The answer is people gather information to make casual attribution rationally and logically. To simplify, the major assumption of Kelley’s covariation model of attribution is people gather information to make casual attribution rationally and logically. The covariation model of Kelley is the best-recognized attribution theory in which he established a logical model for judging whether a particular action must be attributed to some characteristics that are internal of the person or the environment that is external. The term covariation merely means that a person has information from multiple interpretations at different times and circumstances that can distinguish the covariation of an observed effect and its causes.