BEHAVIOURISM is a direct outgrowth of studies in ani mal behaviour during the first decade of the 2oth century. C. Lloyd Morgan, the British psychologist, must be looked upon as the founder, virtually, of the American school of animal psychol ogy. His books, Introduction to Comparative Psychology and Animal Behaviour (1900), broke away from the traditional an thropomorphic interpretations of animal acts. He first empha sized the necessity of tracing all the steps in any act we see the animal performing before the interpretation of that act becomes possible. His actual experiments upon the learning of animals were few in number but rich in interpretative value. His studies emphasized the trial and error nature of all animal learning. Mor gan's work undoubtedly inspired the American animal psycholo gist, E. L. Thorndike, who first instigated systematic experimenta tion upon chicks, dogs, cats and monkeys in the United States. There soon followed in that country a host of experimentation upon mammalian learning. We mention in passing the work of Small, Yerkes, Kinnaman, Davis, Allen, Porter, Carr, Franz, Johnson, Ulrich, Richardson, Yoakum, Haggerty and Watson.
"Behaviourism when first conceived was based largely upon the rather loose concept of habit formation. The work of Pawlow and his students on the conditioned reflex, while known to the behaviourists, played at first a relatively minor role in their formulations. This was due to the fact that his experiments were chiefly concerned with conditioned glandular reflexes, which at that time was a subject hardly touched upon by psychologists. Bechterew's work on the conditioned motor reflex, where human subjects were used, had from the first a very much greater in fluence upon behaviourism. The work of Lashley in conditioning the human salivary reflex and of Watson and Rayner on con ditioning human emotional reaction (fear) showed the great range of application of the conditioned reflex methods to human be haviour. This work has led to an attempt to formulate all habit (organization) in terms of conditioned glandular and motor re action. In spite of the fact that behaviourism did not at first utilize to any extent the conditioned reflex methods, Pawlow and Bechterew must be looked upon as furnishing the keystone to its arch. During the period of the general formulation of behaviour ism as a system rather than as an approach to psychology, or as a specialised method in psychology, the writings of E. B. Holt, A. P. Weiss and K. S. Lashley are noteworthy." The behaviourist takes the position at the outsqt that the total behaviour of man from infancy to death is the subject-matter of (human) psychology. Behaviour can be observed like the phe nomena of all other natural sciences; e.g., chemistry, physics, physiology or biology. The same general types of methods used in the natural sciences can be used in behaviour psychology. So far in his objective study of man no behaviourist has observed anything that he can call consciousness, sensation, perception, imagery or will. Not finding these so-called mental processes in his observations, he has reached the conclusion that all such terms can be dropped out of the description of man's activity.
All behaviouristic observations apparently can be presented in the form of stimulus and response. The simple schema used is S--*R. A behaviouristic problem is solved when both the stimu lus and the response are known. For a very simple example, sub stitute in the above formula for S, contact on the cornea, and for R, blinking. The behaviourist's problem is solved when this has been done as a result of verified controlled experimentation. The neurologist has a problem to solve in this same phenomenon, namely, in determining the neural connections involved, their course, their numbers, the timing and spread of the neural im pulse, etc. The behaviourist does not encroach upon it. The phys ical chemist has a problem to solve here also. His problem is not encroached upon either by the behaviourist or by the neurologist.
His problem is the determination of the physical and chemical nature of the neural impulses, the amount of work done in the reaction and the like. In every human reaction there is thus a behaviourist's problem ; a neuro-physiological problem and a physicochemical problem. When the phenomena of behaviour are once accurately formulated in terms of stimulus and response, the behaviourist achieves predictability with reference to his phe nomena and control over them—the two essentials every science demands. One might put it in another way. Suppose the behav iourist were given the problem of how to cause a human being to blink, he solves it by touching the cornea with a hair (control). In more complicated reactions, especially those labelled "social" the S–*R relationships are not so easy to solve. For example, present the stimulus prohibition (S) to any given nation, what will the response (R) be? It may take years to determine R completely. Many behaviouristic problems have to wait for their solution upon the slow experimentation of science as a whole. Regardless of how complicated the stimulus-response relation ships may be, the behaviourist does not admit for a moment that any human reactions cannot be so described.
The general goal of behaviourism, then, is to so amass observa tions upon human behaviour that in any given case, given the stimulus (or better situation), the behaviourist can predict in ad vance what the response will be ; or, given the response, he will be able to state what situation is calling out the reaction. Looked at in this broad way, it is easy to see that behaviourism is far away from its goal. But while its problems may be difficult, they are not insuperable. The one thing that makes the approach of the behaviourist difficult is the fact that stimuli not at first call ing out any given response can come later to call out a specified type of response. We call this a process of conditioning (earlier called habit formation) .
