Abstract
Physics and mind are “dark matters” governing the structure of a visual scene. Even a simple physics-mind combination can generate remarkably rich events. In a leashed-chasing display introduced here, a disc (“wolf”) has the mind of chasing another disc (“sheep”), while the wolf is physically constrained by a leash controlled by a third disc (“master”). Competing forces from physics and mind can cause complicated motions, such as a wolf being dragged away from the target it is chasing. Therefore, the task of vision is to jointly infer the physics-mind combination that can best explain the observed motions. Guided by this theory, we demonstrate four discoveries with the leashed-chasing display. First, social perception of the wolf’s mind is robust, even when its motion severely deviates from its goal, provided the deviation can be explained away by physics. Second, social perception is robust even when the wolf is not shown as an isolated object by explicitly drawing a line connecting it to its master, provided the line is modeled as a physically realistic spring. Third, disrupting physics impairs social perception. By simply offsetting the master’s trajectory by 500ms in the visual display, the wolf-master system cannot be modeled by any intuitive physics. Accuracy of perceived chasing dropped dramatically, as there was no physics to “explain away” the wolf’s deviation from its goal. Fourth, disrupting an agent’s mind impairs the perception of physics. The mind of the wolf is disrupted by making it chase a “phantom”, achieved by turning its target invisible. Observers were asked to report whether the leash is a physically realistic spring, or just an arbitrary line connecting two independently moving objects. The results showed that accuracy of spring detection dropped dramatically when the wolf’s mind was disrupted. These results collectively demonstrate a joint perception of physics and mind.