducing everything to muscle twitch or the secretion of a gland. It is just as fair to accuse the behaviorist, or indeed the conventional psychologist as far as that goes, of reducing everything to the ionic constitution of matter. All of us believe that matter is constituted as the physicists would have us believe, but his formulation does not help us very much in specific psychological problems. On the psychological side, we can describe a man's behavior in selecting and marrying a wife. We can show how that event has influenced his whole life after marriage. In detail, how the increased responsibility stabilized certain emotional mal-adjustments, how the added financial burden led him to work longer hours and to study the PSYCHOLOGICAL METHODS 41 details of his profession so that his salary would be increased and his number of business connections enlarged. It would not help us very much in the present state of science to be able to trace the molecular changes in cell constitution — they certainly exist, but are aside from our problem. Our problem is the effect of marriage upon the general behavior of this one individual.
In the psychological laboratory we do find it necessary often to study the details of the total activity we see in daily life. When it becomes necessary to make such observations1 we find it extremely difficult to observe the part or individual reactions of our own bodies. We pointed out above that observation is often impossible without the use of instrumentation and the control of the experimental setting. Hence the movements which we would have to make in the manipulation of the instruments and the setting would interfere always with the movements we are trying to observe in ourselves. It is perfectly possible for a subject to make observations by the use of his eyes of the num- ber of drops coming from the salivary glands after some one has attached the apparatus for him; but in reaching for acids, water to wash out the mouth, etc., certain variable factors are intro- duced which disturb the purity and the scientific character of the observation. Physiology has to answer this same question; but who doubts that the physiologist can make observations of a kind upon his own heart, respiration, and movements of the food particles in the intestines? But if the physiologist limited himself to what he could learn from observing and experimenting upon his own organs, he would long ago have given up the science. But now and then the physiologist and the physician, like other human beings, observe that something goes wrong with one of their organs. They immediately put themselves into the hands of a skilled observer who brings all of the technic of modern science to bear upon the observation he is about to make. His report may be that there are adhesions, mitral leaks, or an enlarged spleen. In other words, in physiology and in medicine self-observation is crude and inexact and is discarded just as soon as other methods can be brought to bear. We suffer in psychology to-day greatly because methods for observing what goes on in 42 PSYCHOLOGY another individual's internal mechanisms in general are lacking. For this reason we have to depend in part at least upon his own report of what is taking place. We are gradually breaking away from this inexact method; we shall break away very rapidly wlu-n the need is more generally recognized. Suppose we have a subject in the laboratory. We record his arm and finger re- sponses to a given experimental situation. During the course of the experiment we may also want to know whether there is an increased tension in the leg muscles. We ask the subject: When you move your hands in this experiment do your leg muscles contract? He may say "yes" or "no" and he may be right. But if we want a scientific answer to depend upon, we immedi- ately attach an instrument which will record any change in the tension of the leg muscles. We discard crude self-observation and turn to instrumentation wherever it is necessary or possible. But in many spheres of psychology and especially in psy- chiatry, self-observation, which is usually expressed in words by the subject, is the only kind of observation at our immediate dis- posal. The patient comes to the psychiatrist and says: "I feel 'sad' and 'gloomy' "; or, "Doctor, I am under a terrible strain —I fear I am going to kill my wife and children." This is a psychological situation which the physician must meet. The physician then by a series of skillful questions begins to take the word responses of the patient. These responses, however, are from the physician's standpoint as objective as would be a mov- ing-picture photograph of the subject's activity in weaving a rug or basket. The responses are a part of the record of the subject's way of adjusting to his world. These responses the physician can in virtue of his past training connect with the remote and immediate situations in the life of the patient which have produced the mal-adjustment. The physician has found that when speech reactions of such and such types are made by the patient, they are to be associated with disturbances of the remaining action systems— the individual's action systems are no longer integrated and no longer function as a unit, as is neces- sarily the case when the patient is well.
PSYCHOLOGICAL METHODS 43 IV. METHODS OF TESTING.