What Makes User Reactions Useful for Fake News Detection?

Yassine Toughrai, David Langlois, Smaili


Abstract
Fake news detection is often treated as a content-centered task, yet social media posts are embedded in user reactions that express skepticism, endorsement, correction, ridicule, and affective responses. This paper asks what makes user reactions useful for fake news detection. We study performance according to different dimensions: text only, emotions in comments, and number of available comments. We study this question across Fakeddit and Weibo20 under both standard and temporal splits (in a temporal split, most recent posts are included in the testing split). Robustness of results is measured across two encoder families (BERT-base, RoBERTa-base) and two English emotion taxonomies (dair-ai/emotion, GoEmotions). Across these configurations, comment-only representations outperform post-only baselines in most evaluation regimes, though this gain depends on dataset, split, and number of available comments. Emotion-fine-tuned comment encoders produce a temporal-shift-specific significant benefit compared to non-temporal splits.

We compare post-only representations, generic comment representations, emotion-fine-tuned comment representations, and post–reaction fusion models, while varying comment availability, showing that a minimum number of comments is necessary to improve detection of fakes. In addition, we show that fine-tuning comment or reaction-encoders on relevant auxiliary tasks such as emotions has a significant impact on the distribution of embeddings of fake and real posts in their representation space.

In light of these findings, we believe that user responses—and their emotional structure for example—should be taken into account when detecting fake news or compiling datasets for this purpose.
Anthology ID:
2026.aacl-long.192
Volume:
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
November
Year:
2026
Address:
Hengqin, China
Editors:
Yue Zhang, Ruifeng Xu, Ayu Purwarianti, Tong Rong, Jun Suzuki
Venues:
AACL | IJCNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
4282–4297
Language:
URL:
https://aclanthology.org/2026.aacl-long.192/
DOI:
Bibkey:
Cite (ACL):
Yassine Toughrai, David Langlois, and Smaili. 2026. What Makes User Reactions Useful for Fake News Detection?. In Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers), pages 4282–4297, Hengqin, China. Association for Computational Linguistics.
Cite (Informal):
What Makes User Reactions Useful for Fake News Detection? (Toughrai et al., AACL-IJCNLP 2026)
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PDF:
https://aclanthology.org/2026.aacl-long.192.pdf