This study examined developmental changes in concept formation, rule switching, and perseverative behaviors of children in the WCST by altering visual features of the test and using a new test score--the "zigzag" error score--which shows the number of shifts made between two incorrect concepts or rules. Instead of the original four 3-dimensional…

Adapted Keil's predictability method to examine adults' and preschoolers' conceptions of numbers, focusing on the ontological distinction between numbers and sets of objects. Found that children, like adults, attribute spatial-arrangement properties to collections much more than to numbers, although both are considered to have quantitative…

Two experiments examined preschoolers' and adults' relative reliance on visual and verbal information in identification of animals and machines. Findings include both children and adults can use either visual or verbal cues in categorization, and a stricter definition is used in identifying animals. Results suggest that a perceptual to conceptual…