Four studies based on two longitudinal investigations examined the relation between social rejection and increased antisocial behavior. Found that early peer rejection (ages 6 to 8) predicted growth in aggression (at ages 10 to 12); findings were replicated in children ages 5 to 8. Rejection exacerbated antisocial development only among children initially disposed toward aggression. Social information-processing patterns mediated partially the effect of early rejection on later aggression. (Author/KB)