Toward a Middle-Range Theory of Environmental Message Credibility in Online Social Networks: An Extended Reasoning Model

We propose and empirically examine an extended reasoning model of science-based environmental message credibility on online social networks (OSNs). Building on traditional claim-evidence reasoning, the model incorporates message source, evidence vividness, and group-based identity as key antecedents of perceived credibility. Results from our survey-embedded experiment show that the extended model explains 38% of the variance in the perceived credibility of science-based environmental OSN posts. Both message reasoning style and individuals’ group identities play a significant role in credibility assessments. We found that vivid evidence increased the credibility of the science-based environmental claim to a level comparable to that of claims supported by graphical evidence presented with scientific backing. Additionally, we uncovered an interaction between group-based identity and the message source, which provides a novel explanation of the complex relationship between group-based identity and perceptions of environment-related message credibility. Post hoc analyses further show that, among younger individuals, higher education is associated with greater credibility perceptions of science-based environmental claims, regardless of group identity. We discuss the implications of our findings and present significant opportunities for future research.