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When expertise backfires: contrast and assimilation effects in persuasion
Gerd Bohner1, Markus Ruder, Hans-Peter Erb
1Universität Bielefeld, Germany. Gerd.Bohner@uni-bielefeld.de
The British Journal of Social Psychology
|February 21, 2003
Summary
Source cues influence persuasion differently based on message clarity. Expectancy violations lead to contrast effects, while ambiguous messages result in bias effects, impacting attitudes and thoughts.
Area of Science:
- Social Psychology
- Cognitive Psychology
- Persuasion Science
Background:
- Source cues, like expertise, can shape how individuals process persuasive messages.
- Existing theories propose contrasting or biasing effects depending on message content and expectancies.
Purpose of the Study:
- To investigate how source expertise cues interact with message argument strength and ambiguity to influence persuasion.
- To test the contrast and bias hypotheses regarding source cue effects on message processing.
Main Methods:
- Two experiments (N = 123) were conducted using student participants.
- Participants evaluated arguments of varying strength (strong vs. weak) and ambiguity presented by sources of differing expertise (high vs. low).
- Measures included participants' thoughts and attitudes towards the messages.
Main Results:
- Weak arguments from high-expertise sources led to less favorable thoughts/attitudes (contrast).
- Strong arguments from low-expertise sources also elicited less favorable thoughts/attitudes (contrast).
- Ambiguous arguments led to more favorable thoughts/attitudes from high-expertise sources and less favorable from low-expertise sources (bias).
Conclusions:
- Findings support both contrast and bias hypotheses in persuasion.
- The interplay between source expertise, message expectancy violation, and ambiguity determines attitude formation.
- Results inform dual-process vs. single-process models of persuasion and social judgment models.