One of the most important concepts to emerge from the early days of social network analysis was balance theory. The early focus in balance theory was on the cognition or awareness of sociometric relations, usually positive and negative affect relations such as friendship, liking, or disliking, from the perspective of an individual.

The idea of balance arose in Fritz Heider's (1946) study of an individual's cognition or perception of social situations. Heider focused on a single individual and was concerned about how this individual's attitudes or opinions coincided with the attitudes or opinions of other “entities” or people. The entities could be not only people, but also objects or statements for which one might have opinions. He considered ties, which were signed, among a pair or a triple of entities. Specifically, Heider (1946) states:

For example, we can consider two individuals, focusing on one of them as primary, and their opinions about a statement, such as “We must protect the environment.” If both actors are friends, then they should react similarly to this statement — either both should oppose the statement (and hence, both have a negative opinion about it) or both should favor it (and have positive opinions).