Abstract
Children from kindergarten, first- and second-grade, and unschooled adults were tested on a version of Palmer’s (1977) task, which requires to detect a part within a figure. In positive trials, each part was paired with several figures that contained it so that different degrees of embeddedness were obtained. In this situation, any effect of the degree of embeddedness cannot be attributed to either the intrinsic properties of the part or an incorrect notion of part, as might be the case with the material previously used by Kolinsky et al. (1987). However, the main findings of this study were replicated. Unschooled adults, even those who have learned to read and write in special classes, were both very poor at detecting parts of low and medium goodness value, and not better than kindergarteners. First- and especially second-graders displayed much better detection performance. Thus, processes of visual postperceptual analysis that seem relatively unsophisticated may not develop spontaneously but rather under the influence of specific training provided in primary school.