Attribution is one’s perception of the reasons for behavior. When we observe others’ behavior, we do not know the reason for it. So we make a judgment as to why people do the things they do.
So attribution theory is how we perceive the causes of behavior, which in turn affects our subsequent choices and behaviors. For example, if a person calls you a name in a joking way, why did they do it? Are they being mean or kidding around? How do you respond?
As you may have heard, it is not good to assume. You are better off asking about the behavior and getting it right than guessing and getting in wrong.