REVIEW 3 major objections 6 minor 33 references
Learn from the Past: Language-conditioned Object Rearrangement with Large Language Models
T0 review · 3 major / 6 minor · reviewed 2026-08-09 · deepseek-v4-flash
Pith's one-line read Drawing on a similar remembered arrangement lets an LLM predict object goal positions more accurately, lifting the mean human rating from 7.93 to 9.14 in zero-shot robot rearrangement tests.
desk verdict A plausible RAG-for-spatial-reasoning idea undermined by an evaluation that lets the memory overlap with the test tasks. 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 mechanism is retrieval-augmented generation applied to spatial reasoning. A small memory of ten handcrafted successful arrangements (the 'outer knowledge') is kept outside the model; the same LLM that will predict positions first assigns a similarity score between the new instruction and each stored instruction, selects the highest-scoring experience, and injects that experience's object names, centroids, bounding boxes, and rotations into the prompt as a template. Visual grounding is handled by SAM for segmentation and CLIP for open-vocabulary object classification, so the prompt contains spatial facts about both the current scene and the reference. The LLM then outputs target pixel coordinates and a rotation for each object, keeping the initial rotation unless a collision is detected.
What would settle it
Run the same user study on instructions that have no close counterpart among the ten stored arrangements, such as 'stack the cup on the saucer' when every stored example places objects side by side; if the mean rating with reference does not exceed the no-reference version, the claimed benefit of retrieval fails. Alternatively, add a deliberately misleading arrangement to memory and observe whether scores drop, which would show sensitivity to reference quality.
Extended reading notes
Core claim
The central claim is that adding a retrieved 'outer knowledge' reference—a previously successful human arrangement with its instruction, object centroids, bounding boxes, and rotations—materially improves an LLM's spatial reasoning for goal-position prediction. Across three scenes (single-object placement, multi-object arrangement, and long sequential instructions), the full method achieves the highest mean evaluation score of 9.14, outperforming the same framework without a reference (7.93), Dream2Real (6.81), and geometric or random baselines. The paper reports that incorporating references increases the mean score by 1.21 overall, and by 1.52 and 2.24 for Llama3-8B and Mistral-7B respectively, narrowing the gap with ChatGPT-4; success rates (ratings at least 7) rise by 18.22, 18.67, and 29.34 percentage points for ChatGPT-4, Llama3, and Mistral when references are used.
Load-bearing premise
The ten handcrafted arrangements in memory are representative enough that the LLM's similarity scoring reliably selects a useful reference for any new instruction; if no stored experience resembles the task, the framework falls back to the no-reference condition and the measured advantage disappears.
Editorial extensions
If this is right
- Reference guidance improves the mean evaluation score by 1.21 over the no-reference version with ChatGPT-4, and by larger margins with smaller backbones (1.52 for Llama3-8B, 2.24 for Mistral-7B).
- Success rates (ratings at least 7) increase by 18.22, 18.67, and 29.34 percentage points for ChatGPT-4, Llama3, and Mistral, respectively, when references are provided.
- The framework works zero-shot: it needs no task-specific training data for goal-position prediction and handles free-form instructions including sequential orders.
- Because the memory can be extended by recording successful robot executions, the system could improve over time as it accumulates its own past arrangements.
- Smaller, cheaper language models benefit most from the reference mechanism, suggesting that retrieval can reduce the computational capacity needed for reasonable spatial reasoning.
Reading between the lines
- If the reference mechanism is the main driver of accuracy, then the composition of the ten stored arrangements is critical; a memory that lacks any arrangement similar to the current instruction would presumably degrade to the no-reference condition, so a retrieval-coverage analysis would be a natural next test.
- The same retrieval pattern could extend beyond text instructions to visual or multimodal goal specification, where the similarity scoring would be done by a vision-language model over scene layouts rather than by an LLM over text.
- A practical deployment would need to decide when a stored reference is 'similar enough'; adding a rejection threshold on the similarity score could prevent misleading references from being injected, at the cost of falling back to no-reference behavior.
