From Past To Path: Masked History Learning for Next-Item Prediction in Generative Recommendation

Kaiwen Wei, Kejun he, Xiaomian Kang, Jie Zhang, Ymyang, Li Jin, Zhenyang Li, Jiang Zhong, Richard He Bai, Junnan Zhu


Abstract
Generative recommendation, which directly generates item identifiers, has emerged as a promising paradigm for recommendation systems. However, this left-to-right paradigm inherently biases the model towards local contexts, failing to capture deeper historical dependencies necessary for understanding complex user intents.To address this limitation, we propose Masked History Learning (MHL), a novel training framework that shifts the objective from simple next-step prediction to deep comprehension of history. MHL augments the standard autoregressive objective with an auxiliary task of reconstructing masked historical items, compelling the model to understand "why” an item path is formed from the user’s past behaviors, rather than just "what” item comes next.We introduce two key contributions to enhance this framework: (1) an entropy-guided masking policy that intelligently targets the most informative historical items for reconstruction, and (2) a curriculum learning scheduler that progressively transitions from history reconstruction to future prediction.Experiments on three public datasets show that our method significantly outperforms state-of-the-art generative models, highlighting that a comprehensive understanding of the past is crucial for accurately predicting a user’s future path. The code is available at https://github.com/CQU-MM-Intelligent-Lab/MHL.
Anthology ID:
2026.acl-long.475
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
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ACL
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Publisher:
Association for Computational Linguistics
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Pages:
10421–10441
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https://preview.aclanthology.org/ingest-acl/2026.acl-long.475/
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Cite (ACL):
Kaiwen Wei, Kejun he, Xiaomian Kang, Jie Zhang, Ymyang, Li Jin, Zhenyang Li, Jiang Zhong, Richard He Bai, and Junnan Zhu. 2026. From Past To Path: Masked History Learning for Next-Item Prediction in Generative Recommendation. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 10421–10441, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
From Past To Path: Masked History Learning for Next-Item Prediction in Generative Recommendation (Wei et al., ACL 2026)
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https://preview.aclanthology.org/ingest-acl/2026.acl-long.475.pdf
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