REVIEW 3 major objections 4 minor 2 cited by
Can Multimodal Large Language Models Understand Spatial Relations?
T0 review · 3 major / 4 minor · reviewed 2026-08-07 · deepseek-v4-flash
Pith's one-line read The paper claims that a new bounding-box-free, perspective-changing multiple-choice benchmark of 5,392 spatial questions scores today's best multimodal model at 48.14% accuracy, far below the 98.40% human level, with text-only performance…
desk verdict A useful new benchmark for spatial reasoning in MLLMs, but the in-image perspective labels need a sharper definition of observer orientation before the headline numbers are fully trustworthy. read the letter →
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
What carries the argument
The load-bearing object is the spatial coordinate system defined in Table 2: the observer is the origin, gravity points down the negative Z-axis, the X-axis runs left-to-right, and the Y-axis runs back-to-front. Each of the six relations is an inequality on these axes, e.g., the subject is 'left of' the object when $x_s < x_o$ and 'on/above' when $z_s > z_o$. This converts perspective questions into one objective reference frame, lets annotators label first- and third-person views without changing the rule, and makes the benchmark's ground truth mechanical rather than impressionistic. Around it sits a three-round annotation procedure (annotate, check, review) and three question-template families that enforce the no-bbox, no-prior-knowledge, and perspective-substitution properties.
What would settle it
Re-annotate a random sample of, say, 200 SpatialMQA test items with a fresh team using the same Table 2 rules and compare labels. If pairwise agreement is far below the reported 98.40% human accuracy, or if flipping a question from first-person to third-person changes the SCS-derived label, the ground truth is not stable enough to support the claimed human-model gap.
Extended reading notes
Core claim
The central claim is that SpatialMQA is the first spatial-relation benchmark that combines four properties at once: no bounding boxes, objective-world labels, perspective substitution, and no prior-knowledge answers. Under that combination, the best model's accuracy is 48.14%, far below the 98.40% human score, and text-only human accuracy drops to 24.40%, essentially random. The authors attribute the failure to perspective substitution in particular, since errors of that type are the most frequent in their error analysis, followed by misrecognizing subjects and objects and lack of commonsense reasoning. The benchmark's value is diagnostic: each question is grounded in a six-relation coordinate system, so low scores can be traced to specific axes (X, Y, or Z) and specific question perspectives.
Load-bearing premise
The whole measurement rests on the assumption that the coordinate system in Table 2 tells annotators unambiguously which of the six relations holds for any image from any of the three perspectives; if 'front' or 'left' is genuinely underdetermined in even a modest fraction of images, both the 48.14% model score and the 98.40% human score become noisy, and the benchmark would reward annotation agreement more than spatial understanding.
Editorial extensions
If this is right
- Any model that scores near 48% or below on SpatialMQA cannot be credited with human-like spatial grounding; the benchmark gives a single number that separates image-grounded reasoning from text-only guessing.
- Instruction tuning on objective-world spatial data is a promising lever, since LoRA tuning lifted SpaceLLaVA from 31.32% to 48.14% accuracy.
- Evaluation reports should separate X-, Y-, and Z-axis relations and the three question perspectives, because models are uneven across them (SpaceLLaVA ranges from 31.41% on Z-axis items to 56.00% on X-axis items).
- Few-shot comparisons need to control whether in-context examples match the question type; GPT-4o's accuracy drops when examples are misaligned, while Gemini's rises with more examples.
- The near-random text-only scores (24.40% for humans, 17.20-26.40% for models) confirm that SpatialMQA measures image understanding, not world knowledge.
Reading between the lines
- Beyond the paper: because the spatial coordinate system is a formal rule, synthetic image generators or renderers could produce unlimited training samples with exact labels, testing whether data scale closes the human-model gap.
- Beyond the paper: the coordinate rules imply a consistency check — asking the same question from first-person and third-person perspectives should produce complementary labels; a model that fails that swap reveals axis-based guessing rather than spatial grounding.
- Beyond the paper: the coordinate system could be extended from six discrete relations to continuous 'how far' judgments, since it already encodes direction via coordinate differences but discards distance.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. This paper presents SpatialMQA, a multiple-choice question-answering benchmark for spatial relation reasoning built on COCO2017. The benchmark contains 5,392 human-annotated samples covering six relations (left of, right of, in front of, behind, on/above, below) across three perspective types: out-of-image, first-person in-image, and third-person in-image. The authors claim that SpatialMQA avoids reliance on bounding boxes, filters out questions answerable from prior knowledge without an image, and tests perspective substitution. They evaluate several open- and closed-source MLLMs and report that the best model (SpaceLLaVA with LoRA) achieves 48.14% accuracy, far below human performance at 98.40%. The paper also includes analyses of question types, answer types, ICL alignment, image dependence, and error categories.
