ToxiTrace: Gradient-Aligned Training for Explainable Chinese Toxicity Detection

Boyang Li, Hongzhe Shou, Yuanyuan Liang, JingBin Zhang, Fang Zhou


Abstract
Existing Chinese toxic content detection methods mainly target sentence-level classification but often fail to provide readable and contiguous toxic evidence spans. We propose ToxiTrace, an explainability-oriented method for BERT-style encoders with three components: (1) CuSA, which refines encoder-derived saliency cues into fine-grained toxic spans with lightweight LLM guidance; (2) GCLoss, a gradient-constrained objective that concentrates token-level saliency on toxic evidence while suppressing irrelevant activations; and (3) ARCL, which constructs sample-specific contrastive reasoning pairs to sharpen the semantic boundary between toxic and non-toxic content. Experiments show that ToxiTrace improves classification accuracy and toxic span extraction while preserving efficient encoder-based inference and producing more coherent, human-readable explanations. The core training code is available at https://github.com/ZhouF-ECNU/ToxiTrace.
Anthology ID:
2026.findings-acl.354
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
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Findings
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Publisher:
Association for Computational Linguistics
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Pages:
7121–7138
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https://preview.aclanthology.org/ingest-acl/2026.findings-acl.354/
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Cite (ACL):
Boyang Li, Hongzhe Shou, Yuanyuan Liang, JingBin Zhang, and Fang Zhou. 2026. ToxiTrace: Gradient-Aligned Training for Explainable Chinese Toxicity Detection. In Findings of the Association for Computational Linguistics: ACL 2026, pages 7121–7138, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
ToxiTrace: Gradient-Aligned Training for Explainable Chinese Toxicity Detection (Li et al., Findings 2026)
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