Core geometry in perspective

Abstract

Research on animals, infants, children, and adults provides evidence that distinct cognitive systems underlie navigation and object recognition. Here we examine whether and how these systems interact when children interpret 2D edge-based perspectival line drawings of scenes and objects. Such drawings serve as symbols early in development, and they preserve scene and object geometry from canonical points of view. Young children show limits when using geometry both in non-symbolic tasks and in symbolic map tasks that present 3D contexts from unusual, unfamiliar points of view. When presented with the familiar viewpoints in perspectival line drawings, however, do children engage more integrated geometric representations? In three experiments, children successfully interpreted line drawings with respect to their depicted scene or object. Nevertheless, children recruited distinct processes when navigating based on the information in these drawings, and these processes depended on the context in which the drawings were presented. These results suggest that children are flexible but limited in using geometric information to form integrated representations of scenes and objects, even when interpreting spatial symbols that are highly familiar and faithful renditions of the visual world.

Figure 1

Line drawings and photographs used in Experiment 1. Pictures of scenes and objects were designed to be as structurally similar as possible. In the line drawings, lines demarcated changes in contour, superposition, and perspective, but not changes in brightness.

Figure 2

Overhead schematic of the target (x) and non-target locations used in both the scene and object contexts in Experiment 1. Six target locations and 10 possible response locations allowed for precise classification of successful and erroneous responses. If children ignored landmark information, then they might have confused the corner by the door with the geometrically equivalent corner by the window. Moreover, if children ignored directional information, then they might have confused the corners to the left and to the right of the window. Error classification in the object context resembled that of the scene context but occurred with reference to the corresponding sides and landmarks of the Lego object.

Figure 3

(A) Proportion of correct responses at targets located at the junction of extended surfaces (corners) or at landmarks. Children were more successful at corner targets in the scene context and landmark targets in the object context. (B) Children's error responses also varied across the two contexts, with relatively more errors where they ignored landmarks in the scene context and relatively more errors where they ignored direction in the object context.

Figure 4

Experiment 2: Partial regression plot showing the relationship between children's scores on the reorientation task and the line drawing interpretation task depicting scenes, after controlling for age and verbal intelligence.

Figure 5

Experiment 3: Partial regression plot showing the relationship between children's scores on the visual form analysis task and their scores on the line drawing task depicting objects, after controlling for age.