Significance. If the ground-truth labels are reliable, SpatialMQA addresses a real gap in spatial reasoning benchmarks by combining objective-world reference, perspective substitution, and a multiple-choice format that prevents bbox-based shortcuts. The released code, human evaluation, text-only control (24.40%), and the large human-model gap are strengths that support the benchmark's usefulness for future research. However, the benchmark's validity rests on the consistency of annotation conventions for in-image perspectives, which are currently under-specified, and on the comparability of evaluation protocols across model families. These issues must be resolved before the reported accuracy gap can be attributed to spatial reasoning ability.
major comments (3)
- [Section 3.2 and Table 2] The spatial coordinate system is defined with 'the observer as the origin' and the X/Y axes tied to the observer's left/right/front/back, but no rule is given for establishing the observer's orientation when the observer is inside the image. Since Table 3 reports that 60% of samples are in-image (Q2 first-person and Q3 third-person), the labels 'left of', 'right of', 'in front of', and 'behind' are not uniquely determined for objects without an intrinsic facing direction (e.g., a keyboard or bottle in Q2) or for living beings whose facing direction is not specified (Q3). The paper does not report inter-annotator agreement, so there is no evidence that the three annotators, two checkers, and reviewer all applied the same orientation convention. This under-specification is load-bearing because the human 98.40% accuracy and the model accuracies are measured against labels whose correctness depends on this unspecified convention.
- [Section 4 and Section 5.1] The train/dev/test split is stated only as a 7:1:2 ratio, without specifying whether the split is by image or by sample. If multiple samples from a COCO2017 image appear in both the training and test sets, instruction-tuned open-source models (e.g., SpaceLLaVA LoRA, Table 4) could benefit from image-level leakage, which would inflate the reported 48.14% accuracy. The authors should clarify the split granularity and, if the split is sample-level, re-split at the image level and re-report the affected results.
- [Section 5.1 and Table 4] The closed-source models (GPT-4o, Gemini-1.5-flash) and the human evaluation are run on 'randomly select 500 samples', while the open-source models are evaluated on the full test set of 1,076 samples. Table 4 presents all models in one table without indicating that the closed-source and human numbers are based on a subset. Unless the same stratified 500-sample subset is used for all these evaluations and is representative of the full test set, the comparison between GPT-4o (40.20%), Gemini (35.40%–38.00%), and SpaceLLaVA LoRA (48.14%) is not valid. This should be clarified, and the closed-source results should either be reported on the full test set or clearly separated.
minor comments (4)
- [Section 1, paragraph 2] 'To fully the scene of four students' is missing a verb; it should be 'To fully understand the scene of four students'.
- [Throughout] The model names 'LLaV A' and 'SpaceLLaV A' contain an unintended space (likely a LaTeX rendering issue); please fix throughout.
- [Section 5.3 and Table 5] The human evaluation is based on 500 samples, but no confidence intervals or per-question-type sample sizes are reported in Table 5, making it difficult to assess the stability of the 98.40% estimate.
- [Table 2] The formal conditions for 'in front of' and 'behind' use ys and yo without explicitly stating that these are signed distances along the observer's Y-axis; a one-sentence clarification would improve reproducibility.
Circularity Check
No significant circularity: SpatialMQA is an externally evaluated benchmark with human-labeled ground truth, so model and human accuracies are not forced by construction.
full rationale
This paper constructs a new benchmark and evaluates MLLMs against it; there is no formal derivation whose conclusion is equivalent to its inputs. The central quantities (human accuracy 98.40%, best MLLM 48.14%) are measurements on held-out test samples against independently human-annotated ground truth. The annotation guidelines define the spatial coordinate system; labels are produced by a three-round human process and checked by separate annotators, not fitted to the models being evaluated. The claim that questions cannot be answered from prior knowledge is empirically tested via a text-only condition (24.40%, near random), not assumed into the benchmark construction in a way that would force the accuracy results. No parameter in the paper is fitted to the reported accuracies, no uniqueness theorem is imported from the authors' own prior work, and no known result is renamed. Concern about possible ambiguity in the in-image coordinate system (how an inanimate first-person observer is oriented) is a validity or annotation-reliability limitation, not circularity, because it does not make the reported numbers equal to the benchmark's definition by construction. Therefore the paper is not circular.
