Study traces the origins of “wait” tokens in reasoning models
A paper under review by Kou and eight coauthors argues that reinforcement learning does not necessarily teach reasoning models to write “wait” before reconsidering a step. Across analyzed open models, the marker often appeared during mid-training or reasoning-trace fine-tuning, while reinforcement learning substantially improved MATH-500 accuracy without introducing it in models whose bases lacked the word. The authors also report that some reinforcement-learning recipes multiplied markers already present in the base, so the effect depends on the recipe. They further warn that marker frequency alone does not demonstrate reinforcement-learning-induced reasoning and that LLM-as-a-judge revision metrics may reverse human-labeled trends.
The study challenges the common attribution of “wait” tokens to reinforcement learning and cautions against treating marker frequency or automated revision metrics as reliable evidence that reinforcement learning induced a particular reasoning behavior.
Computer Science > Machine Learning
arXiv:2610.30882 (cs)
[Submitted on 22 Oct 2026]
Title:Inherited, Not Invented: Tracing the Provenance of Wait in Reasoning Models
Authors:Zhizhuo Kou, Sizai Hou, Long Chen, Jian Yang, Junyu Luo, Jingshu Peng, Wenkai Zhang, Sirui Han, Yike Guo
View a PDF of the paper titled Inherited, Not Invented: Tracing the Provenance of Wait in Reasoning Models, by Zhizhuo Kou and 8 other authors