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Main Authors: Wang, Rui, Lin, Qihan, Liu, Jiayu, Zong, Qing, Zheng, Tianshi, Guo, Dadi, Shi, Haochen, Wang, Weiqi, Song, Yangqiu
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2508.08992
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author Wang, Rui
Lin, Qihan
Liu, Jiayu
Zong, Qing
Zheng, Tianshi
Guo, Dadi
Shi, Haochen
Wang, Weiqi
Song, Yangqiu
author_facet Wang, Rui
Lin, Qihan
Liu, Jiayu
Zong, Qing
Zheng, Tianshi
Guo, Dadi
Shi, Haochen
Wang, Weiqi
Song, Yangqiu
contents Prospect Theory (PT) models human decision-making behaviour under uncertainty, among which linguistic uncertainty is commonly adopted in real-world scenarios. Although recent studies have developed some frameworks to test PT parameters for Large Language Models (LLMs), few have considered the fitness of PT itself on LLMs. Moreover, whether PT is robust under linguistic uncertainty perturbations, especially epistemic markers (e.g. "likely"), remains highly under-explored. To address these gaps, we design a three-stage workflow based on a classic behavioural economics experimental setup. We first estimate PT parameters with economics questions and evaluate PT's fitness with performance metrics. We then derive probability mappings for epistemic markers in the same context, and inject these mappings into the prompt to investigate the stability of PT parameters. Our findings suggest that modelling LLMs' decision-making with PT is not consistently reliable across models, and applying Prospect Theory to LLMs is likely not robust to epistemic uncertainty. The findings caution against the deployment of PT-based frameworks in real-world applications where epistemic ambiguity is prevalent, giving valuable insights in behaviour interpretation and future alignment direction for LLM decision-making.
format Preprint
id arxiv_https___arxiv_org_abs_2508_08992
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Rethinking Prospect Theory for LLMs: Revealing the Instability of Decision-Making under Epistemic Uncertainty
Wang, Rui
Lin, Qihan
Liu, Jiayu
Zong, Qing
Zheng, Tianshi
Guo, Dadi
Shi, Haochen
Wang, Weiqi
Song, Yangqiu
Artificial Intelligence
Prospect Theory (PT) models human decision-making behaviour under uncertainty, among which linguistic uncertainty is commonly adopted in real-world scenarios. Although recent studies have developed some frameworks to test PT parameters for Large Language Models (LLMs), few have considered the fitness of PT itself on LLMs. Moreover, whether PT is robust under linguistic uncertainty perturbations, especially epistemic markers (e.g. "likely"), remains highly under-explored. To address these gaps, we design a three-stage workflow based on a classic behavioural economics experimental setup. We first estimate PT parameters with economics questions and evaluate PT's fitness with performance metrics. We then derive probability mappings for epistemic markers in the same context, and inject these mappings into the prompt to investigate the stability of PT parameters. Our findings suggest that modelling LLMs' decision-making with PT is not consistently reliable across models, and applying Prospect Theory to LLMs is likely not robust to epistemic uncertainty. The findings caution against the deployment of PT-based frameworks in real-world applications where epistemic ambiguity is prevalent, giving valuable insights in behaviour interpretation and future alignment direction for LLM decision-making.
title Rethinking Prospect Theory for LLMs: Revealing the Instability of Decision-Making under Epistemic Uncertainty
topic Artificial Intelligence
url https://arxiv.org/abs/2508.08992