a model that postulates a single process underlying attitude formation and change in which all information relevant to the persuasion context is processed as evidence using if–then syllogistic reasoning. According to the model, the processing of such information can vary in the extent to which it occurs in an effortful versus noneffortful manner. See also elaboration-likelihood model; heuristic-systematic model. [proposed by the U.S. psychologist Arie W. Kruglanski (1939– )]