LLMs Know More Than They Show: On the Intrinsic Representation of LLM Hallucinations
2025-01-22 · ICLR 2025 Poster · anchor
Findings
- IC-181Truthfulness in Mistral-7B, Mistral-7B-Instruct, Llama3-8B, and Llama3-8B-Instruct is linearly decodable from internal representations at exact answer tokens, with middle-to-late layers being most informative
- IC-182Truthfulness encoding in Mistral-7B, Mistral-7B-Instruct, Llama3-8B, and Llama3-8B-Instruct is skill-specific rather than universal; probing classifiers do not meaningfully generalize across different task types beyond logit-based baselines
- IC-183Error types in Mistral-7B, Mistral-7B-Instruct, Llama3-8B, and Llama3-8B-Instruct are linearly predictable from internal representations, encoding fine-grained information beyond binary correctness
- IC-184Mistral-7B, Mistral-7B-Instruct, Llama3-8B, and Llama3-8B-Instruct can internally encode the correct answer while externally generating an incorrect one, with the discrepancy most pronounced for error types where the model shows no external preference for the correct answer