This document summarizes several theories about the effects of mass media on audiences: - Walter Lippmann's theory that media shape our perceptions of things we haven't directly experienced - Early theories that media have direct, powerful effects but were later challenged by theories finding mostly indirect, minimal effects - Two-step flow model where media affect individuals through opinion leaders - Agenda-setting theory where media tell people what to think about - Uses and gratifications theory where people choose media to meet needs like surveillance, diversion, socialization - Consistency theory where people control media effects by choosing messages consistent with existing views

1. Media effects