Social judgment theory (SJT) is a self-persuasion theory proposed by Carolyn Sherif, Muzafer Sherif, and Carl Hovland, defined by Sherif and Sherif as the perception and evaluation of an idea by comparing it with current attitudes. According to this theory, an individual weighs every new idea, comparing it with the individual's present point of view to determine where it should be placed on the attitude scale in an individual's mind. SJT is the subconscious sorting out of ideas that occurs at the instant of perception.
Social judgment theory is a framework that studies human judgment. It is a meta-theory that directs research on cognitive perspective, which is how you perceive the situations. Brunswik's work with probabilistic functionalist psychology found that a person's psychological processes are adapted to factors of their environment.Motivation and cognitive capacity are central variables in major models of social judgment and persuasion, however, the exact nature of their interplay in judgment processes has remained ambiguous. Social judgment theory arose from Egon Brunswik's probabilistic functionalist psychology and his lens model, which are socio-psychological theories. It also comes from judgment theory. The psychophysical principle involved for example, is when a stimulus is farther away from one's judgmental anchor, a contrast effect is highly possible; when the stimulus is close to the anchor, an assimilation effect can happen. Social judgment theory represents an attempt to generalize psychophysical judgmental principles and the findings to the social judgment. With the person's preferred position serving as the judgmental anchor, SJT is a theory that mainly focuses on the internal processes of a person's own judgment in regards to the relation within a communicated message. The concept was intended to be an explanatory method designed to detail when persuasive messages are most likely to succeed.
Attitude change is the fundamental objective of persuasive communication. SJT seeks to specify the conditions under which this change takes place and predict the direction and extent of the attitude change, while attempting to explain how likely a person might be to change his or her opinion, the probable direction of that change, their tolerance toward the opinion of others, and their level of commitment to their position. The SJT researchers claimed expectations regarding attitude change could be based on the message receiver's level of involvement, the structure of the stimulus (and how many alternatives it allows), and the value (credibility) of the source.