Story of Psychology - Morton Hunt [193]
Similar experiments with eight still younger children, ranging in age from eight to thirteen months, were conducted a little later by a young German psychologist, Karl Duncker, who had studied with both Wertheimer and Köhler at Berlin. He used a simple problem situation. The children sat at a table on which an attractive toy lay beyond reach; a stick was at hand. Only two children had insight almost at once; five others played with the stick until they either deliberately or accidentally moved it close to the toy, at which point they abruptly perceived the stick as a retrieval implement. The youngest child never solved the problem.28
Duncker’s more important work involved a series of problem-solving studies conducted between 1926 and 1935 with adult subjects. One of his research methods was to present a problem and ask the subject to think out loud as he tried to solve it; Duncker recorded what was said and then analyzed his “protocol” or written record to see how the subject formulated the problem and searched for a solution. This was one of the two problems:
Given a human being with an inoperable stomach tumor, and rays which destroy organic tissue at sufficient intensity, by what procedure can one free him of the tumor by these rays and at the same time avoid destroying the healthy tissue which surrounds it?29
A typical subject’s protocol (excerpted and much abbreviated here) read like this:
Send rays through the esophagus.
Expose the tumor by operating.
One ought to decrease the intensity of the rays on their way; for example—would this work?—turn the rays on at full strength only after the tumor has been reached.
Either the rays must enter the body or the tumor must come out.Perhaps one could alter the location of the tumor—but how?
Through pressure? No.
The intensity ought to be variable.
Adapt the healthy tissues by previous weak application of the rays.
I see no more than two possibilities: either to protect the body or to make the rays harmless.
(Experimenter: How could one decrease the intensity of the rays en route [as you suggested earlier]?)
Somehow divert… diffuse rays… disperse… stop! Send a broad and weak bundle of rays through a lens in such a way that the tumor lies at the focal point and thus receives intensive radiation. 30
This protocol and others showed that when faced with such a problem, people use a number of different heuristic (exploratory) techniques. Most often they start with mechanical or routine heuristics, such as trying random possibilities based on the most immediate or obvious characteristics of the problem; such heuristics usually yield poor solutions or none. In the above protocol, sending rays through the esophagus or exposing the tumor by operating are efforts of this kind.
Eventually, after reaching a number of dead ends, many subjects get around to more productive “functional” heuristics (a few others use them from the outset), such as trying to identify the essential properties of the problem. They ask themselves, for instance, what the fundamental goal is, and only then do they look for a specific solution. In the above protocol, the subject began thinking this way when he said, “One ought to decrease the intensity of the rays on their way.” He then reverted to the first kind of thinking (“Perhaps one could alter the location of the tumor”), but after the experimenter reminded him of his more basic heuristic he suddenly had his dramatic insight into a feasible solution. The mechanical heuristics are analogous to the chicken’s running back and forth along the fence, the functional heuristics to looking at the situation in broad perspective and seeing a less direct but effective way of reaching the goal.
Duncker