Humans in Space: Can MLLMs Construct Human-Centric Spatial Understanding via Active Exocentric Exploration?
Organizations: The University of Queensland · Follow Me AI Pty LTD · Australian Institute for Machine Learning, Adelaide University · University of Technology Sydney
Abstract
While Multimodal Large Language Models (MLLMs) excel at zero-shot reasoning, their spatial capabilities are primarily evaluated through static, passive observation. In complex, human-centric scenes, occlusion often hides crucial geometric evidence, and passive benchmarks force models to guess rather than recognize their own visual uncertainty. To bridge this gap, we introduce SATE-Bench, a novel interactive benchmark comprising 316 real-world scenes and 2,525 multi-turn QA pairs to evaluate visual self-awareness and active exocentric view-exploration. It combines a Passive multi-view control with an Active exploration setting, where models start from a severely occluded view and must iteratively query adjacent viewpoints until they gather enough evidence to fully ``sate'' the question, scored by a step-penalized efficiency reward. Evaluating state-of-the-art MLLMs reveals that they terminate exploration prematurely while reporting high confidence, and struggle with fine-grained 3D geometric tasks; matched-view controls further attribute the Active--Passive gap primarily to insufficient evidence acquisition. Moreover, fine-tuning with Group Relative Policy Optimization (GRPO) shows that rewarding view-seeking increases active exploration but lowers overall accuracy, as models over-explore and fail to fuse expanding multi-view contexts across turns. These findings indicate that scaling passive multi-view perception does not intrinsically yield active spatial reasoning, highlighting the need for models that know where to look, how to integrate what they see, and when to stop. Code and data are available at https://gtc-gh.github.io/SATE-Bench/
Figures & tables
| Benchmark | Act. | Pas. | Real | MT | DEMV | SA | SO | HC |
|---|---|---|---|---|---|---|---|---|
| BLINK [ 11 ] | ✗ | ✓ | ✓ | ✗ | ✗ | ✗ | ✗ | ✗ |
| MuirBench [ 48 ] | ✗ | ✓ | ✓ | ✗ | ✗ | ✗ | ✗ | ✗ |
| MMSI-Bench [ 57 ] | ✗ | ✓ | ✓ | ✗ | ✗ | ✗ | ✗ | ✗ |
| AllAnglesBench [ 59 ] | ✗ | ✓ | ✓ | ✗ | ✗ | ✗ | ✗ | ✗ |
| MindCube [ 60 ] | ✗ | ✓ | ✓ | ✗ | ✗ | ✗ | ✓ | ✗ |
| CVBench [ 18 ] | ✗ | ✓ | ✓ | ✗ | ✗ | ✗ | ✗ | ✓ |
| Question Name | # QA Pairs | Avail. Views | Passive Views |
|---|---|---|---|
| Fine-grained Action and Pose | 301 | 5.23 | 2.22 |
| Human Counting | 308 | 6.41 | 3.27 |
| Human Existence | 203 | 7.57 | 3.33 |
