Bahash-AI at ArGuard Shared Tasks: Multimodal Ensemble Learning for Hateful Meme Detection

Ahmadullah Laskar, Sahinur Rahman Laskar


Abstract
Hateful content in memes is difficult to detect automatically, as harmful intent often emerges from the interaction between image and text rather than either modality alone, a challenge compounded in Arabic by dialectal variation and sarcasm. This paper presents the system submitted by team Bahash-AI to Subtask A1 (binary hateful meme detection) of the ArGuard shared task at ArabicNLP 2026. A late-fusion classifier combining MARBERTv2 and ViT-base is first developed and evaluated as a standalone development-phase system. Building on this, the final submission ensembles a CLIP-based text-image classifier with this same late-fusion classifier, retrained on the combined train, development, and development-test partitions. Class imbalance (approximately 30% Hateful) is addressed via class-weighted losses, oversampling, and threshold selection. The final ensemble achieves a Macro-F1 of 0.7457 and an accuracy of 0.7680 on the blind test set, ranking 12th of 16 teams on the official leaderboard and outperforming the development-phase system by 9 Macro-F1 points. Error analysis using per-class precision and recall shows that the two systems reach a similar Hateful-class F1 gap through opposite error patterns.
Anthology ID:
2026.arabicnlp-sharedtasks.55
Volume:
Proceedings of The Fourth Arabic Natural Language Processing Conference: Shared Tasks
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Muhammad Abdul-Mageed, Tamer Elsayed, Houda Bouamor, Samhaa El-Beltagy, Hend Al-Khalifa, Ahmed Abdelali, AbdelRahim Elmadany, Abdellah El Mekki, Kareem Darwish, Sakhar Alkhereyf, Hamzah Luqman, Salam Khalifa, Samar Magdy, Zaid Alyafeai, Injy Hamed, Wajdi Zaghouani, Imed Zitouni
Venue:
ArabicNLP
SIG:
SIGARAB
Publisher:
Association for Computational Linguistics
Note:
Pages:
432–436
Language:
URL:
https://aclanthology.org/2026.arabicnlp-sharedtasks.55/
DOI:
Bibkey:
Cite (ACL):
Ahmadullah Laskar and Sahinur Rahman Laskar. 2026. Bahash-AI at ArGuard Shared Tasks: Multimodal Ensemble Learning for Hateful Meme Detection. In Proceedings of The Fourth Arabic Natural Language Processing Conference: Shared Tasks, pages 432–436, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Bahash-AI at ArGuard Shared Tasks: Multimodal Ensemble Learning for Hateful Meme Detection (Laskar & Laskar, ArabicNLP 2026)
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PDF:
https://aclanthology.org/2026.arabicnlp-sharedtasks.55.pdf