Abstract
People judged the inclination of hills viewed either out-of-doors or in a computer-simulated virtual environment. Angle judgments were obtained by having people (1) provide verbal estimates, (2) adjust a representation of the hill’s cross-section, and (3) adjust a tilt board with their unseen hand. Geographical slant was greatly overestimated according to the first two measures, but not the third. Apparent slant judgments conformed to ratio scales, thereby enhancing sensitivity to the small inclines that must actually be traversed in everyday experience. It is proposed that the perceived exaggeration of geographical slant preserves the relationship between distal inclination and people’s behavioral potential. Hills are harder to traverse as people become tired; hence, apparent slant increased with fatigue. Visually guided actions must be accommodated to the actual distal properties of the environment; consequently, the tilt board adjustments did not reflect apparent slant overestimations, nor were they influenced by fatigue. Consistent with the fact that steep hills are more difficult to descend than to ascend, these hills appeared steeper when viewed from the top.
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This research was supported by NIMH Grant MH5240-01 and NASA Grant NCC2-5074 to the first author. The authors are very grateful for the assistance provided by Marco Bertamini, Bennett Bertenthal, Sarah Creem, Jim Durbin, Frank Durgin, Jane Joseph, and Shahwar Qureshi. The development of our ideas benefitted greatly from numerous conversations with Jack Loomis. Nicola Bruno, William Ittelson, and Johan Wagemans provided valuable criticism on an earlier version of this paper.
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Proffitt, D.R., Bhalla, M., Gossweiler, R. et al. Perceiving geographical slant. Psychon Bull Rev 2, 409–428 (1995). https://doi.org/10.3758/BF03210980
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DOI: https://doi.org/10.3758/BF03210980