Sparse autoencoders reveal stable feature hierarchies across scales
Researchers have validated a foundational theory of how language models encode meaning through atomic features, challenging the prevailing assumption that sparse autoencoders (SAEs) produce unstable, fragmented representations as they scale. By testing SAEs ranging from 512 to 131,072 dimensions across embedding models, they demonstrate that larger dictionaries consistently recover a stable hierarchy of features present in smaller ones, with cross-dataset validation confirming that prevalent features persist across different training corpora. This stability principle reshapes interpretability work by suggesting that feature discovery is cumulative rather than chaotic, potentially enabling more reliable mechanistic understanding of model internals and better-grounded approaches to alignment and safety research.68






