Monoculture False Alarms: Collusion Detectors Mistake Shared AI Models for Conspiracy
Maryam Hampaei · Team Singularity Momentum
Submitted to AI Collusion Research Sprint. Sprint projects are early-stage work by participants, not Apart Research publications.
Collusion detectors assume that innocent firms act independently, but AI pricing agents running the same base model react alike without coordinating. We tested 11 standard collusion detectors, including correlation measures, an information-theoretic test (pairwise net influence) and an LLM judge, in a pre-registered repeated pricing game with innocent and seeded colluding pairs. Most detectors falsely flagged about one in three innocent same-model pairs, and almost no innocent cross-model pairs. Net influence, applied to LLM agents for the first time, was protected only when every firm used the same model. Real colluders who agreed a price and held it looked less suspicious than innocent same-model pairs. Setting thresholds separately for same-model and cross-model pairs cut false alarms to 13–21%. Auditors therefore need to know which model each AI agent runs.
Reviews
No public critique yet.
Cite this project
@misc{hampaei2026monoculture,
title = {{Monoculture False Alarms: Collusion Detectors Mistake Shared AI Models for Conspiracy}},
author = {Maryam Hampaei},
year = {2026},
month = oct,
note = {Submitted to AI Collusion Research Sprint, an Apart Research Sprint},
howpublished = {\url{https://apartresearch.com/sprints/projects/monoculture-false-alarms-collusion-detectors-mistake-shared-ai-models-for-conspiracy-cnd5}},
url = {https://apartresearch.com/sprints/projects/monoculture-false-alarms-collusion-detectors-mistake-shared-ai-models-for-conspiracy-cnd5}
}More from AI Collusion Research Sprint
- View project: Collusion, Competion and Collapse
Collusion, Competion and Collapse
Atelier Alex Cline
Do AI traders collude when nobody tells them to? We built agora, a six-market benchmark with exact competitive and collusive benchmarks, and ran seven open-weight 2-4B models in 590 completed games under five …
- View project: Making AI Guardrails Understandable and Testable: A Framework Illustrated by a Simulated Bond Market
Making AI Guardrails Understandable and Testable: A Framework Illustrated by a Simulated Bond Market
Rogue Agents in Jail 🕵️🕵️♀️👮♂️
In order to advance AI safety research into shaping public policy, the development of technical controls needs to have a clear purpose, evidence, and limitations that are understandable for the people responsible for …
- View project: Extending Information-Theoretic Collusion Detection to Large Language Model Agents
Extending Information-Theoretic Collusion Detection to Large Language Model Agents
Gamma Ray
We test whether the information-theoretic collusion detector of Bonjour et al, validated on scripted agents, works on LLM agents. Gemma, Mistral and Qwen played 1000 rounds of three-player Rock-Paper-Scissors in three …