Story of Psychology - Morton Hunt [195]
It was not the human mind, however, but the mind of the hen that provided the first solid evidence that associationist and S-R theories of learning were seriously inadequate. Köhler, during his stay on Tenerife, conducted a tedious but enlightening experiment with four chickens. He allowed two of them to peck at grain scattered on a light gray square of paper but shooed them away whenever they tried to peck at grain on a darker gray square of paper. He gave the other two chickens the opposite treatment. Chickens are notoriously stupid, but after four hundred to six hundred trials the first two would peck only at grain on the lighter paper and the second two only at grain on the darker paper.
Köhler then altered both situations. He kept the background color the chickens had been trained to eat from but replaced the other one, substituting a still lighter paper in the first case, a still darker one in the second. Associationist and S-R theory would predict that since the chickens had learned to associate eating with a particular shade of gray, they would continue to do so, but in 70 percent of the trials they pecked at grain on the new backgrounds rather than the old ones. The pair that had been trained to eat from the lighter of two backgrounds now mostly chose the new, still lighter background; the two who had been trained to peck at the darker of two backgrounds now mostly chose the new, still darker background. Gestalt theory offered an answer: The chickens had learned to associate food not with a specific color but with a relationship— in one case the lighter, in the other case the darker, of two backgrounds.32
Köhler repeated the experiment with chimpanzees and with a three-year-old child. He presented each with two boxes, one of a dull color, the other of a bright color. When a chimpanzee was the subject, the bright-colored box had a bit of food in it; when the child was the subject, a bit of candy. After the chimpanzee and the child learned that the bright box contained the reward, Köhler eliminated the dull box and substituted a new one, even brighter than the reward box. This time he put a reward in both boxes so that there was no incentive for the subjects to choose either except its color relationship to the other—and in fact the chimpanzees and the child usually chose the new, brighter box.
Behaviorists and Wundt’s followers had known that an animal can be trained to choose one of two different-colored objects, but had refused to believe that what the animal learned was the relationship between the colors. To these “elementalist” psychologists, a relationship could not be a primary psychological fact. As Solomon Asch, a student of Wertheimer’s, observed, “This premise was sufficiently potent to blot out the ceaseless evidence of experience.”33
But Köhler’s experiment showed conclusively that the relationship between the colors was indeed the primary fact the animals had learned, since they transposed it to a different situation.34 It was an example of the general rule, said Asch, that animals and humans perceive and learn nearly everything in terms of relationships. This object stands on top of that one, is between two others, is bigger than, smaller than, earlier or later than another, and so on. Relations are the key to perception, learning, and memory. That truth had been excluded from psychology but was reinstated by the Gestaltists.
Wertheimer, Köhler, Koffka, and many of their students did research on learning, but much of the credit for promulgating their cognitive view of it goes to Koffka. That shy, self-doubting, homely little man with his odd, high-pitched voice was at his best when assembling facts and theory on paper; in print he could be masterful and scathing.
Koffka himself conducted no noteworthy research on learning; nearly all his experimental work was on the perception of depth, color, and motion. But because his English was excellent, the editor of the Psychological Bulletin,