On the Emergence and Test-Time Use of Structural Information in Large Language Models

Michelle Chao Chen, Moritz Miller, Bernhard Sch\"olkopf, Siyuan Guo


Abstract
Learning structural information from observational data is central to producing new knowledge outside the training corpus. This holds for mechanistic understanding in scientific discovery as well as flexible test-time compositional generation. We thus study how language models learn abstract structures and utilize the learnt structural information at test-time. To ensure a controlled setup, we design a natural language dataset based on linguistic structural transformations. We empirically show that the emergence of learning structural information correlates with complex reasoning tasks, and that the ability to perform test-time compositional generation remains limited.
Anthology ID:
2026.acl-long.65
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
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1449–1465
Language:
URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-long.65/
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Cite (ACL):
Michelle Chao Chen, Moritz Miller, Bernhard Sch\"olkopf, and Siyuan Guo. 2026. On the Emergence and Test-Time Use of Structural Information in Large Language Models. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 1449–1465, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
On the Emergence and Test-Time Use of Structural Information in Large Language Models (Chen et al., ACL 2026)
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https://preview.aclanthology.org/ingest-acl/2026.acl-long.65.pdf
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