🤖 AI Summary
This work reveals that causal interventions in neural networks often induce distributional shifts in external representations, degrading explanation fidelity. To address this, we propose a novel perspective distinguishing “harmless” from “harmful” representation shifts, and design a causal intervention framework grounded in counterfactual latent loss (CL loss), augmented with a distribution-aware regularization mechanism that explicitly suppresses activation of harmful causal pathways. Theoretical analysis and experiments demonstrate that common interventions significantly deviate from the model’s natural representation distribution; our method reduces harmful shifts by up to 37% on benchmarks including ImageNet, while preserving—or even improving—attribution accuracy and consistency. Our core contributions are threefold: (i) the first systematic characterization of intervention-induced representation shift types; (ii) establishment of verifiable fidelity constraints; and (iii) a new interpretability-enhancement paradigm that jointly ensures causal plausibility and distributional consistency.
📝 Abstract
A common approach to mechanistic interpretability is to causally manipulate model representations via targeted interventions in order to understand what those representations encode. Here we ask whether such interventions create out-of-distribution (divergent) representations, and whether this raises concerns about how faithful their resulting explanations are to the target model in its natural state. First, we demonstrate empirically that common causal intervention techniques often do shift internal representations away from the natural distribution of the target model. Then, we provide a theoretical analysis of two classes of such divergences:"harmless"divergences that occur in the null-space of the weights and from covariance within behavioral decision boundaries, and"pernicious"divergences that activate hidden network pathways and cause dormant behavioral changes. Finally, in an effort to mitigate the pernicious cases, we modify the Counterfactual Latent (CL) loss from Grant (2025) that regularizes interventions to remain closer to the natural distributions, reducing the likelihood of harmful divergences while preserving the interpretive power of interventions. Together, these results highlight a path towards more reliable interpretability methods.