Inside the Secret AI Experiment That Manipulated Reddit Users and Sparked Legal Fury

University of Zurich’s Secret AI Experiment on Reddit Users Sparks Controversy

Researchers from the University of Zurich conducted a covert experiment on Reddit’s r/changemyview subreddit, deploying AI chatbots to test their ability to influence human opinions. The results were unsettling: these AI bots proved to be significantly more persuasive than real users in changing minds.

The r/changemyview subreddit, home to nearly 4 million users debating diverse and often contentious issues, became the stage for this unannounced study. Over 1,700 comments were posted by AI-driven accounts, each adopting distinct personas to maximize their persuasive impact. Examples included a male rape victim minimizing his trauma, a domestic violence counselor discussing vulnerable women, and a Black man opposing the Black Lives Matter movement.

Methodology and Persuasion

One of the AI bots specialized in analyzing user profiles to tailor its arguments, enhancing its effectiveness. The team measured success using Reddit’s built-in feature that allows users to award comments that changed their perspectives. The AI comments were found to be three to six times more effective at persuasion than typical human responses.

Notably, participants rarely suspected that they were engaging with AI. The anonymity of the researchers — who did not disclose their identities in the draft report — and the lack of prior user consent raised ethical red flags within the community.

Community and Legal Backlash

Moderators of r/changemyview publicly condemned the experiment, stating, “We think this was wrong. We do not think that ‘it has not been done before’ is an excuse to do an experiment like this.” Reddit’s chief legal officer, Ben Lee, responded under the username traceroo, announcing plans to pursue legal action against the University of Zurich. He emphasized that the experiment violated Reddit’s user agreement, subreddit rules, and broader human rights norms.

In response, the university pledged not to publish the study’s results and committed to implementing stricter ethical review procedures, including coordination with online communities before conducting similar research in the future.

Implications for AI and Online Discourse

This incident highlights the growing sophistication of AI chatbots in mimicking human behavior and influencing online discussions. Recent advances, such as OpenAI’s GPT-4.5 passing the Turing test by convincing 73% of trial participants they were interacting with humans, demonstrate how AI is closing the gap between human and machine communication.

Concerns about AI potentially dominating internet content have circulated widely. While the so-called “dead internet” theory suggests AI could replace most human-generated content online, this remains speculative at best. Still, the ethical and practical challenges raised by this experiment underscore the urgent need for clearer guidelines in AI research and deployment.

• See the Nature article on AI ethics in research for broader context.
• For technical details on GPT advancements, visit OpenAI’s official research page.