question: We investigated how heuristic credibility cues affected credibility judgments and decisions. Participants saw advice in comments in a simulated online health forum. Each comment was accompanied by credibility cues, including author expertise and peer reputation ratings (by forum members) of comments and authors. In Experiment 1, participants' credibility judgments of comments and authors increased with expertise and increased with the number of reputation ratings for supportive ratings and decreased with number of ratings for disconfirmatory ratings. Also, results suggested that the diagnosticity (informativeness) of credibility cues influenced credibility judgments. Using the same credibility cues and task context, Experiment 2 found that when high-utility choices had low credibility, participants often chose alternatives with lower utility but higher credibility. They did this more often when less utility had to be sacrificed and when more credibility was gained. The influence of credibility and utility information on participants' choices was mediated by their explicit credibility judgments. These findings supported the predictions of a Bayesian belief-updating model and an elaboration of Prospect Theory (Budescu, Kuhn, Kramer, & Johnson, 2002). This research provides novel insights into how cues including valence and relevance influence credibility judgments and how utility and credibility trade off during decision making. (PsycInfo Database Record (c) 2020 APA, all rights reserved).