Conditioned Reflex

Normally dogs snatch at food; elephants reach out their trunks for it. A man will pull his hand away from a hot plate. These are examples of unconditioned reflexes, fully developed in infancy. They constitute the equipment with which the animal faces life, according to the behaviorists.* By modifying the conditions, the simple reflexes may be changed, becoming more complicated, or conditioned. The process of changing an unconditioned reflex into a conditioned reflex was clearly demonstrated to an audience of psychiatrists at the Academy of Medicine last week, in a cinema entitled "The Mechanics of the Brain."

The cinema showed dogs which dripped saliva at the sound of a bell, monkeys which marathoned to the food box at the sight of a red card, children who opened hungry mouths when their wrists were pressed. These are examples of conditioned reflexes and upon this conditioning is based the difference between the lower and the higher animals, including man.

The unconditioned reflex is the simplest nervous reaction. A dog will smell food and turn in its direction. Nature believes in preparedness and the dog will secrete saliva as he goes for the food. Only the lower parts of the brain are concerned in this reaction. But, if a bell is rung every time the food appears, there will come a time when the dog will secrete saliva at the sound of the bell when there is no food in sight.

The simple reflex has been conditioned by the bell; the dog has associated the food with the sound; the power house of the upper brain has gone into action, and the intelligent animal now reacts to an idea. This is the learning mechanism in its elementary form. If the upper brain is now removed, the learned reaction will be lost.

Not only can animals be taught to associate widely different stimuli, but they can be taught to discriminate. Example:

Old Lady, wise ape, was presented repeatedly and alternately with a red card, and with a blue card. With the red card came, always, food in a food box. With the blue card came the food box but no food. After a while, the food box was removed to a distant corner. Red and blue cards kept flashing before Old Lady's eyes. When the blue card flashed, Old Lady gazed at it in polite boredom and went on quietly with her toilet. They couldn't fool her. But when the blue card disappeared and the red card showed, Old Lady's eyes gleamed. She swung herself from her perch, rushed down the ladder with unladylike haste and made for the food box in the corner.

Here is the rejection of one idea and the acceptance of another; a more complicated instance of learning.

The evolution of the animal depends on the development of the upper brain: the greater the development the more complicated the conditioned reflexes become. The ability to learn by experience, which is simply a matter of conditioning the reflexes, increases; the animal can adjust to ever more varied environments. Man has the most intricately convoluted upper brain of the whole animal kingdom and can therefore adapt himself to a wide range of conditions.

When animals were first studied by the psychologists, their behavior was interpreted anthropomorphically. The knowledge of human psychology was thrown into reverse and the animals were credited with consciousness, introspective, free will, after the German school led by Wilhelm Max Wundt. First to throw brilliant new light on the problem was Ivan Petrovich Pavlov. Son of a priest in a Russian village, he was early confronted with Spirit & Mind v. Matter. Long years in scientific study got him a doctor's degree at the age of 34. Six years later, 1890, he was appointed director of the physiology department of the Institute of Experimental Medicine at St. Petersburg (Leningrad). From then on, his path was undeviating, scrupulous, relentless. His "Work of the Digestive Glands" was crowned by the Nobel Prize in 1904. Having mastered the mechanics of digestion he started speculating on psychic stimulation, the power of suggestion on the lower organs. He conditioned various animals to a bell, to a light, to a color, to the beats of a metronome, and in each case, after appearing with the food a few times, the object itself when presented without food caused the salivary gland to secrete steadily.

The dogs could be taught to discriminate between a metronome beating 68 beats per minute to one having a rate of 200. Food appeared with the 200 rate, nothing happened at 68. After the dog had been conditioned the metronome was placed near him and started at 200. Immediately saliva dripped into the little tube connected with his salivary gland. The metronome slowed to 68. The dog was no longer interested. Two hundred again and the flow of saliva recommenced.

Pavlov then studied an emotion, pain.

A ticking metronome was set beside a dog. Simultaneously he was given a slight electric shock in the leg. This was repeated several times. Finally the metronome alone was used. As soon as it started ticking, up came the paw, the dog's face contracted with pain and he remained in agony until the instrument was removed.

Three years ago Pavlov came to America. Confused by rush and roar he sat for a moment on a seat in Grand Central Station, Manhattan. A small handbag containing much of his money lay on the seat beside him and with characteristic absorption in the seething human laboratory around him, he forgot his worldly goods completely. When he rose to go, the handbag was gone. It had been taken from under his very nose. "Ah, well," sighed Pavlov gently, "one must not put temptation in the way of the needy."

So fundamental are these researches that during the War and the aftermath, when all of Russia existed on starvation rations, Pavlov's laboratory continued to function as in times of peace. There was no bread to eat, but there were test tubes, metronomes, platinum wires, and as Pavlov remarked gratefully "always plenty of paper and pencils to write down experiments."

Pavlov's researches have revolutionized the study of human psychology. Man is now regarded as a higher member of the animal kingdom psychologically as well as physiologically. On account of the greater complexity of the human brain, more types of reaction are possible but the underlying mechanics are the same. The recent work on shell shock has demonstrated what harm can arise from badly conditioned reflexes.

Physiologist Pavlov has reached the point where he can create a nervous condition in animals similar to the nervous states of man which border on insanity. He is now applying his results to the reconditioning of the insane and the education of the mentally deficient.

* The behaviorists claim that all behavior, no matter how complicated or idealistic, is the effect of the environment on the unconditioned reflexes. Chief exponent of behaviorism--John Broadus Watson.