CultAct-ML: Measuring Cultural Value Defaults in Multilingual LLM Agents Under Action

Ahmad Fahmid, Jannatul Ferdous Mim, Md Adnan Arefeen


Abstract
Measuring which cultural values a languagemodel agent falls back on when it must act is a fundamental problem in multilingual and culturally-grounded evaluation. Current agent benchmarks are designed primarily to measure task success in high-resource languages such as English, which creates major limitations when the question is whose culture an agent’s committed action encodes. The key challenges are the absence of an acting-based value-conflict benchmark and the difficulty of preserving culturallyloaded meaning when a scenario is carried into a low-resource language such as Bangla. In this paper, to study these cultural defaults under action, we present CultAct-ML, a benchmark of 39 value-conflict dilemmas recast as secondperson agent actions and evaluated with a twophase plan–act agent over English, Indonesian, and Bangla. We further introduce three metrics that measure the Western-cluster default, its reliability across languages, and the drift of the agent’s plan, and every Bangla item is verified by a native speaker. Across three models and three repeats, a total of 1,053 plan–act decisions are produced, all valid. We find that a Western default holds above chance for Qwen2.5-72B and Kimi K2 in every language but fades to chance for Qwen3-235B outside English. After stratifying the plan drift by the language of the plan, we further find that Qwen3-235B plans in English rather than Bangla on 70.1% of Bangla scenarios, highlighting a cross-language effect that a pooled analysis hides entirely. The scenarios, code, and all metrics are publicly released.1
Anthology ID:
2026.oracle-main.22
Volume:
The Proceedings of the Workshop on Open Reasoning Across Cultures Languages (ORACLE)
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Leonardo Ranaldi, Giulia Pucci, Federico Ranaldi, Marco Valentino, Alexandra Birch, Fabio Massimo Zanzotto
Venues:
ORACLE | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
329–338
Language:
URL:
https://aclanthology.org/2026.oracle-main.22/
DOI:
Bibkey:
Cite (ACL):
Ahmad Fahmid, Jannatul Ferdous Mim, and Md Adnan Arefeen. 2026. CultAct-ML: Measuring Cultural Value Defaults in Multilingual LLM Agents Under Action. In The Proceedings of the Workshop on Open Reasoning Across Cultures Languages (ORACLE), pages 329–338, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
CultAct-ML: Measuring Cultural Value Defaults in Multilingual LLM Agents Under Action (Fahmid et al., ORACLE 2026)
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PDF:
https://aclanthology.org/2026.oracle-main.22.pdf