Rewarding Intellectual Humility Learning When Not To Answer In Large Language Models

Fuente: arXiv
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Autores principales: Jha, Abha, Mahajan, Akanksha, Aravindan, Ashwath Vaithinathan, Saravanan, Praveen, Policharla, Sai Sailaja, Gehlot, Sonal Chaturbhuj
Formato: Preprint
Publicado: 2026
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author Jha, Abha
Mahajan, Akanksha
Aravindan, Ashwath Vaithinathan
Saravanan, Praveen
Policharla, Sai Sailaja
Gehlot, Sonal Chaturbhuj
author_facet Jha, Abha
Mahajan, Akanksha
Aravindan, Ashwath Vaithinathan
Saravanan, Praveen
Policharla, Sai Sailaja
Gehlot, Sonal Chaturbhuj
contents Large Language Models (LLMs) often produce hallucinated or unverifiable content, undermining their reliability in factual domains. This work investigates Reinforcement Learning with Verifiable Rewards (RLVR) as a training paradigm that explicitly rewards abstention ("I don't know") alongside correctness to promote intellectual humility. We fine-tune and evaluate Granite-3.3-2B-Instruct and Qwen-3-4B-Instruct on the MedMCQA and Hendrycks Math benchmarks using a ternary reward structure ($-1$, r_abs, 1) under varying abstention reward structures. We further study the effect of combining RLVR with supervised fine-tuning strategies that teach abstention prior to reinforcement learning. Our results show that moderate abstention rewards (r_abs $\approx -0.25$ to 0.3) consistently reduce incorrect responses without severe accuracy degradation on multiple-choice tasks, with larger models exhibiting greater robustness to abstention incentives. On open-ended question answering, we observe limitations due to insufficient exploration, which can be partially mitigated through supervised abstention training. Overall, these findings demonstrate the feasibility and flexibility of verifiable reward design as a practical approach for hallucination mitigation in language models. Reproducible code for our abstention training framework is available here https://github.com/Mystic-Slice/rl-abstention.
format Preprint
id arxiv_https___arxiv_org_abs_2601_20126
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Rewarding Intellectual Humility Learning When Not To Answer In Large Language Models
Jha, Abha
Mahajan, Akanksha
Aravindan, Ashwath Vaithinathan
Saravanan, Praveen
Policharla, Sai Sailaja
Gehlot, Sonal Chaturbhuj
Computation and Language
Artificial Intelligence
Machine Learning
Large Language Models (LLMs) often produce hallucinated or unverifiable content, undermining their reliability in factual domains. This work investigates Reinforcement Learning with Verifiable Rewards (RLVR) as a training paradigm that explicitly rewards abstention ("I don't know") alongside correctness to promote intellectual humility. We fine-tune and evaluate Granite-3.3-2B-Instruct and Qwen-3-4B-Instruct on the MedMCQA and Hendrycks Math benchmarks using a ternary reward structure ($-1$, r_abs, 1) under varying abstention reward structures. We further study the effect of combining RLVR with supervised fine-tuning strategies that teach abstention prior to reinforcement learning. Our results show that moderate abstention rewards (r_abs $\approx -0.25$ to 0.3) consistently reduce incorrect responses without severe accuracy degradation on multiple-choice tasks, with larger models exhibiting greater robustness to abstention incentives. On open-ended question answering, we observe limitations due to insufficient exploration, which can be partially mitigated through supervised abstention training. Overall, these findings demonstrate the feasibility and flexibility of verifiable reward design as a practical approach for hallucination mitigation in language models. Reproducible code for our abstention training framework is available here https://github.com/Mystic-Slice/rl-abstention.
title Rewarding Intellectual Humility Learning When Not To Answer In Large Language Models
topic Computation and Language
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2601.20126