The role of good form in young Infants' perception of partly occluded objects

Young infants have been reported to perceive the unity of a center-occluded object when the visible ends of the object undergo common motion, but not on the basis of stationary information (e.g., P. J. Kellman & E. S. Spelke, 1983). We investigated the possibility that 4-month-old infants will attend to and utilize the global configuration (i.e., the "good form") of a partly occluded, moving object to perceive its unity and coherence behind the occluder. In the first experiment, infants viewed a partly occluded circle or cross that translated laterally. Infants who habituated in the minimum number of trials ("fast habituators") showed a reliable posthabituation preference for a broken object over a complete object, indicating perception of unity in the habituation display. Slow habituators exhibited no posthabituation preference. In the second experiment, infants were presented with small ring and cross displays, and the infants looked longer at the broken object. There were no reliable differences in performance between fast and slow habituators. A control group demonstrated no reliable posthabituation preference. In three additional conditions, infants viewed either a partly occluded half ring or a display in which two rod parts were either relatable and nonaligned or nonrelatable. The results indicated that curvature per se provided information in support of completion, in addition to global configuration and motion. Implications for theories of infants' visual development are discussed.