BiasGym: A Simple and Generalizable Framework for Analyzing and Removing Biases through Injection

Sekh Mainul Islam, Nadav Borenstein, Siddhesh Milind Pawar, Haeun Yu, Arnav Arora, Isabelle Augenstein


Abstract
Understanding biases and stereotypes encoded in the weights of Large Language Models (LLMs) is crucial for developing effective mitigation strategies. However, biased behavior is often subtle and non-trivial to isolate, even when deliberately elicited, making systematic analysis and debiasing particularly challenging. To address this, we introduce a simple, cost-effective, and generalizable framework BiasGym for reliably injecting, analyzing, and mitigating conceptual associations of biases within LLMs. BiasGym consists of two modules: Inject, which injects specific biases into the model via token-based fine-tuning while keeping the model frozen, followed by two debiasing methods that leverage these injected signals to identify and reliably suppress (Scope) or Steer the components responsible for biased behavior. Our framework enables consistent bias elicitation for better localization of bias conceptual association in the model space, supports targeted debiasing without degrading performance on downstream tasks, and generalizes to biases unseen during fine-tuning. We demonstrate the effectiveness of our proposed framework in reducing real-world stereotypes (e.g., people from Italy being ‘reckless drivers’), showing its utility for both safety interventions and interpretability research.
Anthology ID:
2026.findings-emnlp.1004
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
21249–21270
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1004/
DOI:
Bibkey:
Cite (ACL):
Sekh Mainul Islam, Nadav Borenstein, Siddhesh Milind Pawar, Haeun Yu, Arnav Arora, and Isabelle Augenstein. 2026. BiasGym: A Simple and Generalizable Framework for Analyzing and Removing Biases through Injection. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 21249–21270, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
BiasGym: A Simple and Generalizable Framework for Analyzing and Removing Biases through Injection (Islam et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1004.pdf