NJUSTKMG at SemEval 2026 Task 10 PsyCoMark—Subtask 2:Conspiracy Detection

Yuhan Zheng, Yang Yang


Abstract
This paper describes our system designed forSemEval-2026 Task 10: PsyCoMark—Subtask2: Conspiracy Detection. We proposed a two-stage approach that leverages large-scale pre-trained models and a fine-tuned smaller modelto detect conspiracy theories in text. In thefirst stage, we utilize a large model to test allthe test samples and filter out those that areclearly unrelated to conspiracy theories. Forthe remaining samples, we apply a retrieval-enhanced custom prompt strategy combinedwith the Roberta-Large model in the secondstage. This allows us to fine-tune the modelwith weighted predictions based on relevantretrieved information, enhancing detection ac-curacy. Our system achieved first place onthe leaderboard, with an impressive F1 Scoreof 0.8874. We also present a brief analysisof the effectiveness of the methods used, in-cluding the advantages and limitations of largemodel-based filtering and retrieval-augmentedfine-tuning.
Anthology ID:
2026.semeval-1.128
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:
932–937
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.128/
DOI:
Bibkey:
Cite (ACL):
Yuhan Zheng and Yang Yang. 2026. NJUSTKMG at SemEval 2026 Task 10 PsyCoMark—Subtask 2:Conspiracy Detection. In Proceedings of the 20th International Workshop on Semantic Evaluation (2026), pages 932–937, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
NJUSTKMG at SemEval 2026 Task 10 PsyCoMark—Subtask 2:Conspiracy Detection (Zheng & Yang, SemEval 2026)
Copy Citation:
PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.128.pdf
Supplementarymaterial:
 2026.semeval-1.128.SupplementaryMaterial.zip