Planning, encoding, and overcoming conflict in partial occlusion drawing: A neo-Piagetian model and an experimental analysis

A theoretical model of partial occlusion drawing is presented, along with three experiments. The experiments used the materials similarity effect, i.e., the fact that it is easier to draw partial occlusion when the model objects are quite different from each other (Cox, 1985). Experiment 1, with 172 5- to 8-year-old subjects, manipulated materials (similar vs dissimilar objects) and viewing condition (unlimited visibility vs screened after 5 s), to study whether planning or scanning is involved in partial occlusion drawing. The results were consistent with the planning hypothesis, but not with the scanning hypothesis. Experiment 2, with 76 first-graders, explored group-encoding of similar objects. Encoding was assessed from verbal descriptions. Layouts were described differently (similar objects yielding group descriptions), and different descriptions were correlated with different drawing strategies. We suggest that group-encoding of similar objects creates a drawing problem (Experiment 2), and planning is required to solve it (Experiment 1). A neo-Piagetian model that accounts for drawing performance in terms of incompatible sets of activated schemes and of an activation balance between them is presented. Both experimental manipulations and differences among subjects in attentional resources are assumed to affect this balance. Three predictions were derived on the conjoint effects of object similarity and subject's M capacity and field dependence on drawing; Experiment 3, with 79 first-graders, successfully tested them. (C) 1996 Academic Press, Inc.