ICA rivals sparse autoencoders for LLM interpretability with 7–43× less memory

patrickmineault · x · 2026-10-23

Researchers revisited Independent Component Analysis and found it surprisingly competitive with public SAEs for interpreting LLM activations. Across GPT-2 Small, Gemma 2 2B, and Qwen 3.5 9B Base, ICA matches SAEs on interpretability, sparse reconstruction, concept prediction, and targeted probe perturbation — while fitting in minutes per layer and using 7–43× less parameter memory. They released ICA Lens, a tool to discover, annotate, and evaluate interpretable directions in residual-stream activations without training another dictionary.

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