The first membership-inference attack on self-distillation broke every baseline that was given the same access
AspireAI community · National University of Singapore (arXiv)
Self-distillation trains a model on its own outputs, removing the need for an external teacher, and that teacher-free design has a privacy question nobody had measured: using two coupled views of the same training example may strengthen memorisation of it. This paper is the first study of membership-inference attacks against on-policy self-distillation, and it finds that existing attacks are essentially random guessing even in the gray-box setting where the attacker can see the teacher-student residual correction directly. The proposed attack, OP-Print, exploits the finding that the supervision imprint in self-distillation is sparse and structured, concentrating on uncertainty-sensitive correction sites rather than spreading across the rollout, and it is validated as effective in both gray-box and black-box settings. The limitation is scope: it is an attack paper on distillation schemes and models the authors tested, so it measures exposure rather than the prevalence of the behaviour across the ecosystem.
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Two sparse-autoencoder analyses have resisted scaling: matching semantically similar features across layers, and compressing large feature circuits into interpretable supernodes. This paper argues both are the same underlying problem, estimating semantic distances between SAE features that sit on different activation manifolds. Its representation treats each feature not as a single decoder vector but as an activation-weighted distribution over the hidden states expressing it, projects those distributions into a shared reference space, and compares them with Wasserstein distance. The representation is proved invariant to activation rescaling and stable under perturbation, and recovers true matches under finite-sample margin conditions. Empirically it outperformed decoder-vector and LLM-based baselines and captured subtle functional distinctions between related features, and it compressed large feature circuits into interpretable supernodes automatically. The limitation is that this is interpretability tooling: the paper demonstrates better feature matching and circuit compression, not that downstream interpretability claims become more accurate.