A Theory of Response Sampling in LLMs: Part Descriptive and Part Prescriptive

Sarath Sivaprasad, Pramod Kaushik, Sahar Abdelnabi, Mario Fritz


Abstract
Large Language Models (LLMs) are increasingly utilized in autonomous decision-making, where they sample options from vast action spaces. However, the heuristics that guide this sampling process remain under-explored. We study this sampling behavior and show that this underlying heuristics resembles that of human decision-making: comprising a descriptive component (reflecting statistical norm) and a prescriptive component (implicit ideal encoded in the LLM) of a concept. We show that this deviation of a sample from the statistical norm towards a prescriptive component consistently appears in concepts across diverse real-world domains like public health, and economic trends. To further illustrate the theory, we demonstrate that concept prototypes in LLMs are affected by prescriptive norms, similar to the concept of normality in humans. Through case studies and comparison with human studies, we illustrate that in real-world applications, the shift of samples toward an ideal value in LLMs’ outputs can result in significantly biased decision-making, raising ethical concerns.
Anthology ID:
2025.acl-long.1454
Volume:
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Wanxiang Che, Joyce Nabende, Ekaterina Shutova, Mohammad Taher Pilehvar
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
30091–30135
Language:
URL:
https://preview.aclanthology.org/ingestion-acl-25/2025.acl-long.1454/
DOI:
Bibkey:
Cite (ACL):
Sarath Sivaprasad, Pramod Kaushik, Sahar Abdelnabi, and Mario Fritz. 2025. A Theory of Response Sampling in LLMs: Part Descriptive and Part Prescriptive. In Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 30091–30135, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
A Theory of Response Sampling in LLMs: Part Descriptive and Part Prescriptive (Sivaprasad et al., ACL 2025)
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PDF:
https://preview.aclanthology.org/ingestion-acl-25/2025.acl-long.1454.pdf