Assumptions & free parameters
assumptions (3)
- domain assumption The spatial coordinate system in Table 2 defines the correct answer for every question.
- domain assumption Human annotation is the gold standard for spatial relations.
- domain assumption The 5,392 samples are a representative and unbiased sample of spatial relations in COCO images.
Cite this review
Pith. "Pith review of Can Multimodal Large Language Models Understand Spatial Relations?." pith.science (2026). https://pith.science/paper/D42YTSRA
@misc{pith2026250519015,
author = {Pith},
title = {Pith review of: Can Multimodal Large Language Models Understand Spatial Relations?},
year = {2026},
howpublished = {\url{https://pith.science/paper/D42YTSRA}},
note = {Machine review of arXiv:2505.19015}
}
read the original abstract
Spatial relation reasoning is a crucial task for multimodal large language models (MLLMs) to understand the objective world. However, current benchmarks have issues like relying on bounding boxes, ignoring perspective substitutions, or allowing questions to be answered using only the model's prior knowledge without image understanding. To address these issues, we introduce SpatialMQA, a human-annotated spatial relation reasoning benchmark based on COCO2017, which enables MLLMs to focus more on understanding images in the objective world. To ensure data quality, we design a well-tailored annotation procedure, resulting in SpatialMQA consisting of 5,392 samples. Based on this benchmark, a series of closed- and open-source MLLMs are implemented and the results indicate that the current state-of-the-art MLLM achieves only 48.14% accuracy, far below the human-level accuracy of 98.40%. Extensive experimental analyses are also conducted, suggesting the future research directions. The benchmark and codes are available at https://github.com/ziyan-xiaoyu/SpatialMQA.git.
Figures
Figures from the paper (3 more)
Forward citations
Cited by 2 Pith papers
-
AnatomiX, an Anatomy-Aware Grounded Multimodal Large Language Model for Chest X-Ray Interpretation
AnatomiX, a two-stage anatomy-first multimodal LLM for chest X-ray interpretation, reports >25% relative gains on anatomy grounding and grounded captioning, but some aggregate benchmark numbers are internally inconsis...
-
Spatial-aware Vision Language Model for Autonomous Driving
LVLDrive fuses LiDAR point clouds into a pre-trained vision-language driving model through a zero-initialized gated Q-Former and a spatial-aware QA dataset, improving open-loop planning and 3D grounding over image-onl...
Reference graph
Works this paper leans on
-
[1]
online" 'onlinestring :=
ENTRY address archivePrefix author booktitle chapter edition editor eid eprint eprinttype howpublished institution journal key month note number organization pages publisher school series title type volume year doi pubmed url lastchecked label extra.label sort.label short.list INTEGERS output.state before.all mid.sentence after.sentence after.block STRING...
-
[2]
write newline
" write newline "" before.all 'output.state := FUNCTION n.dashify 't := "" t empty not t #1 #1 substring "-" = t #1 #2 substring "--" = not "--" * t #2 global.max substring 't := t #1 #1 substring "-" = "-" * t #2 global.max substring 't := while if t #1 #1 substring * t #2 global.max substring 't := if while FUNCTION word.in bbl.in capitalize " " * FUNCT...
