I Can't Afford Both: Walk-through-ability Affordance Judgments do not Correlate to the Distance on Hill Effect

摘要

Previous research has shown that visual perception is fundamentally linked to information about the perceiver's body. The ecological approach to visual perception states that perception of affordances (i.e. environmental cues about action capabilities) is anchored to physical dimensions of the perceiver's body in a task relevant way, while the action-specific account for visual perception states that visual perception is linked to internal cues about action capability. For instance, the "distance on hill (DoH)" effect demonstrates that distance judgments are bioenergetically scaled, such that distances on hills are perceived as farther than equal distances on flat ground, due to the increased energy requirement to walk the distance on a hill versus on flat ground. Both theories posit that cues related to the perceiver's body and its potential for action modulate visual perception. However, this theoretical convergence is unexplored. We conducted an individual differences study by comparing participants' performance on a DoH task and an affordance task. For the DoH paradigm participants were presented a virtual hill on an Oculus Rift DK2. They then performed a visual matching task on the egocentric distance to both a cone on the hill and a cone on the flat ground. As expected, distances on hills were judged to be farther away than distances on flat ground, F(1,158)=85.25, p .001. For the affordance paradigm, participants made judgments on their ability to walk through a doorway aperture. Their affordance judgments were correlated with their actual abilities, r=.456, p .001. However, when we compared performance on these two tasks, there was no significant correlation between DoH effect and accuracy of affordance judgements, r=.014, p=.859. These data suggest that, although the action specific and ecological accounts for visual perception theoretically converge, they do not employ the same underlying mechanism.