Object individuation and object identity in infancy: The role of spatiotemporal information, object property information, and language

Recent work on object individuation and object identity in infancy indicate s that at least three sources of information may be used for object individ uation and object identity: spatiotemporal information, object property inf ormation, and object kind information. Several experiments have shown that a major developmental change occurs between 10 and 12 months of age (Xu & C arey, 1996; Xu, Carey & Welch, in press; Van de Walle, Prevor & Carey, unde r review; Xu, Carey & Quint, in preparation): Infants at 10 months and youn ger readily use spatiotemporal information in object individuation and obje ct identity tasks, but not until about 12 months of age are infants able to use object property or object kind information to do so. This paper propos es a two-part conjecture about the mechanism underlying this change. The fi rst part borrows ideas from object-based attention and the distinction betw een "what" and "where" information in visual processing. The hypothesis is that (1) young infants encode object motion and location information separa tely from object property information; and (2) toward the end of the first year, infants integrate these two sources of information. The second part o f the conjecture posits an important role for language. Infants may take di stinct labels as referring to distinct kinds of objects from the onset of w ord learning, and infants use this information in solving the problem of ob ject individuation and object identity. Evidence from human adults, infants , and non-human primates is reviewed to provide support for the conjecture. (C) 1999 Elsevier Science B.V. All rights reserved. PsycINFO classificatio n. 7820.