Inducing Epistemological Humility in Large Language Models: A Targeted SFT Approach to Reducing Hallucination

TL;DR

This paper presents a targeted supervised fine-tuning dataset and benchmark to teach large language models epistemological humility, significantly reducing hallucinations while maintaining overall performance.

Contribution

Introduction of HypoTermInstruct dataset and HypoTermQA-Enhanced benchmark to improve models' recognition of their knowledge limits through specialized fine-tuning.

Findings

Significant improvement in hallucination reduction metrics.

Maintained performance on general knowledge tasks.

Targeted data effectively teaches meta-cognitive skills.

Abstract

Large language models (LLMs) often hallucinate, producing fluent but false information, partly because supervised fine-tuning (SFT) implicitly rewards always responding. We introduce $\textit{HypoTermInstruct}$, an SFT dataset (31,487 responses for 11,151 questions) designed to teach models epistemological humility-the ability to recognize the limits of their own knowledge and admit uncertainty. This is achieved through questions about non-existent "hypothetical" terms. We also release $\textit{HypoTermQA-Enhanced}$, a benchmark for hallucination tendency strengthened through multiple validations. We conducted 800 controlled LoRA SFT runs across $\textit{Llama3.1-8B}$ and $\textit{Gemma3-4B}$ (base and instruct), testing 100 fine-tuning configurations with paired controls. Our results demonstrate that replacing generic instruction data with $\textit{HypoTermInstruct}$ significantly improves the HypoTerm Score (median increases of 0.19% to 25.91%) and FactScore (+0.39% to +0.86%), while maintaining stable performance on MMLU (minimal decreases of 0.26% to 0.35%). Our work demonstrates that targeted, high-quality SFT data teaching meta-cognitive skills can effectively reduce hallucination without preference/RL pipelines, providing mechanistic insights and a practical path toward more reliable AI systems.