Achievement

Trainee Steve Cholewiak and advisor Manish Singh investigated the perception of the physical stability of 3D objects. This is important for guiding motor actions and shows how people are able to interpret the physics of the environment. Participants adjusted the tilt of 3D objects on the edge of a virtual table so that the object seemed equally likely to fall off or to return to its upright position. They showed strong biases to underestimate this critical angle for objects that were short and wide. They also showed a surprising neglect of the contribution of a small attached part of the object. This work, presented at the annual meeting of the Visual Sciences Society, shows that people are not able to make accurate judgments of stability. The perceptual system, which is dominated by the organization of objects according to part structure, is optimal for object recognition but not for realistic appreciation of physical laws.