The organization of perceived space

Summary Perceptions tend often to be proportional to proximal stimuli with reduced conditions of observation and proportional to distal stimuli under multicue conditions. Two explanations of this phenomena are examined. One, termed the core context hypothesis, postulates that the response to the proximal stimulus (the core) is modified by distance information (the context). The second, termed invariance hypotheses, postulates an interaction between two or more perceptions, one of which is often perceived distance. In order for invariance hypotheses to be valid it is necessary that a perceived distance occur under reduced cues of distance. It is asserted that perceived distance under these conditions is supplied by observer tendencies termed the specific distance and equidistance tendency. Perceptual interactions occur in situations other than those relevent to invariance hypotheses and the evidence for perceptual interactions is discussed in relation to perceived motion, perceived depth from exocentric cues, the adjacency principle, and other phenomena. It is suggested that the analysis of many perceptions in terms of perceptual interactions is parsimonious in that the effect of the independent perception, e.g., perceived distance, upon the dependent perception, e.g., perceived size, motion, or depth, is the same regardless of the cues by which the particular value of the independent perception is achieved.Preparation of this chapter was supported by PHS research grant number MH 15651 from the National Institute of Mental Health and PHS research grant number NS 18883 from the National Institute of Neurological Diseases and Stroke.