The document summarizes several response theories that were developed to explain how audiences interact with and are influenced by media messages:
1) The Hypodermic Needle Theory from the 1920s-1930s suggests media messages are directly "injected" into passive audiences' brains.
2) The Inoculation Model proposes supplying information to audiences beforehand to make them more resistant to future messages.
3) The Two-Step Flow Model asserts that media information flows from media to opinion leaders to the general public in two stages.
4) Uses and Gratifications Theory examines how audiences actively use media to fulfill various needs and gratifications.
5) Reception Theory understands that audiences play an essential role