Abstract not found

we act on the world, we care which glass is ours, which object we already have retrieved, and whether all the cows that left the barn in the morning have returned. Object individuation consists of determining the numerically distinct (distinct in the sense of distinct one) objects that articulate a given scene. Studies of object individuation in infancy typically concern the simplest individuation problem: es- tablishing whether one single object or two distinct objects are involved in some event. Adults bring a wide variety of information to bear on the task of object indi- viduation, including spatiotemporal information (one object cannot be in two places at the same time), property information (a red plastic entity seen on one oc- casion is unlikely to be the same individual as a yellow cloth entity seen on an- other), and kind information (a dog cannot be the same individual as a table). Under many circumstances, spatiotemporal information is primary; if we see an enti

ts, like adults, draw upon spatiotemporal information---information about the spatial arrangements and motions of visible surfaces---to establish representations of discrete individuals. Two objects separated in space (on the frontal plane or in depth), or moving on spatiotemporally discontinuous trajectories, are resolved into distinct individuals (e.g., Baillargeon, 1991, 1995; Spelke, 1991; Spelke, von Hofsten, & Kestenbaum, 1989; von Hofsten & Spelke, 1985; Xu & Carey, 1996). In her previous work, Needham has shown that by 4.5 months of age, infants also draw upon featural information to resolve ambiguous displays 55 Journal of Experimental Child Psychology 78, 55--60 (2001) doi:10.1006/jecp.2000.2603, available online at http://www.idealibrary.com on 0022-0965/01 $35.00 Copyright 2001 by Academic Press All rights of reproduction in any form reserved. Address correspondence and reprint requests to Susan Carey, Department of Psychology, New York University, 6 Washington Place, 7t

I argue that there are ways of individuating the objects of perception without using sortal concepts. The result is an moderate anti-sortalist position on which one can single out objects without knowing what sort of thing those objects are. Sortal concepts Sortal concepts are concepts of kinds of things.

Using the violation-of-expectancy method, we investigated 10-month-old infants’ ability to rely on dynamic features in object individuation processes. Infants were first familiarized to events in which two different objects repeatedly appeared and disappeared, one at a time from behind a screen; at test, the screen was removed, revealing either one or two objects. In Experiment 1, one self-moving non-rigid agent and one inert object were involved in each trial, while in Experiment 2 two different agents were presented. Infants preferred to look at one-object outcomes in Experiment 1, but they did not show any preference for one- or two-object outcomes in Experiment 2. The results suggest that infants can use dynamic information to detect agents in complex individuation tasks before they can rely on shape or surface features. We propose that the sortals AGENT and INERT OBJECT appear in development before 12 months without a substantial contribution of linguistic experience. These findings may motivate a revision of current theories on the development of kind-based individuation and object files.