Perception is Biased by Newtonian Prediction

The aim of this study was to determine whether the perception of a collision event is achieved through currently available information or a predictive strategy. Participants viewed billiard collisions in virtual reality, where the cue ball could strike the target on the left, right, or middle. Participants then indicated the resulting trajectory of the target. When both balls disappeared upon collision, trajectory judgments were consistent with Newtonian mechanics. In other trials, participants viewed 40 or 80 ms of target ball motion (independent of collision point) after the collision. In these trials, judgments reflected a combination of the additional visual information and a Newtonian prediction based on the collision event. This was especially apparent when post and pre-collision information was inconsistent. Another experiment suggests that the cue combination rule depends on the reliability of visual information and the system is more biased by predictions in ambiguous scenarios. These results demonstrate that mechanical event perception is affected by internal models and that these models have a Newtonian structure.