A Source Like Any Other? Field and Survey Experiment Evidence on How Interest Groups Shape Public Opinion

Abstract

Interest groups increasingly communicate with the public, yet we know little about how effective they are in shaping opinions. Since interest groups differ from other public communicators, we propose a theory of interest group persuasion. Interest groups typically have a low public profile, and so most people are unlikely to have strong attitudes regarding them. Source-related predispositions, such as credibility assessments, are therefore less relevant in moderating effects of persuasive appeals by interest groups than those of high-profile communicators. We test this argument in multiple large-scale studies. A parallel survey and field experiment (N = 4,659) establishes the persuasive potential of low-profile interest groups in both controlled and realistic settings. An observational study (N = 700) shows that substantial portions of the public are unable to assess interest group credibility. A survey experiment (N = 8,245) demonstrates that credibility assessments moderate the impact of party but not interest group communication.