The Hypodermic needle theory is a linear communication theory that suggests that media messages are injected directly into the brains of passive audiences.
In this theory the media is seen as powerful and able to ‘inject’ ideas into an audience who are seen as weak and passive and could be influenced by a message. In Nazi Germany in the 1930’s and during World War 2 films were used to ‘inject’ propaganda ideas promoting the Nazi cause to the German audience. Today we still see party political broadcasts on television during elections.
The Hypodermic theory comes from a fear of the mass media, and gives the media much more power than it can ever have in a democracy. The concept ignores the idea that not everyone in an audience behaves in the same way. How can an audience be passive –there will be many times when you have disagreed with something you have seen on television or failed to laugh at a comedy show or just thought a TV programme was terrible.
This video explains the Hypodermic needle theory.