When we look around the world, we see objects that are separate from one another, each of which is defined by a unique size, shape, surface pattern, and distance. Our ability to perceive coherent objects overcomes incomplete input to the visual system, which is actually fragmented across space and time. That is, most objects we see are partly occluded by other, nearer objects, and may go in and out of sight as they move or as we move. Commonsense notions of "object permanence," the knowledge that objects persist when away from direct perceptual contact, are central to this experience. Origins of object concepts in children have long been a source of interest among philosophers and researchers. Most notably, the pioneering studies of the eminent child psychologist Piaget provided evidence that object concepts develop only after months of experience handling and reaching for objects.
More recently, some researchers have challenged Piaget's account on the grounds that it relies too much on reaching as an index of object concepts. Reaching may be difficult for infants, and may underestimate "true" object knowledge. Infants' object concepts, instead, have been proposed to be rooted in innate knowledge structures, such as "object continuity," the understanding that an object, seen to have become occluded, maintains its existence and location or trajectory when out of sight. Such concepts are claimed to be revealed when looking time methods are employed, and an event is presented to an infant that violates some expectation of object permanence (this attracts longer looking than would be expected normally). Such accounts, however, have themselves come under fire for failing to furnish viable explanations of developmental mechanism: Even if some ability is innate, it must have developed somehow. In addition, these "violation of expectation" methods have been criticized as leading to ambiguity in interpretation. In general, then, there is much disagreement about the origins of fundamental kinds of object knowledge in infants.
The present proposal investigates this question by testing the role of specific visual cues in young infants' perceptions of object motions, as well as recording eye movements and reaching patterns in response to occlusion displays. The results are expected to yield important information on infants' perceptual and cognitive development, by providing converging evidence from multiple methods including assessments of object continuity, intermodal (visual-auditory) object perception, object "identity" (the ability to distinguish objects on the basis of appearance, location, and movement), and depth perception. It is anticipated that these findings will provide evidence and accounts that elucidate fundamental mechanisms of development, and it is hoped that such work will help guide theorizing on vital questions of the emergence of object concepts in infancy.
