train-the-model-not-the-reader-decodability-supervision-for-verifiable-activation-explanations-6b8c0e3e·1 events·first seen Aliases: Train the Model, Not the Reader: Decodability Supervision for Verifiable Activation Explanations
A new arXiv paper identifies a fundamental flaw in natural-language autoencoder-based explanation methods for neural activations: high reconstruction scores do not certify individual factual claims, and the standard training recipe produces co-adapted private codes (false wordings that reconstruct well) in all tested runs. The authors introduce two audit protocols and RECAP (Readable Encodings via Co-trained Auxiliary Predictors), which trains linear probe heads alongside the target model to keep designated content independently decodable. On RECAP-trained models, fresh verbalizers state designated content truthfully and private codes vanish, with probes achieving AUC 0.96 for distinguishing true from false claims—and remaining robust (AUC 0.95) against adversarial explanation edits that collapse control probes to chance. The work has direct implications for mechanistic interpretability and AI safety, as it challenges a widely-used faithfulness test and proposes a more verifiable alternative.