According to the historical use of the term, people tend to select specific aspects of exposed information which they incorporate into their mindset. These selections are made based on their perspectives, beliefs, attitudes and decisions. People can mentally dissect the information they are exposed to and select favorable evidence, while ignoring the unfavorable. The foundation of this theory is rooted in the cognitive dissonance theory , which asserts that when individuals are confronted with contrasting ideas, certain mental defense mechanisms are activated to produce harmony between new ideas and pre-existing beliefs, which results in cognitive equilibrium. Cognitive equilibrium, which is defined as a state of balance between a person's mental representation of the world and his or her environment, is crucial to understanding selective exposure theory. According to Jean Piaget, when a mismatch occurs, people find it to be "inherently dissatisfying".