SNS users' opinion expression: Focusing on suppression effect in spiral of silence

• This study presents an extended research model that combines SOS and IM theories. • Fear of negative evaluation showed a positive influence on SNS impression management. • SOS effect can be understood better by considering SNS impression management. Based on the spiral of silence (SOS) and impression management (IM) theories, this study suggested perceived opinion support, fear of negative evaluation, and social network service (SNS) impression management as motivational factors of SNS users’ opinion expression. The empirical analysis results revealed that perceived opinion support had a negative effect on fear of negative evaluation and that fear of negative evaluation showed a negative influence on willingness to speak out. In contrast to the hypothesis presented in this study, fear of negative evaluation showed a positive influence on SNS impression management. Finally, SNS impression management had a positive influence on willingness to speak out. As a result, there was a competitive mediation, so further analysis revealed that SNS impression management acted as a suppression variable in the structural model. This study found a theoretical limitation that had been overlooked in SOS theory and suggested a new theoretical framework to reveal the process of opinion expression on social media using a theoretical combination with IM theory.