Paper 01
Sparse features recover monosemantic structure in a 1.4B parameter transformer
Dictionary learning on residual stream activations yields a basis of 32,768 features, of which 71.2 percent are judged monosemantic by held-out human raters. Feature density falls off as a power law in layer depth. We release the trained dictionary, the activation cache, and the rater protocol so the fit can be reproduced without our compute.
Fig. 1 Fraction monosemantic against dictionary width