Story of Psychology - Morton Hunt [291]
(From many such studies, plus the results of brain scans showing what areas are activated by the effort to visualize something, it has become fairly clear that mental images are not located like filed pictures in any one or several places, but that the components of each image—its shape, its color, its texture, and so on—are filed away separately and that summoning up a mental image uses many of the same processes that perception itself does, calling up and coordinating these several elements into one final, more or less complete image. But not a pictorial image; just as the letters of this sentence symbolize things they don’t physically resemble, the patterns of firing of brain neurons represent objects and events in the outside world.6 Why did evolution devise this scheme? Let the evolutionary psychologists figure out that one.)
These are but a few of the mysteries of visual perception; perhaps no area of psychology has produced as much research data and as relatively few definitive answers. Some years ago, James J. Gibson, a controversial but noted perception theorist, flatly asserted that most of what perception researchers had learned in the past hundred years was “irrelevant and incidental to the practical business of perception.”7 A trifle more moderately, the perception psychologists Stephen M. Kosslyn and James R. Pomerantz said in 1977 that, despite all the accumulated data, perception is still poorly understood.8 Still, they added, “we do know some things about it.” And, they could add today, they now know a good deal more about it. Indeed, enough to begin to understand it, to answer at least some of the interesting questions, and to discard others in favor of more cogent ones.
Styles of Looking at Looking
For centuries, philosophers debated about whether we are born with mental equipment that makes sense of what we see (the Kantian or nativist view), or must learn from experience to interpret what we see (the Lockean or empiricist view). When psychology became experimental, the findings of perception research not only failed to answer the question but added to the evidence for each side. Although today the terms have been redefined and the hypotheses have become more sophisticated, the debate continues.
Locke, Berkeley, and other philosophers and psychologists sometimes fantasized a test case that would definitively resolve the issue: a person blind from birth who, through an operation or some other intervention, suddenly gains sight. Would he know, without touching what he was looking at, that the object was a cube rather than a sphere, a dog rather than a cat? Or would his perceptions be meaningless until he learned what they meant? Such a person’s experiences might hold the key.
In recent centuries a handful of such cases have, in fact, turned up. The most carefully reported was that of an Englishman with opaque corneas who, in the early 1960s, at the age of fifty-two was able to see for the first time.9 S.B., as he is called by Richard L. Gregory, a British psychologist and perception expert who studied him closely, was an active and intelligent man who had made a good adaptation to his blindness: He was skilled at reading Braille, made objects with tools, often chose to walk without the customary white cane even though he sometimes bumped into things, and would go bicycling with a friend holding his shoulder to guide him.
In S.B.’s middle years, corneal transplants became possible, and he underwent an operation. According to Gregory’s report, when the bandages were removed from his eyes, he heard the surgeon’s voice and turned toward what he knew must be a face. He saw only a blur.
Experience, however, rapidly clarified his perceptions: Within days he could see faces, walk along a hospital corridor without touching the walls, and recognize that the moving objects he saw through the window were cars and trucks. Spatial perception, however, came to him more slowly. For a while, he judged the distance to the ground below his hospital window to be such that he could touch