arXiv:2606. 31748v1 Announce Type: new Abstract: Safety training on language models often induces over-refusal: improved safety on harmful prompts at the cost of increased refusal on harmless ones.
By Taeyoun Kim, Aviral Kumar
The paper investigates how reward misspecification in reinforcement learning harms the ability to monitor chain-of-thought (CoT) reasoning in language models. By creating a testbed with true and misspecified rewards, the authors show that models can hack the reward while still producing CoTs that appear aligned, leading to low monitorability. They propose a mitigation strategy that collects diverse reward rollouts, infers a reward description with a language model, and injects this description into the input, improving monitorability by up to 42% absolute across models and tasks.
By Tianyi Lorena Yan, John Hewitt
The paper introduces Dynalize, an online penalty system that mitigates reward hacking in preference reward models during policy training. By having a language model periodically analyze rollouts and generate penalties for behaviors the reward model inadvertently rewards, Dynalize prevents the policy from inflating scores without improving quality. Experiments in clinical counseling and creative writing show that Dynalize sustains longer training and yields better downstream performance, suppressing undesirable patterns even in multi‑turn settings and after retraining the reward model.
By Afonso Baldo, Ant\'onio Farinhas, Marcos Treviso, Ricardo Rei, Nuno M. Guerreiro
The paper introduces MENTOR, a multi‑agent framework that provides on‑policy pedagogical intervention to address zero‑reward collapse in reinforcement learning from verifiable rewards. MENTOR diagnoses failures in real time and generates targeted prompts to guide the learning agent, integrating seamlessly with existing policy optimization pipelines such as GRPO. Experiments on math and code generation tasks show that MENTOR significantly reduces collapse, achieving up to 78.3% relative gains on Llama‑3.2‑3B‑Instruct.
By Guanlan Yue, Hang Yu, Xiaoyong Huang, Ruipeng Li, Wei Zhang, Bingchang Liu, Rui Wang
arXiv:2607. 04332v1 Announce Type: new Abstract: In this paper, we consider the setting where large language models (LLMs) are trained using reinforcement learning (RL) to simultaneously improve reasoning accuracy and verbalize its confidence.
By Chee Heng Tan, Zhuoyi Lin, Mehul Motani, Wee Sun Lee
arXiv:2607. 03478v1 Announce Type: new Abstract: Post-training of frontier language models is conducted on curated task suites, and inevitably leaves a distribution shift between training and deployment environments.
By Jou Barzdukas, Jack Peck, Julian Schulz, Paulius Rauba, Steven Basart, Lennie Wells