The more the merrier? The effects of system-aggregated group size information on user's efficacy and intention to participate in collective actions

Social media platforms are increasingly used by activists to mobilize collective actions online and offline. Social media often provide visible information about group size through system-generated cues. This study is based on social cognitive theory and examines how visible group size on social media influences individuals' self-efficacy, collective efficacy and intentions to participate in a collective action among groups with no prior collaboration experiences.

A between-subject online experiment was conducted with a sample of 188 undergraduate participants in a large public university in the United States. Six versions of a Facebook event page with identical contents were created. The study manipulated the group size shown on the event page (control, 102, 302, 502, 702 and 902). Participants were randomly assigned to one of the six conditions and asked to read and assess an event page that calls for a collective action. Then their collective efficacy, self-efficacy and intentions to participate were measured.

The results showed that the system-aggregated group size was not significantly associated with perceived collective efficacy, but there was a curvilinear relationship between the group size and perceived self-efficacy. Self-efficacy partially mediated the relationship between group size and intentions to participate; collective efficacy did not.

The study contributes to social movement theories by moving beyond personal grievance and identity theories to examine how individuals' efficacy beliefs can be affected by the cues that are afforded by social media platforms. The study shows that individuals use system-generated cues about the group size for assessing the perceived self-efficacy and collective efficacy in a group with no prior affiliations. Group size also influenced individual decisions to participate in collective actions through self-efficacy and collective efficacy.