Originally, researchers thought that persuasive messages went directly from the sender to the receiver with immediate effect. PR people seem to look at communication effects as a series of dominos which, if knocked down in the proper order, elicit the proper effect.
Research also suggests that the mind operates four rings of defenses against unwanted information.
We forget the unpleasant or block out the unwanted. Hedging and Wedging Based on the understanding that human beings are capable of holding more than one opinion about a subject, even if the opinions conflict. To hedge is to create positive actions in order to counter negative actions. Probably heard about it in the mass media. Still getting info from mass media, only more detailed.