Abstract
Using spiral of silence and social loafing theories, this study proposed a parallel mechanism to explain why people defend their stances on controversial sociopolitical issues through political consumption behaviors (i.e., boycott and buycott) when they read about corporate advocacy messages on social media. A 2 (personal stance: supporting vs. opposing gun control) * 3 (other Instagram commenters' stances: majority supporting gun control vs. majority opposing gun control vs. balanced opinions) between-subjects quasi-experiment was conducted to test the mediating effects of feeling of being in the majority opinion group and feeling of others not contributing enough on boycott/buycott intentions. Results showed that people defend their stances through boycott/buycott actions, because of the feeling of being in the majority opinion group. Keywords: spiral of silence, social loafing, gun control, boycott, buycott