InductionBench: LLMs Fail in the Simplest Complexity Class

Wenyue Hua, Tyler Wong, Fei Sun, Liangming Pan, Adam Jardine, William Yang Wang


Abstract
Large language models (LLMs) have shown remarkable improvements in reasoning and many existing benchmarks have been addressed by models such as o1 and o3 either fully or partially. However, a majority of these benchmarks emphasize deductive reasoning, including mathematical and coding tasks in which rules such as mathematical axioms or programming syntax are clearly defined, based on which LLMs can plan and apply these rules to arrive at a solution. In contrast, inductive reasoning, where one infers the underlying rules from observed data, remains less explored. Such inductive processes lie at the heart of scientific discovery, as they enable researchers to extract general principles from empirical observations. To assess whether LLMs possess this capacity, we introduce InductionBench, a new benchmark designed to evaluate the inductive reasoning ability of LLMs. Our experimental findings reveal that even the most advanced modelw available struggle to master the simplest complexity classes within the subregular hierarchy of functions, highlighting a notable deficiency in current LLMs’ inductive reasoning capabilities. Coda and data are available https://anonymous.4open.science/r/inductive_reasoning_benchmark-BB2D.
Anthology ID:
2025.acl-long.1287
Volume:
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Wanxiang Che, Joyce Nabende, Ekaterina Shutova, Mohammad Taher Pilehvar
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
26526–26546
Language:
URL:
https://preview.aclanthology.org/ingestion-acl-25/2025.acl-long.1287/
DOI:
Bibkey:
Cite (ACL):
Wenyue Hua, Tyler Wong, Fei Sun, Liangming Pan, Adam Jardine, and William Yang Wang. 2025. InductionBench: LLMs Fail in the Simplest Complexity Class. In Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 26526–26546, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
InductionBench: LLMs Fail in the Simplest Complexity Class (Hua et al., ACL 2025)
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PDF:
https://preview.aclanthology.org/ingestion-acl-25/2025.acl-long.1287.pdf