Attention in Space: Functional Roles of VLM Heads for Spatial Reasoning

Fuente: arXiv
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Autori principali: Ma, Xueqi, Yang, Shuo, Jiang, Yanbei, Liu, Shu, Liu, Zhenzhen, Ao, Jiayang, Ma, Xingjun, Erfani, Sarah Monazam, Bailey, James
Natura: Preprint
Pubblicazione: 2026
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author Ma, Xueqi
Yang, Shuo
Jiang, Yanbei
Liu, Shu
Liu, Zhenzhen
Ao, Jiayang
Ma, Xingjun
Erfani, Sarah Monazam
Bailey, James
author_facet Ma, Xueqi
Yang, Shuo
Jiang, Yanbei
Liu, Shu
Liu, Zhenzhen
Ao, Jiayang
Ma, Xingjun
Erfani, Sarah Monazam
Bailey, James
contents Despite remarkable advances in large Vision-Language Models (VLMs), spatial reasoning remains a persistent challenge. In this work, we investigate how attention heads within VLMs contribute to spatial reasoning by analyzing their functional roles through a mechanistic interpretability lens. We introduce CogVSR, a dataset that decomposes complex spatial reasoning questions into step-by-step subquestions designed to simulate human-like reasoning via a chain-of-thought paradigm, with each subquestion linked to specific cognitive functions such as spatial perception or relational reasoning. Building on CogVSR, we develop a probing framework to identify and characterize attention heads specialized for these functions. Our analysis across diverse VLM families reveals that these functional heads are universally sparse, vary in number and distribution across functions. Notably, spatially specialized heads are fewer than those for other cognitive functions, highlighting their scarcity. We propose methods to activate latent spatial heads, improving spatial understanding. Intervention experiments further demonstrate their critical role in spatial reasoning: removing functional heads leads to performance degradation, while emphasizing them enhances accuracy. This study provides new interpretability driven insights into how VLMs attend to space and paves the way for enhancing complex spatial reasoning in multimodal models.
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id arxiv_https___arxiv_org_abs_2603_20662
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Attention in Space: Functional Roles of VLM Heads for Spatial Reasoning
Ma, Xueqi
Yang, Shuo
Jiang, Yanbei
Liu, Shu
Liu, Zhenzhen
Ao, Jiayang
Ma, Xingjun
Erfani, Sarah Monazam
Bailey, James
Artificial Intelligence
Computer Vision and Pattern Recognition
Despite remarkable advances in large Vision-Language Models (VLMs), spatial reasoning remains a persistent challenge. In this work, we investigate how attention heads within VLMs contribute to spatial reasoning by analyzing their functional roles through a mechanistic interpretability lens. We introduce CogVSR, a dataset that decomposes complex spatial reasoning questions into step-by-step subquestions designed to simulate human-like reasoning via a chain-of-thought paradigm, with each subquestion linked to specific cognitive functions such as spatial perception or relational reasoning. Building on CogVSR, we develop a probing framework to identify and characterize attention heads specialized for these functions. Our analysis across diverse VLM families reveals that these functional heads are universally sparse, vary in number and distribution across functions. Notably, spatially specialized heads are fewer than those for other cognitive functions, highlighting their scarcity. We propose methods to activate latent spatial heads, improving spatial understanding. Intervention experiments further demonstrate their critical role in spatial reasoning: removing functional heads leads to performance degradation, while emphasizing them enhances accuracy. This study provides new interpretability driven insights into how VLMs attend to space and paves the way for enhancing complex spatial reasoning in multimodal models.
title Attention in Space: Functional Roles of VLM Heads for Spatial Reasoning
topic Artificial Intelligence
Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2603.20662