Bias Mitigation or Cultural Commonsense? Evaluating LLMs with a Japanese Dataset

Taisei Yamamoto, Ryoma Kumon, Danushka Bollegala, Hitomi Yanaka


Abstract
Large language models (LLMs) exhibit social biases, prompting the development of various debiasing methods. However, debiasing methods may degrade the capabilities of LLMs. Previous research has evaluated the impact of bias mitigation primarily through tasks measuring general language understanding, which are often unrelated to social biases. In contrast, cultural commonsense is closely related to social biases, as both are rooted in social norms and values. The impact of bias mitigation on cultural commonsense in LLMs has not been well investigated. Considering this gap, we propose SOBACO (SOcial BiAs and Cultural cOmmonsense benchmark), a Japanese benchmark designed to evaluate social biases and cultural commonsense in LLMs in a unified format. We evaluate several LLMs on SOBACO to examine how debiasing methods affect cultural commonsense in LLMs. Our results reveal that the debiasing methods degrade the performance of the LLMs on the cultural commonsense task (up to 75% accuracy deterioration). These results highlight the importance of developing debiasing methods that consider the trade-off with cultural commonsense to improve fairness and utility of LLMs.
Anthology ID:
2025.emnlp-main.874
Volume:
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Month:
November
Year:
2025
Address:
Suzhou, China
Editors:
Christos Christodoulopoulos, Tanmoy Chakraborty, Carolyn Rose, Violet Peng
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EMNLP
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Publisher:
Association for Computational Linguistics
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Pages:
17306–17324
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URL:
https://preview.aclanthology.org/ingest-emnlp/2025.emnlp-main.874/
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Cite (ACL):
Taisei Yamamoto, Ryoma Kumon, Danushka Bollegala, and Hitomi Yanaka. 2025. Bias Mitigation or Cultural Commonsense? Evaluating LLMs with a Japanese Dataset. In Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing, pages 17306–17324, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
Bias Mitigation or Cultural Commonsense? Evaluating LLMs with a Japanese Dataset (Yamamoto et al., EMNLP 2025)
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