Bias after Prompting: Persistent Discrimination in Large Language Models

Fuente: arXiv
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Main Authors: Sivakumar, Nivedha, Mackraz, Natalie, Khorshidi, Samira, Patel, Krishna, Theobald, Barry-John, Zappella, Luca, Apostoloff, Nicholas
Format: Preprint
Published: 2025
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author Sivakumar, Nivedha
Mackraz, Natalie
Khorshidi, Samira
Patel, Krishna
Theobald, Barry-John
Zappella, Luca
Apostoloff, Nicholas
author_facet Sivakumar, Nivedha
Mackraz, Natalie
Khorshidi, Samira
Patel, Krishna
Theobald, Barry-John
Zappella, Luca
Apostoloff, Nicholas
contents A dangerous assumption that can be made from prior work on the bias transfer hypothesis (BTH) is that biases do not transfer from pre-trained large language models (LLMs) to adapted models. We invalidate this assumption by studying the BTH in causal models under prompt adaptations, as prompting is an extremely popular and accessible adaptation strategy used in real-world applications. In contrast to prior work, we find that biases can transfer through prompting and that popular prompt-based mitigation methods do not consistently prevent biases from transferring. Specifically, the correlation between intrinsic biases and those after prompt adaptation remain moderate to strong across demographics and tasks -- for example, gender (rho >= 0.94) in co-reference resolution, and age (rho >= 0.98) and religion (rho >= 0.69) in question answering. Further, we find that biases remain strongly correlated when varying few-shot composition parameters, such as sample size, stereotypical content, occupational distribution and representational balance (rho >= 0.90). We evaluate several prompt-based debiasing strategies and find that different approaches have distinct strengths, but none consistently reduce bias transfer across models, tasks or demographics. These results demonstrate that correcting bias, and potentially improving reasoning ability, in intrinsic models may prevent propagation of biases to downstream tasks.
format Preprint
id arxiv_https___arxiv_org_abs_2509_08146
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Bias after Prompting: Persistent Discrimination in Large Language Models
Sivakumar, Nivedha
Mackraz, Natalie
Khorshidi, Samira
Patel, Krishna
Theobald, Barry-John
Zappella, Luca
Apostoloff, Nicholas
Computation and Language
Machine Learning
A dangerous assumption that can be made from prior work on the bias transfer hypothesis (BTH) is that biases do not transfer from pre-trained large language models (LLMs) to adapted models. We invalidate this assumption by studying the BTH in causal models under prompt adaptations, as prompting is an extremely popular and accessible adaptation strategy used in real-world applications. In contrast to prior work, we find that biases can transfer through prompting and that popular prompt-based mitigation methods do not consistently prevent biases from transferring. Specifically, the correlation between intrinsic biases and those after prompt adaptation remain moderate to strong across demographics and tasks -- for example, gender (rho >= 0.94) in co-reference resolution, and age (rho >= 0.98) and religion (rho >= 0.69) in question answering. Further, we find that biases remain strongly correlated when varying few-shot composition parameters, such as sample size, stereotypical content, occupational distribution and representational balance (rho >= 0.90). We evaluate several prompt-based debiasing strategies and find that different approaches have distinct strengths, but none consistently reduce bias transfer across models, tasks or demographics. These results demonstrate that correcting bias, and potentially improving reasoning ability, in intrinsic models may prevent propagation of biases to downstream tasks.
title Bias after Prompting: Persistent Discrimination in Large Language Models
topic Computation and Language
Machine Learning
url https://arxiv.org/abs/2509.08146