Abstract not found

Much of what psychologists know about infant perception and cognition is based on habituation, but the process itself is still poorly understood. Here the authors offer a dynamic field model of infant visual habituation, which simulates the known features of habituation, including familiarity and novelty effects, stimulus intensity effects, and age and individual differences. The model is based on a general class of dynamic (time-based) models that integrate environmental input in varying metric dimensions to reach a single decision. Here the authors provide simulated visual input of varying strengths, distances, and durations to 2 coupled and interacting fields. The 1st represents the activation that drives “looking, ” and the 2nd, the inhibition that leads to “looking away, ” or habituation. By varying the parameters of the field, the authors simulate the time course of habituation trials and show how these dynamics can lead to different depths of habituation, which then determine how the system dishabituates. The authors use the model to simulate a set of influential experiments by R. Baillargeon (1986, 1987a, 1987b) using the well-known “drawbridge ” paradigm. The dynamic field model provides a coherent explanation without invoking infant object knowledge. The authors show that small changes in model parameters can lead to qualitatively different outcomes. Because in typical infant cognition experiments, critical parameters are unknown, effects attributed to conceptual knowledge may be explained by the dynamics of habituation.

ssing. We suggest that some types of similarity are determined automatically. When the cognitive system recognizes similarities, they influence cognitive processing, even when the person does not intend for their processing to be affected by similarities. In order to support this claim, we first outline three different approaches to similarity. Then, we examine how similarity can influence both low-level processes like attention and memory retrieval and higher cognitive processes like analogical reasoning and decision making. Next, we explore a number of examples in which cognitive processing is influenced by the presence of similarities in a stimulus set. Finally, we broaden the discussion to include similarities in more deliberate cognitive processes. Three Approaches to Similarity Representation and Similarity When a person makes a similarity comparison, the result is typically both a judgment of similarity and also some awareness of the commonalities and differences of the pair com

This report has been prepared in the form of an HTML document, which is available on the World-Wide Web at ftp:##ftp.cs.indiana.edu#pub#gasser#Playpen#TR1#tr#tr.html. It makes extensive use of color #gures, animated applets, and hyperlinks. There is a compressed Postscript version of the report available by anonymous ftp to ftp.cs.indiana.edu at #pub#gasser#Playpen#TR1.ps.Z. This includes the color #gures but not the applets and hyperlinks. Therefore we highly recommend the version on the Web

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

Abstract not found

Infants seem sensitive to hidden objects in habituation tasks at 3.5 months but fall to retrieve hidden objects until 8 months. The authors first consider principle-based accounts of these successes and failures, in which early successes imply knowledge of principles and failures are attributed to ancillary deficits. One account is that infants younger than 8 months have the object permanence principle but lack means-ends abilities. To test this, 7-month-olds were trained on means-ends behaviors and were tested on retrieval of visible and occluded toys. Means-ends demands were the same, yet infants made more toy-guided retrievals in the visible case. The authors offer an adaptive process account in which knowledge is graded and embedded in specific behavioral processes. Simulation models that learn gradually to represent occluded objects show how this approach can account for success and failure in object permanence tasks without assuming principles and ancillary deficits.

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