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Harlowâ€™s (1949) research examined the ability of monkeys to solve discrimination problems, as shown in Figure 6.7. The problems are extremely simple: One of the two objects always covers a piece of food, and the animal must learn that it will be rewarded when it picks up that object. This situation is called discrimination learning, because the animal must learn to discriminate between the two objects when making its choice. Monkeys only gradually learn to pick only the object that covers the food.
The innovative aspect of Harlowâ€™s study was to give the animal a series of several hundred discrimination problems. After the animal had learned to pick one object consistently to get a reward, a new problem was presented with a different randomly chosen pair of objects. The underlying solution principle was always the same, however: Food was always under only one of the objects. By the end of that long series of problems, the animalsâ€™ behavior toward each problem had changed significantly; they now needed only one choice to learn what to do. When a new problem was presented, the animals picked one stimulus; if the food was under it, they picked it consistently from then on. If the food was not under that stimulus, then the animals switched to the other from then on.
Figure 6.7 Examples of Harlowâ€™s discrimination problems Source: Weisberg (1993).
The Question of Insight in Problem Solving
If you had seen one of those animals at the beginning of the experiment, when it was fumbling its way through a problem, you would have said that it was a â€śThorndike animal,â€ť behaving on the basis of blind trial and error, with only a gradual strengthening of the correct response. By the end of the experiment, however, one could describe the animalsâ€™ behavior in Gestalt terms, by saying that they were showing insight into the structure of the problems. Thus, in the same situation, the same animal can behave by trial and error and can also show insight; the crucial element is the large amount of experience needed before insight develops. Once again we see that insight into the structure of even seemingly simple problems may require much knowledge about those problems.
The Role of Analysis and Experience in Failure to Solve the Nine-Dot Problem
As discussed earlier, the concept of fixation was brought forth to explain peopleâ€™s striking inability to solve the Nine-Dot problem (e.g., Burnham & Davis, 1969; Lung & Dominowski, 1985; Weisberg & Alba, 1981). The Gestalt psychologists proposed that fixation on the shape of the square makes the problem impossible to solve (Scheerer, 1963). Solution would be within our grasp if only we could structure the situation in the correct way, by breaking away from the fixation brought about by the shape of the set of dots. In an early test of the Gestalt view of fixation in the Nine-Dot problem, Weisberg and Alba (1981) gave college students the Nine-Dot problem with a hint: In order to solve the problem, they had to draw lines beyond the boundaries of the square. The students were instructed that if the lines were kept within the shape of the square, solution was impossible (see also Burnham & Davis, 1969). Weisberg and Alba assumed, on the basis of the Gestalt view, that if the hint made people think about going beyond the squareâ€™s boundaries, then restructuring should occur, fixation should be eliminated, and solution should become relatively frequent. In addition, the solution should be produced as an integrated whole, rather than in bits and pieces, as happens when a solution comes about through trial and error.
The go outside hint was not very effective in producing solutions, however (Weisberg & Alba, 1981): Only about 25 percent solved the problem. The hint did result in most people drawing lines beyond the boundaries of the square, so it seemed to have broken the fixation on the square. Furthermore, those people who solved the problem after the hint took an average of more than 11 additional solution attempts to do so, indicating that the solution was not suddenly seen as an integrated whole, as the Gestalt view of restructuring and insight might lead one to expect. In another experi-
Creativity: Understanding Innovation
ment, Weisberg and Alba (1981) gave undergraduates some practice solving simple connect-the-dots problems, in which they had to draw lines outside the shape defined by the dots (Figure 6.8A). This practice facilitated performance on the Nine-Dot problem, although still only a minority of the participants (46 percent) solved it.
Those results were extended by research carried out by Lung and Domi-nowski (1985), who also studied the effects of practice and instructions on performance on the Nine-Dot problem. Lung and Dominowski gave participants six practice problems before the Nine-Dot problem, two of which are shown in Figure 6.8B. They also provided what they called strategy instructions, shown in Figure 6.8C, which provided information about the logic of constructing a solution. The effects of all this information on performance on the Nine-Dot problem are shown in Figure 6.8D, and here too we find support for the idea that insight depends on more than a simple restructuring of the situation. Both the practice and the strategy instructions were effective in facilitating solution to the target problem, but even with both strategy instructions and six practice problems, only about 60 percent of the participants solved the Nine-Dot problem, and those people still took an average of more than eight attempts to do so.