Less Is Moral: A CHARMing Framework for Moral Foundations Detection in Endorsement Behaviour

Huixiang Fu, Marian-Andrei Rizoiu


Abstract
Moral language plays a central role in shaping online endorsement and the diffusion of information, yet existing moral foundation detection systems often suffer from poor cross-domain generalization, weak rationale grounding, and reliance on costly prompting-based large language models (LLMs). We introduce CHARM, a MA**C** and **H**ate-speech-**A**ware **R**ationale-aligned **M**oral foundation detection framework built on a lightweight fine-tuned LLM, which integrates complementary moral grounding, rationale alignment, and polarity-aware hate speech signals to support more robust and faithful moral prediction. Unlike prior dictionary-, fine-tune-, or prompt-based detectors, which decouple computation from psychological theory, CHARM is built so that each component — MAC cross-attention, rationale alignment, and hate-speech modulation — operationalises a distinct psychological construct. Using only 30% of the training data required by prior fine-tuned baselines, CHARM improves AUC by up to 15.3% in-domain, surpasses these baselines on every out-of-domain dataset in both AUC and F1, and offers a scalable, low-cost alternative to LLM-based detectors. We further apply CHARM to large-scale COVID-19 discourse on Twitter and show that moral value alignment is strongly associated with online endorsement behavior. By making moral framing measurable at scale, CHARM offers a practical tool for studying the spread of morally charged misinformation.
Anthology ID:
2026.emnlp-main.912
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
21003–21025
Language:
URL:
https://aclanthology.org/2026.emnlp-main.912/
DOI:
Bibkey:
Cite (ACL):
Huixiang Fu and Marian-Andrei Rizoiu. 2026. Less Is Moral: A CHARMing Framework for Moral Foundations Detection in Endorsement Behaviour. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 21003–21025, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Less Is Moral: A CHARMing Framework for Moral Foundations Detection in Endorsement Behaviour (Fu & Rizoiu, EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.912.pdf