title: Structured perceptual input imposes an egocentric frame of reference-pointing, imagery, and spatial self-consciousness.
abstract: Perceptual input imposes and maintains an egocentric frame of reference, which enables orientation. When blindfolded, people tended to mistake the assumed intrinsic axes of symmetry of their immediate environment (a room) for their own egocentric relation to features of the room. When asked to point to the door and window, known to be at mid-points of facing (or adjacent) walls, they pointed with their arms at 180 degrees (or 90 degrees) angles, irrespective of where they thought they were in the room. People did the same when requested to imagine the situation. They justified their responses (inappropriately) by logical necessity or a structural description of the room rather than (appropriately) by relative location of themselves and the reference points. In eight experiments, we explored the effect on this in perception and imagery of: perceptual input (without perceptibility of the target reference points); imaging oneself versus another person; aids to explicit spatial self-consciousness; order of questions about self-location; and the relation of targets to the axes of symmetry of the room. The results indicate that, if one is deprived of structured perceptual input, as well as losing one's bearings, (a) one is likely to lose one's egocentric frame of reference itself, and (b) instead of pointing to reference points, one demonstrates their structural relation by adopting the intrinsic axes of the environment as one's own. This is prevented by providing noninformative perceptual input or by inducing subjects to imagine themselves from the outside, which makes explicit the fact of their being located relative to the world. The role of perceptual contact with a structured world is discussed in relation to sensory deprivation and imagery, appeal is made to Gibson's theory of joint egoreception and exteroception, and the data are related to recent theories of spatial memory and navigation.
authors.affiliation: Medical Research Council, Cognition and Brain Sciences Unit, 15 Chaucer Road, Cambridge CB2 2EF, UK. tony.marcel@mrc-cbu.cam.ac.uk
authors.forename: Anthony
authors.initials: A
authors.lastname: Marcel
authors.forename: Christian
authors.initials: C
authors.lastname: Dobel
mesh_terms: D000328:Adult; D003221:Confusion; D003463:Cues; D004777:Environment; D006801:Humans; D007092:Imagination; D008875:Middle Aged; D009949:Orientation; D011581:Psychological Tests; D011597:Psychomotor Performance; D012649:Self Concept; D012683:Sensory Deprivation; D013028:Space Perception