-
[3]
Josh Achiam, Steven Adler, Sandhini Agarwal, Lama Ahmad, Ilge Akkaya, Florencia Leoni Aleman, Diogo Almeida, Janko Altenschmidt, Sam Altman, Shyamal Anadkat, et al. 2023. Gpt-4 technical report. arXiv preprint arXiv:2303.08774
arXiv 2023
-
[4]
Anja Belz, Adrian Muscat, Pierre Anguill, Mouhamadou Sow, Ga \'e tan Vincent, and Yassine Zinessabah. 2018. Spatialvoc2k: A multilingual dataset of images with annotations and features for spatial relations between objects. In Proceedings of the 11th International Conference on Natural Language Generation, pages 140--145
work page 2018
-
[5]
Wenxiao Cai, Yaroslav Ponomarenko, Jianhao Yuan, Xiaoqi Li, Wankou Yang, Hao Dong, and Bo Zhao. 2024. Spatialbot: Precise spatial understanding with vision language models. arXiv preprint arXiv:2406.13642
arXiv 2024
-
[6]
Boyuan Chen, Zhuo Xu, Sean Kirmani, Brain Ichter, Dorsa Sadigh, Leonidas Guibas, and Fei Xia. 2024. Spatialvlm: Endowing vision-language models with spatial reasoning capabilities. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14455--14465
2024
-
[7]
An-Chieh Cheng, Hongxu Yin, Yang Fu, Qiushan Guo, Ruihan Yang, Jan Kautz, Xiaolong Wang, and Sifei Liu. 2024. Spatialrgpt: Grounded spatial reasoning in vision language model. arXiv preprint arXiv:2406.01584
arXiv 2024
-
[8]
Sijie Cheng, Zhicheng Guo, Jingwen Wu, Kechen Fang, Peng Li, Huaping Liu, and Yang Liu. 2023. Can vision-language models think from a first-person perspective? arXiv preprint arXiv:2311.15596
arXiv 2023
Show all 37 references
-
[9]
Wenliang Dai, Junnan Li, Dongxu Li, Anthony Meng Huat Tiong, Junqi Zhao, Weisheng Wang, Boyang Li, Pascale N Fung, and Steven Hoi. 2024. Instructblip: Towards general-purpose vision-language models with instruction tuning. Advances in Neural Information Processing Systems, 36
2024
-
[10]
Mengfei Du, Binhao Wu, Zejun Li, Xuanjing Huang, and Zhongyu Wei. 2024. Embspatial-bench: Benchmarking spatial understanding for embodied tasks with large vision-language models. arXiv preprint arXiv:2406.05756
2024 arXiv
-
[11]
Chaoyou Fu, Peixian Chen, Yunhang Shen, Yulei Qin, Mengdan Zhang, Xu Lin, Zhenyu Qiu, Wei Lin, Jinrui Yang, Xiawu Zheng, Ke Li, Xing Sun, and Rongrong Ji. 2023. Mme: A comprehensive evaluation benchmark for multimodal large language models. ArXiv, abs/2306.13394
2023 arXiv
-
[12]
Haoxiang Gao, Yaqian Li, Kaiwen Long, Ming Yang, and Yiqing Shen. 2024. A survey for foundation models in autonomous driving. arXiv preprint arXiv:2402.01105
2024 arXiv
-
[13]
Ankit Goyal, Kaiyu Yang, Dawei Yang, and Jia Deng. 2020. Rel3d: A minimally contrastive benchmark for grounding spatial relations in 3d. Advances in Neural Information Processing Systems, 33:10514--10525
2020
-
[14]
Zixian Guo, Bowen Dong, Zhilong Ji, Jinfeng Bai, Yiwen Guo, and Wangmeng Zuo. 2023. Texts as images in prompt tuning for multi-label image recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 2808--2817
2023
-
[15]
Zachary Hawes and Daniel Ansari. 2020. What explains the relationship between spatial and mathematical skills? a review of evidence from brain and behavior. Psychonomic bulletin & review, 27:465--482
2020
-
[16]
Edward J Hu, Yelong Shen, Phillip Wallis, Zeyuan Allen-Zhu, Yuanzhi Li, Shean Wang, Lu Wang, and Weizhu Chen. 2021. Lora: Low-rank adaptation of large language models. arXiv preprint arXiv:2106.09685
2021 arXiv
-
[17]
Drew A Hudson and Christopher D Manning. 2019. Gqa: A new dataset for real-world visual reasoning and compositional question answering. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 6700--6709
2019
-
[18]
Justin Johnson, Bharath Hariharan, Laurens Van Der Maaten, Li Fei-Fei, C Lawrence Zitnick, and Ross Girshick. 2017. Clevr: A diagnostic dataset for compositional language and elementary visual reasoning. In Proceedings of the IEEE CVPR, pages 2901--2910
2017
-
[19]
Hugo Lauren c on, Daniel van Strien, Stas Bekman, Leo Tronchon, Lucile Saulnier, Thomas Wang, Siddharth Karamcheti, Amanpreet Singh, Giada Pistilli, Yacine Jernite, et al. 2023. Introducing idefics: An open reproduction of state-of-the-art visual language model, 2023. URL http...
2023
-
[20]
Junnan Li, Dongxu Li, Silvio Savarese, and Steven Hoi. 2023. Blip-2: Bootstrapping language-image pre-training with frozen image encoders and large language models. In International conference on machine learning, pages 19730--19742. PMLR
2023
-
[21]
Junnan Li, Dongxu Li, Caiming Xiong, and Steven Hoi. 2022. Blip: Bootstrapping language-image pre-training for unified vision-language understanding and generation. In International conference on machine learning, pages 12888--12900. PMLR
2022
-
[22]
Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Doll \'a r, and C Lawrence Zitnick. 2014. Microsoft coco: Common objects in context. In Computer Vision--ECCV 2014: 13th European Conference, Zurich, Switzerland, September 6-12, 2014, ...
