Heuristic Information Processing as a Mediating Factor in the Process of Exposure to COVID-19 Vaccine Information and Misinformation Sharing on Social Media.

Social media use for risk communication during the COVID-19 pandemic has caused considerable concerns about an overabundance of information, particularly misinformation. However, how exposure to COVID-19 information on social media can lead to subsequent misinformation sharing during the pandemic has received little research attention. This study adopted the social amplification of risk framework to delineate how exposure to COVID-19 vaccine information on social media can be associated with individuals' misinformation sharing through heuristic information processing. The role of social media trust was also examined. Results from an online survey (N = 1488) of Chinese Internet users revealed that exposure to COVID-19 vaccine information on social media was associated with misinformation sharing, mediated by both affect heuristics (i.e., negative affect toward the COVID-19 pandemic in general) and availability heuristics (i.e., perceived misinformation availability). Importantly, both high and low levels of trust in social media strengthened the mediating associations. While a low level of trust strengthened the association between exposure to COVID-19 vaccine information on social media and the affect heuristics, a high level of trust strengthened its association with the availability heuristics, both of which were associated with misinformation sharing. Our findings suggest that heuristic information processing is essential in amplifying the spread of misinformation after exposure to risk information on social media. It is also suggested that individuals should maintain a middle level of trust in social media, being open while critical of risk information on social media.