Evading Visual Aphasia: Contrastive Adaptive Semantic Token Pruning for Vision-Language Models

Fuente: arXiv
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Autori principali: Ma, Jie, Liu, Yihang, Qiu, Zhike, Ji, Jiayi, Sun, Xiaoshuai
Natura: Preprint
Pubblicazione: 2026
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author Ma, Jie
Liu, Yihang
Qiu, Zhike
Ji, Jiayi
Sun, Xiaoshuai
author_facet Ma, Jie
Liu, Yihang
Qiu, Zhike
Ji, Jiayi
Sun, Xiaoshuai
contents Are low-attention visual tokens truly redundant in vision-language reasoning? Existing pruning methods often assume so, ranking visual tokens by shallow text-to-image attention and discarding low-scoring patches to accelerate LVLM inference. We show that this scalar criterion is unreliable for compositional reasoning: tokens ignored in early layers can later become essential for resolving secondary objects, spatial relations, and contextual cues. Premature pruning can therefore induce Visual Aphasia, a failure mode in which the model loses visual grounding and falls back on language priors. We introduce COAST (COntrastive Adaptive Semantic Token Pruning), a training-free pruning framework that casts compression as adaptive semantic routing. COAST uses native cross-modal attention to identify query-specific anchors and estimate contextual dispersion via attention entropy, then adapts the retention trade-off between semantic evidence and spatial context. It further uses a contrastive routing score to preserve both anchor-aligned evidence and complementary spatial context. Across seven benchmarks, COAST reduces visual tokens by 77.8% and achieves a 2.15x latency speedup while retaining 98.64% of the original average performance. Beyond a single backbone or compression setting, COAST consistently outperforms strong pruning baselines across token budgets and generalizes across multiple LVLM families, showing that adaptive semantic routing is a robust alternative to one-shot scalar pruning
format Preprint
id arxiv_https___arxiv_org_abs_2605_09429
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Evading Visual Aphasia: Contrastive Adaptive Semantic Token Pruning for Vision-Language Models
Ma, Jie
Liu, Yihang
Qiu, Zhike
Ji, Jiayi
Sun, Xiaoshuai
Computer Vision and Pattern Recognition
Artificial Intelligence
Are low-attention visual tokens truly redundant in vision-language reasoning? Existing pruning methods often assume so, ranking visual tokens by shallow text-to-image attention and discarding low-scoring patches to accelerate LVLM inference. We show that this scalar criterion is unreliable for compositional reasoning: tokens ignored in early layers can later become essential for resolving secondary objects, spatial relations, and contextual cues. Premature pruning can therefore induce Visual Aphasia, a failure mode in which the model loses visual grounding and falls back on language priors. We introduce COAST (COntrastive Adaptive Semantic Token Pruning), a training-free pruning framework that casts compression as adaptive semantic routing. COAST uses native cross-modal attention to identify query-specific anchors and estimate contextual dispersion via attention entropy, then adapts the retention trade-off between semantic evidence and spatial context. It further uses a contrastive routing score to preserve both anchor-aligned evidence and complementary spatial context. Across seven benchmarks, COAST reduces visual tokens by 77.8% and achieves a 2.15x latency speedup while retaining 98.64% of the original average performance. Beyond a single backbone or compression setting, COAST consistently outperforms strong pruning baselines across token budgets and generalizes across multiple LVLM families, showing that adaptive semantic routing is a robust alternative to one-shot scalar pruning
title Evading Visual Aphasia: Contrastive Adaptive Semantic Token Pruning for Vision-Language Models
topic Computer Vision and Pattern Recognition
Artificial Intelligence
url https://arxiv.org/abs/2605.09429