Perception of objects and object boundaries by 3‐month‐old infants

Abstract
Perception of object boundaries was tested by habituating infants to an arrangement of two objects and then presenting test displays in which either one object appeared in a new position, changing the two‐object configuration, or both objects appeared in new positions, preserving the two‐object configuration. If infants perceived the objects as distinct units, they were expected to look equally at the two test displays, since both displays consisted of the same units in new positions. If infants perceived each two‐object configuration as a single unit, in contrast, they were expected to look longer at the display that changed this configuration, since that display would present the infants with a unit that was new or altered. Two experiments provided evidence that objects were perceived as distinct units when they were spatially separated in depth, even if their images overlapped fully in the visual field. In contrast, objects were perceived as a single unit when they were adjacent in depth, even if the objects differed in colour, texture, and form and if both objects were stably and independently supported. Unlike adults, young infants do not appear to perceive object boundaries in accord with the Gestalt principles of similarity, good continuation, and good form, or in accord with implicit knowledge about gravity and relations of support. Infants do appear to perceive object boundaries by detecting information for the arrangement of surfaces in the three‐dimensional layout.