Equity Theory
Equity Theory states that humans have a natural tendency to maintain equity in their social relationships. Equity is a sense of fairness in the exchange of goods, services, time, and effort. Relationship partners will try to balance their own cost/benefit ratios to avoid getting a raw deal in the relationship as well as to avoid shortchanging their partner. For example, if you feel a friend has been overly generous in doing favors for you, you may buy them a present to reduce your feelings of imbalance and to make the friendship feel more “even.”