ActTraitBench: Quantifying the Knowledge-Decision Gap in Large Language Models via Human-Grounded Behavioral Validation

Yutong Yang, Chenxi Miao, Weikang Li, Yunfang Wu


Abstract
While Large Language Models (LLMs) can convincingly simulate personas in explicit self-reports, they often deviate in implicit behavioral decisions, revealing a substantial Knowledge–Decision Gap (GKD). Existing benchmarks struggle to measure this discrepancy due to limited construct validity, multidimensional entanglement, and distributional biases in LLM-based evaluation. To address these issues, we propose ActTraitBench, a human-grounded evaluation framework for measuring personality consistency in LLMs. Grounded in empirical human data, ActTraitBench establishes one-to-one mappings between psychometric facets and behavioral paradigms and applies Distributional Calibration via Quantile Mapping to reduce distributional mismatch between LLM-judge scores and human responses. Experiments on 14 mainstream LLMs reveal substantial knowledge–decision gaps and show that assigned personas are reflected more consistently in self-reports than in behavioral decisions for most evaluated models. To mitigate this gap, we further introduce the Chain of Cognitive Alignment (CoCA), an inference-time intervention that reduces GKD for 12 of the 13 models with paired results. Code and resources are available at https://github.com/Selina233/ActTraitBench.
Anthology ID:
2026.findings-emnlp.2068
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
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Pages:
44018–44030
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URL:
https://aclanthology.org/2026.findings-emnlp.2068/
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Cite (ACL):
Yutong Yang, Chenxi Miao, Weikang Li, and Yunfang Wu. 2026. ActTraitBench: Quantifying the Knowledge-Decision Gap in Large Language Models via Human-Grounded Behavioral Validation. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 44018–44030, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
ActTraitBench: Quantifying the Knowledge-Decision Gap in Large Language Models via Human-Grounded Behavioral Validation (Yang et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.2068.pdf