Thinking effort aligns between humans and reasoning models in abductive reasoning

Henry Arthur


Abstract
A major question in cognitive modeling concerns the behavioral alignment between large language models and humans across linguistic and non-linguistic tasks. Unlike standard LLMs, large reasoning models (LRMs) are optimized with reinforcement learning from verifiable rewards, encouraging correct solutions to reasoning tasks rather than preference-aligned responses. Recent work (de Varda et al., 2025) investigates the cost of thinking in humans and LRMs by comparing human reaction times with model reasoning traces across a range of reasoning tasks. We isolate this alignment by turning to abductive reasoning: unlike deductive tasks, its difficulty cannot be inferred from formal structure and offers no shortcuts a model could exploit to mimic effort without genuine search, providing firmer ground for empirical claims of shared effort. We find further evidence of alignment between LRM and human reasoning effort, as well as evidence that models and humans tend to make similar errors. Finally, we show that decoding methods that let models explore multiple reasoning paths increase alignment in reasoning cost between humans and LRMs across the three models tested.
Anthology ID:
2026.findings-emnlp.531
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
11136–11149
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.531/
DOI:
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Cite (ACL):
Henry Arthur. 2026. Thinking effort aligns between humans and reasoning models in abductive reasoning. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 11136–11149, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Thinking effort aligns between humans and reasoning models in abductive reasoning (Arthur, Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.531.pdf