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 st E. S. Spelke . 1983). We investigated the possibility that 4-month-old infants will atte nd to and utilize the global configuration (i.e., the "good form") of a par tly 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 n umber of trials ("fast habituators") showed a reliable posthabituation pref erence for a broken object over a complete object, indicating perception of unity in the habituation display. Slow habituators exhibited no posthabitu ation preference. In the second experiment, infants were presented with sma ll ring and cross displays, and the infants looked longer at the broken obj ect. There were no reliable differences in performance between fast and slo w habituators. A control group demonstrated no reliable posthabituation pre ference. In three additional conditions. infants viewed either a partly occ luded half ring or a display in which two rod parts were either relatable a nd nonaligned or nonrelatable. The results indicated that curvature per se provided information in support of completion. in addition to global config uration and motion. Implications for theories of infants' visual developmen t are discussed. (C) 2000 Academic Press.