Probing for Emergent Deception in Multi-Agent Negotiations
Teanna Sims · Team Simsity
Submitted to AI Manipulation Hackathon. Sprint projects are early-stage work by participants, not Apart Research publications.
Can we catch deception by looking inside the model? I built negotiation scenarios where lying becomes rational without ever mentioning deception in the prompt, then trained probes on Gemma 2B activations. Results show above chance detection and evidence for implicit encoding, but different deception types are represented at completely different layers.
Track: Open
Reviews
This seems like a really good experiment to run. To me the idea that perked me up was "incentivizing deception is different than instructing deception", and I would have been very excited to have that be more of the explicit focus. Instead the work started off with this motivation, and then it seems like the analysis tended towards how we can identify deception - which Apollo has previously done good work on. So the impact for me here is solid, but not higher.
So for instance I would have really liked to see the core premise play out in the activations - is telling the model to do deception structurally different from incentivizing it to do so? It is implicit in "different kinds of deception show up differently in the activations" (! important result), but making this explicit would be impactful for me.
The lack of statistical power hurt (the admitted only have 300 samples and needing 3000) but is also understandable considering time and resource constraints.
I thought you were very thoughtful in laying out the motivations and the conclusions. That was very well done. As in - the plain English text, motivating, focus on the "so what" were all really great. I found the figures to be a little distracting or forced. Some of those could have been a small table or just a few lines in the text, and I found some of them to detract from what was otherwise a very well structured and laid out report.
Read full reviewShow less
This is a solidly executed project with a clear motivation for measuring naturally arising deception through incentive design, rather than through explicit instruction. I expect experiments with Gemma 2B to be quite noisy by default, and would like to see this replicated on larger models. The GM vs Agent label comparison result is interesting, and worth further exploration.
Cite this project
@misc{sims2026probing,
title = {{Probing for Emergent Deception in Multi-Agent Negotiations}},
author = {Teanna Sims},
year = {2026},
month = jan,
note = {Submitted to AI Manipulation Hackathon, an Apart Research Sprint},
howpublished = {\url{https://apartresearch.com/sprints/projects/probing-for-emergent-deception-in-multiagent-negotiations-522l}},
url = {https://apartresearch.com/sprints/projects/probing-for-emergent-deception-in-multiagent-negotiations-522l}
}More from AI Manipulation Hackathon
- 1st placeView project: Who Does Your AI Serve? Manipulation By and Of AI Assistants
Who Does Your AI Serve? Manipulation By and Of AI Assistants
Cart Abandonment Issues 🛒
AI assistants can be both instruments and targets of manipulation. In our project, we investigated both directions across three studies. AI as Instrument: Operators can instruct AI to prioritise their interests at the …
- 2nd placeView project: Eliciting Deception on Generative Search Engines
Eliciting Deception on Generative Search Engines
Ardy
Large language models (LLMs) with web browsing capabilities are vulnerable to adversarial content injection—where malicious actors embed deceptive claims in web pages to manipulate model outputs. We investigate whether …
- 3rd placeView project: Cross-Linguistic Sycophancy in Frontier LLMs: A Benchmark Study
Cross-Linguistic Sycophancy in Frontier LLMs: A Benchmark Study
Talex
We developed a cross-linguistic sycophancy benchmark testing whether frontier AI models exhibit different manipulation behaviours across English, Japanese, and Bengali. Our results show significant language-dependent …