Replies to commentaries by Mandler (1988) and Rochat and Striano (1988), focusing on Mandler's comments. Maintains that their disagreements are the result of deep meta-theoretical differences regarding a representational theory of mind rather than misrepresentations of fact. Discusses how their meta-theoretical differences result in several basic…

Investigated the emergence of class and propositional reasoning skills as a function of the developing ability to coordinate increasingly complex negation and affirmation operations with children from grades 1, 3, 5, and 7. Found that children's reasoning follows a logical development sequence and that different groups of items account for…