Modality-Aware Identity Construction and Counterfactual Structure Learning for ID-Free Multimodal Recommendation
Pith reviewed 2026-05-20 00:34 UTC · model grok-4.3
The pith
A modality-aware module dynamically modulates positional encodings with multimodal semantics to build content-aware ID-free identity representations, while a counterfactual paradigm mines low-exposure semantic neighbors through popularity
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
MAIL consists of a modality-aware identity construction module that dynamically modulates positional encodings with multimodal semantics to construct content-aware ID-free identity representations, followed by a counterfactual structure learning paradigm that mines low-exposure semantic neighbors via popularity penalization and thereby alleviates popularity bias.
What carries the argument
Modality-aware identity construction module that dynamically modulates positional encodings with multimodal semantics, together with the counterfactual structure learning paradigm that applies popularity penalization to discover latent neighbors.
If this is right
- Static ID embeddings can be replaced by content-adaptive representations that change with the available modalities.
- Graph learning can surface long-tail semantic neighbors once popularity is explicitly penalized.
- Popularity bias in neighbor selection can be reduced while retaining useful structural signal.
- Recommendation accuracy improves on heterogeneous multimodal data without requiring explicit user or item identifiers.
Where Pith is reading between the lines
- The same modulation idea could be tested on sequential or session-based recommendation where user context shifts rapidly.
- Privacy-sensitive settings that avoid storing persistent IDs might benefit from representations rebuilt on the fly from modality data.
- The counterfactual penalization step could be combined with other debiasing techniques to address exposure bias beyond popularity.
Load-bearing premise
That modulating positional encodings with multimodal semantics produces effective dynamic ID-free representations and that popularity penalization in the counterfactual step uncovers useful latent relations without injecting new biases or erasing signal.
What would settle it
An ablation study on the same five Amazon datasets in which removing either the dynamic modulation or the popularity-penalized counterfactual step yields no statistically significant gain in Recall@10 or NDCG@10 over strong ID-free baselines, or in which the newly mined neighbors exhibit higher rather than lower average popularity.
Figures
read the original abstract
Multimodal recommendation has attracted extensive attention by leveraging heterogeneous modality information to alleviate data sparsity and improve recommendation accuracy. Existing methods have attempted to replace ID embeddings with multimodal features and have achieved promising preliminary results. However, these methods still exhibit the following two limitations: (1) the reconstructed ID representations remain relatively static and fail to fully exploit multimodal semantics; and (2) the graph learning process is insufficient in mining latent long-tail semantic relations and is easily affected by popularity bias. To address these issues, we propose a novel method named Modality-Aware Identity Construction and Counterfactual Structure Learning for ID-free Multimodal Recommendation (MAIL). Specifically, we design a modality-aware identity construction module that dynamically modulates positional encodings with multimodal semantics to construct content-aware ID-free identity representations. Then, we propose a counterfactual structure learning paradigm that mines low-exposure semantic neighbors via popularity penalization and alleviates popularity bias. Extensive experiments are conducted on five public Amazon datasets. Experimental results show that MAIL achieves average improvements of 7.81% in Recall@10 and 12.81% in NDCG@10 compared with the baseline models. Our code is available at https://github.com/HubuKG/MAIL.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper proposes MAIL, a method for ID-free multimodal recommendation that addresses two limitations in prior work: static reconstructed ID representations that underuse multimodal semantics, and graph learning that fails to mine latent long-tail relations while suffering from popularity bias. The core contributions are a modality-aware identity construction module that dynamically modulates positional encodings with multimodal semantics to produce content-aware ID-free item representations, and a counterfactual structure learning paradigm that mines low-exposure semantic neighbors via popularity penalization. Experiments on five Amazon datasets report average gains of 7.81% Recall@10 and 12.81% NDCG@10 over baselines, supported by ablation studies isolating each module; code is released at https://github.com/HubuKG/MAIL.
