From Language to Cognition: How LLMs Outgrow the Human Language Network

Fuente: arXiv
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Main Authors: AlKhamissi, Badr, Tuckute, Greta, Tang, Yingtian, Binhuraib, Taha, Bosselut, Antoine, Schrimpf, Martin
Format: Preprint
Published: 2025
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author AlKhamissi, Badr
Tuckute, Greta
Tang, Yingtian
Binhuraib, Taha
Bosselut, Antoine
Schrimpf, Martin
author_facet AlKhamissi, Badr
Tuckute, Greta
Tang, Yingtian
Binhuraib, Taha
Bosselut, Antoine
Schrimpf, Martin
contents Large language models (LLMs) exhibit remarkable similarity to neural activity in the human language network. However, the key properties of language shaping brain-like representations, and their evolution during training as a function of different tasks remain unclear. We here benchmark 34 training checkpoints spanning 300B tokens across 8 different model sizes to analyze how brain alignment relates to linguistic competence. Specifically, we find that brain alignment tracks the development of formal linguistic competence -- i.e., knowledge of linguistic rules -- more closely than functional linguistic competence. While functional competence, which involves world knowledge and reasoning, continues to develop throughout training, its relationship with brain alignment is weaker, suggesting that the human language network primarily encodes formal linguistic structure rather than broader cognitive functions. We further show that model size is not a reliable predictor of brain alignment when controlling for feature size and find that the correlation between next-word prediction, behavioral alignment and brain alignment fades once models surpass human language proficiency. Finally, using the largest set of rigorous neural language benchmarks to date, we show that language brain alignment benchmarks remain unsaturated, highlighting opportunities for improving future models. Taken together, our findings suggest that the human language network is best modeled by formal, rather than functional, aspects of language.
format Preprint
id arxiv_https___arxiv_org_abs_2503_01830
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle From Language to Cognition: How LLMs Outgrow the Human Language Network
AlKhamissi, Badr
Tuckute, Greta
Tang, Yingtian
Binhuraib, Taha
Bosselut, Antoine
Schrimpf, Martin
Computation and Language
Large language models (LLMs) exhibit remarkable similarity to neural activity in the human language network. However, the key properties of language shaping brain-like representations, and their evolution during training as a function of different tasks remain unclear. We here benchmark 34 training checkpoints spanning 300B tokens across 8 different model sizes to analyze how brain alignment relates to linguistic competence. Specifically, we find that brain alignment tracks the development of formal linguistic competence -- i.e., knowledge of linguistic rules -- more closely than functional linguistic competence. While functional competence, which involves world knowledge and reasoning, continues to develop throughout training, its relationship with brain alignment is weaker, suggesting that the human language network primarily encodes formal linguistic structure rather than broader cognitive functions. We further show that model size is not a reliable predictor of brain alignment when controlling for feature size and find that the correlation between next-word prediction, behavioral alignment and brain alignment fades once models surpass human language proficiency. Finally, using the largest set of rigorous neural language benchmarks to date, we show that language brain alignment benchmarks remain unsaturated, highlighting opportunities for improving future models. Taken together, our findings suggest that the human language network is best modeled by formal, rather than functional, aspects of language.
title From Language to Cognition: How LLMs Outgrow the Human Language Network
topic Computation and Language
url https://arxiv.org/abs/2503.01830