- The authors' plan to record robot-executed successes into the memory suggests a lifelong-learning loop; the interesting open question is whether a bad or noisy execution stored as 'successful' would poison future predictions, so memory curation matters.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper proposes an LLM-based framework for language-conditioned object rearrangement. A robot uses SAM and CLIP to detect object positions, then uses a retriever (LLM similarity scoring) to select the most similar past successful arrangement from a manually created memory of 10 examples, and finally prompts an LLM to predict goal positions. The authors claim that referencing past successes improves the mean user-study rating by 1.21 over the same system without a reference, and that the improvement holds across three LLM backbones. The paper also compares against random placement, a geometric baseline, and a Dream2Real adaptation, reporting the highest average score of 9.14.
Significance. The core idea is intuitive and timely: using successful past arrangements as in-context references could improve LLM spatial reasoning in rearrangement tasks, and the paper provides a real-robot implementation with open web materials. If the claimed improvement were robust and shown to generalize beyond a hand-curated memory of near-duplicate references, the framework would be a useful contribution to few-shot language-conditioned manipulation. However, the current evidence is not yet strong enough. The user study is small (15 participants, 3 scenarios), no significance tests are reported, and the retrieval memory is manually curated with instructions that overlap heavily with the test set, so the reported +1.21 gain may mostly reflect few-shot prompting with almost-answer examples. The paper's own admission in Section IV-B that only 10 arrangements were used 'to highlight how they improve the results' underscores that the memory-scaling and retrieval-generalization claims are not yet evaluated. The strengths are the clear system design, a concrete robotic setup, and a reproducible prompt engineering approach.
major comments (3)
- [Section IV-C, Table I] The claim that incorporating references 'significantly enhances' performance is not supported by statistical evidence. The evaluation uses 15 participants and 3 scenarios, with mean ratings and standard deviations, but no significance tests are reported. The overall mean difference between 'Ours' (9.14) and 'Ours w/o reference' (7.93) is 1.21, but per-scenario differences are small and the standard deviations overlap substantially (e.g., Multiple objects: 9.24±1.44 vs 8.92±1.85; Sequential order: 9.51±0.86 vs 9.37±1.17). Given the small sample and the repeated-measures design, the differences could plausibly arise from chance. I ask for paired statistical tests (e.g., Wilcoxon signed-rank across the 15 participants per scenario), effect sizes, and confidence intervals, or at minimum a per-scenario bootstrap analysis.
- [Section IV-B and Section IV-C, Fig. 5] The 10 manually created reference arrangements contain instructions that are near-isomorphic to the test instructions, so the retrieval step E* = argmax_j LLM(L, L_j, Q_sim) in Section III-B is likely to retrieve a template that almost directly solves the test task. For example, the reference 'Put tomatoes on the plate' appears alongside the test 'put the potatoes on the plate'; 'Put peppers beside the plate' parallels 'put the potatoes beside the plate'; and 'Put the pineapple on the right of the bottle' parallels 'put the eggplant on the right of the potato, then on the left of the pineapple'. With such overlap, the 'with reference' condition is effectively few-shot prompting with an almost-answer example, not a demonstration of retrieval from a general memory of past successes. The paper reports no retrieval-failure analysis, no sensitivity to memory composition, and no experiment with a memory that is disjoint from the test instructions. This is load-bearing because the novelty claim—'learn from the past'—depends on retrieval functioning over a growing, uncurated memory. Please add an evaluation with test instructions that are disjoint from the reference set in both object names and spatial predicates, and report retrieval success/failure rates for individual instructions.
- [Section III-B] The retrieval rule always selects an experience (the argmax of the similarity scores) and never declines to use a reference when no similar experience exists. The framework therefore has no mechanism to detect that the memory lacks a relevant template; in that case it either degrades to the 'without reference' condition or, worse, a dissimilar reference may mislead the LLM. The paper does not analyze how often a useful reference exists for the tested instructions, nor how the method behaves with an empty or mismatched memory. Since the central claim depends on retrieval improving reasoning across an accumulating memory, this missing coverage analysis weakens the argument. Please add an ablation with a random reference selection and a study of performance as the memory composition changes, including cases where the most similar reference is semantically unrelated.
minor comments (6)
- [Abstract and Section I] The paper repeatedly describes the method as 'zero-shot', but the framework uses reference examples from a memory at inference time, which is few-shot in-context learning. Please clarify the intended sense of 'zero-shot' or rephrase to avoid ambiguity.
