Internal Causal Mechanisms Robustly Predict Language Model Out-of-Distribution Behaviors

Interpretability research now offers a variety of techniques for identifying abstract internal mechanisms in neural networks. Can such techniques be used to predict how models will behave on out-of-distribution examples? In this work, we provide a positive answer to this question. Through a diverse set of language modeling tasks--including symbol manipulation, knowledge retrieval, and instruction following--we show that the most robust features for correctness prediction are those that play a distinctive causal role in the model's behavior. Specifically, we propose two methods that leverage causal mechanisms to predict the correctness of model outputs: counterfactual simulation (checking whether key causal variables are realized) and value probing (using the values of those variables to make predictions). Both achieve high AUC-ROC in distribution and outperform methods that rely on causal-agnostic features in out-of-distribution settings, where predicting model behaviors is more crucial. Our work thus highlights a novel and significant application for internal causal analysis of language models.

@article{huang2025_2505.11770,
  title={ Internal Causal Mechanisms Robustly Predict Language Model Out-of-Distribution Behaviors },
  author={ Jing Huang and Junyi Tao and Thomas Icard and Diyi Yang and Christopher Potts },
  journal={arXiv preprint arXiv:2505.11770},
  year={ 2025 }
}