Geometric complexity and object search in infancy.

Abstract

After moving through space adults can usually relocate stable objects and positions even if the objects are not visible and their positions are not marked by distinctive landmarks. We can determine the location of an object by using of its original position and of our path of movement. Given the distance and direction of the object relative to our starting point and of our starting point relative to our final position, we can infer the object's distance and direction from our final position. Such inferences about location follow logically from geometric principles relating positions; they are similar to logical deductions, although they are neither conscious nor effortful. The ability to make such inferences is fundamental to human activities, allowing humans both to relocate invisible objects and to plot new paths toward invisible goals. This ability is also of theoretical interest, because inferences require premises, that is a body of principles concerning geometric objects and geometric relationships that has been termed spatial knowledge (Landau, Spelke, & Gleitman, 1984). In this article, we focus on the developmental origins of in infancy. Although inferences of the sort discussed above come quite naturally to adults and even to 2-year-old children (Landau et al., 1984; Rieser & Heiman, 1982), studies of infants have revealed some significant difficulties in relocating objects after self-movement (Acredolo, 1978). In the absence of rich external landmarks, for example, 6- and 11-month-old infants have been found to search for a hidden object at egocentrically defined locations, ignoring the effects of their own displacements. Such results have been taken