Story of Psychology - Morton Hunt [311]
At the New School for Social Research Rock fell under the spell of the Gestaltists who were there and became an ardent one himself. Certain basic Gestalt laws of organization and relational thinking are still part of his theory. But those laws describe essentially automatic processes, and Rock came to believe that many perceptual phenomena could be accounted for only by mental processes of a thoughtlike character.81
This idea first occurred to him when he conducted the 1957 experiment, described above, in which he tilted a square so that it looked like a diamond, then tilted the perceiver. Since the perceiver still saw the square as a diamond, Rock reasoned that he must have used visual and visceral cues to interpret what he saw. Rock spent many years devising and conducting other experiments to test the hypothesis that, more often than not, perception requires higher-level processes than those taking place in the visual cortex. These studies led him, finally, to the thesis that “perception is intelligent in that it is based on operations similar to those that characterize thought.”82
And indeed, Rock has said, perception may have led to thought; it may be the evolutionary link between low-level sensory processes in primitive organisms and high-level cognitive processes in more complex forms of life. If what the eye sees, he argues, is an ambiguous and distortion-prone representation of reality, some mechanism had to evolve to yield reliable and faithful knowledge of that reality. In his words, “Intelligent operations may have evolved in the service of perception.”83
This is not to say that all perception is thoughtlike; Rock specifically cited the waterfall illusion as explicable in low-level neural terms. But most facts about motion perception and other kinds of perception seemed to him to require high-level processes. Unconscious inference, as in our use of texture gradient cues to sense distance, is only one of them.84 Description that results in interpretation is another. In the ambiguous old hag–young woman figure by Boring, what one sees is not the result of simply recognizing an image but of describing to oneself what a particular curve is like: like a nose or like a cheek. Many perceived forms or objects are not instantly recognizable; recognizing what they are comes about through such a process.85
Perception also often calls for problem solving of one sort or another. One hardly thinks of perception as the solving of problems, but Rock marshaled a considerable amount of evidence—much from earlier studies by others, some from his own original experiments—to show that in many cases we seek a hypothesis to account for what we see, weigh that hypothesis against other possibilities, and choose the one that seems to solve the problem of making sense of what we see. All of this usually takes place in a fraction of a second.
One example: In a laboratory phenomenon known since the time of Helmholtz, if a wavelike curved line is passed horizontally behind a slit, as in the above figure, most observers first see it as a small element moving up and down, but after a while some of them will suddenly see the sinuous line moving at right angles to and behind the aperture. What produces their altered and correct perception? Rock found that one clue they use is the changing slope of the line as it passes the slit; another is the end of the curved line, if it comes into view. Such clues suggest to the mind an alternative hypothesis—that a curve is moving past the slit horizontally, rather than that a small element is moving up and down. This hypothesis is so much better that the mind accepts it and sees the line as it really is.86
FIGURE 38
Anorthoscopic perception: The dot moves up and down but the mind figures out what is happening.
Rock summed up his theory as follows:
On a theoretical level, at least according to the theory presented here, both perception and thought entail reasoning. In some cases, generalizations or rules are arrived at in perception by induction. These rules are then used deductively