The purpose of this study was the development and validation of a paper-and-pencil instrument to assess the formal stage of development as defined by Piaget. Initially, a 42-item test was constructed; item content included syllogisms, verbal analogies, combinatorial and probabilistic reasoning, and questions similar to Piagetian tasks. This…

This researcher investigated the relationship of hierarchical classification processes in subjects categorized as to developmental level as defined by Piaget's theory, and explored the validity of the hierarchical model and test used in the study. A hierarchical classification test and a battery of four Piaget-type tasks were administered…