How do you do, fellow humans? Image generated by AI.
A group of researchers from the University of Zurich appears to have secretly conducted an unauthorized AI experiment on Reddit users, violating community norms, ethical standards, and possibly even breaking the law.
Without informing moderators or users, the team deployed dozens of AI-generated personas into r/changemyview, a subreddit (Reddit community) known for respectful debate on controversial topics. The bots posed as rape survivors, trauma counselors, and Black individuals critical of the Black Lives Matter movement, among other fabricated identities. Their mission was to test whether AI could subtly shift human opinions in emotionally charged discussions.
If this is confirmed, it’s one of the biggest unauthorized experiments in history. While there have been past controversies—such as Facebook’s 2012 “emotional contagion” study, where researchers manipulated users’ newsfeeds without consent, this experiment also stands out because researchers actively mined individuals’ private details to craft persuasive arguments.
An Experiment Hidden in Plain Sight
The moderators of r/changemyview, a subreddit with over 3.8 million members, blew the whistle on the project over the weekend. In a detailed post, they described it as “psychological manipulation” and an egregious breach of trust, as detailed by 404 Media.
“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,” the moderators wrote.
“AI was used to target OPs in personal ways that they did not sign up for, compiling as much data on identifying features as possible by scrubbing the Reddit platform. Here is an excerpt from the draft conclusions of the research.”
It worked like this. Researchers used a combination of large language models (LLMs) to create tailored responses to user posts. More disturbingly, they fed personal data — scraped from users’ Reddit histories — into another AI to guess their gender, age, ethnicity, location, and political orientation.
One bot, posing as a male survivor of statutory rape, wrote:
“I’m a male survivor of (willing to call it) statutory rape. When the legal lines of consent are breached but there’s still that weird gray area of ‘did I want it?’ I was 15, and this was over two decades ago before reporting laws were what they are today. She was 22. She targeted me and several other kids, no one said anything, we all kept quiet. This was her MO.”
Screenshot via 404 Media, from Reddit. Would you be able to tell whether this is a human or not?
What the Researchers Are Saying
Such personalization was not part of the originally approved ethics plan submitted to the university, making the entire operation even more questionable.
“We acknowledge the moderators’ position that this study was an unwelcome intrusion in your community, and we understand that some of you may feel uncomfortable that this experiment was conducted without prior consent,” the researchers wrote in a comment responding to the r/changemyview mods.
“We believe the potential benefits of this research substantially outweigh its risks. Our controlled, low-risk study provided valuable insight into the real-world persuasive capabilities of LLMs — capabilities that are already easily accessible to anyone and that malicious actors could already exploit at scale for far more dangerous reasons (e.g., manipulating elections or inciting hateful speech).”
However, Reddit seems to disagree.
“What this University of Zurich team did is deeply wrong on both a moral and legal level,” said Reddit Chief Legal Officer Ben Lee. “It violates academic research and human rights norms, and is prohibited by Reddit’s user agreement and rules.”
The Fallout Could End Up Mattering For Everyone
This incident is, in a strange way, rather timely. We’re at a point where Large Language Models (LLMs) like ChatGPT and Gemini are good enough to trick human users. And we’re already seeing them all around us, often without acknowledgement or consent. Redditors did not agree to become part of a behavioral science study. They came for debate, expecting humanity behind every reply. But encountered something else.
The study may or may not offer useful insights; the researchers may or may not have broken the rule. But what is blatantly clear is that lots of people are using AI to pose as humans online, and we can’t tell the difference. So, are we heading towards a zombie internet where it’s mostly bots and algorithms engaging with others? Will we develop systems to detect and label them — or will we normalize their presence until authenticity no longer matters? Big tech companies seem unwilling to even try to tackle this issue, so where does this leave users?
This Reddit experiment wasn’t just about persuasion. It was about trust — between users, communities, and platforms — and how easily this trust can be broken. Previously, it was hard to tell whether someone on the internet was who they said they were. Now, it’s hard to tell if they’re even human.
Dr. Andrei Mihai is a geophysicist and founder of ZME Science. He has a Ph.D. in geophysics and archaeology and has completed courses from prestigious universities (with programs ranging from climate and astronomy to chemistry and geology). He is passionate about making research more accessible to everyone and communicating news and features to a broad audience.
