This document discusses key concepts in communication and diffusion of innovations, including opinion leadership, models of communication flows, homophily and heterophily in communication networks, and the strength of weak ties. It defines opinion leaders as individuals who informally influence others' attitudes and behaviors. It describes the two-step flow model where ideas flow from mass media to opinion leaders and then to their followers through interpersonal communication.

2. “Every herd of wild cattle has its leaders, its influential
heads.” The Laws of Imitation (1903)

3. Opinion Leadership
 The degree to which an individual is able informally
to influence other individuals’ attitudes or overt
behavior in a desired way with relative frequency.
 Do you know anyone that fits the bill?
 These people are called opinion leaders.

4. Opinion Leaders
 Drive diffusion to critical mass through interpersonal
communication
 Peer to peer
 Their behavior helps determine the rate of adoption
in a social system
 Most likely members of the social system.

5. Models of Communication
Flows
 Hypodermic Needle
 Postulates that mass media has direct and immediate
effects on a mass audience.
 Two-Step Flow
 Postulates that mass media messages flow to a mass
audience first with information, then from opinion
leaders to their followers through interpersonal
communication with influence.

6. “The most fundamental principle of human communication is
that exchange of ideas occurs most frequently between
individuals who are alike.”

7. Homophily vs Heterophily
Communication Networks
 Homo = same
 Hetero = different
 Homophily occurs frequently because humans avoid
dissonance.
 The more communication within a group, the more
homophilous the group will become
 Homophily accelerates the diffusion process, but
limits the spread of an innovation to those
individuals connected in a close-knot network.

8. Heterophilous Networks
 Often connect two cliques, spanning two sets of
socially dissimilar individuals in a system
 We call these links, “bridges”
 Especially important in conveying information about
innovations (strength of weak ties)
 i.e., Agricultural Communicators
 Agricultural science to consumer-base
 Agricultural science to producer

9. Strength of Weak Ties
 “The general notion of classifying network links on the
basis of the degree to which they convey information.”
 Weak ties are often “bridge” links
 “I know someone who knows someone”
 “I met someone once that knows about that”
 “My roommate's boyfriend works there”
 Weak vs. strong ties are measured by communication
proximity.
 Degree to which two individuals in a network have personal
communication networks that overlap

11. Generalizations of SoWT
 The information-exchange potential is negatively
related to their degree of communication proximity
and homophily
 Individuals tend to be linked to others who are close
to them in physical distance and who are relatively
homophilous in social characterics

12. Characteristic of Opinion
Leaders
 External Communication
 Opinion leaders have greater exposure to mass media
than their followers.
 Opinion leaders are more cosmopolite than their
followers.
 Opinion leaders have greater contact with change
agents than their followers.

13. Characteristic of Opinion
Leaders
 Accessibility
 Opinion leaders have greater social participation than
their followers.

14. Characteristic of Opinion
Leaders
 Socioeconomic Status
 Opinion leaders have high socioeconomic status than
their followers.

15. Characteristic of Opinion
Leaders
 Innovativeness
 Opinion leaders are more innovative than their
followers.