Story of Psychology - Morton Hunt [192]
With chimpanzees, some of the most dramatic instances of insight were elicited by another problem. Köhler would put an ape in a cage and a bunch of bananas outside, out of reach. In the cage would be several sticks; a chimpanzee might not realize for some time that it could reach the bananas with a stick but then all at once see that it could. A female chimpanzee, Tschego, first tried to reach the bananas with her hands and after half an hour got discouraged and lay down. But when a few other chimpanzees came into view outside the cage, she leaped to her feet, seized a stick, and deftly pulled the bananas within reach. Apparently the sight of other apes nearing the food served as motivation and produced the click of insight.
In another stick problem, the moment of illumination was even more dramatic. Köhler’s account of it:
Sultan cannot reach the fruit, which lies outside, by means of his only available short stick. A longer stick is deposited outside the bars. [It] cannot be grasped with the hand, but it can be pulled within reach by means of the small stick. Sultan tries to reach the fruit with the smaller of the two sticks. Not succeeding, he tears at a piece of wire that projects from the netting of his cage, but that too is in vain. Then he gazes about him (there are always in the course of these tests some long pauses, during which the animals scrutinize the whole visible area). He suddenly picks up the little stick once more, goes up to the bars directly opposite the long stick, scratches it toward him with the “auxiliary,” seizes it, and goes with it to the point opposite the objective, which he secures.23
In an even more complicated problem, the bananas lay beyond reach with either of two available sticks; one of them, however, was thinner than the other and could be pushed into the thick one to combine their lengths. Even clever Sultan did not quickly see this solution. He spent about an hour trying to reach the fruit, to no avail; Köhler gave him a hint by sticking one of his own fingers into the end of a stick, but Sultan did not get the idea. Then:
Sultan squats indifferently on a box, which has been left standing a little back from the bars; then he gets up, picks up the two sticks, sits down again on the box, and plays carelessly with them. While doing this it happens that he finds himself holding one rod in either hand in such a way that they lie in a straight line. He pushes the thinner one a little way into the opening of the thicker, jumps up and is already on a run toward the bars, to which he had up to now half turned his back, and begins to draw a banana toward him with the double stick.24
One of Köhler’s most important findings, with sweeping implications for the psychology of learning, was that insight learning does not depend on rewards, as did the stimulus-response learning of Thorndike’s cats. The chimpanzees were, of course, seeking a reward, but their learning was not brought about by the reward; they solved the problem before eating the fruit.25
Another important finding was that when animals achieved an insight, they learned more than the solution to that particular problem; they were able to generalize and apply the solution in modified form to different problems.26 In psychological terms, insight learning is capable of “positive transfer”; in lay terms, the chimpanzees became test-wise.
Köhler reported his findings in a monograph in 1917 and in a book, The Mentality of Apes, in 1921. Both monograph and book made a considerable impression in the world of psychology, and not only as a study of animal problem solving; Köhler’s observations prepared the way for Gestaltist studies, using the same techniques, of human problem solving.
In 1928, a psychologist at Teachers College, Columbia University, used Köhler-type situations with children ranging in age from a year and a half to four years. Instead of bananas, the desirable objects were toys, which she placed out of reach, either outside the bars of a playpen or on a shelf. Sticks were available in the playpen experiment,