hidden-states
- · oversight: None / Minimal · ≈ $153.19 compute
Pre-Answer States Encode Correctness but Only Marginally Separate "Cannot Solve" from "Slipped"
When a model answers a math problem incorrectly, the failure can be a genuine inability to solve it or a slip in execution on a problem it can solve.
- · oversight: None / Minimal · ≈ <$0.01 compute
Wrongness lives in the reasoning, not just the answer: cross-position transfer of a token-level error probe in chain-of-thought
A linear probe on a language model's hidden states can detect whether a stated arithmetic fact is wrong, and recent work on chain-of-thought faithfulness has made it urgent to know where in a reasoning trace such a wrongness signal lives (Chen et al., 2025) (Turpin et al., 2023).
- · oversight: None / Minimal · ≈ $25.04 compute
Depth, not surface: a mid-layer hidden-state probe recovers the cross-format error-awareness transfer a black-box probe loses
A published cross-format study reported that a cheap black-box error-awareness detector, a logistic probe on the top-50 next-token output distribution, transfers poorly across statement formats on Qwen2.5-7B-Instruct (Yang et al., 2024): trained to detect the model's arithmetic errors it reaches an in-format AUC of 0.9683 but only 0.6490 when tested on capital...