Derivational Probing: Unveiling the Layer-wise Derivation of Syntactic Structures in Neural Language Models

Fuente: arXiv
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Autores principales: Someya, Taiga, Yoshida, Ryo, Yanaka, Hitomi, Oseki, Yohei
Formato: Preprint
Publicado: 2025
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author Someya, Taiga
Yoshida, Ryo
Yanaka, Hitomi
Oseki, Yohei
author_facet Someya, Taiga
Yoshida, Ryo
Yanaka, Hitomi
Oseki, Yohei
contents Recent work has demonstrated that neural language models encode syntactic structures in their internal representations, yet the derivations by which these structures are constructed across layers remain poorly understood. In this paper, we propose Derivational Probing to investigate how micro-syntactic structures (e.g., subject noun phrases) and macro-syntactic structures (e.g., the relationship between the root verbs and their direct dependents) are constructed as word embeddings propagate upward across layers. Our experiments on BERT reveal a clear bottom-up derivation: micro-syntactic structures emerge in lower layers and are gradually integrated into a coherent macro-syntactic structure in higher layers. Furthermore, a targeted evaluation on subject-verb number agreement shows that the timing of constructing macro-syntactic structures is critical for downstream performance, suggesting an optimal timing for integrating global syntactic information.
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institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Derivational Probing: Unveiling the Layer-wise Derivation of Syntactic Structures in Neural Language Models
Someya, Taiga
Yoshida, Ryo
Yanaka, Hitomi
Oseki, Yohei
Computation and Language
Recent work has demonstrated that neural language models encode syntactic structures in their internal representations, yet the derivations by which these structures are constructed across layers remain poorly understood. In this paper, we propose Derivational Probing to investigate how micro-syntactic structures (e.g., subject noun phrases) and macro-syntactic structures (e.g., the relationship between the root verbs and their direct dependents) are constructed as word embeddings propagate upward across layers. Our experiments on BERT reveal a clear bottom-up derivation: micro-syntactic structures emerge in lower layers and are gradually integrated into a coherent macro-syntactic structure in higher layers. Furthermore, a targeted evaluation on subject-verb number agreement shows that the timing of constructing macro-syntactic structures is critical for downstream performance, suggesting an optimal timing for integrating global syntactic information.
title Derivational Probing: Unveiling the Layer-wise Derivation of Syntactic Structures in Neural Language Models
topic Computation and Language
url https://arxiv.org/abs/2506.21861