Abstract: Information source is a key factor affecting the psychological response of Weibo users in social media. Effectively identifying the cognitive and emotional response of Weibo users in sudden natural disasters is of great significance for accurate public opinion guidance. From the perspective of information source, based on the characteristics of credibility and influence, and in combination with the dual system theory and involvement theory, this paper constructs a user psychological response model of cognitive and emotional in sudden natural disasters. Taking the public opinion data of “Jiuzhaigou Earthquake” on Weibo as an example, this paper uses the simultaneous equation model for empirical study. The results show that credibility negatively affects users’ cognitive response, while influence positively affects users’ cognitive response. Credibility and influence both negatively affect users’ positive emotional responses and positively affect users’ negative emotional response. User involvement weakens the effect of credibility on psychological response, while the moderating effect of user involvement between influence and users’ psychological response is not significant. From the perspective of heuristic and analytical dual process of information processing, this paper enriches the dual system theory to the field of sudden natural disasters and expands the research field of user involvement in combination with user characteristics. The conclusions have important implications for the online public opinion guidance of social media users in sudden natural disasters.

Key words: the credibility of information source, the influence of information source, cognitive response, emotional response, user involvement