CUET-823 at SemEval-2026 Task 9: LoRA-Based Instruction Fine-Tuning of LLMs vs. Transformer Models for Bengali Polarization Detection

Arpita Mallik, Ratnajit Dhar


Abstract
The rapid growth of social media has gone hand in hand with a sharp increase in heated public discussions, where debates about elections, conflicts, protests, and identity often turn into divisive and polarized rhetoric. In this paper, we present our system for SemEval 2026 Task 9 – Subtask 1: Multilingual Text Classification Challenge-Polarization Detection, focusing specifically on the Bengali language. The task is a binary classification problem aimed at determining whether a social media post exhibits attitude polarization, such as intolerance, dehumanization, deindividuation, vilification, or stereotyping toward others’ opinions, identities, or beliefs. Among 49 participating teams, our approach ranked 2nd, achieving a macro-F1 score of 0.8582. We experimented with both transformer-based models and large language models (LLMs), and observed that LoRA-based instruction fine-tuned LLM-based approaches delivered the strongest performance in detecting nuanced and context-dependent polarization in Bengali text.
Anthology ID:
2026.semeval-1.154
Volume:
Proceedings of the 20th International Workshop on Semantic Evaluation (2026)
Month:
July
Year:
2026
Address:
San Diego, California, USA
Editors:
Ekaterina Kochmar, Debanjan Ghosh, Kai North, Mamoru Komachi
Venues:
SemEval | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1128–1135
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.154/
DOI:
Bibkey:
Cite (ACL):
Arpita Mallik and Ratnajit Dhar. 2026. CUET-823 at SemEval-2026 Task 9: LoRA-Based Instruction Fine-Tuning of LLMs vs. Transformer Models for Bengali Polarization Detection. In Proceedings of the 20th International Workshop on Semantic Evaluation (2026), pages 1128–1135, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
CUET-823 at SemEval-2026 Task 9: LoRA-Based Instruction Fine-Tuning of LLMs vs. Transformer Models for Bengali Polarization Detection (Mallik & Dhar, SemEval 2026)
Copy Citation:
PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.154.pdf
Supplementarymaterial:
 2026.semeval-1.154.SupplementaryMaterial.zip