Two experiments are reported identifying the circumstances In which high credibility either facilitates, inhibits, or has no effect on the communicator's persuasiveness in relation to a less credible source. These data provide support for the cognitive response view of information processing and suggest the importance of message recipient's initial opinion as a determinant of persuasion.

There are two routes to persuasion:
You can persuade by building strong 'central arguments' or you can persuade by trying to appeal to your audience by associating that which you want it to accept with favorable 'peripheral cues.' Richard Petty and John Cacioppo have argued that persuasion usually takes one of these two forms.

Petty and Cacioppo (1986a, 1986b) state that there are two “routes” to persuasion: central and peripheral. The central route to persuasion consists of thoughtful consideration of the arguments (ideas, content) of the message. The peripheral route to persuasion occurs when the listener decides whether to agree with the message based on other cues besides the strength of the arguments or ideas in the message.

Central route to persuasion was first discussed by Richard Petty and John Cacioppo. Petty and Cacioppo believed that there were two ways in which people's attitudes can be modified. One method is through a central route to persuasion.

Some of the most chilling examples of persuasive communication come from the middle of the last century – in particular the speeches made by Adolf Hitler at the gigantic Nazi Party rallies in the 1930s and early 1940s. The assembled masses appeared mesmerized to the extent that they would do whatever the dictator willed them to do. More generally, the study of persuasive communication connects with the study of leadership, rhetoric, and social mobilization and crowd behavior.

The art of “winning men’s minds by words” has occupied the attention of philosophers since long before the time of Plato’s and Aristotle’s commentaries on rhetoric. But not until the twentieth century has there been any concerted effort of empirically oriented scholars to describe objectively the conditions under which persuasion succeeds or fails.

In order to be effective persuaders, we must first get people’s attention, then send an effective message to them, and then ensure that they process the message in the way we would like them to. Furthermore, to accomplish these goals, persuaders must take into consideration the cognitive, affective, and behavioral aspects of their methods. Persuaders also must understand how the communication they are presenting relates to the message recipient—his or her motivations, desires, and goals.