In light of the growing politicization of social media, the spiral of silence theory and its predictions on the conditions under which individuals express political opinions have gained increasing scholarly attention. This study contributes to this line of research by identifying the influence of a central characteristic of social media: message persistence. It was expected that high technical durability of political messages reduces users’ propensity to voice their opinion, moderating the silence effect. A pre-registered experiment (N = 772) revealed a small-to-medium persistence effect in three out of four topical contexts. While perceived congruence with the opinion climate was not associated with the likelihood of opinion expression, the latter could be explained by a mental cost-benefit calculus that was shaped by message persistence. Theoretical implications are discussed referring to (a) a situational approach regarding silencing processes on social media and (b) its connection to a behavioral calculus of human communication.

随着社交媒体政治化的发展，沉默理论的螺旋式发展及其对个人表达政治观点的条件的预测越来越受到学术界的关注。这项研究通过确定社交媒体的核心特征（消息持久性）的影响，为这一研究领域做出了贡献。预计政治消息的高技术耐用性会降低用户表达意见的倾向，从而减轻沉默效果。预先注册的实验（N = 772）在四个主题背景中的三个主题背景中显示了中小型的持续性影响。虽然与观点氛围的感知一致性与观点表达的可能性无关，但后者可以通过由消息持久性影响的心理成本效益演算来解释。讨论的理论含义是指（a）关于社交媒体沉默过程的一种情境方法，以及（b）它与人类传播行为演算的联系。