A research team at the University of Zurich spent the past few months running an AI experiment on Reddit users that targeted the “r/changemyview” (CMV) subreddit with AI-generated comments to see if they could change the viewpoints of real Reddit users. Their research was carried out without the permission — or knowledge — of Reddit, CMV’s moderators, or any of the subreddit’s users.
Analyzing the experiment
The original experiment was designed to test the efficacy of the current generation of large language models (LLMs) and their ability to change people’s minds regarding various ethical scenarios. Researchers pursued this goal by using AI to respond to the comments of real Reddit users.
The AI attempted to personalize these responses by detecting the personal details of the real users participating in these conversations and assumed several different personas throughout the experiment. These personas included that of a male sexual assault survivor, a black male who disagreed with the Black Lives Matter movement, and a person who didn’t believe in rehabilitating criminals.
Researchers at the University of Zurich ultimately revealed their use of generative AI tools by emailing the subreddit’s moderators, according to a report by The Register. “We recognize that our experiment broke the community rules against AI-generated comments and apologize,” their email read, in part. “We believe, however, that given the high societal importance of this topic, it was crucial to conduct a study of this kind, even if it meant disobeying the rules.”
Exploring the repercussions
Moderators of the CMV subreddit eventually revealed the experiment to the public via an announcement in late April 2025 that read, in part: “The CMV Mod Team needs to inform the CMV community about an unauthorized experiment conducted by researchers from the University of Zurich on CMV users. This experiment deployed AI-generated comments to study how AI could be used to change views.”
Reddit has since removed user accounts associated with the research team, but this is only the beginning of their worries. Reddit’s legal team has already contacted the University of Zurich with formal legal demands, but those demands have not been released to the public. The University of Zurich has yet to respond to Reddit’s legal inquiry.The question of ethical (and legal) AI implementation