In a covert study that has ignited fierce legal and ethical debate, researchers from the University of Zurich deployed artificial intelligence bots to covertly influence discussions on Reddit, without informing participants or securing consent. The experiment took place within the subreddit r/ChangeMyView, a platform dedicated to reasoned debates on divisive topics and followed by nearly four million users.
According to a report by404 Media, the AI agents posted over 1,700 comments while posing as genuine users, engaging in emotionally and politically charged conversations. Pseudonymous personas included a male rape survivor downplaying trauma and a black man expressing criticism of the Black Lives Matter movement. None of these interactions were flagged as artificial, and users were unaware they were engaging with machines.
The controversial research aimed to assess how persuasive AI-generated arguments could be. Findings revealed that the bots were significantly more influential than real users—between three and six times more persuasive, as measured by Reddit’s built-in system for awarding opinion changes.
To achieve this, the AI tools accessed and analysed users’ posting histories to tailor their replies, a move that raised serious privacy concerns. Remarkably, none of the interactions prompted suspicion that the responses were AI-generated.
Once the study had concluded, researchers and subreddit moderators disclosed the experiment and linked to a draft version of the findings. The fallout was immediate. Moderators of r/ChangeMyView condemned the project, calling it “immoral” and “unauthorised.” They also questioned whether the novelty of the method justified bypassing ethical protocols.
Ben Lee, Reddit’s Chief Legal Officer, joined the criticism under his account ‘traceroo’, branding the experiment a violation of both user trust and basic human rights standards. He confirmed that Reddit would be pursuing legal action against the University of Zurich for breaching the platform’s user agreement.
In response to the backlash, the University of Zurich told404 Media it would withhold publication of the research. The university’s ethics board has since revised its guidelines to avoid similar breaches in future studies.
