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Main Authors: Avogaro, Niccolo, Debnath, Nayanika, Mi, Li, Frick, Thomas, Wang, Junling, He, Zexue, Hua, Hang, Schindler, Konrad, Rigotti, Mattia
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2602.06566
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author Avogaro, Niccolo
Debnath, Nayanika
Mi, Li
Frick, Thomas
Wang, Junling
He, Zexue
Hua, Hang
Schindler, Konrad
Rigotti, Mattia
author_facet Avogaro, Niccolo
Debnath, Nayanika
Mi, Li
Frick, Thomas
Wang, Junling
He, Zexue
Hua, Hang
Schindler, Konrad
Rigotti, Mattia
contents Despite recent successes, test-time scaling - i.e., dynamically expanding the token budget during inference as needed - remains brittle for vision-language models (VLMs): unstructured chains-of-thought about images entangle perception and reasoning, leading to long, disorganized contexts where small perceptual mistakes may cascade into completely wrong answers. Moreover, expensive reinforcement learning with hand-crafted rewards is required to achieve good performance. Here, we introduce SPARC (Separating Perception And Reasoning Circuits), a modular framework that explicitly decouples visual perception from reasoning. Inspired by sequential sensory-to-cognitive processing in the brain, SPARC implements a two-stage pipeline where the model first performs explicit visual search to localize question-relevant regions, then conditions its reasoning on those regions to produce the final answer. This separation enables independent test-time scaling with asymmetric compute allocation (e.g., prioritizing perceptual processing under distribution shift), supports selective optimization (e.g., improving the perceptual stage alone when it is the bottleneck for end-to-end performance), and accommodates compressed contexts by running global search at lower image resolutions and allocating high-resolution processing only to selected regions, thereby reducing total visual tokens count and compute. Across challenging visual reasoning benchmarks, SPARC outperforms monolithic baselines and strong visual-grounding approaches. For instance, SPARC improves the accuracy of Qwen3VL-4B on the $V^*$ VQA benchmark by 6.7 percentage points, and it surpasses "thinking with images" by 4.6 points on a challenging OOD task despite requiring a 200$\times$ lower token budget.
format Preprint
id arxiv_https___arxiv_org_abs_2602_06566
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle SPARC: Separating Perception And Reasoning Circuits for Test-time Scaling of VLMs
Avogaro, Niccolo
Debnath, Nayanika
Mi, Li
Frick, Thomas
Wang, Junling
He, Zexue
Hua, Hang
Schindler, Konrad
Rigotti, Mattia
Computer Vision and Pattern Recognition
Artificial Intelligence
Computation and Language
Despite recent successes, test-time scaling - i.e., dynamically expanding the token budget during inference as needed - remains brittle for vision-language models (VLMs): unstructured chains-of-thought about images entangle perception and reasoning, leading to long, disorganized contexts where small perceptual mistakes may cascade into completely wrong answers. Moreover, expensive reinforcement learning with hand-crafted rewards is required to achieve good performance. Here, we introduce SPARC (Separating Perception And Reasoning Circuits), a modular framework that explicitly decouples visual perception from reasoning. Inspired by sequential sensory-to-cognitive processing in the brain, SPARC implements a two-stage pipeline where the model first performs explicit visual search to localize question-relevant regions, then conditions its reasoning on those regions to produce the final answer. This separation enables independent test-time scaling with asymmetric compute allocation (e.g., prioritizing perceptual processing under distribution shift), supports selective optimization (e.g., improving the perceptual stage alone when it is the bottleneck for end-to-end performance), and accommodates compressed contexts by running global search at lower image resolutions and allocating high-resolution processing only to selected regions, thereby reducing total visual tokens count and compute. Across challenging visual reasoning benchmarks, SPARC outperforms monolithic baselines and strong visual-grounding approaches. For instance, SPARC improves the accuracy of Qwen3VL-4B on the $V^*$ VQA benchmark by 6.7 percentage points, and it surpasses "thinking with images" by 4.6 points on a challenging OOD task despite requiring a 200$\times$ lower token budget.
title SPARC: Separating Perception And Reasoning Circuits for Test-time Scaling of VLMs
topic Computer Vision and Pattern Recognition
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2602.06566