hfavr@mtuxo.UUCP (07/15/86)
I have not read Kelley's book, but as a psychologist I am familiar with Gibson's "environmental" (or "ecological") theory of perception. In the standard contemporary conceptualization of perception, from which Gibson dissented, the input to the perceptual process is thought to be the sensory impression; for example, in visual perception, the pattern of retinal stimulation. According to the standard theory, the task of the perceptual system is to derive, from that pattern, a representation whose features are analogous to those features of the environment which originally caused the retinal pattern. If the perceptual system is thought of as physically limited to the eye and the brain, the standard view is close to being a logical necessity. It is from this conceptualization that Gibson dissented. In Gibson's view, the perceptual system is not limited to the confines of the organism, but extends into the environment. In the course of its evolution, the organism has assimilated physical mechanisms present in its natural environment to function as integral parts of its perceptual system. Thus, the perceptual processes implemented in the eye and the brain have evolved to function as the back-end of an integral process of perception that begins at the perceived object. In this view, the natural light sources present in the environment, the reflective properties of the surfaces of objects, and the optical characteristics of the atmosphere are as much a part of the human perceptual system as the eyes and the brain. Thus, the retinal stimulation pattern is not the input to perception, but rather an internal stage in the process. The input to the perceptual process is the object itself; the output is the organism's awareness of the object. The information contained in this awareness is the original, and not a re- (or transformed), presentation of the object to consciousness. According to Gibson, the experimental psychologist's laboratory use of two-dimensional representations, tachistoscopic stimuli, illusions, and other materials that were not part of the ecological environment in which the human perceptual system evolved, amounts to studying the human perceptual system with some of its key parts removed. This is rather like trying to find out how a computer works after pulling out some of its chips, or deducing normal physiology from the results of the surgical removal of organs. To yield valid information, the results of such experiments must be interpreted with special attention to the fact that one is not studying an intact or properly functioning system. Adam Reed (ihnp4!npois!adam)