| Human-Object Interaction | 165 | 6.79 | 2.75 |
| Object Counting | 232 | 5.17 | 3.46 |
| Object Existence | 218 | 4.06 | 3.71 |
| Text Length Statistics | |
|---|---|
| Metric | Value |
| Average Question Length | 102.89 |
| Max Question Length | 253.00 |
| Average Option Length | 49.33 |
| Max Option Length | 148.00 |
| Average ‘Purely Text’ Option Length | 60.67 |
| Model | HC | OC | FAP | HOI | HE | OE | RD-H | RD-O | VDO | VSD | Avg. | Avg. | Avg. | Active | Inf. Time |
| Acc (%) | Steps | Reward | Rate (%) | (hours) | |||||||||||
| Baselines | |||||||||||||||
| Random Guess | 18.2 | 22.8 | 19.5 | 15.6 | 50.5 | 54.0 | 22.1 | 16.7 | 21.3 | 21.9 | 24.8 | 1.0 | 22.5 | 0.0 | 0.0 |
| Blind (Text-only) | 0.4 | 6.3 | 20.5 | 3.3 | 46.8 | 53.2 | 21.5 | 21.7 | 20.0 | 31.2 | 20.9 | 2.1 | 19.1 | 21.5 | 1.9 |
| Human | 88.2 | 76.8 | 79.6 | 83.1 | 81.4 | 87.6 | 78.9 | 87.1 | 80.7 | 84.3 | 82.7 | 4.7 | 55.6 | 88.1 | 10.0 |
| Oracle-View ∗ | 42.2 | 26.3 | 67.9 | 17.1 | 60.4 | 57.4 | 73.5 | 59.7 | 25.8 | 33.3 | 54.7 | - | - | - | 1.0 |
| Model | Avg. Acc (%) | Model | Avg. Acc (%) |
|---|---|---|---|
| Gemini-3.5-flash | 37.9 | GPT-5.2-2025-12-11 | 37.3 |
| Gemini-3.1-flash-lite | 37.9 | GPT-5-mini-2025-08-07 | 39.6 |
| Gemini-2.5-flash | 37.3 | GPT-5-nano-2025-08-07 | 35.0 |
| Model | Avg. | Avg. | Avg. | Active | Inf. Time |
|---|---|---|---|---|---|
| Acc (%) | Steps | Reward | Rate (%) | (hours) | |
| Standard Active ( moves) | |||||
| Gemini-3.1-flash-lite | 38.0 | 1.5 | 31.5 | 24.8 | 1.5 |
| Gemini-2.5-flash | 45.4 | 1.9 | 35.3 | 41.2 | 8.3 |
| Expanded Active ( moves) | |||||
| Gemini-3.1-flash-lite | 37.9 | 1.4 | 33.1 | 21.0 | 1.1 |
| Model | Setting | Avg. Acc (%) | Avg. Steps | Avg. Reward | Active Rate (%) |
|---|---|---|---|---|---|
| Gemini-3.1-lite | Active | 38.0 | 1.5 | 31.5 | 24.8 |
| Gemini-3.1-lite | Passive | 40.3 | - | - | - |
| GPT-5-mini | Active | 41.4 | 1.4 | 34.0 | 29.4 |
| GPT-5-mini | Passive | 41.9 | - | - | - |
| Model | Avg. | Avg. | Avg. | Active | Last 3rd | Penult. | Final |
|---|---|---|---|---|---|---|---|
| Acc (%) | Steps | Reward | Rate (%) | Conf (%) | Conf (%) | Conf (%) | |
| Gemini-3.1-lite | 37.3 | 1.4 | 33.0 | 16.2 | 82.1 | 85.2 | 95.1 |
| GPT-5-mini | 41.4 | 1.4 | 36.4 | 26.3 | 73.2 | 78.5 | 84.7 |
| Dataset | License Type | Publicly Available | Access Requirement | Released Artifacts | Re-identification |
|---|---|---|---|---|---|
| M3GYM | Non-Commercial Academic | Yes | Requires Signed Agreement | Extraction Scripts | No |
| Ego-Exo4D | Ego4D License Agreement | Yes | Requires Signed Agreement | Extraction Scripts | No |
