Story of Psychology - Morton Hunt [295]
Other psychologists revived the long-neglected study of illusions, and by the 1950s it was again a topic of active research. The remarkable subjective triangle shown in FIGURE 25, created in 1950 by Gaetano Kanizsa, an Italian psychologist, was only one of many new illusions used to investigate mental processes of vision. A special kind of illusion was used to explore the mind’s interpretation of ambiguous figures. The following classic example, created in 1930 by Boring, can be seen at will either as an old hag turned partly toward the viewer or as a young woman turned partly away.
FIGURE 26
What kind of woman is this? That depends on what you choose to see.
The capacity to see either of two different images in ambiguous figures like this one or in figure-ground reversal patterns like the Rubin vase (Figure 12) cannot be explained by any known physiological mechanism, the British psychologist Stuart Anstis has said, but is the result of higher perceptual processes.*19 The same is true of the mind’s acceptance of, or bewilderment by, the “impossible objects” created by perception researchers in the 1940s and 1950s, of which these are classic examples:
FIGURE 27
Two “impossible objects”
It is the mind, not the retina, optic nerves, or specialized cells of the neural cortex, that interprets the cues in such a figure as a picture of an object and simultaneously realizes that no such object could exist in the real world.
Another cognitive approach to perception was that of a number of American psychologists who, beginning in the 1940s, sought to discover how needs, motivations, and mental sets affect perception. Jerome Bruner and Leo Postman of Harvard, two leaders in this endeavor, showed toys and plain blocks, all three inches in height, to young children, and asked them to judge the objects’ size; the children thought the toys were taller. In an extension of the experiment, they told the children they would get to keep the toys, but temporarily broke their promise. When the toys seemed unavailable, the children judged them as even larger than they had previously. Other researchers asked hungry and not-hungry subjects to estimate the size of food items; the hungry ones saw them as bigger than did the others. These and similar experiments demonstrated that need, desire, and frustration influence perception.20
So do certain traits of personality, according to other studies of that era. By means of a written test and an interview, Else Frenkel-Brunswik, a psychologist who was trained in Vienna and had immigrated to America, rated a group of children on ethnic prejudice, a trait she associated with the rigid “authoritarian personality pattern.” She then showed the children a picture of a dog, followed by a series of transitional pictures in which the image gradually became that of a cat. Those who had scored high on prejudice tended to see the image as a dog longer than the unprejudiced, who were more flexible. Much the same was true when she asked children to identify the color of a series of cards that changed from one hue to another.21
Other cognitive studies of perception in the 1940s and 1950s explored “perceptual defenses”—forms of mental resistance to seeing something disturbing. Researchers used tachistoscopes to flash words on a screen very briefly (for a hundredth of a second or so), and found that subjects were less likely to recognize taboo words than neutral ones. The effect was strongest when the subjects were females and the experimenter male. One team used a tachistoscope to display achievement-related words like “compete” and “mastery,” and neutral words like “window” and “article”; subjects who