University of Utah Undergraduate Research Abstracts, Volume 2, Spring 2002

Geographical Slant Perception in a Simulated Environment

Geographical Slant Perception In A Simulated Environment Former studies on slant perception demonstrate that people tend to overestimate hill steepness when making measurements verbally and visually, but not when using visually guided actions (Bhalla & Proffitt, 1999; Creem and Proffitt, 1998; Proffitt, Bhalla, Gossweiler & Midget, 1995). One theory explaining this phenomenon suggests that there are two perceptual streams from the visual cortex; one directs the perception of an object's identity and the other deals with interactions with that object. This theory may explain why hills are often verbally overestimated but still able to be traversed. Our research has been a continuation of these initial studies. We have examined the influence of movement on judgments of slant perception in a simulated environment using a locomotion interface. The locomotion interface consists of projection screens surrounding a treadmill capable of simulating forces associated with walking on different terrains. In our experiments, subjects were transported on each trial to a location at the bottom of a hill in a virtual environment. In Experiment 1, observers looked at a target on the hill while remaining stationary. In Experiment 2, they were "passively translated" (giving the impression that they were flying over the land) up the hill to the target. In Experiment 3, they walked up the hill. All participants made hill-slant judgments using three different methods: a verbal report, an adjustment of a pie-shaped segment of disk, and a visually guided action (adjusting a palm board to correspond to the hill slant). Our results show that-in comparison to no movement or passive movement-walking on hills with simulated forces (Exp 3) greatly increases estimations of slant. These results differ from previous findings that manipulations of physiological potential on a stationary observer do not affect motor responses (Bhalla & Proffitt, 1999). This difference may have resulted from the interaction of physical walking and the ambiguity of the graphical information in the visual display. This may implicate a bi-directional interaction between action and perception. Cynthia J Shepherd Class Standing: Sophomore Major: Psychology and Math E-mail: [e-mail] Faculty Sponsor: Sarah Creem-Regehr Department of Psychology Email: [e-mail]