| 4D-OR | MIT | Yes | Requires Signed Agreement | Extraction Scripts | No |
| MM-OR | Apache-2.0 | Yes | Requires Signed Agreement | Extraction Scripts | No |
| Harmony4D | MIT | Yes | Direct Download | Multi-View Frames | No |
| HOI-M3 | Apache-2.0 | Yes | Direct Download | Multi-View Frames | No |
| No move | After moving | |||||
|---|---|---|---|---|---|---|
| Model | Acc. | T1-Ans. | T1-Abs. | Part. | All | None |
| Gemini-3.5-flash | 56.8 | 19.0 | 2.0 | 65.1 | 13.5 | 0.4 |
| Gemini-2.5-flash | 45.4 | 45.9 | 15.8 | 28.4 | 9.2 | 0.7 |
| Gemini-3.1-flash-lite | 38.0 | 50.6 | 25.1 | 17.0 | 6.9 | 0.3 |
| Gemini-2.5-flash-lite | 28.1 | 26.2 | 57.2 | 9.9 | 0.5 | 6.3 |
| GPT-5.2 | 46.4 | 34.5 | 9.5 | 54.9 | 0.9 | 0.2 |
| Model | HC | OC | FAP | HOI | HE | OE | RD-H | RD-O | VDO | VSD | Avg. |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Acc (%) | |||||||||||
| Gemini-3.5-flash | 25.8 | 16.5 | 39.0 | 15.6 | 65.8 | 50.0 | 47.4 | 42.8 | 29.3 | 31.2 | 37.9 |
| Gemini-3.1-flash-lite | 25.3 | 15.0 | 49.7 | 15.6 | 70.3 | 37.9 | 47.1 | 39.4 | 18.7 | 38.5 | 37.9 |
| Gemini-2.5-flash | 24.9 | 15.7 | 40.0 | 12.2 | 77.5 | 50.0 | 51.0 | 34.4 | 17.3 | 27.1 | 37.3 |
| Gemini-2.5-flash-lite | 19.1 | 15.0 | 17.4 | 13.3 | 69.4 | 37.1 | 31.7 | 31.7 | 26.7 | 37.5 | 28.9 |
| GPT-5.2-2025-12-11 | 26.7 | 14.2 | 36.9 | 21.1 | 61.3 | 42.7 | 54.5 | 38.3 | 17.3 | 32.3 | 37.3 |
| Model | HC | OC | FAP | HOI | HE | OE | RD-H | RD-O | VDO | VSD | Avg. | Avg. | Avg. | Active | Inf. Time |
| Acc (%) | Steps | Reward | Rate (%) | (hours) | |||||||||||
| Original Active Setting (Unrestricted 8-View Exploration) | |||||||||||||||
| Gemini-3.1-flash-lite | 29.8 | 21.3 | 47.2 | 14.4 | 68.5 | 40.3 | 44.6 | 38.9 | 18.7 | 37.5 | 38.0 | 1.5 | 31.5 | 24.8 | 1.5 |
| Gemini-2.5-flash | 41.3 | 31.5 | 48.2 | 12.2 | 69.4 | 57.3 | 52.9 | 51.1 | 28.0 | 34.4 | 45.4 | 1.9 | 35.3 | 41.2 | 8.3 |
| Ablated Active Setting (Restricted to Maximum Views) | |||||||||||||||
| Gemini-3.1-flash-lite | 30.7 | 18.9 | 45.6 | 16.7 | 68.5 | 41.1 | 45.2 | 36.1 | 20.0 | 37.5 | 37.9 | 1.4 | 33.1 | 21.0 | 1.1 |
| Model | Modality | HC | OC | FAP | HOI | HE | OE | RD-H | RD-O | VDO | VSD | Avg. Acc (%) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Gemini-3.1-flash-lite | Multi-Image | 59.0 | 31.6 | 68.9 | 26.8 | 58.5 | 70.2 | 82.7 | 70.8 | 32.3 | 27.8 | 62.6 |
| Gemini-3.1-flash-lite | Video | 51.8 | 30.3 | 68.9 | 17.1 | 52.8 | 55.3 | 78.6 | 66.9 | 25.8 | 27.8 | 57.6 |
| GPT-5-mini-2025-08-07 | Multi-Image | 61.4 | 42.1 | 65.1 | 34.1 | 47.2 | 67.0 | 85.7 | 77.3 | 25.8 | 36.1 | 64.6 |
