The document discusses four theories of how audiences interact with media: 1) The hypodermic needle theory suggests media directly injects messages into audiences' minds. 2) Uses and gratification theory holds that people seek out media to fulfill needs like knowledge or social interaction. 3) Reception theory proposes media producers encode messages that audiences then decode, bringing their own interpretations. 4) Two-step flow theory argues information passes from media to opinion leaders and then to broader audiences.