The ability of the human observer to perceive and recognize objects in the three-dimensional environment is based on a large number of interacting cues and on complex information processing that we are just beginning to understand. Some of these cues involve motion of the observer or of objects in the environment. Motion parallax refers to the relationship between the speed at which the image of an object moves across the eye and the distance of the object from the observer. Structure from motion refers to the relative image motions of parts of an object. For example, the shape of an object can be derived from its motion if the parts are assumed to be rigidly connected. In our laboratory we study motion parallax, structure from motion, and interactions between motion and other cues, such as stereopsis, in the perception and recognition of three-dimensional objects. Our current research is concerned with the relationship between information that indicates the depth in a three-dimensional scene and information about the shapes of objects in the scene. For example, an object may be too far away to perceive the relative distances from the eye to the front and back of the object directly, but we can develop a perception of these relative distances from information about the shape of the object coupled with information about the position of the object in the scene.