I sat next to John Cacioppo once, almost exactly 12 months after I finished my PhD - which used his theoretical co-contribution to social influence, the Elaboration Likelihood Model of Persuasion, as the spine of my thesis.
I don't get star-struck, but i was categorically not able to speak with him.
And so this week on N of Us, I tackle this, the the most enduring of persuasion theories. It's a kinda homage.
The ELM is what's called a dual process theory. This means there are one of two "pathways" a person may go down towards being persuaded, depending upon the circumstances at the point of persuasive message.
If a person is invested in the content of the persuasive message, s/he will go down the central route and pay more attention to the content of the argument. If persuaded, this is likely to lead to long-term behaviour/attitude change.
If sh/e isn't invested in the content, peripheral cues will take over - like the number of times the persuasive message is repeated, or the attractiveness of the person delivering the message, or the novelty of the persuasive message. The outcome of this is more likely to be short-term compliance in attitude/behaviour change, but no internal shift of belief.
Take time to read the original here, and dig the flow chart on page 126.