LLMs Learn Better In-Context from Rules than from Examples

Xiang Fu, Seungmin Cho, Yukyung Lee, Najoung Kim


Abstract
Large language models (LLMs) exhibit in-context learning capabilities, where they can learn new tasks from prompt contexts without weight updates. We compare the learning efficacies of two prominent modes of in-context learning: (1) learning from descriptions of rules (instruction following); and (2) learning from examples of input-output demonstrations (few-shot prompting). Through five learning tasks that cover diverse domains (games, arithmetic, linguistic inferences), we compare two modes of learning (rules vs. examples) specifying the same underlying task. We furthermore explore model and task properties that modulate the learning efficacies. We find that models generally learn more reliably from rules than from examples alone, and additional examples on top of rules or simply scaling up the number of examples do not lead to consistent and significant gains. Instruction tuning amplifies the benefit of rule-based learning while keeping example-based learning capacities intact. Surprisingly, we find no privileged effect of example-based learning in base models, and rules still lead to gains in algebraic task domains. Overall, the comparative efficacy of rules over examples is larger when the task recruits algebraic abstractions and computations, and smaller when the task requires distributional sensitivity and/or recruits parametric knowledge.
Anthology ID:
2026.emnlp-main.1722
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
39279–39313
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1722/
DOI:
Bibkey:
Cite (ACL):
Xiang Fu, Seungmin Cho, Yukyung Lee, and Najoung Kim. 2026. LLMs Learn Better In-Context from Rules than from Examples. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 39279–39313, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
LLMs Learn Better In-Context from Rules than from Examples (Fu et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1722.pdf