The University of Zurich secretly experimented on Reddit users

Moderators of the r/changemyview (CMV) subreddit have uncovered a secret, months-long study by scientists at the University of Zurich who used AI-generated comments to test the persuasiveness of large language models without the participants' prior consent. The experiment, which moderators called "psychological manipulation," was conducted in one of the platform's largest communities, 404Media reports.

According to moderators, the researchers used language models to generate responses under fictional personas, from a sexual assault victim to a trauma psychologist and “a black man who denies the Black Lives Matter movement.” To increase personalization, the AI allegedly obtained information about the authors’ gender, age, ethnicity, location and political views from their post history.

“The CMV moderation team must inform its community about an unauthorized experiment conducted by researchers from the University of Zurich,” they said in an official statement. The moderators added that the researchers violated the subreddit’s internal rules, which prohibit automated accounts and require disclosure of the use of AI, and have already filed a complaint with the university asking it not to publish the results of the study.

Reddit's legal department has also launched a response to the incident. The company's chief legal officer, Ben Lee, called the researchers' actions "morally and legally unacceptable" and confirmed that all accounts associated with the experiment have already been suspended. Reddit plans to strengthen its systems for detecting suspicious activity and send formal legal demands to the University of Zurich.

In response to the criticism, the researchers said their project had been approved by the university's ethics committee and aimed to explore the real potential of AI for manipulation to help online communities protect themselves from malicious scenarios involving the use of language models - for example, to interfere in elections or spread hateful material. "We understand the concerns of moderators, but we are convinced that the benefits of the study far outweigh the risks," the scientists said.

Moderators of r/changemyview strongly denied the need for such an experiment, noting that other research groups have already studied Reddit's open data without direct user participation. "Users come here to interact with people, not with AI and not to become research subjects," they explained.