The research developed at Yale University became the first systematic approach to persuasion. Under this approach, a persuasive message to change the attitude and behavior has to change the thoughts or beliefs prior recipient of the message. Thus, the process of persuasion conceived as a set of steps, in which a number of key elements. The effectiveness of a persuasive message depends primarily on the effect on the receiver to produce four key elements: the source, the contents of the message, the communication channel and context. The effects of these ...