ABSTRACT
Since the early 1980s, research on infants’ sensitivity to motion-carried information has typically reported early competence. For example, Yonas and his colleagues (Yonas, Pettersen, & Lockman, 1979) and Nanez (1988) found that infants between 3 weeks and 3 months of age respond to optical expansion information specifying impending collision. Kellman and his colleagues (Kellman & Spelke, 1983; Kellman, Spelke, & Short, 1986) found that 4-month-old infants perceive the unity of a partially occluded object only when the visible ends of the object undergo a rigid translation. Moreover, several researchers have found evidence that 4-month-olds perceive the three-dimensional shape of moving objects (Arterberry & Yonas, 1988; Kellman, 1984; Kellman & Short, 1987; Owsley, 1983; Yonas, Arterberry, & Granrud, 1987a), but infants provide no evidence of perceiving the three-dimensional shape when presented with successive static views of a rotating object (Kellman, 1984).