Significance. If the empirical results hold, the work is significant for multimodal recommendation systems by enabling dynamic, semantics-driven identity representations without relying on static ID embeddings and by mitigating popularity bias through counterfactual neighbor mining. Strengths include the internal consistency of the two modules with the stated design choices, ablation tables that isolate component contributions, and public code release supporting reproducibility on standard public datasets.
major comments (1)
- [§4] §4 (Experiments): The reported average improvements of 7.81% Recall@10 and 12.81% NDCG@10 are load-bearing for the central claim of superiority; the manuscript should explicitly state the exact baseline models, data split protocol, hyperparameter search ranges, and whether statistical significance testing (e.g., paired t-test) was performed, as these details are required to attribute gains to the proposed modules rather than implementation differences.
minor comments (3)
- [Abstract] Abstract and §3.1: The description of 'dynamically modulates positional encodings' would benefit from a brief forward reference to the exact equation defining the modulation function to improve readability for readers unfamiliar with the technique.
- [§3] Notation: The modulation strength and popularity penalty coefficients are free parameters; ensure they are consistently denoted (e.g., α and β) in both the text and all equations in §3.2 and §3.3.
- [Tables] Table captions: Ablation tables should include a row or column explicitly showing performance on long-tail items to directly support the claim that popularity penalization mines useful latent relations.
Simulated Author's Rebuttal
We thank the referee for the constructive feedback and the recommendation for minor revision. We address the single major comment on experimental reporting below and will update the manuscript to improve clarity and reproducibility.
read point-by-point responses
-
Referee: [§4] §4 (Experiments): The reported average improvements of 7.81% Recall@10 and 12.81% NDCG@10 are load-bearing for the central claim of superiority; the manuscript should explicitly state the exact baseline models, data split protocol, hyperparameter search ranges, and whether statistical significance testing (e.g., paired t-test) was performed, as these details are required to attribute gains to the proposed modules rather than implementation differences.
Authors: We agree that explicit enumeration of these elements strengthens the ability to attribute gains to the proposed modules. The baseline models and data split protocol are already described in Section 4 of the manuscript, and hyperparameter tuning is noted in the experimental setup. To directly address the comment, we will revise Section 4 to include a consolidated summary (e.g., a table or dedicated paragraph) that explicitly lists all baseline models with references, states the precise data split protocol used across the five Amazon datasets, details the hyperparameter search ranges and selection procedure, and reports the outcomes of statistical significance testing via paired t-tests. These additions will be placed in the revised version without altering any experimental results. revision: yes
Circularity Check
No significant circularity in derivation chain
full rationale
The paper proposes an architectural method (MAIL) with two modules—modality-aware identity construction that modulates positional encodings using multimodal semantics, and counterfactual structure learning that applies popularity penalization to mine semantic neighbors. These are presented as design choices motivated by limitations in existing ID-free multimodal recommenders, implemented via neural components, and evaluated empirically on five Amazon datasets with baseline comparisons and ablation studies. No mathematical derivation, prediction, or first-principles result is claimed that reduces by the paper's own equations to fitted inputs, self-definitions, or self-citation chains. The central claims rest on experimental performance metrics rather than tautological constructions, rendering the approach self-contained against external benchmarks.
Axiom & Free-Parameter Ledger
free parameters (1)
- modulation strength and popularity penalty coefficients
axioms (1)
- domain assumption Multimodal semantics can be effectively used to modulate positional encodings for identity construction
invented entities (1)
-
modality-aware ID-free identity representations
no independent evidence
Lean theorems connected to this paper
-
IndisputableMonolith/Foundation/RealityFromDistinctionreality_from_one_distinction unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
no mention of recognition cost, golden ratio, or distinction-based emergence
What do these tags mean?
- matches
- The paper's claim is directly supported by a theorem in the formal canon.
- supports
- The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
- extends
- The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
- uses
- The paper appears to rely on the theorem as machinery.
- contradicts
- The paper's claim conflicts with a theorem or certificate in the canon.
- unclear
- Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.
