Seeing Others Receive Support Online: Effects of Self-Disclosure and Similarity on Perceived Similarity and Health Behavior Intention.

Participation in online support groups leads to improved health. While viewing others' interactions is one of the major activities in online support groups and lurkers comprise the majority of online support group participants, the literature on how participants benefit from viewing others' posts and comments is sparse. Building upon the Social Penetration Theory and the narrative persuasion process, this study focused on two key features of online support groups, self-disclosure and similarity. It tested their direct effects on viewers' perceived similarity with the poster and indirect effects on viewers' behavior intention through three mediators: perceived similarity, identification, and perceived support availability. A 2 (similarity vs. dissimilarity) by 3 (factual vs. cognitive vs. emotional self-disclosure) online experiment involving 280 overweight adult participants was conducted. Findings showed similarity of health status led to increased level of perceived similarity and moderated the effects of self-disclosure. Self-disclosure and similarity increased dieting intention through increasing perceived similarity, identification, and perceived support availability. This study provides experimental evidence suggesting viewers can benefit from online support groups through a narrative persuasion process.