A2NLP at StanceNakba Shared Task: Fine-Tuned AraBERT for Topic-Based Arabic Stance Detection

Alaa Nairat, Aysar Mahmoud Nairat


Abstract
AbstractThis paper describes A2NLP’s system for Subtask B of the StanceNakba Shared Task, which addresses cross-topic Arabic stance detection. The goal is to classify sentence–topic pairs into pro, against, or neutral labels. We introduce a topic-conditioned prompting strategy built on AraBERTv0.2-Twitter, where each instance is reformulated into a structured prompt that explicitly models the interaction between the sentence and its target topic. The model is trained using 5-fold stratified cross-validation with class-weighted loss to ensure robustness under mild label imbalance. Our final submission achieves a Macro-F1 score of 0.8483 on the official test set, outperforming the AraBERTv2 baseline (0.810) and ranking fifth overall. Ablation analysis confirms that topic-conditioned prompting substantially improves generalization across topics. The findings demonstrate the importance of structured input design and domain-aligned pretraining for reliable stance detection in dialectal Arabic social media discourse.
Anthology ID:
2026.nakbanlp-1.20
Volume:
Proceedings of the 2nd International Workshop on Nakba Narratives as Language Resources @ LREC 2026
Month:
May
Year:
2026
Address:
Palma, Mallorca (Spain)
Editors:
Mustafa Jarrar, Mo El-Haj, Amal Haddad, Serin Atiani, Shadi Abudalfa, Terry Regier, Paul Rayson, Khalil Sima’an, Camille Mansour
Venues:
NakbaNLP | WS
SIG:
Publisher:
ELRA Language Resources Association (ELRA)
Note:
Pages:
147–159
Language:
External URL:
https://lrec.elra.info/lrec2026-ws-nakbanlp-20
DOI:
10.63317/5jy5nrvfrzzk
Bibkey:
Cite (ACL):
Alaa Nairat and Aysar Mahmoud Nairat. 2026. A2NLP at StanceNakba Shared Task: Fine-Tuned AraBERT for Topic-Based Arabic Stance Detection. In Proceedings of the 2nd International Workshop on Nakba Narratives as Language Resources @ LREC 2026, pages 147–159, Palma, Mallorca (Spain). ELRA Language Resources Association (ELRA).
Cite (Informal):
A2NLP at StanceNakba Shared Task: Fine-Tuned AraBERT for Topic-Based Arabic Stance Detection (Nairat & Nairat, NakbaNLP 2026)
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