Beyond Static Visual Tokens: Structured Sequential Visual Chain-of-Thought Reasoning
Organizations: Beijing Institute of Mathematical Sciences and Applications · University of Bristol · University of Birmingham
Abstract
Current multimodal LLMs encode images as static visual prefixes and rely on text-based reasoning, lacking goal-driven and adaptive visual access. Inspired by human visual perception-where attention is selectively and sequentially shifted from the most informative regions to secondary cues-we propose Structural Sequential Visual CoT SSV-CoT. First, a question-relevant saliency map identifies and organizes key visual regions, explicitly modeling the spatial distribution of visual importance. Second, reasoning is performed following this discriminative order, inducing a curriculum-like semantic progression from primary to secondary cues. This method is trained end-to-end, using text cot and answer supervision, without relying on region-level annotations or specialized external tools. Experiments on diverse visual reasoning benchmarks show gains, validating structured and sequential visual cognition.
Figures & tables
| Methods | M3CoT | ScienceQA | LLaVA-W |
| ACC.↑ | ACC.↑ | ROUGE-L↑ | |
| Qwen2-VL-7B | 43.6 | 56.3 | 32.7 |
| MultimodalCoT | 40.1 | 51.3 | 30.7 |
| CCoT | 43.3 | 56.4 | 29.4 |
| DDCoT | 42.6 | 55.2 | 31.2 |
| SCAFFOLD | 41.7 | 53.7 | 31.8 |
| Model | MathVista | MathVision | Average |
| Acc. | Acc. | Acc. | |
| MiniCPM-V-2.6 | 60.8 | 18.4 | 39.6 |
| VITA-1.5 | 66.2 | 19.5 | 42.9 |
| LLaVA-CoT | 52.5 | 19.9 | 36.2 |
| Qwen2-VL-7B | 60.9 | 16.3 | 38.6 |
| InternVL2.5 | 64.5 | 17.0 | 40.8 |
| Methods | M3CoT | ScienceQA | LLaVA-W |
| ACC.↑ | ACC.↑ | ROUGE-L↑ | |
| SSV-CoT | 44.9 | 57.3 | 35.7 |
| w/o SR | 43.5 ( -1.4 ) | 56.1 ( -1.2 ) | 33.9 ( -1.8 ) |
| w/o SS | 43.8 ( -1.1 ) | 56.4 ( -0.9 ) | 34.2 ( -1.5 ) |
| w/o AS | 44.3 ( -0.6 ) | 56.9 ( -0.4 ) | 35.0 ( -0.7 ) |
| Order (Acc@1 %) | ||
| Visual repr. | Random | Cognition |
| Patch subset | 63.1 | 65.4 |
| Saliency regions | 68.0 | 72.2 |
| Strategy | Acc@1 (%) | Avg #regions |
| Fixed- (Seq) | 68.5 | 2.0 |
| Fixed- (Seq) | 71.0 | 3.0 |
| Fixed- (Seq) | 71.3 | 4.0 |
| Adaptive- (Ours) | 72.2 | 2.7 |
Appendix figures & tables5 assets
Supplementary material from the paper’s appendix.
Appendix
| Method | MathVista Acc. | Delta |
| Vanilla Qwen2-VL GRPO-LoRA | 59.5 | – |
| SSV-GRPO-LoRA w/o step state | 62.0 | +2.5 |
| SSV-GRPO-LoRA | 63.5 | +4.0 |
| Method | Training / Supervision | MathVista Acc. |
| TVC-Qwen2-VL-7B | Large-scale SFT, no RL | 68.1 |
| R1-VL-7B ( Zhang et al., 2025 ) | Mulberry-260K ( Yao et al., 2025 ) + StepGRPO | 69.63 |
| MINT-CoT-7B ( Chen et al., 2025a ) | 54K step-level visual-token annotations + SFT + RL | 73.70 |
| SSV-CoT | 50K+ SFT + GRPO, no region-level annotations | 72.2 |
| Method | Updates | Peak GPU | Mean GPU | Mean Update Wall | Train-loop Wall |
| (GiB) | (GiB) | (s) | (h) | ||
| Vanilla GRPO-LoRA | 300 | 52.276 | 44.832 | 55.086 | 4.59 |
| SSV-GRPO-LoRA | 300 | 56.481 | 46.165 | 62.086 | 5.18 |
| (a) Inference efficiency on 200 MathVista samples | |||||
| Method | Acc. | Latency / Sample | Extra Latency | Output Tokens | Throughput |
| (ms) | (tok/s) | ||||
| Qwen2-VL vLLM | 57.0 | 757.4 | – | 121.58 | 160.5 |
| SSV-CoT vLLM | 68.0 | 899.0 | +18.7% | 143.85 | 160.0 |
| (b) Adaptive stopping behavior grouped by question complexity | |||||
| Complexity | Samples | Avg. #Regions | Stop Early 2 | Query More 3 | |
VLM Reasoning
Vision-language model reasoning studies how multimodal systems use visual evidence and language to answer questions, plan, and explain.
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