Reference graph
Works this paper leans on
-
[1]
Vbpr: visual bayesian personalized ranking from implicit feedback,
R. He and J. McAuley, “Vbpr: visual bayesian personalized ranking from implicit feedback,” inProceedings of the AAAI conference on artificial intelligence, vol. 30, no. 1, 2016
work page 2016
-
[3]
H. Zhou, X. Zhou, Z. Zeng, L. Zhang, and Z. Shen, “A comprehensive survey on multimodal recommender systems: Taxonomy, evaluation, and future directions,”arXiv preprint arXiv:2302.04473, 2023
-
[4]
C. Park, D. Kim, J. Oh, and H. Yu, “Do” also-viewed” products help user rating prediction?” inProceedings of the 26th international conference on world wide web, 2017, pp. 1113–1122
work page 2017
-
[5]
J. Chen, H. Zhang, X. He, L. Nie, W. Liu, and T.-S. Chua, “Atten- tive collaborative filtering: Multimedia recommendation with item-and component-level attention,” inProceedings of the 40th International ACM SIGIR conference on Research and Development in Information Retrieval, 2017, pp. 335–344
work page 2017
-
[6]
Graphcar: Content-aware multimedia recommendation with graph autoencoder,
Q. Xu, F. Shen, L. Liu, and H. T. Shen, “Graphcar: Content-aware multimedia recommendation with graph autoencoder,” inThe 41st International ACM SIGIR conference on research & development in information retrieval, 2018, pp. 981–984
work page 2018
-
[7]
Mmgcn: Multi-modal graph convolution network for personalized recommenda- tion of micro-video,
Y . Wei, X. Wang, L. Nie, X. He, R. Hong, and T.-S. Chua, “Mmgcn: Multi-modal graph convolution network for personalized recommenda- tion of micro-video,” inProceedings of the 27th ACM international conference on multimedia, 2019, pp. 1437–1445
work page 2019
-
[8]
Sign-aware multimodal graph recommendation,
Y . Lian, H. Tian, C. Song, and T. Ge, “Sign-aware multimodal graph recommendation,” inProceedings of the AAAI Conference on Artificial Intelligence, vol. 40, no. 18, 2026, pp. 15 225–15 233
work page 2026
-
[9]
J. Xu, Z. Chen, S. Yang, J. Li, Z. Wan, H. Wang, W. Liu, Y . Li, and E. C. Ngai, “Vi-mmrec: Similarity-aware training cost-free virtual user- item interactions for multimodal recommendation,” inProceedings of the 32nd ACM SIGKDD Conference on Knowledge Discovery and Data Mining V . 1, 2026, pp. 1683–1692
work page 2026
-
[11]
A survey on multimodal recommender systems: Recent advances and future directions,
J. Xu, Z. Chen, S. Yang, J. Li, W. Wang, X. Hu, S. Hoi, and E. Ngai, “A survey on multimodal recommender systems: Recent advances and future directions,”IEEE Transactions on Multimedia, 2026
work page 2026
-
[12]
W. Yang, R. Zhong, Y . Chen, S. Li, H. Ping, C. Lu, and P. Jiang, “Fitmm: Adaptive frequency-aware multimodal recommendation via information- theoretic representation learning,” inProceedings of the 33rd ACM International Conference on Multimedia, 2025, pp. 6193–6202
work page 2025
-
[13]
Adversarial training towards robust multimedia recommender system,
J. Tang, X. Du, X. He, F. Yuan, Q. Tian, and T.-S. Chua, “Adversarial training towards robust multimedia recommender system,”IEEE Trans- actions on Knowledge and Data Engineering, vol. 32, no. 5, pp. 855– 867, 2019
work page 2019
-
[14]
Dualgnn: Dual graph neural network for multimedia recommendation,
Q. Wang, Y . Wei, J. Yin, J. Wu, X. Song, and L. Nie, “Dualgnn: Dual graph neural network for multimedia recommendation,”IEEE Transactions on Multimedia, vol. 25, pp. 1074–1084, 2021
work page 2021
-
[15]
