Contextual contrast and perceived knowledge: Exploring the implications for persuasion

The present research tested the notion that perceived target knowledge can be affected by the amount of information one has about other recently encountered stimuli—whether that information is relevant or not. Furthermore, the present research tested the implications of this effect for persuasion. In 4 experiments, participants were presented with a persuasive message promoting a fictitious department store, but first received another message containing more or less information about something else (e.g., another store, a car, or a person). Regardless of the type or valence of initial information received, the initial message had a contrast effect on perceived target knowledge, which influenced target attitudes. The less information the initial message contained, the more persuasive knowledge participants thought they received from the target message, and the more their attitudes agreed with that message. These findings suggest that the perceived amount of persuasive information one has about a target stimulus can be manipulated to increase persuasion, even when the actual amount of information about the target stimulus does not vary.