Article | Journal of Consumer Research

Believe Me, I Have No Idea What I Am Talking About: The Effects of Source Certainty on Consumer Involvement and Persuasion

by Uma R. Karmarkar and Zakary L. Tormala

Abstract

This research explores the effect of source certainty-that is, the level of certainty expressed by a message source-on persuasion. The authors propose an incongruity hypothesis, suggesting that source certainty effects depend on perceived source expertise. In three experiments, consumers receive persuasive messages from sources of varying expertise and certainty. Across studies, low expertise sources violate expectancies, stimulate involvement, and promote persuasion when they express certainty, whereas high expertise sources violate expectancies, stimulate involvement, and promote persuasion when they express uncertainty. Thus, nonexpert (expert) sources can gain interest and influence by expressing certainty (uncertainty).

Keywords: Research; Experience and Expertise; Risk and Uncertainty; Consumer Behavior; Performance Expectations; Interests; Power and Influence;

Citation:

Karmarkar, Uma R., and Zakary L. Tormala. "Believe Me, I Have No Idea What I Am Talking About: The Effects of Source Certainty on Consumer Involvement and Persuasion." Journal of Consumer Research 36, no. 6 (April 2010): 1033–1049.