The social distance corollary is a theory in communication research that concerns the tendency of people to perceive others to be more susceptible to media influence than they actually are.
The notion of social distance was first introduced by the sociologist Emory Bogardus (1925), who referred to it as the degrees of understanding and feeling that people experience regarding each other.
Investigating the third-person effect in regard to political identification, Duck, Hogg, and Terry (1995) found that perception of self-other differences in media vulnerability are influenced by the subjectively salient social relationship between self and other, and are governed by motivational needs, such as self-esteem, social-identity, and differentiation from others.
Other researchers (e.g., Burger, 1981; Schlenker & Miller, 1977) suggested that self-serving biases consider close friends and relatives as an extension of self, whereas such a vague category as "other" might evoke stereotypes in people's minds (Perloff & Fetzer, 1986).
According to Perloff's review (1999), of the 11 studies that have tested the social-distance notion, 9 confirmed it, articulating this phenomenon as "another factor on which the strength of the third-person effect hinges".