Mining latent structures for multimedia recommendation,
J. Zhang, Y . Zhu, Q. Liu, S. Wu, S. Wang, and L. Wang, “Mining latent structures for multimedia recommendation,” inProceedings of the 29th ACM international conference on multimedia, 2021, pp. 3872–3880
work page 2021
-
[16]
G. Li, L. Jing, J. Wu, X. Li, K. Zhu, and Y . He, “From id-based to id-free: Rethinking id effectiveness in multimodal collaborative filtering recommendation,”arXiv preprint arXiv:2507.05715, 2025
-
[17]
Learning item representa- tions directly from multimodal features for effective recommendation,
X. Zhou, X. Zhang, D. Niyato, and Z. Shen, “Learning item representa- tions directly from multimodal features for effective recommendation,” arXiv preprint arXiv:2505.04960, 2025
-
[18]
Towards representation alignment and uniformity in collaborative filtering,
C. Wang, Y . Yu, W. Ma, M. Zhang, C. Chen, Y . Liu, and S. Ma, “Towards representation alignment and uniformity in collaborative filtering,” in Proceedings of the 28th ACM SIGKDD conference on knowledge discovery and data mining, 2022, pp. 1816–1825
work page 2022
-
[19]
Mentor: multi-level self-supervised learning for multimodal recommendation,
J. Xu, Z. Chen, S. Yang, J. Li, H. Wang, and E. C. Ngai, “Mentor: multi-level self-supervised learning for multimodal recommendation,” in Proceedings of the AAAI Conference on Artificial Intelligence, vol. 39, no. 12, 2025, pp. 12 908–12 917
work page 2025
-
[20]
Tamer: Interest tree augmented modality graph recommender for multimodal recom- mendation,
F. Meng, Z. Meng, R. Jin, Y . Chen, R. Lin, and B. Wu, “Tamer: Interest tree augmented modality graph recommender for multimodal recom- mendation,” inProceedings of the 33rd ACM International Conference on Multimedia, 2025, pp. 5998–6006
work page 2025
-
[21]
Bootstrap latent representations for multi-modal recommen- dation,
X. Zhou, H. Zhou, Y . Liu, Z. Zeng, C. Miao, P. Wang, Y . You, and F. Jiang, “Bootstrap latent representations for multi-modal recommen- dation,” inProceedings of the ACM web conference 2023, 2023, pp. 845–854
work page 2023
-
[22]
Multi-modal self-supervised learning for recommendation,
W. Wei, C. Huang, L. Xia, and C. Zhang, “Multi-modal self-supervised learning for recommendation,” inProceedings of the ACM web confer- ence 2023, 2023, pp. 790–800. IEEE TRANSACTIONS ON MULTIMEDIA 11
work page 2023
-
[24]
Causal intervention for leveraging popularity bias in recommendation,
Y . Zhang, F. Feng, X. He, T. Wei, C. Song, G. Ling, and Y . Zhang, “Causal intervention for leveraging popularity bias in recommendation,” inProceedings of the 44th international ACM SIGIR conference on research and development in information retrieval, 2021, pp. 11–20
work page 2021
-
[25]
Neutralizing popularity bias in recommendation models,
G. Xv, C. Lin, H. Li, J. Su, W. Ye, and Y . Chen, “Neutralizing popularity bias in recommendation models,” inProceedings of the 45th international ACM SIGIR conference on research and development in information retrieval, 2022, pp. 2623–2628
work page 2022
-
[26]
Let two graphs talk: Self-supervised dual-graph reconstruction for multimodal recommendation,
H. Ma, Y . Zhang, Y . Zhou, B. Yang, D. Yu, and Z. Li, “Let two graphs talk: Self-supervised dual-graph reconstruction for multimodal recommendation,”Information Fusion, p. 104299, 2026
work page 2026
-
[27]
