A field experiment of social influence and behavioral contagion with bots on Reddit

2026-07-01

AI Summary

This study investigates whether online users are susceptible to prosocial behavioral nudges from both human peers and AI agents, and whether such interventions can trigger behavioral contagion. Conducting a field experiment on Reddit, the authors systematically compare the effects of sender type (human versus bot) and reward rationale—spanning four distinct justifications—on recipients’ subsequent activity and community-wide diffusion. The findings reveal, for the first time in a real-world social setting, that transparently disclosed automated agents play a critical role in platform governance. While symbolic rewards did not enhance user engagement or influence overall, rewards issued by bots under a “raffle” rationale even suppressed participation; however, they significantly increased direct interpersonal interactions among users.

Abstract

Recent advances in AI have heightened scholars' and policy makers' concern with social influence and behavioral contagion in online communities. We conduct a field experiment on Reddit to investigate the extent to which online users are susceptible to positive behavioral stimuli from other users and artificial agents. We let apparent human and bot accounts give symbolic awards to users with one of four rationales: praising the recipient's logical argument, emotional sensitivity, or moral integrity, or explaining that the award resulted from a random draw in a lottery. We evaluate how the different rationales for the award affect the recipients' subsequent behavior on the platform in terms of volume, impact, and content, as well as the further behavioral contagion to other users. We find that awards do not increase user activity and downstream impact, and awards from bots with the lottery rationale can in fact reduce them. Nevertheless, awards encourage direct communication between users. These findings highlight the possible resilience of online users to simple behavioral manipulation from platform algorithms and artificial agents, but not necessarily to more sophisticated schemes that simulate human conversation. Transparently labeling automated agents remains essential for ethical and effective platform governance.

Problem

• social influence
• behavioral contagion
• bots
• online communities
• field experiment

Innovation

• behavioral contagion
• social influence
• AI bots
• field experiment
• online communities