Preschoolers' understanding of individual identity stability in simple objects.

Abstract

One of the major achievements of early cognitive development is grasping the stability of the individual identity of objects and people/animals across time and change. Children must learn to recognize that although the individual people, animals, and artifacts around them may at times change drastically in appearance, behavior, and so on, the individual identity of a specific object remains constant across these changes. The purpose of these studies was to investigate the early development of this understanding in preschoolers within a specific domain of objects (simple artifacts), using specific, individuating, properties to measure identity stability. Four studies (N = 116 overall) were conducted to investigate 3- and 4-year-olds' understanding of the effects of changes in appearance (color or shape) and location on individual object identity. In all studies children were presented with two similar objects (e.g., a red box and a blue box) which were then individuated using specific, objective, properties (e.g., having specific contents, being "found" in one location vs. another, ownership, etc.). Two separate object transformations were then performed. In one transformation, the location of the two objects is simply switched. In the other transformation, either the color or the shape of the two objects was switched. Children were then asked about the stability of the specific individuating properties of each object, (e.g., "point to the box with the X inside"). Stability of the specific properties was taken to indicate stability of the object's individual identity. All children across the 4 studies were able to hold the identity of the objects stable after a simple change in location, but only 4-year-olds were able to do so after a more dramatic change in either the objects' color or shape. By at least age 4 then, children possess an adult-like understanding of individual identity in which changes in appearance do not affect identity. This is significantly younger than previous research has indicated. The results are discussed in terms of the development of object understanding in general.