Researchers from the University of Zurich secretly ran a months-long AI experiment on Reddit’s 3.8M-member r/changemyview community without user consent.
A group of researchers from the University of Zurich ran a covert months-long experiment using AI-generated comments to influence Reddit users without their knowledge or consent.
The experiment took place on r/changemyview, a 3.8M-member subreddit known for civil debate. The researchers deployed large language models (LLMs) to write personalized, persuasive replies, posing as real people, to see if AI could change users’ views.
The details
- AI-generated comments, posing as real users, were posted to sway opinions.
- Personas included trauma survivors and controversial political voices.
- The AI used personal data scraped from users’ histories to tailor persuasive replies.
- None of the activity was disclosed, violating subreddit and Reddit-wide rules.
This wasn’t just about bots.
It was psychological manipulation using personal data to test how effective AI can be at changing people’s minds.
Reddit’s Chief Legal Officer Ben Lee called it “deeply wrong on both a moral and legal level” and confirmed that Reddit is preparing formal legal action.
Photo by Brett Jordan su Unsplash
The researchers’ defense
They claim their ethics board approved the project and argue their goal was to show how AI could be misused to manipulate elections or spread hate speech.
“We believe the potential benefits of this research substantially outweigh its risks,” the researchers wrote.
The backlash
Mods of r/changemyview were outraged, calling the research “unwelcome” and “manipulative.”
They’ve filed a complaint and asked the university to block publication of the study. This experiment reveals a growing threat: AI-powered persuasion at scale, without consent. It shows how easily people can be influenced when AI knows your beliefs and can mimic your peers.
Redditors were used as test subjects.
This wasn’t just an academic exercise. It shows how powerful and subtle AI manipulation can be, especially when it mimics trusted human voices using personal data.
With generative AI becoming widespread, the risk of AI-driven manipulation is no longer theoretical. It’s real, and it just happened on one of the internet’s biggest communities.
Now Reddit, one of the world’s largest online communities, is fighting back.
