Areas for Basic Research in Perception Contemplated at Cornell
J. J. Gibson, Cornell University
The World Wide Web distribution of James Gibson’s “Purple Perils” is for scholarly use with the understanding that Gibson did not intend them for publication. References to these essays must cite them explicitly as unpublished manuscripts. Copies may be circulated if this statement is included on each copy.
1. The description and specification of stimuli with regard to the natural variables of stimulus energy as distinguished from the abstract variables of physical energy. Optics, acoustics, mechanics and biochemistry would be considered in relation to ecology. A study of the relations between stimuli and their environmental sources would provide the basis for a factual survey of stimulus information which could take the place of the rather vague theoretical notion of “cues”.
2. The elaborating of the concept of potential stimuli, and the determining of the conditions under which they become effective. Excitation of the receptors of an individual is known to depend on the species equipment, on the development the sense-organ adjustments, and probably on habits of sensory exploration. Awareness and reaction are said to depend on selective attention, set, and the education of attention. All these presuppose the notion of a potential stimulus.
3. The application of new discoveries in sensory physiology to perception, particularly facts about receptive surfaces and their functional elements.
4. A reclassification of the so-called sensory channels in the light of the information they register rather than in terms of the impressions they yield to analytic introspection. This involves a reconsideration of extero-, proprio- and interoception, which divisions are too simple.
5. The continuing study of classical problems of space and time perception reformulated in terms of the properties of surfaces objects, events, and motions Ð the natural sources of potential stimuli.
6. The isolation and control in the laboratory of stimulus variables of higher order than intensity or frequency Ð variables taken to be representative of the environment Ð for psychophysical judgments by human observers. This is perceptual rather than classical sensory psychophysics.
7. The utilization of animals and children in detection and discrimination experiments, employing an already established response instead of a verbal judgment and a potentially informative input instead of a meaningless variable. This involves the isolating of some chosen feature of the environment, not the stimulating of all features of an environment, i.e. an attempt to set up an artificial “releaser” stimulus. The “optical cliff” is an example.
8. A search for the invariants in natural stimulus inputs, i.e. for a high-order proximal stimulus which does in fact specify its object despite a transformation of the low-order proximal stimulus which does not. This search would be part of an effort to resolve the present theoretical confusion surrounding the problem of perceptual “constancy”. It involves a new approach to the problem of object-perception with a reexamination of the figure-ground hypothesis and a restudy of the “laws” of organization. The emphasis would be on the distinguishing features of different objects which remain unaltered by changes in perspective, visual angle, and illumination.
9. A systematic attack on the central problem of optical pattern stimulation, as distinguished from merely opportunistic experiments on “pattern recognition”. The application of mathematics, information theory, and computer theory to pattern registration is believed to be only in its infancy, and some neurological models for pattern vision seem to be following blind alleys.
10. A taxonomy of optical stimuli for the use of experimenters interested in visual perception. The stimuli would be classified in terms of the ways of controlling light to the eye or eyes of a subject, and the sources of this light (natural objects, arrays, models, pictures, drawings, displays, targets, optical instruments, mirrors, screens, wide-screens, spots, textures, lines, apertures, framed vs. unframed arrays, etc.).
11. A fresh attack on the old problem of the relation of touch to vision, with emphasis on the perceptions arising from exploratory touching rather than local passive “touches”.
12. A survey and reclassification of the various inputs lumped under the term kinaesthesis or proprioception (or feedback or reafference) with consideration of their various functions, and recognition of the fact that all receptive systems, not just one seem to provide information for the control of purposive action.
13. The study of ego-location in relation to space perception; more generally the involvement of bodily awareness in the orientation of an individual to his environment. Such a study would provide foundations for an adequate theory of locomotion; it might for example, resolve the current controversy over “response learning” vs. “place learning” in maze behavior.
14. The continuing study of event perception, and the perception of the change of non-rigid objects by the systematic control of special optical transformations applied to the eyes of an observer.
15. The isolation and control of some of the variables of expressive movement of animals and men in the effort to provide a psychophysical basis for the study of social perception and person perception.
16. In general, the study of perceptual development and perceptual learning in children by experimental rather than clinical methods.
a. The spontaneous increase of sensitivity with age to certain kinds of informative stimuli, with consideration of the possibility of “critical periods” for the development of such sensitivity.
b. Research on the education of attention, with a reexamination of the old experimental methods used to investigate so called “attention”.
c. Continuing study of the improvement of psychophysical discrimination with practice both with and without knowledge of results.
d. Further study of the perceptual differentiation of objects e.g., of cue-items in paired associates learning). The theoretical question here is whether perceptual differentiation is a prerequisite to the forming of associations or whether the forming of associations or whether the forming of associations is prerequisite to perceptual differentiation. Is learning to discriminate objects separable from learning different overt responses to different objects?
e. Further experimental investigations of the development in children of the ability to respond to pictures as if to the scene pictured.
f. Experimental study of the development in children of the ability to respond cognitively to words and symbols as substitutes for realities.