cs.CLFeb 6, 2026

ReBeCA: Causality-Inspired Behavior Analysis for Understanding the Self-Reflection of Language Models

Authors: Tianqiang Yan, Lizhen Qu, Sihan Shang, Yuheng Li, Song Qiu, Hao Peng, Wenjian Luo, Jue Xie, 

Organizations: Monash University · Harbin Institute of Technology, Shenzhen · Hainan University · South China University of Technology · 

Abstract

Self-reflection is a basic self-improvement skill of language agents, yet it does not reliably improve their outputs, where the underlying behavioral mechanism remains opaque. We introduce ReBeCA (self-Reflection Behavior explained through Causality-inspired Analysis), a framework for identifying and validating outcome-relevant reflective behaviors from recorded trajectories. ReBeCA uses reflective codes, an inductive coding schema, to represent each trajectory as a sequence of reflective behaviors. It learns dependencies among these behaviors and the outcome with causal discovery, selects the behaviors that best predict the outcome of held-out trajectories, and tests them for consistency across data subsets and by prompt-based steering. In a controlled case study of four Qwen3 models under fixed-round Self-Refine on mathematical reasoning and translation, ReBeCA identifies compact, round-specific behavioral sets with superior held-out predictive fit and uses prompt-based steering on unseen problems to reveal how individual and combined behavioral directives affect performance (Holm-adjusted p=.020p = .020 on Qwen3-4B). ReBeCA offers a reusable framework that turns agent trajectories into interpretable, verifiable behavioral hypotheses without requiring model internals or preselecting the behaviors to test.

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