Public Choice

, Volume 148, Issue 3, pp 283-312

First online:

The limited effects of testimony on political persuasion

  • Brendan NyhanAffiliated withSchool of Public Health, University of Michigan Email author 

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The procedure of witness testimony and cross-examination under oath, which is institutionalized in the court system and in Congress, may increase the credibility of political messages by strengthening perceived incentives for truth-telling. In this paper, I test the hypothesis that testimony can increase the persuasiveness of empirical claims in realistic political settings. However, results from a large number of experiments, including numerous national survey experiments, indicate that describing statements as being made in congressional or court testimony rarely generates significant change in respondents’ beliefs or attitudes—a result that is robust to numerous experimental design variations.