- [Section IV-C] The text says participants evaluated 9 different methods shown in Tables I and II, but the exact breakdown (e.g., 5 methods in Table I and 6 row-method combinations in Table II, with ChatGPT4 rows overlapping) is not stated. Please specify how the 9 methods are counted and whether each participant rated every method-scenario combination.
- [Section IV-D, Fig. 7] The success rate is defined by a rating threshold of ≥7, which is arbitrary and not justified. Please report the exact distribution of ratings or provide a rationale for the threshold, and include confidence intervals for the success rates.
- [Section IV-B and Section V] The conclusion lists only the 2D surface and sparse-object settings as limitations, but Section IV-B explicitly states that the 10 arrangements were manually created 'to highlight how they improve the results' and that robot-recorded memory expansion is only a potential. Please either test memory expansion or explicitly list the unvalidated memory-scaling assumption as a limitation.
- [Section II-B] The phrase 'for the first time' appears twice in the related-work discussion of LLM-based reference use; please revise to avoid repetition and to be more precise about what is claimed as novel.
- [Fig. 4] The prompt template is described as simplified, but the exact full prompt is not included anywhere. Providing the complete prompt in an appendix or supplementary material would substantially improve reproducibility.
Circularity Check
No significant circularity: the reference is an explicit input and the with/without ablation is a controlled empirical comparison, not a derived quantity.
full rationale
The paper's central claim is empirical, not derivational: it compares LLM goal-position prediction with and without a retrieved reference, and reports that the reference improves mean evaluation score from 7.93 to 9.14. The reference experience E* is an explicit input to the prediction step (Eq. 3: Pt = LLM(O, L, E*)), which is retrieved by LLM similarity scoring, not a fitted parameter disguised as a prediction. The 'w/o reference' ablation provides a controlled baseline, so the reported +1.21 gain is measured rather than forced by construction. The 10 manually created reference arrangements do overlap topically with test instructions (e.g., 'Put tomatoes on the plate' appears as a reference while the test suite includes 'put the potatoes on the plate'), which is a legitimate generalization and retrieval-robustness limitation, but it does not make the prediction equivalent to its inputs by definition, as the LLM must still map the reference to a new scene with different objects, positions, and sizes. The paper's self-citations ([3], [16], [17]) appear only as related-work context and are not load-bearing for the central claim. No self-definitional reduction, uniqueness import, ansatz-smuggling citation, or renaming of a known result is present. Therefore the appropriate circularity score is 0, with the noted evaluation limitation treated as a correctness/robustness concern rather than circularity.
Assumptions & free parameters
free parameters (2)
- Success-rate threshold =
7
- Outer-knowledge memory size =
10
assumptions (6)
- domain assumption SAM produces accurate masks and minimum bounding boxes for objects on the tabletop.
- domain assumption CLIP correctly assigns each segmented mask to one of the object names listed by the LLM.
- ad hoc to paper The 10 human-arranged scenes are both successful and representative of the test instructions.
- domain assumption The LLM's similarity scores between instructions are reliable enough to select a useful reference.
- domain assumption Objects lie on a flat, sparse 2D surface, so pixel coordinates plus depth give valid pick-and-place goals.
- domain assumption User ratings on a 1-10 acceptability scale are a valid measure of rearrangement success.
