AI bots secretly manipulated Reddit users
Originally posted on LinkedIn, April 30, 2025.
University of Zurich researchers ran undisclosed AI bot accounts on r/ChangeMyView to test personalized persuasion on real users.
Researchers at the University of Zurich secretly placed 13 AI-powered fake accounts into Reddit's r/ChangeMyView without moderator approval or user consent. Bots from GPT-4o, Claude 3.5, and LLaMA tailored replies using personal history—gender, age, location, politics, values—and sometimes posed as people with painful life stories. The study highlights consent and ethics when AI persuasion targets real communities online.
Researchers from the University of Zurich secretly inserted 13 AI-powered fake accounts into Reddit’s popular r/ChangeMyView forum. It sounds like an episode of Black Mirror, except it actually happened.
r/ChangeMyView is a subreddit where people share personal opinions and invite others to change their minds. It depends on transparency, humanity, and open dialogue. The researchers neither asked the moderators for permission nor told users they were part of an experiment.
The responses were generated by models including GPT-4o, Claude 3.5, and LLaMA. They were not neutral or academic. The researchers analyzed each participant’s history, including gender, age, location, political affiliation, and values, then produced responses designed to persuade that person emotionally and individually.
The bots posed as real people with painful life stories: a sexual assault survivor, a Palestinian hostile toward Israel who argued that the war was not genocide, a Black man opposed to BLM, a trauma counselor, and a patient who had received failed medical treatment. Each response was written to create empathy and connection while challenging the user’s original position.
The experiment lasted four months. During that time, the accounts posted about 1,783 comments and received more than 10,000 karma points. More than 100 users awarded deltas, indicating that their views had changed, to responses written by AI.
The forum’s moderators learned about the experiment only after it ended. They condemned it as a blatant violation of community rules and ethical standards, then filed a formal complaint with the university. The university issued the researchers a warning and acknowledged that they had crossed a line, but argued that the insights gained justified the experiment.
The moderators demanded a public apology and asked that the research results not be published. Both requests were rejected.
This experiment raises direct questions about psychological manipulation without consent and synthetic content pretending to be human. Anyone building or deploying these models has to consider not only what can be done, but what must not be done.
The moderators documented the experiment in this Reddit post.
FAQ
- Which subreddit did the Zurich study target?
- The experiment inserted fake accounts into Reddit's r/ChangeMyView. Moderators were not asked, and users were not told the accounts were AI.
- Which models powered the Reddit bots?
- Responses came from GPT-4o, Claude 3.5, and LLaMA. The bots personalized arguments using users' history, including gender, age, location, politics, and values.
- What ethical issue does the experiment raise?
- Running covert AI persuasion on real people without consent raises research ethics questions about whether platforms and participants should know when influence is machine-generated.