Understanding LLMs’ Fluid Intelligence Deficiency: An Analysis of the ARC Task

Junjie Wu, Mo Yu, Lemao Liu, Dit-Yan Yeung, Jie Zhou


Abstract
While LLMs have exhibited strong performance on various NLP tasks, it is noteworthy that most of these tasks rely on utilizing the vast amount of knowledge encoded in LLMs’ parameters, rather than solving new problems without prior knowledge. In cognitive research, the latter ability is referred to as fluid intelligence, which is considered to be critical for assessing human intelligence. Recent research on fluid intelligence assessments has highlighted significant deficiencies in LLMs’ abilities. In this paper, we analyze the challenges LLMs face in demonstrating fluid intelligence through controlled experiments, using the most representative ARC task as an example. Our study revealed three major limitations in existing LLMs: limited ability for skill composition, unfamiliarity with abstract input formats, and the intrinsic deficiency of left-to-right decoding. Our data and code will be publicly released, and the data is also attached in the submission.
Anthology ID:
2025.naacl-long.423
Volume:
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Month:
April
Year:
2025
Address:
Albuquerque, New Mexico
Editors:
Luis Chiruzzo, Alan Ritter, Lu Wang
Venue:
NAACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
8339–8360
Language:
URL:
https://preview.aclanthology.org/fix-sig-urls/2025.naacl-long.423/
DOI:
Bibkey:
Cite (ACL):
Junjie Wu, Mo Yu, Lemao Liu, Dit-Yan Yeung, and Jie Zhou. 2025. Understanding LLMs’ Fluid Intelligence Deficiency: An Analysis of the ARC Task. In Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers), pages 8339–8360, Albuquerque, New Mexico. Association for Computational Linguistics.
Cite (Informal):
Understanding LLMs’ Fluid Intelligence Deficiency: An Analysis of the ARC Task (Wu et al., NAACL 2025)
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PDF:
https://preview.aclanthology.org/fix-sig-urls/2025.naacl-long.423.pdf