Much of the research on object individuation in infancy has used a task in which two different objects emerge in alternation from behind a large screen, which is then removed to reveal either one or two objects. In their seminal work, Xu and Carey (1996) found that it is typically not until the end of the first year that infants detect a violation…

In three shape-constancy experiments, 4- and 7-year olds viewed a circular disc oriented at a slant. All subjects exaggerated circularity of the disc when they knew the object was a circle. Findings suggest that knowledge of reality contaminates judgments of appearance in circle task and this is the same bias that features in realist errors in…

Adult and 10- and 12-month olds participated in two experiments to determine reliance of infants on object-kind information in solving problems of object individuation. Findings converge with those of object-first hypothesis of developmental course of object individuation. Findings suggest that young infants may represent one concept as criteria…

This study compared the regulation of cognitive activity in 30 children (ages 15 to 95 months) with autism or mental retardation matched for global, verbal, and nonverbal developmental ages. Testing on tasks of object permanence indicated that the autistic children had a pervasive difficulty in maintenance set, made more perseverative errors, and…

Examined perception of object unity in partial occlusion in 72 infants. Recorded how long subjects looked at a display of complete and incomplete rods. In test and control conditions, infants looked longer at broken rods than at complete rods, suggesting that infants' cognitive, visual, or attentional skills may be insufficient to support…