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Main Authors: Liang, Sichu, Zhu, Hongyu, Wang, Wenwen, Zhou, Deyu
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2602.04355
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author Liang, Sichu
Zhu, Hongyu
Wang, Wenwen
Zhou, Deyu
author_facet Liang, Sichu
Zhu, Hongyu
Wang, Wenwen
Zhou, Deyu
contents Working memory is a central component of intelligent behavior, providing a dynamic workspace for maintaining and updating task-relevant information. Recent work has used n-back tasks to probe working-memory-like behavior in large language models, but it is unclear whether the same probe elicits comparable computations when information is carried in a visual rather than textual code in vision-language models. We evaluate Qwen2.5 and Qwen2.5-VL on a controlled spatial n-back task presented as matched text-rendered or image-rendered grids. Across conditions, models show reliably higher accuracy and d' with text than with vision. To interpret these differences at the process level, we use trial-wise log-probability evidence and find that nominal 2/3-back often fails to reflect the instructed lag and instead aligns with a recency-locked comparison. We further show that grid size alters recent-repeat structure in the stimulus stream, thereby changing interference and error patterns. These results motivate computation-sensitive interpretations of multimodal working memory.
format Preprint
id arxiv_https___arxiv_org_abs_2602_04355
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Can Vision Replace Text in Working Memory? Evidence from Spatial n-Back in Vision-Language Models
Liang, Sichu
Zhu, Hongyu
Wang, Wenwen
Zhou, Deyu
Computation and Language
Working memory is a central component of intelligent behavior, providing a dynamic workspace for maintaining and updating task-relevant information. Recent work has used n-back tasks to probe working-memory-like behavior in large language models, but it is unclear whether the same probe elicits comparable computations when information is carried in a visual rather than textual code in vision-language models. We evaluate Qwen2.5 and Qwen2.5-VL on a controlled spatial n-back task presented as matched text-rendered or image-rendered grids. Across conditions, models show reliably higher accuracy and d' with text than with vision. To interpret these differences at the process level, we use trial-wise log-probability evidence and find that nominal 2/3-back often fails to reflect the instructed lag and instead aligns with a recency-locked comparison. We further show that grid size alters recent-repeat structure in the stimulus stream, thereby changing interference and error patterns. These results motivate computation-sensitive interpretations of multimodal working memory.
title Can Vision Replace Text in Working Memory? Evidence from Spatial n-Back in Vision-Language Models
topic Computation and Language
url https://arxiv.org/abs/2602.04355