Orientation in physical reasoning: determining the edge that would be formed by two surfaces.

Physical reasoning is strongly influenced by various parameters of orientation. The authors report 3 experiments in which this phenomenon was explored for a particularly elementary transformation: the formation of a line from the intersection of 2 planes. Participants perceived pairs of planar surfaces (disks) in a variety of orientations in 3-D space and indicated the orientations of the edges that would result if the surfaces interpenetrated. The ranges of error and response time were large. Performance depended on whether the orientation of the edge that would be formed was the same as components of the orientations of the perceived surfaces, the degree to which the orientation of the edge would be canonical in the environment, and whether the angle between the surfaces would be perpendicular. The results are discussed in the context of a general approach to orientation in perception and physical reasoning.