Proceedings of the Annual Meeting of the Cognitive Science Society

Can observers recognize novel views of three-dimensional (3-D) objects, created by rotations in depth from a single familiar view? Three experiments using 3-D model objects are reported demonstrating that: (a) subjects can indeed recognize novel views under these circumstances, and (b) recognition accuracy depends on the types of objects employed. More precisely, subjects successfully recognized geometricallyregular and irregular objects rotated by 180 degrees about the vertical ^ ) axis. However, only geometricallyregular objects w o e recognized w h e n rotated similarly by 9 0 degrees. Thesefindingscannot be easily accommodated by contemporary object-centered or viewer-centered theories of shape-based object recognition, which m a k e no provisions for rqnesenting different types of objects uniquely. Alternatively, thesefindings support a theory in which inferences about objects' 3-D shapes are generated from information implicit in their two- dimensional (2-D) bounding contours, or silhouettes (Johnson, 1993). Such inferences m a y be premised on rules that C2q)ture importantregularities between 2- D bounding contours and 3-D surface geometry (e.g., Beusmans, Hofiman, & Bennett, 1987; Richards, Koenderink, & Hoffinan. 1987).