Large Language Models Align with the Human Brain during Creative Thinking

Fuente: arXiv
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Autores principales: Ismayilzada, Mete, Luchini, Simone A., Gokce, Abdulkadir, AlKhamissi, Badr, Bosselut, Antoine, Laverghetta Jr., Antonio, van der Plas, Lonneke, Beaty, Roger E.
Formato: Preprint
Publicado: 2026
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author Ismayilzada, Mete
Luchini, Simone A.
Gokce, Abdulkadir
AlKhamissi, Badr
Bosselut, Antoine
Laverghetta Jr., Antonio
van der Plas, Lonneke
Beaty, Roger E.
author_facet Ismayilzada, Mete
Luchini, Simone A.
Gokce, Abdulkadir
AlKhamissi, Badr
Bosselut, Antoine
Laverghetta Jr., Antonio
van der Plas, Lonneke
Beaty, Roger E.
contents Creative thinking is a fundamental aspect of human cognition, and divergent thinking-the capacity to generate novel and varied ideas-is widely regarded as its core generative engine. Large language models (LLMs) have recently demonstrated impressive performance on divergent thinking tests and prior work has shown that models with higher task performance tend to be more aligned to human brain activity. However, existing brain-LLM alignment studies have focused on passive, non-creative tasks. Here, we explore brain alignment during creative thinking using fMRI data from 170 participants performing the Alternate Uses Task (AUT). We extract representations from LLMs varying in size (270M-72B) and measure alignment to brain responses via Representational Similarity Analysis (RSA), targeting the creativity-related default mode and frontoparietal networks. We find that brain-LLM alignment scales with model size (default mode network only) and idea originality (both networks), with effects strongest early in the creative process. We further show that post-training objectives shape alignment in functionally selective ways: a creativity-optimized \texttt{Llama-3.1-8B-Instruct} preserves alignment with high-creativity neural responses while reducing alignment with low-creativity ones; a human behavior fine-tuned model elevates alignment with both; and a reasoning-trained variant shows the opposite pattern, suggesting chain-of-thought training steers representations away from creative neural geometry toward analytical processing. These results demonstrate that post-training objectives selectively reshape LLM representations relative to the neural geometry of human creative thought.
format Preprint
id arxiv_https___arxiv_org_abs_2604_03480
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Large Language Models Align with the Human Brain during Creative Thinking
Ismayilzada, Mete
Luchini, Simone A.
Gokce, Abdulkadir
AlKhamissi, Badr
Bosselut, Antoine
Laverghetta Jr., Antonio
van der Plas, Lonneke
Beaty, Roger E.
Neurons and Cognition
Artificial Intelligence
Computation and Language
Creative thinking is a fundamental aspect of human cognition, and divergent thinking-the capacity to generate novel and varied ideas-is widely regarded as its core generative engine. Large language models (LLMs) have recently demonstrated impressive performance on divergent thinking tests and prior work has shown that models with higher task performance tend to be more aligned to human brain activity. However, existing brain-LLM alignment studies have focused on passive, non-creative tasks. Here, we explore brain alignment during creative thinking using fMRI data from 170 participants performing the Alternate Uses Task (AUT). We extract representations from LLMs varying in size (270M-72B) and measure alignment to brain responses via Representational Similarity Analysis (RSA), targeting the creativity-related default mode and frontoparietal networks. We find that brain-LLM alignment scales with model size (default mode network only) and idea originality (both networks), with effects strongest early in the creative process. We further show that post-training objectives shape alignment in functionally selective ways: a creativity-optimized \texttt{Llama-3.1-8B-Instruct} preserves alignment with high-creativity neural responses while reducing alignment with low-creativity ones; a human behavior fine-tuned model elevates alignment with both; and a reasoning-trained variant shows the opposite pattern, suggesting chain-of-thought training steers representations away from creative neural geometry toward analytical processing. These results demonstrate that post-training objectives selectively reshape LLM representations relative to the neural geometry of human creative thought.
title Large Language Models Align with the Human Brain during Creative Thinking
topic Neurons and Cognition
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2604.03480