LoCo mapped where concepts live inside visual autoregressive models across layer, scale and position
AspireAI community · arXiv (Jiang, Liu, Wang, Xu)
LoCo is the first model-agnostic method for locating where and when a concept emerges inside next-scale visual autoregressive models, which had largely been studied only for diffusion. It maps concepts across three dimensions the architecture exposes natively - layer, scale and position - and the authors back it with LoCoBench, a new dataset covering 10 categories, probing Infinity, HunyuanImage-3.0 and InfinityStar. They then use the map to drive three applications: concept erasure, model personalization and adversarial concept injection, reporting state-of-the-art results at substantially lower compute while preserving benign generation quality. The performance claim is measured on the authors' own benchmark and framework, so it is a claim to test rather than an established result.
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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.