The LLM "know-say gap" looks like a routing problem: you can read a model's confidence from hidden states [P]

My last post was removed - I am not sure why so I have made some edits. A linear probe on a mid-layer hidden state discriminates a model's own correct from incorrect answers at type-2 AUROC ~0.83 to 0.88, across every model I tested (five base models, 7B to 72B, Qwen / Llama / Mistral). On the same items, the model's spoken confidence is close to useless: fine-tuning a model to emit a confidence number lands at ~0.57 to 0.58 type-2 AUROC, near ch