Leon Festinger formulated the cognitive dissonance theory at Stanford University. He asserted, "When attitudes or beliefs conflict with our actions, we are uncomfortable and motivated to try to change." Festinger's theory sets the foundation for the Law of Dissonance.
The Law of Dissonance proves that people will naturally act in a manner that is consistent with their cognitions. What is a cognition? Our cognitions is a mental process that uses thoughts, beliefs, experiences, and past perceptions.
Basically that means when people behave in a manner that is inconsistent with these cognitions, (beliefs, thoughts or values) they find themselves in a state of discomfort. In this uncomfortable state, they will be motivated to adjust their behaviors or beliefs to regain mental and emotional balance. When our beliefs, attitudes, and actions mesh, we feel congruent.
When they don't, we feel dissonance at some level—that is, we feel awkward, uncomfortable, upset, or nervous. In order to eliminate or reduce that tension, we will do everything possible to adjust our beliefs or rationalize our behavior, even if it means doing something we don't want to do.
Imagine that there is a big rubber band inside of you. When dissonance is present, the rubber band begins to stretch. As long as the dissonance exists, the band stretches tighter and tighter. You've got to take action before it reaches a breaking point and snaps.
The motivation to reduce the tension is what causes us to change; we will do everything in our power to get back in mental balance. We like to feel a level of consistency in our day to day actions and interactions. This harmony is the glue that holds everything together and helps us cope with the world and all the decisions we have to make.
The human brain needs to be right. It is hard for us to admit we are wrong. We are programmed to justify what we are doing is right and avoid taking responsibilities when things go wrong. It is easier for us to find ways to prove ourselves right (even when we are wrong) then to admit why we are wrong.
Even when backed into a corner or shown evidence that proves we are wrong, we tend to not change our reasoning or point of view. We will find reasons, proof, or social support why what we did was OK. We will start to believe our lies to ourselves, it couldn’t be our fault and we persuade ourselves why we were justified.