Thorndike's law of effect and its inconsistent description over the years

The law of effect, originally proposed by E. L. Thorndike in a book that was published in 1911, had a major influence on the development of studies of instrumental or operant conditioning in the twentieth century. It remains a core concept in psychology and is invariably covered in undergraduate and graduate courses. Thorndike's law of effect also remains a topic of inquiry in contemporary efforts to understand the nature of habitual responses as contrasted with goal-directed behavior. The mechanisms of the law of effect continue to be studied by behavioral and social psychologists as well as neuroscientists. However, many statements of the law of effect deviate in significant ways from Thorndike's original formulation. The present article reviews the history of Thorndike's law of effect and traces how the law has been, and continues to be, misrepresented. The hope is that familiarity with common misrepresentations of the law of effect will encourage greater consistency and clarity in discussions of the law and better appreciation of its role in contemporary research.