Infants' Individuation of Physical Objects

Rutgers University New Brunswick, New Brunswick NJ

Investigators

Abstract

Cognitive processing in infants has been shown to span a small set of concurrently individuated objects, allowing infants to attend to relations between objects and, within limits, to attend to object numerosity. Some current findings from the study of infancy seem to parallel findings in object-based attention in adults. These parallels have inspired the "object indexing" framework for studying aspects of the infant object concept which, in turn, has yielded a set of hypotheses concerning how infants might attend to physical objects. One general and long term aim of this research is to draw together the study of the "object concept" in infants and objectbased theories of attention in adults. Using standard familiarization-test looking times measures, a series of experiments will probe processes underlying infant object individuation and identification. A key process in object cognition is object individuation - the representation of a specific numerosity of objects in a scene. There is evidence that infants in the first year can individuate up to a small number of physical objects in a given scene but it remains unclear what is the representational basis of this ability. Two mutually compatible possibilities are investigated here: the representations may be numerical in character; the representations may be indexical (and non-numerical) in character. Attempts will be made to gather evidence for both types of representational mechanism. A second specific aim is to investigate the relation between object individuation and object identification in infants. If individuation is the initial establishment of a distinct object representation, then identification addresses whether the object is one that has been encountered before. Although these processes are closely related, it is, useful to distinguish them. Current work shows that under some circumstances infants can individuate objects without subsequently being able to (re)identify them. This gives rise to seemingly paradoxical cases where featural information used as the basis for individuation decisions fails to be used for identification decisions. The object indexing model accounts for these cases by linking identification to the key process of feature binding. Drawing inspiration from object-based theories of attention in adults, the object indexing model requires that featural information be attached to object indexes by a non-default process of binding. Experiments are proposed to reveal the nature of the infant object representation and to probe the development of feature binding in infants from 6 to 13 months of age. Finally, experiments are proposed for an initial investigation of the hypothesis that working memory systems are the location for the construction of object indexes and for the binding of featural information to indexes. Data on the early development of these processes will provide the foundations for building a detailed cognitive model. Such a model would be a landmark accomplishment in developmental cognitive science. This proposal will advance our knowledge of one of the fundamental structures of human thought by exploring connections between the infantile ability to track persistent individual objects in a changing world and object-based mechanisms of selective attention.