Can perception of aperture passability be improved immediately after practice in actual passage? Dissociation between...

Perception of the fit between a person's action capabilities and relevant environmental properties (i.e., affordances) is often fine tuned gradually through experience performing a behavior. However, the immediate effect of such practice on the improvement of affordance perception is unclear. The present study was designed to examine whether a critical factor in the immediate effect of such practice is the opportunity to detect very fine differences between possible and impossible behaviors [i.e., high-resolution (HR) practice]. Participants reported whether apertures of various widths were passable when walking while holding a 69-cm horizontal bar (Experiment 1) or when using a wheelchair (Experiment 2). When practicing passing through apertures, seven different aperture widths, including their minimum passable width (70 cm for both experiments) were presented around the affordance boundary with 1- or 5-cm increments for the HR or low-resolution (LR) conditions, respectively. Accuracy of perception of passability improved following both HR and LR practice when walking. In contrast, no improvement was observed in any condition when using a wheelchair. These findings suggest that the immediate effect of practice was mediated by the form of locomotion but not the resolution of the practice.