| GPT-5-mini-2025-08-07 | Video | 67.5 | 36.8 | 65.1 | 24.4 | 47.2 | 66.0 | 84.2 | 76.0 | 29.0 | 36.1 | 63.7 |
| Model | HC | OC | FAP | HOI | HE | OE | RD-H | RD-O | VDO | VSD | Avg. Acc (%) | Avg. | Avg. | Active |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| (Final Step) | Steps | Reward | Rate (%) | |||||||||||
| Gemini-3.1-flash-lite | 28.9 | 19.7 | 45.6 | 16.7 | 71.2 | 40.3 | 42.6 | 35.6 | 21.3 | 38.5 | 37.3 | 1.4 | 33.0 | 16.2 |
| GPT-5-mini-2025-08-07 | 32.4 | 20.5 | 50.8 | 10.0 | 59.5 | 49.2 | 51.6 | 46.1 | 32.0 | 34.4 | 41.4 | 1.4 | 36.4 | 26.3 |
| Model | History | HC | OC | FAP | HOI | HE | OE | RD-H | RD-O | VDO | VSD | Avg. | Avg. | Avg. | Active |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Acc (%) | Steps | Reward | Rate (%) | ||||||||||||
| Gemini-3.1-flash-lite | Yes | 29.8 | 21.3 | 47.2 | 14.4 | 68.5 | 40.3 | 44.6 | 38.9 | 18.7 | 37.5 | 38.0 | 1.5 | 31.5 | 24.8 |
| Gemini-3.1-flash-lite | No | 21.3 | 7.9 | 48.2 | 12.2 | 69.4 | 40.3 | 47.1 | 38.9 | 20.0 | 34.4 | 36.2 | 2.0 | 32.1 | 23.3 |
| GPT-5-mini-2025-08-07 | Yes | 34.2 | 23.6 | 50.3 | 10.0 | 59.5 | 50.8 | 49.7 | 46.7 | 28.0 | 34.4 | 41.4 | 1.4 | 34.0 | 29.4 |
| GPT-5-mini-2025-08-07 | No | 26.7 | 29.9 | 53.8 | 12.2 | 64.0 | 47.6 | 49.7 | 43.9 | 26.7 | 33.3 | 41.0 | 1.7 | 35.7 | 25.7 |
| Active Setting | Passive Setting | |||||
|---|---|---|---|---|---|---|
| Model | Accuracy (%) | Margin (%) | 95% CI | Accuracy (%) | Margin (%) | 95% CI |
| Gemini-3.5-flash | 56.76 | 2.48 | [54.28, 59.24] | 69.20 | 3.07 | [66.13, 72.26] |
| Gemini-3.1-flash-lite | 38.05 | 2.43 | [35.62, 40.47] | 62.64 | 3.21 | [59.43, 65.86] |
| Gemini-2.5-flash | 45.41 | 2.49 | [42.92, 47.90] | 58.51 | 3.27 | [55.23, 61.78] |
| Gemini-2.5-flash-lite | 28.08 | 2.25 | [25.83, 30.33] | 45.06 | 3.31 | [41.75, 48.36] |
| GPT-5.2-2025-12-11 | 46.45 | 2.50 | [43.95, 48.94] | 62.99 | 3.21 | [59.78, 66.20] |
| Model | HC | OC | FAP | HOI | HE | OE | RD-H | RD-O | VDO | VSD | Avg. | Avg. | Avg. | Active |
| Acc (%) | Steps | Reward | Rate (%) | |||||||||||
| Active Setting (Multi-turn Spatial Exploration) | ||||||||||||||
| Qwen2.5-VL-3B-Instruct | 17.8 | 7.5 | 34.9 | 14.3 | 61.3 | 41.9 | 36.2 | 36.7 | 23.0 | 21.9 | 30.4 | 1.0 | 27.5 | 0.2 |
| Qwen2.5-VL-7B-Instruct | 20.0 | 11.8 | 23.6 | 11.1 | 66.7 | 37.9 | 34.6 | 36.7 | 18.7 | 33.3 | 29.8 | 1.0 | 26.9 | 0.4 |
| Qwen3-VL-8B-Instruct | 9.3 | 9.4 | 27.2 | 11.1 | 58.6 | 37.1 | 44.6 | 44.4 | 20.0 | 31.2 | 30.7 | 1.6 | 27.1 | 15.6 |
| Qwen3-VL-8B-Thinking | 12.0 | 11.8 | 19.5 | 8.9 | 72.1 | 44.4 | 42.3 | 30.6 | 18.7 | 34.4 | 29.8 | 1.1 | 26.7 | 5.8 |
