Abstract
Using perspective displays, observers judged whether two objects that approached each other in midair would collide. When objects were different sizes, observers often did not detect imminent collisions. Errors decreased with equal-sized objects or ground-intercept information. Results from these limited conditions suggest that judgments about collision in perspective displays (e.g., three-dimensional displays of aircraft) can be enhanced by minimizing ambiguities created by pictorial relative size cues. Results are consistent with studies of judgments about object-self collisions.