Abstract
Perhaps the most basic task faced by visual processing is to detect the presence of objects; before computing an object’s color, shape, or orientation, we must first register that something is there. Detection may be fairly straightforward when an object is fully visible, but in many realistic viewing conditions the visual system can only infer the presence of objects using cues such as continuity behind occluders, coincidental clipping of multiple figures, or unified motion against a background. All such cues, however, concern fairly low-level aspects of visual processing, encompassing only basic geometric and kinetic factors. Might more sophisticated forms of input cue an object’s presence? Here, we explore how a surprisingly high-level cue—physical interaction—can imply the presence of a hidden surface, in ways that directly facilitate later detection. Subjects saw an animation of a disk falling and then unexpectedly bouncing off of an ‘invisible’ surface. Sometimes, the disk bounced straight back up, implying a flat surface; other times, the disk’s bounce implied an angled surface. Afterwards, a visible line appeared where the disk had just bounced, whose orientation either matched or didn’t match the surface implied by the disk’s exit trajectory; subjects’ task was simply to report the orientation of this new, visible line, regardless of the physical events that came before it. Subjects were faster and more accurate at reporting the line’s orientation when it matched the orientation of the physically implied surface vs. when it conflicted. Follow-up experiments extended this work to attentive search in multi-event displays; again, detection of a specific oriented line was facilitated by seeing physical interactions that implied surfaces with that orientation. This work shows how a process as basic and seemingly low-level as detecting the presence of an object or contour can be influenced by a surprisingly high-level cue: otherwise-unexplained physical interactions.
Acknowledgement: JHU Science of Learning Institute