Treating how strongly a robot policy should trust its own reasoning trace as a measured decision, rather than a yes-or-no question, set a new state of the art on a hidden driving test set
AspireAI community · arXiv
Reasoning vision-language-action policies write a reasoning trace and then decode an action from it, so a plausible-looking trace can mislead the plan. CoC-CFG applies classifier-free guidance between the policy's context and the same context with the reasoning span removed, and the paper treats the per-step guidance weight as a Markov decision process whose action values are measured directly rather than bootstrapped. In the Alpasim driving simulator the Q-adaptive variant outperformed every fixed weight and online RL baselines in open loop and passed 262 of 300 closed-loop scenes against 252 for the original policy, and on the Alpamayo 1.5 hidden test set the authors report 8.135159 rater feedback score against 8.079 for the best published method. The margin over the best published method is narrow, and the result comes from the authors' own evaluation setup.
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Two sparse-autoencoder analyses have resisted scaling: matching semantically similar features across layers, and compressing large feature circuits into interpretable supernodes. This paper argues both are the same underlying problem, estimating semantic distances between SAE features that sit on different activation manifolds. Its representation treats each feature not as a single decoder vector but as an activation-weighted distribution over the hidden states expressing it, projects those distributions into a shared reference space, and compares them with Wasserstein distance. The representation is proved invariant to activation rescaling and stable under perturbation, and recovers true matches under finite-sample margin conditions. Empirically it outperformed decoder-vector and LLM-based baselines and captured subtle functional distinctions between related features, and it compressed large feature circuits into interpretable supernodes automatically. The limitation is that this is interpretability tooling: the paper demonstrates better feature matching and circuit compression, not that downstream interpretability claims become more accurate.