Cite this review
Pith. "Pith review of Learn from the Past: Language-conditioned Object Rearrangement with Large Language Models." pith.science (2026). https://pith.science/paper/NLCJWUZU
@misc{pith2026250118516,
author = {Pith},
title = {Pith review of: Learn from the Past: Language-conditioned Object Rearrangement with Large Language Models},
year = {2026},
howpublished = {\url{https://pith.science/paper/NLCJWUZU}},
note = {Machine review of arXiv:2501.18516}
}
read the original abstract
Object manipulation for rearrangement into a specific goal state is a significant task for collaborative robots. Accurately determining object placement is a key challenge, as misalignment can increase task complexity and the risk of collisions, affecting the efficiency of the rearrangement process. Most current methods heavily rely on pre-collected datasets to train the model for predicting the goal position. As a result, these methods are restricted to specific instructions, which limits their broader applicability and generalisation. In this paper, we propose a framework of flexible language-conditioned object rearrangement based on the Large Language Model (LLM). Our approach mimics human reasoning by making use of successful past experiences as a reference to infer the best strategies to achieve a current desired goal position. Based on LLM's strong natural language comprehension and inference ability, our method generalises to handle various everyday objects and free-form language instructions in a zero-shot manner. Experimental results demonstrate that our methods can effectively execute the robotic rearrangement tasks, even those involving long sequences of orders.
Figures
Figures from the paper (4 more)
Reference graph
Works this paper leans on
-
[1]
Rearrangement: A challenge for embodied ai,
D. Batra, A. X. Chang, S. Chernova, A. J. Davison, J. Deng, V . Koltun, S. Levine, J. Malik, I. Mordatch, R. Mottaghi, et al., “Rearrangement: A challenge for embodied ai,” arXiv preprint arXiv:2011.01975, 2020
arXiv 2011
-
[2]
Q. Li, S. Luo, Z. Chen, C. Yang, and J. Zhang, Tactile Sensing, Skill Learning, and Robotic Dexterous Manipulation . Academic Press, 2022
work page 2022
-
[3]
Multimodal zero- shot learning for tactile texture recognition,
G. Cao, J. Jiang, D. Bollegala, M. Li, and S. Luo, “Multimodal zero- shot learning for tactile texture recognition,” Robotics and Autonomous Systems, vol. 176, p. 104688, 2024
work page 2024
-
[4]
Metric learning for generalizing spatial relations to new objects,
O. Mees, N. Abdo, M. Mazuran, and W. Burgard, “Metric learning for generalizing spatial relations to new objects,” in 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) , pp. 3175–3182, IEEE, 2017
work page 2017
-
[5]
Sornet: Spatial object- centric representations for sequential manipulation,
W. Yuan, C. Paxton, K. Desingh, and D. Fox, “Sornet: Spatial object- centric representations for sequential manipulation,” in Conference on Robot Learning , pp. 148–157, PMLR, 2022
work page 2022
-
[6]
One-shot imitation learn- ing: A pose estimation perspective,
P. Vitiello, K. Dreczkowski, and E. Johns, “One-shot imitation learn- ing: A pose estimation perspective,” Conference on Robot Learning (CoRL), 2023 , 2023
work page 2023
-
[7]
Dall-e-bot: Introducing web- scale diffusion models to robotics,
I. Kapelyukh, V . V osylius, and E. Johns, “Dall-e-bot: Introducing web- scale diffusion models to robotics,” IEEE Robotics and Automation Letters, 2023
work page 2023
-
[8]
Mental models and lifelong learning,
P. Barker, P. v. Schaik, and S. Hudson, “Mental models and lifelong learning,” Innovations in education and training international , vol. 35, no. 4, pp. 310–318, 1998
work page 1998
Show all 33 references
-
[9]
