The Hypodermic Needle Theory

History and Orientation: 
The "hypodermic needle theory" implied mass media had a direct, immediate and powerful effect on its audiences. The mass media in the 1940s and 1950s were perceived as a powerful influence on behaviour change.
Several factors contributed to this "strong effects" theory of communication, including:
- The fast rise and popularization of radio and television
- The emergence of the persuasion industries, such as advertising and propaganda
- The Payne Fund studies of the 1930s, which focused on the impact of motion pictures on children, and
- Hitler's monopolization of the mass media during WWII to unify the German public behind the Nazi party

The Theory:
The theory suggests that the mass media could influence a very large group of people directly and uniformly by ‘shooting’ or ‘injecting’ them with appropriate messages designed to trigger a desired response. 
The idea of a bullet or injection provides a specific target; a bullet fired from the "media gun" into the viewer's "head". This creates the idea that media is a dangerous means of communicating because the receiver or audience is powerless to resist the impact of the message. There is no escape from the effect of the message in these models. This means that a passive audience could suffer an impact of the "bullet".

Advantages:
- Use statistics to create an accurate representation of trends within audiences, this is a reliable source of information.
- Large Number of participants in order to create long lasting effects. 

Disadvantages: 
- Audiences may change their views from time to time making it hard to analyse the reception of information. Furthermore audiences are more aware of these messages and may not want to make a decision based upon them.
- The media is open to interpretation this can change the message and the message can be to simplistic and makes observing attitudes harder.