Duluth at SemEval-2026 Task 4: A Hybrid Approach to Narrative Similarity using Bi-Encoder Embeddings with Cross-Encoder Tie breaking using Learned Weights

Maxwell Bevers, Aidan Carlson, Ted Pedersen


Abstract
We present a hybrid system for SemEval-2026 Task 4 on Narrative Similarity. Our approach decomposes the stories into four narrative components: theme, plot, emotion, and outcome. Each component is then encoded using a biencoder (all-mpnet-base-v2), and cosine similarities are combined through a learned pairwise ranking model. When similarity scores between candidate stories fall within a small margin of error, a cross-encoder (ms-marcoMiniLM-L-6-v2) is used as a tie-breaker. Our final system achieves 58.5% accuracy on the official test set, placing us at 39th overall. Error analysis reveals that the system struggles with complex themes, multiple protagonists, and contrasting outcomes.
Anthology ID:
2026.semeval-1.127
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:
927–931
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.127/
DOI:
Bibkey:
Cite (ACL):
Maxwell Bevers, Aidan Carlson, and Ted Pedersen. 2026. Duluth at SemEval-2026 Task 4: A Hybrid Approach to Narrative Similarity using Bi-Encoder Embeddings with Cross-Encoder Tie breaking using Learned Weights. In Proceedings of the 20th International Workshop on Semantic Evaluation (2026), pages 927–931, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
Duluth at SemEval-2026 Task 4: A Hybrid Approach to Narrative Similarity using Bi-Encoder Embeddings with Cross-Encoder Tie breaking using Learned Weights (Bevers et al., SemEval 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.127.pdf