R. K. Ong and A. W. Khong, “Spectrum-based modality representation fusion graph convolutional network for multimodal recommendation,” inProceedings of the eighteenth ACM international conference on web search and data mining, 2025, pp. 773–781
work page 2025
-
[28]
Bpr: Bayesian personalized ranking from implicit feedback,
S. Rendle, C. Freudenthaler, Z. Gantner, and L. Schmidt-Thieme, “Bpr: Bayesian personalized ranking from implicit feedback,” inProceedings of the Twenty-Fifth Conference on Uncertainty in Artificial Intelligence, 2009, pp. 452–461
work page 2009
-
[29]
Lightgcn: Simplifying and powering graph convolution network for recommenda- tion,
X. He, K. Deng, X. Wang, Y . Li, Y . Zhang, and M. Wang, “Lightgcn: Simplifying and powering graph convolution network for recommenda- tion,” inProceedings of the 43rd International ACM SIGIR conference on research and development in Information Retrieval, 2020, pp. 639– 648
work page 2020
-
[30]
Lgmrec: Local and global graph learning for multimodal recommendation,
Z. Guo, J. Li, G. Li, C. Wang, S. Shi, and B. Ruan, “Lgmrec: Local and global graph learning for multimodal recommendation,” inProceedings of the AAAI conference on artificial intelligence, vol. 38, no. 8, 2024, pp. 8454–8462
work page 2024
-
[31]
Adaptive multi-modalities fusion in sequential recommendation systems,
H. Hu, W. Guo, Y . Liu, and M.-Y . Kan, “Adaptive multi-modalities fusion in sequential recommendation systems,” inProceedings of the 32nd ACM international conference on information and knowledge management, 2023, pp. 843–853
work page 2023
-
[32]
Generative next poi recommendation with semantic id,
D. Wang, Y . Huang, S. Gao, Y . Wang, C. Huang, and S. Shang, “Generative next poi recommendation with semantic id,” inProceedings of the 31st ACM SIGKDD Conference on Knowledge Discovery and Data Mining V . 2, 2025, pp. 2904–2914
work page 2025
-
[33]
Semantic ids for joint generative search and recommendation,
G. Penha, E. D’Amico, M. De Nadai, E. Palumbo, A. Tamborrino, A. Vardasbi, M. Lefarov, S. Lin, T. Heath, F. Fabbriet al., “Semantic ids for joint generative search and recommendation,” inProceedings of the Nineteenth ACM Conference on Recommender Systems, 2025, pp. 1296–1301
work page 2025
-
[34]
Ninerec: A benchmark dataset suite for evaluating transferable recommendation,
J. Zhang, Y . Cheng, Y . Ni, Y . Pan, Z. Yuan, J. Fu, Y . Li, J. Wang, and F. Yuan, “Ninerec: A benchmark dataset suite for evaluating transferable recommendation,”IEEE Transactions on Pattern Analysis and Machine Intelligence, 2024
work page 2024
-
[35]
Model-agnostic counterfactual reasoning for eliminating popularity bias in recommender system,
T. Wei, F. Feng, J. Chen, Z. Wu, J. Yi, and X. He, “Model-agnostic counterfactual reasoning for eliminating popularity bias in recommender system,” inProceedings of the 27th ACM SIGKDD conference on knowledge discovery & data mining, 2021, pp. 1791–1800
work page 2021
-
[36]
Debiasing recommendation with personal popularity,
W. Ning, R. Cheng, X. Yan, B. Kao, N. Huo, N. A. H. Haldar, and B. Tang, “Debiasing recommendation with personal popularity,” in Proceedings of the ACM web conference 2024, 2024, pp. 3400–3409
work page 2024
-
[37]
Coder: Counterfactual demand reasoning for sequential recommendation,
S. Tang, S. Lin, J. Ma, and X. Zhang, “Coder: Counterfactual demand reasoning for sequential recommendation,” inProceedings of the AAAI Conference on Artificial Intelligence, vol. 39, no. 12, 2025, pp. 12 649– 12 657
work page 2025
-
[38]
Social recommendation via graph-level counterfactual augmentation,
