A Multi-Dimensional Evaluation of Explainability in Media Bias Detection

Ting Chen, Chengjun Zhang, Benjamin M. Ampel, Sagar Samtani


Abstract
Detecting media bias automatically is difficult because biased framing is often subtle, yet in domains such as news analysis, accurate predictions alone are insufficient without explanations that reflect the model’s underlying reasoning. We present a multi-dimensional evaluation of explainability in encoder-based media bias detection using the Bias Annotations By Experts (BABE) dataset. Specifically, we study BERT and RoBERTa as classifiers (base and large variants) along three complementary axes: predictive performance, explanation plausibility (token-level alignment with expert rationales), and mechanistic faithfulness (whether compact sets of attention heads recover predictive signal under counterfactual rationale masking). To induce variation in plausibility, we additionally investigate attention-supervised finetuning, which incorporates expert rationale annotations as an auxiliary training signal. Attention supervision serves as an intervention on attribution plausibility, while the effectiveness of attribution methods varies substantially across architectures. Circuit analysis further reveals substantial variation in mechanistic recoverability across architectures, suggesting that model scale alone does not determine circuit compressibility. Taken together, our findings suggest that predictive performance, attribution plausibility, and mechanistic faithfulness characterize different aspects of model behavior and should be evaluated separately when studying explainability in media bias detection.
Anthology ID:
2026.blackboxnlp-1.35
Volume:
Proceedings of the 9th BlackboxNLP Workshop: Analyzing and Interpreting Neural Networks for NLP
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Dana Arad, Yonatan Belinkov, Hanjie Chen, Nils Feldhus, Aaron Mueller, Hosein Mohebbi, Gabriele Sarti, Martin Tutek
Venues:
BlackboxNLP | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
590–602
Language:
URL:
https://aclanthology.org/2026.blackboxnlp-1.35/
DOI:
Bibkey:
Cite (ACL):
Ting Chen, Chengjun Zhang, Benjamin M. Ampel, and Sagar Samtani. 2026. A Multi-Dimensional Evaluation of Explainability in Media Bias Detection. In Proceedings of the 9th BlackboxNLP Workshop: Analyzing and Interpreting Neural Networks for NLP, pages 590–602, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
A Multi-Dimensional Evaluation of Explainability in Media Bias Detection (Chen et al., BlackboxNLP 2026)
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PDF:
https://aclanthology.org/2026.blackboxnlp-1.35.pdf