The three-child policy constitutes a hotly debated socio-political issue in China. Upon its announcement, many Chinese citizens have ridiculed the move on social media. Adopting the cognitive mediation model and the influence of presumed influence theory, this study examines how social media exposure to three-child policy-related news and discussions could affect the Chinese public’s attitudes toward the policy. The online survey results show that social media exposure negatively predicts supportive opinion via cognitive elaboration and three types of perceived negative effects of the policy (i.e., perceived negative effects on self, on the public, and on females) in serial. It also finds that institutional trust moderates the relationship between cognitive elaboration and policy support. Only among people with high institutional trust, there is a positive effect of social media exposure on supportive opinion through cognitive elaboration.