Medial and orbital frontal cortex in decision-making and flexible behavior,
M. C. Klein-Fl ¨ugge, A. Bongioanni, and M. F. Rushworth, “Medial and orbital frontal cortex in decision-making and flexible behavior,” Neuron, vol. 110, no. 17, pp. 2743–2770, 2022
2022
-
[10]
The whole prefrontal cortex is premotor cortex,
J. M. Fine and B. Y . Hayden, “The whole prefrontal cortex is premotor cortex,” Philosophical Transactions of the Royal Society B , vol. 377, no. 1844, p. 20200524, 2022
2022
-
[11]
Memory: Brain systems that link past, present and future,
R. Pally, “Memory: Brain systems that link past, present and future,” The International Journal of Psycho-Analysis , vol. 78, no. 6, p. 1223, 1997
1997
-
[12]
Efficient and interpretable robot manipulation with graph neural networks,
Y . Lin, A. S. Wang, E. Undersander, and A. Rai, “Efficient and interpretable robot manipulation with graph neural networks,” IEEE Robotics and Automation Letters , vol. 7, no. 2, pp. 2740–2747, 2022
2022
-
[13]
Tidee: Tidying up novel rooms using visuo-semantic commonsense priors,
G. Sarch, Z. Fang, A. W. Harley, P. Schydlo, M. J. Tarr, S. Gupta, and K. Fragkiadaki, “Tidee: Tidying up novel rooms using visuo-semantic commonsense priors,” in European conference on computer vision , pp. 480–496, Springer, 2022
2022
-
[14]
Automated task planning using object arrangement optimization,
M. Kang, Y . Kwon, and S.-E. Yoon, “Automated task planning using object arrangement optimization,” in 2018 15th international conference on ubiquitous robots (UR) , pp. 334–341, IEEE, 2018
2018
-
[15]
My house, my rules: Learning tidying preferences with graph neural networks,
I. Kapelyukh and E. Johns, “My house, my rules: Learning tidying preferences with graph neural networks,” in Conference on robot learning, pp. 740–749, PMLR, 2022
2022
-
[16]
A learning from demonstration framework for adaptive task and motion planning in varying package- to-order scenarios,
R. Ma, J. Chen, and J. Oyekan, “A learning from demonstration framework for adaptive task and motion planning in varying package- to-order scenarios,” Robotics and Computer-Integrated Manufacturing, vol. 82, p. 102539, 2023
2023
-
[17]
Applying vision-guided graph neural networks for adaptive task planning in dynamic human robot collaborative scenarios,
R. Ma, Y . Liu, E. W. Graf, and J. Oyekan, “Applying vision-guided graph neural networks for adaptive task planning in dynamic human robot collaborative scenarios,” Advanced Robotics , vol. 38, no. 23, pp. 1690–1709, 2024
2024
-
[18]
Visual genome: Connecting language and vision using crowdsourced dense image annotations,
R. Krishna, Y . Zhu, O. Groth, J. Johnson, K. Hata, J. Kravitz, S. Chen, Y . Kalantidis, L.-J. Li, D. A. Shamma, et al. , “Visual genome: Connecting language and vision using crowdsourced dense image annotations,” International journal of computer vision , vol. 123, pp. 32–73, 2017
2017
-
[19]
Ingress: Interactive visual grounding of referring expressions,
M. Shridhar, D. Mittal, and D. Hsu, “Ingress: Interactive visual grounding of referring expressions,” The International Journal of Robotics Research, vol. 39, no. 2-3, pp. 217–232, 2020
2020
-
[20]
What foundation models can bring for robot learning in manipulation: A survey,
D. Li, Y . Jin, H. Yu, J. Shi, X. Hao, P. Hao, H. Liu, F. Sun, B. Fang, et al. , “What foundation models can bring for robot learning in manipulation: A survey,” arXiv preprint arXiv:2404.18201 , 2024
2024
-
[21]
Do as i can, not as i say: Grounding language in robotic affordances,
A. Brohan, Y . Chebotar, C. Finn, K. Hausman, A. Herzog, D. Ho, J. Ibarz, A. Irpan, E. Jang, R. Julian, et al., “Do as i can, not as i say: Grounding language in robotic affordances,” in Conference on robot learning, pp. 287–318, PMLR, 2023
2023
-
[22]
