January 1962
Theoretical Issues and Controversies in the Field of Perception
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 References to these essays must cite them explicitly as unpublished manuscripts.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.
Space and Form Perception
1. Is the third dimension lost in optical stimulation (Berkeley, Helmholtz, Brunswik) or is it specified therein (multiple gradient theory)?
2. Are the distal stimuli of the world to be taken for granted in theories of perception (realism) or are they to be explained by theories of perception (Cantril, Ittelson)? Can objects, in fact, be specified by their stimuli or not (Ames demonstrations)?
3. Are perspective impressions relevant to a theory of space perception or irrelevant? (Boring-Gibson controversy, Psych. Rev., 59, 1952). Also, what is “invariant” in perception?
4. What is the stimulus for an optical system? Ray-optics (textbooks) vs. ecological optics (paper in Vision Research, 1, 1961).
5. What is fundamental for the “organization” of visual perception? Figure – ground hypothesis (Koffa, Principles) vs. the structure – of – light hypothesis (Gibson, What is a form?, Psych. Rev., 58, 1951, and other references).
Physiological Basis for Perception
6. Field – theory (Köhler) vs. neuron theory (various references, including Hebb).
7. Are visual aftereffects always figural (Köhler and Wallach) or are they often negative (Ivo Kohler, Gibson)?
8. Is sense – perception an active process of search or a passive process of registration? (references to be supplied). What is active and what is passive? What are the “potential stimuli” for the senses?
Perception and Learning
9. Does association play an essential or a secondary role in perception? Enrichment vs. differentiation (Postman-Gibson controversy, Psych. Rev., 62, 1955).
10. Is perception based on sensation? if so, what is the process? If not, what is the use of sensation? (For the resolution of this dilemma, consider whether there exist sensationless perceptions. Also, whether perception can occur without sensory excitation.)
11. Does perception develop by the intellectualization of original experience (Piaget) or by the evolution of primitive differences into elaborate and subtle differences? (Various theorists).
12. If perception depends on the traces of past experience, where is the dividing line between perceiving and remembering? (Wallach vs. Gibson on motion perception. Trace memory vs. transformation theory. Cf. also Wm. James on perception and memory).
General Issues
13. Do optical illusions embody laws of perception, or result merely from conflicting stimulus information? (Wertheimer, Köhler, Koffka vs. theory of “informative” stimuli).
14. Is meaning acquired or registered? Theories of association, memory, attitude or conditioning (Hume, Pavlov, Osgood, etc.) vs. a theory of direct apprehension (Michotte, Gibson, and others). Cf. the concept of “raw stimuli” in Woodworth, Dynamics).
15. If the senses convey information do they carry it directly or only in “coded” form? (Application of the mathematical theory of communication to the senses).
16. Continuity vs. discontinuity theory of discrimination. Insight theory vs. association theory of problem-solving.
17. Do animals respond to relative or to absolute stimuli? The “transposition” controversy. Are stimuli punctate entities (Spence) or relations? May one infer perception of a difference without evidence that the animal can respond separately to the objects that differ?
18. The Gottschaldt controversy. Sensory organization vs. past experience as the explanation of perception.
19. The “nativism” controversy. Do “releasers” or “innate perception inlets” exist with infants or animals?
20. How can perceptual learning involve at once a reduction of stimulation – generalization, and an increase in the “generalization” of stimulus? Do particularization and abstraction go together in development; if so how?
21. Do we learn by adjusting to probabilities or uncertain contingencies (Skinner, et al.) or by insight for the laws of the natural environment, and the “ecological validity” of cues?
22. Graham vs. Garner. Is perception merely a special form of behavior, or not? Also, does perception necessarily mediate behavior or not?