@inproceedings{dey-etal-2026-palms,
title = "{PALM}s: Using Multi-Construct Grounded Rationales for Modeling Population Preferences in {LLM}s",
author = "Dey, Priyanka and
Joshi, Brihi and
Poddar, Preyashi and
Zhao, Jieyu and
Ferrara, Emilio",
editor = "Lee, Hung-Yi and
Dev, Sunipa and
Li, Jessy and
Elliott, Desmond",
booktitle = "Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing",
month = oct,
year = "2026",
address = "Budapest, Hungary",
publisher = "Association for Computational Linguistics",
url = "https://aclanthology.org/2026.emnlp-main.888/",
pages = "20475--20517",
ISBN = "979-8-89176-459-0",
abstract = "Large language models are being extensively used to simulate individual user behavior, yet faithfully representing a \textit{population} requires capturing the systematic variation in values, beliefs, and cultural norms that distinguish one group from another. We introduce (), a suite of models each aligned to specific populations, covering five countries: USA, India, Brazil, France and Italy. are created by synthesizing rationales grounded in psychological and cultural constructs and using these as latent supervision during preference tuning for population-specific alignment. Evaluated across four dimensions: personality, values and beliefs, cultural norms, and morality, consistently outperform baselines, including culture-specialized models, achieving an average of 8.59{\%} relative improvement over the best baseline across all five populations. Notably, construct-grounded rationales outperform both demographic prompting and survey-based fine-tuning, suggesting that grounding preference learning in psychology and culture provides a richer inductive signal than surface-level response distributions. We further demonstrate strong generalization to downstream applications without task-specific supervision: outperforming best baselines by 5.19{\%} in personalized reward modeling, 6.34{\%} in population simulation, and showing strong transfer to social reasoning tasks. Datasets and code are available at: \href{https://github.com/limenlp/PALMs}{h}ttps://github.com/limenlp/PALMs."
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<abstract>Large language models are being extensively used to simulate individual user behavior, yet faithfully representing a population requires capturing the systematic variation in values, beliefs, and cultural norms that distinguish one group from another. We introduce (), a suite of models each aligned to specific populations, covering five countries: USA, India, Brazil, France and Italy. are created by synthesizing rationales grounded in psychological and cultural constructs and using these as latent supervision during preference tuning for population-specific alignment. Evaluated across four dimensions: personality, values and beliefs, cultural norms, and morality, consistently outperform baselines, including culture-specialized models, achieving an average of 8.59% relative improvement over the best baseline across all five populations. Notably, construct-grounded rationales outperform both demographic prompting and survey-based fine-tuning, suggesting that grounding preference learning in psychology and culture provides a richer inductive signal than surface-level response distributions. We further demonstrate strong generalization to downstream applications without task-specific supervision: outperforming best baselines by 5.19% in personalized reward modeling, 6.34% in population simulation, and showing strong transfer to social reasoning tasks. Datasets and code are available at: \hrefhttps://github.com/limenlp/PALMshttps://github.com/limenlp/PALMs.</abstract>
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%0 Conference Proceedings
%T PALMs: Using Multi-Construct Grounded Rationales for Modeling Population Preferences in LLMs
%A Dey, Priyanka
%A Joshi, Brihi
%A Poddar, Preyashi
%A Zhao, Jieyu
%A Ferrara, Emilio
%Y Lee, Hung-Yi
%Y Dev, Sunipa
%Y Li, Jessy
%Y Elliott, Desmond
%S Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
%D 2026
%8 October
%I Association for Computational Linguistics
%C Budapest, Hungary
%@ 979-8-89176-459-0
%F dey-etal-2026-palms
%X Large language models are being extensively used to simulate individual user behavior, yet faithfully representing a population requires capturing the systematic variation in values, beliefs, and cultural norms that distinguish one group from another. We introduce (), a suite of models each aligned to specific populations, covering five countries: USA, India, Brazil, France and Italy. are created by synthesizing rationales grounded in psychological and cultural constructs and using these as latent supervision during preference tuning for population-specific alignment. Evaluated across four dimensions: personality, values and beliefs, cultural norms, and morality, consistently outperform baselines, including culture-specialized models, achieving an average of 8.59% relative improvement over the best baseline across all five populations. Notably, construct-grounded rationales outperform both demographic prompting and survey-based fine-tuning, suggesting that grounding preference learning in psychology and culture provides a richer inductive signal than surface-level response distributions. We further demonstrate strong generalization to downstream applications without task-specific supervision: outperforming best baselines by 5.19% in personalized reward modeling, 6.34% in population simulation, and showing strong transfer to social reasoning tasks. Datasets and code are available at: \hrefhttps://github.com/limenlp/PALMshttps://github.com/limenlp/PALMs.
%U https://aclanthology.org/2026.emnlp-main.888/
%P 20475-20517
Markdown (Informal)
[PALMs: Using Multi-Construct Grounded Rationales for Modeling Population Preferences in LLMs](https://aclanthology.org/2026.emnlp-main.888/) (Dey et al., EMNLP 2026)
ACL