Language models as zero-shot planners: Extracting actionable knowledge for embodied agents,
W. Huang, P. Abbeel, D. Pathak, and I. Mordatch, “Language models as zero-shot planners: Extracting actionable knowledge for embodied agents,” in International Conference on Machine Learning , pp. 9118– 9147, PMLR, 2022
2022
-
[23]
Tidybot: Personalized robot assistance with large language models,
J. Wu, R. Antonova, A. Kan, M. Lepert, A. Zeng, S. Song, J. Bohg, S. Rusinkiewicz, and T. Funkhouser, “Tidybot: Personalized robot assistance with large language models,” Autonomous Robots , vol. 47, no. 8, pp. 1087–1102, 2023
2023
-
[24]
Bootstrap your own skills: Learning to solve new tasks with large language model guidance,
J. Zhang, J. Zhang, K. Pertsch, Z. Liu, X. Ren, M. Chang, S.- H. Sun, and J. J. Lim, “Bootstrap your own skills: Learning to solve new tasks with large language model guidance,” arXiv preprint arXiv:2310.10021, 2023
2023 arXiv
-
[25]
Lifelong robot library learning: Bootstrap- ping composable and generalizable skills for embodied control with language models,
G. Tziafas and H. Kasaei, “Lifelong robot library learning: Bootstrap- ping composable and generalizable skills for embodied control with language models,” in 2024 IEEE International Conference on Robotics and Automation (ICRA) , pp. 515–522, IEEE, 2024
2024
-
[26]
Rt-2: Vision-language-action models transfer web knowledge to robotic control,
B. Zitkovich, T. Yu, S. Xu, P. Xu, T. Xiao, F. Xia, J. Wu, P. Wohlhart, S. Welker, A. Wahid, et al. , “Rt-2: Vision-language-action models transfer web knowledge to robotic control,” in Conference on Robot Learning, pp. 2165–2183, PMLR, 2023
2023
-
[27]
Palm-e: An embodied multimodal language model,
D. Driess, F. Xia, M. S. Sajjadi, C. Lynch, A. Chowdhery, B. Ichter, A. Wahid, J. Tompson, Q. Vuong, T. Yu,et al., “Palm-e: An embodied multimodal language model,” in International Conference on Machine Learning, pp. 8469–8488, PMLR, 2023
2023
-
[28]
V oxposer: Composable 3d value maps for robotic manipulation with language models,
W. Huang, C. Wang, R. Zhang, Y . Li, J. Wu, and L. Fei-Fei, “V oxposer: Composable 3d value maps for robotic manipulation with language models,” in Conference on Robot Learning , pp. 540–562, PMLR, 2023
2023
-
[29]
Retrieval- augmented generation for knowledge-intensive nlp tasks,
P. Lewis, E. Perez, A. Piktus, F. Petroni, V . Karpukhin, N. Goyal, H. K ¨uttler, M. Lewis, W.-t. Yih, T. Rockt ¨aschel, et al. , “Retrieval- augmented generation for knowledge-intensive nlp tasks,” Advances in Neural Information Processing Systems , vol. 33, pp. 9459–9474, 2020
2020
-
[30]
Exploring and improving the spatial reasoning abilities of large language models,
M. Sharma, “Exploring and improving the spatial reasoning abilities of large language models,” in I Can’t Believe It’s Not Better Workshop: Failure Modes in the Age of F oundation Models , 2023
2023
-
[31]
Dream2real: Zero- shot 3d object rearrangement with vision-language models,
I. Kapelyukh, Y . Ren, I. Alzugaray, and E. Johns, “Dream2real: Zero- shot 3d object rearrangement with vision-language models,” in 2024 IEEE International Conference on Robotics and Automation (ICRA) , pp. 4796–4803, IEEE, 2024
2024
-
[32]
Mistral 7b,
A. Q. Jiang, A. Sablayrolles, A. Mensch, C. Bamford, D. S. Chaplot, D. d. l. Casas, F. Bressand, G. Lengyel, G. Lample, L. Saulnier, et al., “Mistral 7b,” arXiv preprint arXiv:2310.06825 , 2023
2023 arXiv
-
[33]
The llama 3 herd of models,
A. Dubey, A. Jauhri, A. Pandey, A. Kadian, A. Al-Dahle, A. Letman, A. Mathur, A. Schelten, A. Yang, A. Fan, et al. , “The llama 3 herd of models,” arXiv preprint arXiv:2407.21783 , 2024
2024 arXiv
Reviewed August 9, 2026 · model on record in the stance chip above.
Discussion (0). Continue with ORCID to comment.