Developmental sequences in class reasoning and propositional reasoning.

This study explored the theoretical prediction that class and propositional reasoning skills emerge as a function of the developing ability to coordinate increasingly complex negation and affirmation operations. Children from Grades 1, 3, 5, and 7 (7-, 9-, 11-, and 13-year-olds) were presented with problems from each domain. Rasch analyses of the children's responses were consistent with the hypothesis that both types of problems measured a single underlying dimension (i.e., the coordination of affirmation and negation operations). Qualitatively distinct levels of class and propositional reasoning were identified along this dimension, adding support to the notion that children's reasoning follows a logical developmental sequence. Planned comparisons supported the order-theoretical prediction that different groups of items account for solution differences between grade levels. Results also indicated that children encounter significant difficulties when they have to reason on the basis of negative information.