Steering LLMs? Actually, Sparse Autoencoders can outperform simple baselines
引导LLM?实际上,稀疏自编码器可以胜过简单基线
Mikkel Godsk Jørgensen, Lars Kai Hansen
AI总结 本文通过监督流水线选择并标注特征,证明稀疏自编码器在模型引导任务上可接近LoRA性能,并发现高稀疏性对基于可解释性的引导并非关键。
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稀疏自编码器(SAEs)被视为探索大型语言模型(LLMs)内部机制和引导模型输出生成的有前途的途径。当Wu等人(2025)引入模型引导基准AxBench时,SAEs由于相对于一组简单基线的引导性能较差,似乎并未达到最初的期望。本文作为对稀疏自编码器的部分反驳,表明Wu等人(2025)的结果并未完全公正地评价它们。我们发现,当使用我们的监督流水线选择并标注特征时,稀疏自编码器实际上可以在AxBench基准上达到接近参考LoRA性能的水平。我们还发现,当仅使用基于可解释性的组件时,我们的流水线选择的特征与其识别标签具有令人惊讶的因果性。最后,我们提供证据表明,高稀疏性(低l0)可能对于基于可解释性的成功引导并非关键,这与Wang等人(2025)早期的发现相反。
Sparse Autoencoders (SAEs) have been seen as a promising avenue for exploring the internals of Large Language Models (LLMs) and for steering model output generation. When AxBench - a model steering benchmark - was introduced in Wu et al. (2025), SAEs did not seem to live up to their original hype due to poor steering performance relative to a set of simple baselines. This work serves as a partial rebuttal for Sparse Autoencoders and suggests that the results of Wu et al. (2025) did not do them full justice. We find that Sparse Autoencoders can, in fact, perform close to on par with the reference LoRA performance on the AxBench benchmark, when features are selected and labelled with our supervised pipeline. We also find that our pipeline selects features that are surprisingly causal of their identified labels when using only its interpretability-based components. Lastly, we present evidence that high sparsity (low l0) may not be crucial for successful steering based on interpretability, which is in contrast to the earlier findings in Wang et al. (2025).