This study aims to examine whether and how user-generated comments and reaction emojis on COVID-19 vaccine-promoting Facebook posts induce psychological reactance to posts and vaccine hesitancy in audiences of the posts. An online experiment including 465 American adults showed that, compared with COVID-19 vaccine promotion posts accompanied by pro-vaccine comments, those accompanied by anti-vaccine comments provoked greater reactance in audiences through the mediating effects of bandwagon perception and the presumed influence of the posts on others. Greater reactance, in turn, increased audiences' COVID-19 vaccine hesitancy. Additionally, reaction emojis altered the comments' effects such that pro-vaccine comments triggered less reactance than anti-vaccine comments when the pro-vaccine comments were accompanied by agreement emojis (i.e., “like” and “love”); whereas there was no significant difference between pro-vaccine comments and anti-vaccine comments in reactance when the pro-vaccine comments were accompanied by rejection emojis (i.e., “angry” and “sad”). Furthermore, audiences’ pre-existing attitudes did not affect the effects of opinion cues on their′ reactance and vaccine hesitancy.

本研究旨在检查用户在 COVID-19 疫苗推广 Facebook 帖子上生成的评论和反应表情符号是否以及如何引起帖子受众对帖子的心理反应和疫苗犹豫。一项包括 465 名美国成年人的在线实验表明，与伴随着支持疫苗评论的 COVID-19 疫苗宣传帖子相比，那些伴随着反疫苗评论的帖子通过潮流感知的中介作用和推定的别人的帖子。反之，更大的反抗增加了观众对 COVID-19 疫苗的犹豫。此外，反应表情符号改变了评论的效果，因此当支持疫苗的评论伴随着同意的表情符号（即，“喜欢”和“爱”）；而当支持疫苗的评论伴随着拒绝表情符号（即“愤怒”和“悲伤”）时，支持疫苗的评论和反对疫苗的评论在反应方面没有显着差异。此外，观众预先存在的态度不会影响意见线索对他们的反应和疫苗犹豫的影响。