CCNU at SemEval-2026 Task 10: Conspiracy Marker Extraction and Detection via Multi-task Learning and LLM-based Data Augmentation

Zijun Wang, Guanyi Chen


Abstract
This paper presents the system of CCNU forSemEval-2026 Task 10: Psycholinguistic Con-spiracy Marker Extraction and Detection. Thetask requires identifying fine-grained conspir-acy markers that characterize conspiracy think-ing, as well as determining whether a Redditcomment constitutes conspiratorial discourse.For Conspiracy Marker Extraction (Subtask 1),we adopt a Unified Multi-Task Sequence La-beling Framework that jointly models multi-ple conspiracy markers within a single labelingspace. This formulation enables collaborativelearning across marker types while maintaininga compact architecture. For Conspiracy Detec-tion (Subtask 2), we formulate the problem assentence-level classification. Across both sub-tasks, we apply data augmentation powered bylarge language models and ensemble inferenceto improve robustness and generalization. Oursystem achieves strong performance on Sub-task 1, ranking 3rd on the official test set, anddelivers competitive results on Subtask 2.
Anthology ID:
2026.semeval-1.58
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:
402–408
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.58/
DOI:
Bibkey:
Cite (ACL):
Zijun Wang and Guanyi Chen. 2026. CCNU at SemEval-2026 Task 10: Conspiracy Marker Extraction and Detection via Multi-task Learning and LLM-based Data Augmentation. In Proceedings of the 20th International Workshop on Semantic Evaluation (2026), pages 402–408, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
CCNU at SemEval-2026 Task 10: Conspiracy Marker Extraction and Detection via Multi-task Learning and LLM-based Data Augmentation (Wang & Chen, SemEval 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.58.pdf
Supplementarymaterial:
 2026.semeval-1.58.SupplementaryMaterial.zip