This difficulty forces the behaviourist to resort to the genetic method. He takes the infant at birth and surveys his so-called physiological system of reflexes or, better, embryological re sponses. Having taken this inventory of unconditioned, unlearned responses, he next begins to try to condition them. When this has been done, two striking facts seem to appear. First, the num ber of complicated unlearned responses appearing at birth or at intervals thereafter is relatively small. This leads to the rejection of the whole concept of instinct. Most of the complex responses that the older psychologists called instinctive, such as crawling, climbing, cleanliness, fighting (a long list), are now believed to be built in or conditioned. In other words, the behaviourist no longer finds support for hereditary patterns of behaviour nor for special abilities (musical, art, etc.) which are supposed to run in families. He believes that given the relatively simple list of em bryological responses which are fairly uniform in infants, he can build (granting that both internal and external environment can be controlled) any infant along any specified line—into rich man, poor man, beggar man, thief.
These embryological responses do not appear haphazard—they are not "random." Some definite stimulus calls them out. Let us call all such stimuli unconditioned stimuli, (U)S. Let us call all such responses unconditioned responses (U)R. The formula could be expressed thus :— In the schema A is such an unconditioned stimulus and i is such an unconditioned response. Now if the experimenter takes B and B so far as is known may be any object in the universe—and lets it stimulate the organism simultaneously with A for a certain number of times (sometimes even once is enough) it thereafter will also arouse 1. In the same way one can make C, D, E call out r ; in other words, one can make any object at will call out i (stimulus substitution). This shows how the stimulus side of our life gets more and more complicated as life goes on. In a similar way reactions become complicated as soon as a simple stimulus through the process of conditioning comes to call out a chain of reflexes (integration). In this way the behaviourist tries to take the vague concept of habit formation and to give it a new and exact scientific formulation in terms of conditioned responses. On this basis the most complicated of our adult habits are explicable in terms of chains of simple conditioned responses.
The simplification in psychological theory which comes through the application of behaviouristic principles is best seen in the realm of the emotions. Take fear. The works of Watson and Rayner, Moss, Lecky, Jones and others have shown that the fundamental unconditioned stimulus (U)S calling out a fear reaction is a loud sound or loss of support. Every child with only one exception, of approximately i,000 infants examined, was found to catch his breath, pucker his lips, cry or, if older, crawl away, when a loud sound was given behind his head or when the blanket on which he was lying was suddenly jerked. Nothing else so far observed will produce the fear response in early infancy. Now it is very easy to make the child fear any other object in the universe. All the experimenter has to do is to show the object and strike the steel bar behind his head and repeat the procedure for a few times. The schema of this situation follows:— Conditioning of the emotions (fear, rage, love. etc.) takes place very much earlier in the life of the infant than has hitherto been supposed ; it is a process that brings complexity in response at a rapid rate. This means that an infant two or three years of age is already shot through with thousands of responses built up by the environment in which it lives.
"Take any child when he first begins to talk. Peep through the keyhole and watch him in the early morning. He will sit up in bed with his toys, talk aloud to his toys, talk about them. When a little older, he will plan out his day aloud, say aloud that his nurse is going to take him for a walk, that his daddy is going to bring him a car. In other words, he talks overtly when alone just as naturally as he works overtly. with his hands. A social factor comes in. The father gets to the point where his own morning nap is disturbed. He yells out : `Keep quiet.' The child begins then to mumble to himself—a great many individuals never pass this stage, and they mumble to themselves all through life when ever they try to think. The father does not like the child's mum bling any better than his talking aloud, and so he may slap him on the lips. Finally, the parents get the child to the point where he talks silently to himself. When his lips are closed, it is nobody's business what is going on below. Thus we come to behave as we please if we do not give any external motor sign of i—in other words, our thoughts are our own." A further question comes up for serious consideration : Do we think only in terms of words? "The behaviourist takes the position to-day that whenever the individual is thinking, the whole of his bodily organization is at work (implicitly)—even though the final solution shall be a spoken, written or subvocally expressed verbal formulation. In other words, from the moment the thinking problem is set for the individual (by the situation he is in) activity is aroused that may lead finally to adjustment. Sometimes the activity goes on (a) in terms of implicit manual organization; (b) more frequently in terms of implicit verbal organization; (c) sometimes in terms of implicit (or even overt) visceral organization. If (a) or (c) dominates, thinking takes place without words." Words are thus the conditioned (C)S substitutes for the world of objects and acts. Thinking is a device for manipulating the world of objects when those objects are not present to the senses. Thinking more than doubles human efficiency. It enables the individual to carry his day world to bed with him and manip ulate it at night or when it is a thousand miles away.
Strict behaviourism is making rapid progress in America. It, however, has not yet been universally accepted even here. The older subjective psychology is being profoundly modified by it. One sees very little of introspection and still less of imagery in the writings of the subjectivists.