How confidence in prior attitudes, social tag popularity, and source credibility shape confirmation bias toward antidepressants and psychotherapy in a representative German sample: Randomized controlled web-based study

Abstract

Background: In health-related, Web-based information search, people should select information in line with expert (vs nonexpert) information, independent of their prior attitudes and consequent confirmation bias. Objective: This study aimed to investigate confirmation bias in mental health-related information search, particularly (1) if high confidence worsens confirmation bias, (2) if social tags eliminate the influence of prior attitudes, and (3) if people successfully distinguish high and low source credibility. Methods: In total, 520 participants of a representative sample of the German Web-based population were recruited via a panel company. Among them, 48.1% (250/520) participants completed the fully automated study. Participants provided prior attitudes about antidepressants and psychotherapy. We manipulated (1) confidence in prior attitudes when participants searched for blog posts about the treatment of depression, (2) tag popularity -either psychotherapy or antidepressant tags were more popular, and (3) source credibility with banners indicating high or low expertise of the tagging community. We measured tag and blog post selection, and treatmentefficacy ratings after navigation. Results: Tag popularity predicted the proportion of selected antidepressant tags (beta=.44, SE 0.11; P