This document outlines several mass communication theories: the Magic Bullet Theory which suggests media has a direct influence on audiences; the Two-Step Theory where opinion leaders influence the public; the Agenda-Setting Theory where media tells the public what issues are important; Diffusion Theory where opinion leaders spread messages to influence the masses; and Framing Theory where how an issue is presented influences choices. It provides diagrams and brief explanations of each theory and links to additional mass communication theory resources.

1. MASS COMMUNICATION THEORIES
 Magic Bullet Theory
 Two-Step Theory
 Agenda-Setting Theory
 Diffusion Theory
 Framing Theory

2. MAGIC BULLET/HYPODERMIC NEEDLETHEORY
The "hypodermic needle theory” (aka the “magic bullet theory”)
implies mass media has a direct, immediate and powerful effect
on its audiences.
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 effects of this theory suggest that the media could
manipulate a passive and gullible public, leading theorists to
believe this was one of the primary ways media authors shaped
audience perception.

3. MAGIC BULLET/HYPODERMIC NEEDLE THEORY
Mass Media
Public

4. TWO-STEP THEORY
This theory asserts that information from the media moves in two
distinct stages.
1 - First, individuals (opinion leaders) who pay close attention
to the mass media and its messages receive the
information.Opinion leaders are quite influential in getting
people to change their attitudes and behaviors and are quite
similar to those they influence.
2 - Opinion leaders pass on their own interpretations to the
public.
The theory refined the ability to predict the influence of media
messages on audience behavior, and it helped explain why
certain media campaigns may have failed to alter audience
attitudes an behavior.

5. TWO-STEP THEORY
Mass Media
Opinion Leaders
Public

6. AGENDA-SETTING THEORY
Agenda setting describes a very powerful influence of the media
– the ability to tell us what issues are important.
Agenda-setting is the creation of public awareness and concern
of salient issues by the news media. Two basis assumptions
underlie most research on agenda-setting:
(1) the press and the media do not reflect reality; they filter
and shape it;
(2) media concentration on a few issues and subjects leads
the public to perceive those issues as more important
than other issues.
Agenda-setting theory seems quite appropriate to help us
understand the pervasive role of the media (for example on
political communication systems).

7. AGENDA-SETTING THEORY
Mass Media
Public

8. DIFFUSION THEORY
With the diffusion theory, communicators in society with a
message influence/encourage people that have strong opinions
through the media to influence the masses.
There does not seem to be free will in this case, it is fated as to
what information is received to the masses, they have no choice
to what they are exposed to.
In this sense, the theory is scientific. There is one truth,
dependent on the messages sent and received by the media and
the opinion leaders.

9. DIFFUSION THEORY
Mass Media
Individuals Individuals Individuals
Individuals Individuals Individuals

10. FRAMING THEORY
Framing theory and the concept of framing bias suggests
that how something is presented (the “frame”) influences
the choices people make.
The concept of framing is related to the agenda-setting
tradition but expands the research by focusing on the
essence of the issues at hand rather than on a particular
topic.
The basis of framing theory is that the media focuses
attention on certain events and then places them within a
field of meaning.

11. FRAMING THEORY
Mass Media
Issue/Event
Public

12. LINKS TO MORE THEORIES
 Mass Media Theories:
http://www.utwente.nl/cw/theorieenoverzicht/Theory%2
0clusters/Mass%20Media/
 Mass Communication Theories:
http://www.uky.edu/~drlane/capstone/mass/
 Defining Communication Theories:
http://www.mhhe.com/mayfieldpub/westturner/student_r
esources/theories.htm
 Theories of Communication:
http://www.peoi.org/Courses/Coursesen/mass/mass2.ht
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