NoThink gains may mostly reactivate a model’s hidden Think behavior
Fast NoThink post-training may get much of its accuracy boost by pulling models back toward behavior already available in Think mode, rather than adding new NoThink capability. The paper tests this by steering model activations in a direction derived from the base model: steering reproduces most of the gain, while counter-steering removes a substantial share. Across nine aligned checkpoints, 42% to 79% of positive NoThink gains are attributed to this leakage.