Reddit Bans University of Zurich Researchers for Using AI Bots to Manipulate Commenters

In a controversial move, Reddit banned researchers from the University of Zurich after they used AI bots to manipulate users on the popular subreddit r/changemymind. The researchers aimed to study how persuasive large language models (LLMs) like GPT-4o, Claude 3.5 Sonnet, and Llama 3.1-405B could be in real online environments by deploying bots that impersonated personas such as a trauma counselor, a Black man opposed to Black Lives Matter, and a sexual assault survivor.

These bots posted a total of 1,783 comments and amassed over 10,000 comment karma before their true nature was uncovered. Reddit’s Chief Legal Officer, Ben Lee, condemned the experiment as “improper and highly unethical,” emphasizing that it was “deeply wrong on both a moral and legal level.” The researchers have since been banned from Reddit, and the platform is considering legal action.

The University of Zurich responded by stating they are investigating the methods used in the experiment and will not publish the results. However, parts of the research remain accessible online, though the paper has not undergone peer review and should be approached with caution.

The researchers instructed their AI bots to analyze Reddit users’ posting histories—limited to their last 100 posts and comments—to craft highly convincing replies tailored to each user’s inferred sociodemographic characteristics. They also manually deleted any comments flagged as ethically problematic or those that explicitly revealed their AI origin, attempting to conceal the experiment’s nature.

One particularly troubling aspect was a prompt falsely claiming that Reddit users had given informed consent for their data to be used, which was not the case. This deception has further fueled ethical concerns surrounding the experiment.

While some have marveled at the bots’ ability to outperform humans in persuading others—achieving success rates three to six times higher than human baselines—the experiment’s design inherently favored the bots’ manipulative capabilities. This raises important questions about the potential misuse of AI in online discourse.

The researchers themselves acknowledged the risks, warning that such AI bots could be exploited by malicious actors to sway public opinion or interfere in elections. They called on online platforms to implement robust detection mechanisms, content verification protocols, and transparency measures to combat AI-generated manipulation.

This incident highlights the urgent need for ethical guidelines and technical safeguards in the deployment of AI technologies within social media. As AI becomes increasingly sophisticated, platforms must proactively address the challenges of AI-driven manipulation to protect user trust and the integrity of online conversations.

For developers, businesses, and policymakers, this case serves as a cautionary tale about balancing innovation with ethical responsibility. It underscores the importance of transparency, user consent, and the development of AI detection tools to prevent misuse.