2014
-
[23]
Fangyu Liu, Guy Emerson, and Nigel Collier. 2023 a . Visual spatial reasoning. Transactions of the Association for Computational Linguistics, 11:635--651
2023
-
[24]
Haotian Liu, Chunyuan Li, Qingyang Wu, and Yong Jae Lee. 2024. Visual instruction tuning. Advances in neural information processing systems, 36
2024
-
[25]
Weihao Liu, Fangyu Lei, Tongxu Luo, Jiahe Lei, Shizhu He, Jun Zhao, and Kang Liu. 2023 b . Mmhqa-icl: Multimodal in-context learning for hybrid question answering over text, tables and images. arXiv preprint arXiv:2309.04790
2023 arXiv
-
[26]
Xiao Liu, Kaixuan Ji, Yicheng Fu, Weng Lam Tam, Zhengxiao Du, Zhilin Yang, and Jie Tang. 2021. P-tuning v2: Prompt tuning can be comparable to fine-tuning universally across scales and tasks. arXiv preprint arXiv:2110.07602
2021 arXiv
-
[27]
Michael J Proulx, Orlin S Todorov, Amanda Taylor Aiken, and Alexandra A de Sousa. 2016. Where am i? who am i? the relation between spatial cognition, social cognition and individual differences in the built environment. Frontiers in psychology, 7:158846
2016
-
[28]
Mustafa Shukor, Alexandre Rame, Corentin Dancette, and Matthieu Cord. 2023. Beyond task performance: evaluating and reducing the flaws of large multimodal models with in-context-learning. In The Twelfth International Conference on Learning Representations
2023
-
[29]
Alane Suhr, Mike Lewis, James Yeh, and Yoav Artzi. 2017. A corpus of natural language for visual reasoning. In Proceedings of the 55th Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers), pages 217--223
2017
-
[30]
Gemini Team, Rohan Anil, Sebastian Borgeaud, Yonghui Wu, Jean-Baptiste Alayrac, Jiahui Yu, Radu Soricut, Johan Schalkwyk, Andrew M Dai, Anja Hauth, et al. 2023. Gemini: a family of highly capable multimodal models. arXiv preprint arXiv:2312.11805
2023 arXiv
-
[31]
Junjie Wang, Wei Li, Yinjian Wang, Ran Tao, and Qian Du. 2023. Representation-enhanced status replay network for multisource remote-sensing image classification. IEEE Transactions on Neural Networks and Learning Systems
2023
-
[32]
Lei Wang, Yi Hu, Jiabang He, Xing Xu, Ning Liu, Hui Liu, and Heng Tao Shen. 2024. T-sciq: Teaching multimodal chain-of-thought reasoning via large language model signals for science question answering. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 38...
2024
-
[33]
Chuan Wen, Dinesh Jayaraman, and Yang Gao. 2024. Can transformers capture spatial relations between objects? arXiv preprint arXiv:2403.00729
2024 arXiv
-
[34]
Kaiyu Yang, Olga Russakovsky, and Jia Deng. 2019. Spatialsense: An adversarially crowdsourced benchmark for spatial relation recognition. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2051--2060
2019
-
[35]
Qinghao Ye, Haiyang Xu, Guohai Xu, Jiabo Ye, Ming Yan, Yiyang Zhou, Junyang Wang, Anwen Hu, Pengcheng Shi, Yaya Shi, et al. 2023. mplug-owl: Modularization empowers large language models with multimodality. arXiv preprint arXiv:2304.14178
2023 arXiv
-
[36]
Daoan Zhang, Junming Yang, Hanjia Lyu, Zijian Jin, Yuan Yao, Mingkai Chen, and Jiebo Luo. 2024. Cocot: Contrastive chain-of-thought prompting for large multimodal models with multiple image inputs. arXiv preprint arXiv:2401.02582
2024 arXiv
-
[37]
Ge Zheng, Bin Yang, Jiajin Tang, Hong-Yu Zhou, and Sibei Yang. 2023. Ddcot: Duty-distinct chain-of-thought prompting for multimodal reasoning in language models. Advances in Neural Information Processing Systems, 36:5168--5191
2023
Reviewed August 7, 2026 · model on record in the stance chip above.
Discussion (0). Sign in to comment.