Festinger introduces cognitive dissonance as the aversive arousal that arises when individuals perceive inconsistency among their cognitions (beliefs, attitudes, values, or actions). To reduce dissonance, people may alter their beliefs or behaviors, add new consonant cognitions, or trivialize the importance of the inconsistency. The theory accounts for phenomena such as post‑decision rationalization, effort justification, selective exposure to information, and attitude change following behavior. Festinger’s framework laid a foundation for understanding how internal psychological tensions influence motivation, decision‑making, and social behavior.