Parts and Relations in Young Children's Shape-Based Object Recognition

Abstract

The ability to recognize common objects from sparse information about geometric shape emerges during the same period in which children learn object names and object categories. Hummel and Biederman's (1992) theory of object recognition proposes that the geometric shapes of objects have two components-geometric volumes representing major object parts, and the spatial relations among those parts. In the present research, 18- to 30-month-old children's ability to use separate information about object part shapes and part relations to recognize both novel (Experiment 1) and common objects (Experiment 2) was examined. Children succeeded in matching novel objects on part shapes despite differences in part relations but did not match on part relations when there were differences in part shapes. Given known objects, children showed that they did represent the relational structure of those objects. The results support the proposal that children's representations of the geometric structures of objects are built over time and may require exposure to multiple instances of an object category. More broadly, the results suggest that the distinction between object part shape and part relations as two components of object shape similarity is psychologically real and developmentally significant.

FIGURE 1

A) Realistic toy representations of three common object categories. B) Shape caricature representations of the same three object categories, with major parts represented by simple volumes in grey Styrofoam, with relational structure of the represented object preserved. (Color figure available online.)

FIGURE 2

Experiment 1. Example sets of novel objects used in the Part Shapes and Part Relations Tests of 1.5- to 2-year-old children. A) Part Shapes Test set: an exemplar object, an identical test object, and two distracters differing from the exemplar in part shapes, matching in relations among parts. B) Part Relations Test set: an exemplar object, an identical test object, and two distracters matching the exemplar in part shapes, differing in relations among the parts. (Color figure available online.)

FIGURE 3

Experiment 2. Example sets of shape caricature representations of common objects. A) Part Shapes Test set: three representations of an ice cream cone that differ only in the shape of one part. B) Part Relations Test set: three representations of an ice cream cone that differ only in the spatial arrangement of the parts.