Perceived Epistemic Authority (Source Credibility) of a TV Interviewer Moderates the Media Bias Effect Caused by His Nonverbal Behavior

The Media Bias Effect (MBE) represents the biasing influence of the nonverbal behavior of a TV interviewer on viewers’ impressions of the interviewee. In the MBE experiment, participants view a 4-min made-up political interview in which they are exposed only to the nonverbal behavior of the actors. The interviewer is friendly toward the politician in one experimental condition and hostile in the other. The interviewee was a confederate filmed in the same studio, and his clips are identical in the two conditions. This experiment was used successfully in a series of studies in several countries (Babad and Peer in J Nonverbal Behav 34(1):57–78, 2010. 10.1007/s10919-009-0078-x) and was administered in the present research. The present investigation focused on the interviewer's source credibility and its persuasive influence. The viewers filled out questionnaires about their impressions of both the interviewer and the interviewee. A component of "interviewer's authority" was derived in PCA, with substantial variance in viewers' impressions of the interviewer. In our design, we preferred the conception of Epistemic Authority (Kruglanski et al. in Adv Exp Soc Psychol 37:345–392, 2005)—based on viewers' subjective perceptions for deriving authority status—to the conventional design of source credibility studies, where dimensions of authority are pre-determined as independent variables. The results demonstrated that viewers who perceived the interviewer as an effective leader demonstrated a clear MBE and were susceptible to his influencing bias, but no bias effect was found for viewers who did not perceive the interviewer as an effective leader. Thus, Epistemic Authority (source credibility) moderated the Media Bias Effect.