The present study investigates the role of source characteristics, the quality of evidence, and prior beliefs of the topic in adult readers' credibility evaluations of short health-related social media posts. The researchers designed content for the posts concerning five health topics by manipulating the source characteristics (source's expertise, gender, and ethnicity), the accuracy of the claims, and the quality of evidence (research evidence, testimony, consensus, and personal experience) of the posts. After this, accurate and inaccurate social media posts varying in the other manipulated aspects were programmatically generated. The crowdworkers (N = 844) recruited from two platforms were asked to evaluate the credibility of up to ten social media posts, resulting in 8380 evaluations. Before credibility evaluation, participants' prior beliefs on the topics of the posts were assessed. The results showed that prior belief consistency and the source's expertise affected the perceived credibility of the accurate and inaccurate social media posts the most after controlling for the topic of the post and the crowdworking platform. In contrast, the quality of evidence supporting the health claim mattered relatively little. The source's gender and ethnicity did not have any effect. The results are discussed in terms of first- and second-hand evaluation strategies.

翻译：本研究探讨了来源特征、证据质量及读者对话题的先验信念在成年读者对健康类社交媒体短帖可信度评估中的作用。研究者通过操控信息来源特征（专业性、性别、族裔）、陈述准确性及证据质量（研究证据、证言、共识、个人经验），设计了涉及五个健康话题的帖子内容，并通过程序生成准确与不准确且在其他操控维度存在差异的社交媒体帖子。从两个平台招募的众包工作者（N=844）被要求评估最多十篇社交媒体帖子的可信度，共获得8380条评估。在可信度评估前，研究先测量了参与者对帖子话题的先验信念。结果表明，在控制帖子话题与众包平台后，先验信念一致性与来源专业性对准确及不准确社交媒体帖子的感知可信度影响最大，而支撑健康主张的证据质量影响相对较小。来源性别与族裔未产生任何效应。研究从第一手与第二手评估策略的角度对结果进行了讨论。