Two memories for geographical slant: Separation and interdependence of action and awareness

Abstract

The present study extended previous findings of geographical slant perception, in which verbal judgments of the incline of hills were greatly overestimated but motoric (haptic) adjustments were much more accurate. In judging slant from memory following a brief or extended time delay, subjects' verbal judgments were greater than those given when viewing hills. Motoric estimates differed depending on the length of the delay and place of response. With a short delay, motoric adjustments made in the proximity of the hill did not differ from those evoked during perception. When given a longer delay or when taken away from the hill, subjects' motoric responses increased along with the increase in verbal reports. These results suggest two different memorial influences on action. With a short delay at the hill, memory for visual guidance is separate from the explicit memory informing the conscious response. With short or long delays away from the hill, short-term visual guidance memory no longer persists, and both motor and verbal responses are driven by an explicit representation. These results support recent research involving visual guidance from memory, where actions become influenced by conscious awareness, and provide evidence for communication between the "what" and "how" visual processing systems.Hills appear steeper than they actually are, an intriguing phenomenon recently described by Proffitt, Bhalla, Gossweiler, and Midgett (1995). For example, a 5°hill is consistently judged to be about 20°. Although people judge hills to be much steeper than they actually are, they can traverse them with no difficulty. Despite an exaggeration in conscious perceptual judgment, people do not manifest this overestimation in a visually guided action directed toward the hill. Proffitt et al. showed that a motoric (haptic) adjustment of slant did not reflect the overestimation seen in conscious reports ofthe hill inclination. They proposed that the perceived exaggeration of geographical slant preserves the relationship between distal inclination and people's behavioral potential. The steepness of a hill that one perceives gives the observer information about the effort required to traverse that hill. Furthermore, Proffitt et al. suggested that the differences between verbal and motoric estimates of hill slants illustrate the separation of the visual pathways that mediate conscious perception and visually guided action.We recently asked people to judge the slants of familiar hills from memory. We found that people remembered hills to be even steeper than they had perceived them to be. This research was supported by NIMH Grant MH52640 and NASA Grant NCC-2-925 to D. R. P. The authors wish to thank Mukul Bhalla for many discussions of ideas, Arthur Shulman for providing valuable comments on an earlier version of this paper, and Valerie Lewis and Gavin Sacks for their help in running the experiments. Correspondence should be addressed to S. H. Creem, Department of Psychology, 102 Gilmer Hall, University of Virginia, Charlottesville, ...

Transient and enduring spatial representations under disorientation and self-rotation.

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Working Memory in Wayfinding—A Dual Task Experiment in a Virtual City

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