Toward Honest Language Models for Deductive Reasoning

Fuente: arXiv
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Main Authors: Liu, Jiarui, Dhole, Kaustubh, Wang, Yingheng, Wen, Haoyang, Zhang, Sarah, Mao, Haitao, Li, Gaotang, Varshney, Neeraj, Liu, Jingguo, Pan, Xiaoman
Format: Preprint
Published: 2025
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author Liu, Jiarui
Dhole, Kaustubh
Wang, Yingheng
Wen, Haoyang
Zhang, Sarah
Mao, Haitao
Li, Gaotang
Varshney, Neeraj
Liu, Jingguo
Pan, Xiaoman
author_facet Liu, Jiarui
Dhole, Kaustubh
Wang, Yingheng
Wen, Haoyang
Zhang, Sarah
Mao, Haitao
Li, Gaotang
Varshney, Neeraj
Liu, Jingguo
Pan, Xiaoman
contents Deductive reasoning is the process of deriving conclusions strictly from the given premises, without relying on external knowledge. We define honesty in this setting as a model's ability to respond only when the conclusion is logically entailed by the premises, and to abstain otherwise. However, current language models often fail to reason honestly, producing unwarranted answers when the input is insufficient. To study this challenge, we formulate honest deductive reasoning as multi-step tasks where models must either derive the correct conclusion or abstain. We curate two datasets from graph structures, one for linear algebra and one for logical inference, and introduce unanswerable cases by randomly perturbing an edge in half of the instances. We find that prompting and existing training methods, including GRPO with or without supervised fine-tuning initialization, struggle on these tasks. In particular, GRPO optimize only for final task outcomes, leaving models vulnerable to collapse when negative rewards dominate early training. To address this, we propose ACNCHOR, a reinforcement learning method that injects ground truth trajectories into rollouts, preventing early training collapse. Our results demonstrate that this method stabilizes learning and significantly improves the overall reasoning performance, underscoring the importance of training dynamics for enabling honest deductive reasoning in language models.
format Preprint
id arxiv_https___arxiv_org_abs_2511_09222
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Toward Honest Language Models for Deductive Reasoning
Liu, Jiarui
Dhole, Kaustubh
Wang, Yingheng
Wen, Haoyang
Zhang, Sarah
Mao, Haitao
Li, Gaotang
Varshney, Neeraj
Liu, Jingguo
Pan, Xiaoman
Computation and Language
Deductive reasoning is the process of deriving conclusions strictly from the given premises, without relying on external knowledge. We define honesty in this setting as a model's ability to respond only when the conclusion is logically entailed by the premises, and to abstain otherwise. However, current language models often fail to reason honestly, producing unwarranted answers when the input is insufficient. To study this challenge, we formulate honest deductive reasoning as multi-step tasks where models must either derive the correct conclusion or abstain. We curate two datasets from graph structures, one for linear algebra and one for logical inference, and introduce unanswerable cases by randomly perturbing an edge in half of the instances. We find that prompting and existing training methods, including GRPO with or without supervised fine-tuning initialization, struggle on these tasks. In particular, GRPO optimize only for final task outcomes, leaving models vulnerable to collapse when negative rewards dominate early training. To address this, we propose ACNCHOR, a reinforcement learning method that injects ground truth trajectories into rollouts, preventing early training collapse. Our results demonstrate that this method stabilizes learning and significantly improves the overall reasoning performance, underscoring the importance of training dynamics for enabling honest deductive reasoning in language models.
title Toward Honest Language Models for Deductive Reasoning
topic Computation and Language
url https://arxiv.org/abs/2511.09222