Impact of Postural Stability and Modality on the Perception of Passage and Surface Climbing

The foundation for this study is the belief that an accurate understanding of affordance perception requires consideration of the observer-ground surface interface. More specifically, it is argued that variations in the organism-environment interface will affect postural stability that, in turn, will affect affordance judgments. It is further expected that the impact of variations in postural stability should be independent of the perceptual system employed by the perceiver. Participants in this study wore shoes meant to create varying degrees of postural stability and used either vision or sound to determine whether a gap afforded passage or a surface could be stepped upon. The results revealed that the manipulation of postural stability significantly affected judgments of passage and climbability. Although modality alone did not influence affordance judgments, it did so in combination with postural stability. Discussion is given to the notion that an accurate understanding of perception requires consideration of the perceiver and the environment as a single unit.