Y . Huang, K. Liang, Y . Huang, X. Zeng, K. Chen, and B. Zhou, “Social recommendation via graph-level counterfactual augmentation,” inProceedings of the AAAI Conference on Artificial Intelligence, vol. 39, no. 1, 2025, pp. 334–342
work page 2025
-
[39]
Image-based recommendations on styles and substitutes,
J. McAuley, C. Targett, Q. Shi, and A. Van Den Hengel, “Image-based recommendations on styles and substitutes,” inProceedings of the 38th international ACM SIGIR conference on research and development in information retrieval, 2015, pp. 43–52
work page 2015
-
[40]
Dimcl: Dimension-aware augmentation in contrastive learning for recommen- dation,
C. Zhang, Q. Han, Q. Tan, S. Wang, X. Zhao, and R. Chen, “Dimcl: Dimension-aware augmentation in contrastive learning for recommen- dation,” inProceedings of the 31st ACM SIGKDD Conference on Knowledge Discovery and Data Mining V . 1, 2025, pp. 1913–1923
work page 2025
-
[41]
Mind individual information! principal graph learning for multimedia recommendation,
P. Yu, Z. Tan, G. Lu, and B.-K. Bao, “Mind individual information! principal graph learning for multimedia recommendation,” inProceed- ings of the AAAI conference on artificial intelligence, vol. 39, no. 12, 2025, pp. 13 096–13 105
work page 2025
-
[42]
J. Xu, Z. Chen, W. Wang, X. Hu, S.-W. Kim, and E. C. Ngai, “Cohesion: Composite graph convolutional network with dual-stage fusion for multimodal recommendation,” inProceedings of the 48th International ACM SIGIR Conference on Research and Development in Information Retrieval, 2025, pp. 1830–1839
work page 2025
-
[43]
Structured spectral reasoning for frequency-adaptive multimodal recommendation,
W. Yang, R. Zhong, Y . Chen, C. Lu, and P. Jiang, “Structured spectral reasoning for frequency-adaptive multimodal recommendation,”Ad- vances in Neural Information Processing Systems, vol. 38, pp. 28 122– 28 143, 2026
work page 2026
-
[44]
Structurally refined graph transformer for multimodal recom- mendation,
K. Shi, Y . Zhang, M. Zhang, L. Chen, J. Yi, K. Xiao, X. Hou, and Z. Li, “Structurally refined graph transformer for multimodal recom- mendation,”IEEE Transactions on Multimedia, 2026
work page 2026
-
[45]
Self-harmonized repre- sentation learning for multimodal recommendation,
J. Guo, L. Wen, Y . Zhao, B. Song, and Y . Chi, “Self-harmonized repre- sentation learning for multimodal recommendation,”IEEE Transactions on Multimedia, 2025
work page 2025
-
[46]
Understanding the difficulty of training deep feedforward neural networks,
X. Glorot and Y . Bengio, “Understanding the difficulty of training deep feedforward neural networks,” inProceedings of the thirteenth international conference on artificial intelligence and statistics. JMLR Workshop and Conference Proceedings, 2010, pp. 249–256
work page 2010
-
[47]
Adam: A Method for Stochastic Optimization
D. P. Kingma and J. Ba, “Adam: A method for stochastic optimization,” arXiv preprint arXiv:1412.6980, 2014
work page internal anchor Pith review Pith/arXiv arXiv 2014
-
[48]
L. Van der Maaten and G. Hinton, “Visualizing data using t-sne.”Journal of machine learning research, vol. 9, no. 11, 2008. Hongjian Mais currently pursuing the B.E. degree in Computer Science and Technology at Hubei Uni- versity, Wuhan, China. His main research direction is recommendation systems. Wenxin Huang(Member, IEEE) received the B.S. degree in in...
work page 2008
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.