Step 1: Understanding the Concept:
The question refers to cognitive consistency theories, which propose that people are motivated to maintain coherence among their cognitions (beliefs, attitudes). Several theorists proposed models for this.
Step 2: Detailed Explanation:
Leon Festinger proposed the theory of Cognitive Dissonance, which deals with the discomfort felt when holding conflicting beliefs or when actions conflict with beliefs.
Fritz Heider proposed the Balance Theory, often called the P-O-X model. It describes attitude structures in a triad (P-Person, O-Other person, X-Attitude object). The theory states that people prefer a "balanced" state where the attitudes in the triad are consistent. An "imbalanced" state creates tension, motivating a change to restore balance.
Richard LaPiere is famous for his 1934 study showing a discrepancy between attitudes and behaviors regarding prejudice.
Gordon Allport was a pioneering psychologist in the study of personality and attitudes, but he is not primarily associated with a "balance" theory.
The specific concept of 'balance' is central to Fritz Heider's theory.
Step 3: Final Answer:
The concept of 'balance' in attitude change theory was used by Fritz Heider.