| Model | Abstention Selection Rate (Active) | Accuracy on Abstention (Active) | Abstention Selection Rate (Passive) | Accuracy on Abstention (Passive) |
|---|---|---|---|---|
| Gemini-2.5-flash | 14.57% | 47.37% | 2.24% | 18.75% |
| Gemini-2.5-flash-lite | 54.38% | 92.11% | 16.36% | 75.00% |
| Gemini-3.1-flash-lite | 22.25% | 71.05% | 2.10% | 18.75% |
| Gemini-3.5-flash | 2.50% | 0.00% | 0.98% | 12.50% |
| GPT-5-mini-2025-08-07 | 5.62% | 18.42% | 0.56% | 6.25% |
| GPT-5-nano-2025-08-07 | 12.41% | 36.84% | 0.70% | 18.75% |
| Model | ||||
|---|---|---|---|---|
| Gemini-3.5-flash | 45.85 | 40.60 | 32.25 | 17.48 |
| Gemini-3.1-flash-lite | 33.67 | 31.45 | 27.56 | 19.04 |
| Gemini-2.5-flash | 38.69 | 35.31 | 29.75 | 18.97 |
| Gemini-2.5-flash-lite | 26.15 | 24.49 | 21.51 | 14.83 |
| GPT-5.2-2025-12-11 | 39.56 | 36.50 | 31.15 | 19.80 |
| GPT-5-mini-2025-08-07 | 36.24 | 33.95 | 29.88 | 20.69 |
| Metric | Value |
|---|---|
| Average Question Length | 119.63 |
| Max Question Length | 344.00 |
| Average Option Length | 37.48 |
| Max Option Length | 185.00 |
| Average ‘Purely Text’ Option Length | 45.03 |
| Average Correct Answer Length | 33.74 |
| Hyperparameter | Value |
|---|---|
| Training & Optimization | |
| Base Model | Qwen2.5-VL-3B-Instruct |
| Learning Rate | |
| Train Batch Size (per device) | 2 |
| Gradient Accumulation Steps | 16 |
| Max Training Steps | 300 |
| Model | HC | OC | FAP | HOI | HE | OE | RD-H | RD-O | VDO | VSD | Avg. | Avg. | Avg. | Active |
| Acc (%) | Steps | Reward | Rate (%) | |||||||||||
| Active Setting: Base Model vs. GRPO Tuned Models | ||||||||||||||
| Qwen2.5-VL-3B (Base) | 17.8 | 7.5 | 34.9 | 14.3 | 61.3 | 41.9 | 36.2 | 36.7 | 23.0 | 21.9 | 30.4 | 1.0 | 27.5 | 0.2 |
| Qwen2.5-VL-3B-Instruct-005 | 20.9 | 8.2 | 12.8 | 5.4 | 73.0 | 44.4 | 17.3 | 14.4 | 11.5 | 30.2 | 22.5 | 4.3 | 15.0 | 49.5 |
| Qwen2.5-VL-3B-Instruct-02 | 18.7 | 7.5 | 11.8 | 7.1 | 73.0 | 46.0 | 17.6 | 15.6 | 13.8 | 24.0 | 22.2 | 4.7 | 14.6 | 55.1 |
| Qwen2.5-VL-3B-Instruct-04 | 24.9 | 7.5 | 11.8 | 7.1 | 69.3 | 40.3 | 14.7 | 13.3 | 12.6 | 28.1 | 21.7 | 4.7 | 14.0 | 56.3 |
| Model | Fallback Used | Usage (%) |
|---|---|---|
| Active | ||
| Gemini-2.5-flash | 0 | 0.00 |
| Gemini-2.5-flash-lite | 0 | 0.00 |
| Gemini-3.1-flash-lite | 0 | 0.00 |
| Gemini-3.5-flash | 0 | 0.00 |
| GPT-5-mini-2025-08-07 | 0 | 0.00 |
Spatial Reasoning Benchmarks
Spatial reasoning benchmarks test whether AI systems can perceive, represent, and act on geometric, relational, and viewpoint-dependent information.
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