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This investigation is concerned with the effects of two kinds of contradiction on the correction of errors in a structurally simple but deceptively difficult logical problem. The task was to choose from partially concealed material those stimuli which were necessary to evaluate the truth or falsity of a general statement. Hypothetical contradiction is assumed to occur when the subject makes an inference which is inconsistent with a previous incorrect choice. Concrete contradiction is assumed to occur when the subject's current choice is shown to be inconsistent with the fully revealed material. Of the 32 subjects, two were substantially correct in their initial choices, 14 were correct after encountering two hypothetical contradictions, 12 were correct after encountering a concrete contradiction, and four failed altogether. The results suggest either that Piaget's theory of ‘formal operations’ requires modification, or that some of the subjects may have temporarily regressed to more primitive modes of thinking.
P. C. Wason (Sat,) studied this question.