Cognitive dissonance is a state of tension that occurs when a person's attitudes and behaviors are inconsistent. Leon Festinger originally developed the theory of cognitive dissonance in 1951 to understand how conflicts between attitudes and behaviors influence human psychology. When cognitive dissonance occurs, the person experiences negative feelings and will typically change their attitudes or behaviors to resolve the dissonance and restore stability. Two common ways people resolve cognitive dissonance are changing their beliefs to align with their behaviors, or adjusting their attitudes to be more accepting of inconsistent behaviors.