Normative Reasoning in Large Language Models: A Comparative Benchmark from Logical and Modal Perspectives

TL;DR

This paper evaluates large language models' ability to perform normative reasoning from logical and modal perspectives, revealing their strengths and inconsistencies, and providing a new benchmark dataset for future research.

Contribution

It introduces a comprehensive dataset and systematic evaluation framework for normative reasoning in LLMs, comparing their performance on normative and epistemic modalities.

Findings

LLMs generally follow valid reasoning patterns

Notable inconsistencies in normative reasoning types

Presence of cognitive biases similar to humans

Abstract

Normative reasoning is a type of reasoning that involves normative or deontic modality, such as obligation and permission. While large language models (LLMs) have demonstrated remarkable performance across various reasoning tasks, their ability to handle normative reasoning remains underexplored. In this paper, we systematically evaluate LLMs' reasoning capabilities in the normative domain from both logical and modal perspectives. Specifically, to assess how well LLMs reason with normative modals, we make a comparison between their reasoning with normative modals and their reasoning with epistemic modals, which share a common formal structure. To this end, we introduce a new dataset covering a wide range of formal patterns of reasoning in both normative and epistemic domains, while also incorporating non-formal cognitive factors that influence human reasoning. Our results indicate that, although LLMs generally adhere to valid reasoning patterns, they exhibit notable inconsistencies in specific types of normative reasoning and display cognitive biases similar to those observed in psychological studies of human reasoning. These findings highlight challenges in achieving logical consistency in LLMs' normative reasoning and provide insights for enhancing their reliability. All data and code are released publicly at https://github.com/kmineshima/NeuBAROCO.