There are three types of noise, which garble a communication: semantic (i.e., speech impediments or misspelling), environmental (i.e., background noise), and tech (i.e., static).
There are also three types of filters, which determine how a communication gets interpreted by the receiver:
info (i.e., the message is in a language unknown to the receiver), physical (i.e., the receiver is fatigued), or psych (i.e., the receiver is prejudiced in some way toward the communicator or message).
The hypodermic needle model is a model of communications. It is also referred to as the "magic bullet", or the "profound effects" theory. Essentially this model holds that an intended message is directly received and wholly accepted by the receiver.
The most famous example of what would be considered the result of the Magic Bullet or Hypodermic Needle Model was the 1938 broadcast of The War of the Worlds and the subsequent reaction of the mass American audience that was tuned in.
The phrasing "Hypodermic needle" is meant to give a mental image of a message's direct infusion into an individual. This view tends to ignore things like interpretation and for this fatal flaw it is clearly less than perfect.
A more modern version is the Two-step flow of communication theory (or "minimal effects" theory). The two-step flow model was propouded by Paul Lazarsfeld and Elihu Katz. Unlike the hypodermic needle model which considers mass media effects to be direct, the two-step flow model stresses human agency. (One way of looking at it is that media doesn't tell us what to think, it tells us what to think about.)
According to Lazarsfeld and Katz, mass media information is channeled to the "masses" through opinion leadership. The people with most access to media, and having a more literate understanding of media content, explain and diffuse the content to others.
Two-step flow model laid the foundation for diffusion of innovations.
Developed by Professor George Gerbner, the Cultivation Theory focuses on the effects of long term repetition of messages. This view of media's influence on culture states that it occurs over time through a distortion of reality. Cultivation Theory does not rely on extensive consumption of media, but that the media cultivates cultural change over time throughout society.
The effects of cultivation of the media are exacerbated by an homogenized media landscape, where media outlets, through financial or other pressures, become similar or uniform. If all people receive a similar media message, portraying uniform values, then audiences will more quickly perceive those representations to be accurate.
Elitist and Populist Media
Broadly speaking, there are two views of media's place in society. One is Elitist (media should educate), and the other is Populist (media should be whatever the people want).
Marshall McLuhan was a famous media and communication theorist. He coined the term "global village" while discussing his belief that the effect of the television would be to unite the world. He also believed that print media changes the way you think, and that the written word could make language "official."