James A. Thomas’s research while affiliated with Rensselaer Polytechnic Institute and other places

In their 1958 work, B. Inhelder and Piaget offer a single protocol as their only evidence that a fully developed formal operational thinker uses all 16 binary operations of truth-functional logic. The present study attempted to replicate the Inhelder-Piaget results with a random sample of 18 9-yr-old, 19 12-yr-old, and 20 16-yr-old Ss. Not one of the Ss used more than 5 of the 16 operations, and there was no developmental trend with regard to the number of operations used (p > .05). A trend was manifest, however, since the more developed reasoner used the same operations as the less developed reasoner, but in a more complex and sophisticated manner. (PsycINFO Database Record (c) 2012 APA, all rights reserved)

According to Inhelder and Piaget, a fully developed formal operational thinker uses all 16 binary operations of truth-functional logic in solving problems. The only evidence offered, however, was a single protocol from the physical task, Role of Invisible Magnetism. Using this 1 protocol and the Inhelder-Piaget method of analysis, an attempt was made to duplicate the results of Inhelder and Piaget. Examples and evidence, were found for only 8 operations; 8 of the Inhelder-Piaget analyses were faulty. Several important questions are raised, e.g., do fully developed formal operational thinkers actually use all l6 binary operations of truth-functional logic? (PsycINFO Database Record (c) 2012 APA, all rights reserved)