Triggering participation: Exploring the effects of third-person and hostile media perceptions on online participation

• We tested how the presence of online comments affects the third-person effect (TPE) and hostile media perception (HMP).
• We examined factors predicting subjects’ likelihood of commenting on an online news story.
• Presence of comments lowers self-other differences and consequently attenuates TPE.
• Perceptions of media bias significantly predict likelihood of commenting.

Using a 2 × 3 mixed between-within subjects experiment (N = 102), we tested how the presence of online comments affects self-other differences and perceptions of media bias, as well as factors predicting subjects’ likelihood of commenting on an online news story. We found that (a) presence of comments lowers self-other differences and consequently attenuates the third-person effect, and (b) perceptions of media bias significantly predict likelihood of commenting. Additionally, we found that subjects were more likely to comment on stories they found biased against their position as a form of corrective action, and that subjects were more likely to share and like stories they found biased in favor of their position as a form of promotional action.