Do VLMs Have a Moral Backbone? A Study on the Fragile Morality of Vision-Language Models

Fuente: arXiv
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Hauptverfasser: Liu, Zhining, Wang, Tianyi, Lin, Xiao, Ouyang, Penghao, Li, Gaotang, Yang, Ze, Liu, Hui, Keswani, Sumit, Pardeshi, Vishwa, Zhao, Huijun, Fan, Wei, Tong, Hanghang
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Veröffentlicht: 2026
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author Liu, Zhining
Wang, Tianyi
Lin, Xiao
Ouyang, Penghao
Li, Gaotang
Yang, Ze
Liu, Hui
Keswani, Sumit
Pardeshi, Vishwa
Zhao, Huijun
Fan, Wei
Tong, Hanghang
author_facet Liu, Zhining
Wang, Tianyi
Lin, Xiao
Ouyang, Penghao
Li, Gaotang
Yang, Ze
Liu, Hui
Keswani, Sumit
Pardeshi, Vishwa
Zhao, Huijun
Fan, Wei
Tong, Hanghang
contents Despite substantial efforts toward improving the moral alignment of Vision-Language Models (VLMs), it remains unclear whether their ethical judgments are stable in realistic settings. This work studies moral robustness in VLMs, defined as the ability to preserve moral judgments under textual and visual perturbations that do not alter the underlying moral context. We systematically probe VLMs with a diverse set of model-agnostic multimodal perturbations and find that their moral stances are highly fragile, frequently flipping under simple manipulations. Our analysis reveals systematic vulnerabilities across perturbation types, moral domains, and model scales, including a sycophancy trade-off where stronger instruction-following models are more susceptible to persuasion. We further show that lightweight inference-time interventions can partially restore moral stability. These results demonstrate that moral alignment alone is insufficient and that moral robustness is a necessary criterion for the responsible deployment of VLMs.
format Preprint
id arxiv_https___arxiv_org_abs_2601_17082
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Do VLMs Have a Moral Backbone? A Study on the Fragile Morality of Vision-Language Models
Liu, Zhining
Wang, Tianyi
Lin, Xiao
Ouyang, Penghao
Li, Gaotang
Yang, Ze
Liu, Hui
Keswani, Sumit
Pardeshi, Vishwa
Zhao, Huijun
Fan, Wei
Tong, Hanghang
Computers and Society
Artificial Intelligence
Computation and Language
Computer Vision and Pattern Recognition
Machine Learning
Despite substantial efforts toward improving the moral alignment of Vision-Language Models (VLMs), it remains unclear whether their ethical judgments are stable in realistic settings. This work studies moral robustness in VLMs, defined as the ability to preserve moral judgments under textual and visual perturbations that do not alter the underlying moral context. We systematically probe VLMs with a diverse set of model-agnostic multimodal perturbations and find that their moral stances are highly fragile, frequently flipping under simple manipulations. Our analysis reveals systematic vulnerabilities across perturbation types, moral domains, and model scales, including a sycophancy trade-off where stronger instruction-following models are more susceptible to persuasion. We further show that lightweight inference-time interventions can partially restore moral stability. These results demonstrate that moral alignment alone is insufficient and that moral robustness is a necessary criterion for the responsible deployment of VLMs.
title Do VLMs Have a Moral Backbone? A Study on the Fragile Morality of Vision-Language Models
topic Computers and Society
Artificial Intelligence
Computation and Language
Computer Vision and Pattern Recognition
Machine Learning
url https://arxiv.org/abs/2601.17082