Forbidden Facts: An Investigation of Competing Objectives in Llama 2

Tony Wang, Miles Kai, Kaivalya Hariharan, Nir Shavit

Keywords: mechanistic interpretability, computational irreducibility

Abstract: LLMs often face competing pressures (for example helpfulness vs. harmlessness). To understand how models resolve such conflicts, we study Llama-2-7b-chat on the \textit{forbidden fact} task. Specifically, we instruct Llama 2 to truthfully complete a factual recall statement while forbidding it from saying the correct answer. This often makes the model give incorrect answers. We decompose Llama 2 into 1057 different components, and rank each one with respect to how useful it is for forbidding the correct answer. We find that in aggregate, 41 components are enough to reliably implement the full suppression behavior. However, we find that these components are fairly heterogeneous and that many operate using faulty heuristics. We find that one of these heuristics can be exploited via manually designed adversarial attacks, which we call California Attacks. Our results highlight some roadblocks standing in the way of being able to successfully interpret advanced ML systems.

Submission Number: 74