A psychological phenomenon that occurs when a person holds two or more contradictory beliefs, values, or attitudes, or when their actions are inconsistent with their beliefs.

This causes mental discomfort or stress, which motivates the person to reduce the dissonance by changing their beliefs, attitudes, or behaviors, or by rationalization or justifying them.

Cognitive dissonance can affect various aspects of human behavior and decision making, such as attitude change, persuasion, conformity, self-justification, and cognitive bias

→ Can cause us to change our attitude Attitude Formation

Festinger & Carlsmith (1959)


  1. Inconsistency or Dissonance: Cognitive dissonance occurs when an individual becomes aware of a discrepancy between their beliefs, attitudes, or values. This inconsistency creates a state of psychological discomfort, which motivates them to resolve or minimize the dissonance.
  2. Magnitude of Dissonance: The intensity of the discomfort or dissonance is influenced by the importance of the beliefs or attitudes involved and the degree of inconsistency between them. The greater the significance of the discrepancy, the more pronounced the discomfort.
  3. Dissonance Reduction: To reduce the discomfort, individuals engage in various cognitive and behavioral strategies. They may modify their beliefs or attitudes, acquire new information to support their existing beliefs, or change their behaviors to align with their beliefs.
  4. Processes for Reducing Dissonance: - Changing Beliefs or Attitudes: Individuals may modify or adjust their beliefs or attitudes to make them consistent with their behavior or new information.
    Seeking Information Consistent with Beliefs: People might actively seek out information that aligns with their current beliefs to reduce dissonance. Minimizing Importance: Individuals may downplay the importance or relevance of the inconsistency to reduce its impact on their overall attitude or beliefs.
  5. Consequences of Resolving Dissonance: Resolving cognitive dissonance leads to a sense of relief and internal consistency, providing psychological comfort and a sense of coherence in one’s beliefs and actions.

Initiation - difficult initiation into a group influences us to like the group more, due to the justification of effort

“An experiment was conducted to test the hypothesis that persons who undergo an unpleasant initiation to become members of a group increase their liking for the group; that is, they find the group more attractive than do persons who become members without going through a severe initiation. This hypothesis was derived from Festinger’s theory of cognitive dissonance.” - Aronson and Mills (1959)


In Elliot Aronson’s Theories of Cognitive Consistency (1973), he states: “Dissonance theory does not rest upon the assumption that man is a rational animal; rather, it suggests that man is a rationalizing animal – that he attempts to appear rational, both to others and to himself.”