1. Theories of Communication Effects: Communication Science & Research
Introduction to
Theories of Communication Effects:
Diffusion Theory
A service of the
Communication Science & Research
Resource Group

2. Recap: Theory map MODEL STAGE (Early --> Late) Message learning
Reasoned
action
Social
Diffusion
Attention…….Comprehension…….Yielding…..Retention……………….. Action
Attitudes
Subjective norms.….Intention to act……………………………. Action
Perceived control
Attention...Retention...Reproduction...Motivation…………………..Performance
Knowledge……Persuasion...Decision…….Implementation….Confirmation

3. Origins of Diffusion Theory
(Everett Rogers)
George Washington Carver (1896)
Iowa State agricultural extension system and “movable schools”
Gabriel Tarde (1903)
The Laws of Imitation - the S-curve
Ryan & Gross (1943)
Diffusion of hybrid corn varieties
Post-WWII modernization
Green Revolution, family planning
News diffusion studies (1960s)
Kennedy assassination

4. What is diffusion?
“The process by which an innovation is communicated through certain channels over time among members of a social system.”
Rogers, 1995

5. What is diffusion?
“The process by which an innovation is communicated through certain channels over time among members of a social system.”
Rogers, 1995

6. What is diffusion?
“The process by which an innovation is communicated through certain channels over time among members of a social system.”
Rogers, 1995

7. What is diffusion?
“The process by which an innovation is communicated through certain channels over time among members of a social system.”
Rogers, 1995

8. What is diffusion?
“The process by which an innovation is communicated through certain channels over time among members of a social system.”
Rogers, 1995

9. What is diffusion?
“The process by which an innovation is communicated through certain channels over time among members of a social system.”
Rogers, 1995
Innovation = any idea, attitude, or behavior that is new to the members of a social system

10. Critiques of diffusion
Pro-modernity, anti-tradition bias
Pro-technology bias
Ignores structural inequity
Widens the have-have not gap
Manipulative and top-down
--> Like any theory, diffusion can be and has been misused

11. Key concepts Innovation-decision process Attributes of innovations
Adopter/audience categories
Homophily-heterophily
Opinion leaders
Strength of weak ties

12. Innovation-decision process

13. Diffusion curve (S-curve)
100
Cumulative
percent
who have
adopted
Time

14. Rate of diffusion 100 Cumulative percent who have adopted Take off
Time

15. Rate of diffusion 100 Cumulative percent Faster who have diffusion
adopted
Faster
diffusion
Time

16. Rate of diffusion 100 Cumulative percent Faster who have diffusion
adopted
Faster
diffusion
Slower
diffusion
Time

17. The KAP Gap

18. The KAP Gap

19. What predicts rate of diffusion/ adoption?
1. Attributes of the innovation
2. Attributes of the audience
3. Environmental constraints/facilitators
4. Characteristics of the communication system

20. 1. Attributes of the innovation
Relative advantage
> Does the new behavior offer any advantage over the current behavior?
Compatibility
> Is the new behavior compatible with current behaviors, beliefs, and values?
Complexity
> How difficult is the new behavior to perform?

21. 1. Attributes of the innovation
Trialability
> Can it be tried without too much risk before making a decision?
Observability
> Are there opportunities to see what happens to others who adopt this behavior?

22. 2. Attributes of the audience

23. 2. Attributes of the audience
Education
Literacy
Social mobility
Size & connectedness of networks
Degree of social participation
Attitude toward change
Tolerance for ambiguity & risk
Exposure to media
Exposure to interpersonal channels
Information seeking behavior

24. 2. Attributes of the audience

25. 3. Constraints & facilitators
Access to education
Access to information & means of communication
Access to the innovation
Normative pressure
Disposable income, ability to absorb loss

26. 4. Communication system
Key concepts:
Homophily-
heterophily

27. 4. Communication system
Key concept:
Strength of
weak ties

28. Diffusion Theory
Key concept:
Opinion leader

30. Putting it to work Where is your audience?
What can you tell them and how?
Confirmation
Implementation
Decision
Diffusion Theory addresses all stages in the hierarchy of effects, but is particularly useful for thinking about Knowledge and Persuasion.
Persuasion
Knowledge

31. Using Diffusion Theory in Programs
Identify how audience thinks of the innovation
Relative advantage, complexity, etc?
Identify people who are key network members
Who is nodal?
Who is an opinion leader?
Identify messages that address concerns about the innovation
Show the benefits
Show how to do it in simple terms
Show what happens if you do it
Show how new behavior fits with or grows out of current practices
Motivate or provide opportunities to try
Encourage discussion

32. Looking ahead
Next Week:
Bounded normative influence
How an innovation becomes a norm