social impact theory
a theory of social influence postulating that the amount of influence exerted by a source on a target depends on (a) the strength of the source compared to that of the target (e.g., the social status of the source versus that of the target); (b) the immediacy of the source to the target (e.g., the physical or psychological distance between them); and (c) the number of sources and targets (e.g., several sources influencing a single target). The impact of the source on the target increases as the source’s strength, immediacy, and number increase relative to the target. See also dynamic social impact theory. [originally proposed by U.S. social psychologist Bibb Latané (1937– )]