There are three major sources of construal in human beings: the need to feel good about ourselves, the need to be accurate, and the need to belong. The American social psychologist Leon Festinger was one of the first to acknowledge that these needs may not always coincide (see cognitive dissonance). The Austrian social psychologist Fritz Heider described the concept of construal when he said, "Generally, a person reacts to what he thinks the other person is perceiving, feeling, and thinking, in addition to what the other person may be doing." In other words, a person bases his or her opinions and actions on the opinions and action of everybody else.