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Heads You Lose: Why Ablation-Reversible Interpretability Doesn’t Transfer

TL;DR for operators The paper is a useful slap on the wrist for anyone tempted to turn an interpretability result into an operational control too quickly.1 It asks a simple question: when an attention head looks important, contains readable information, and can restore model behaviour after ablation, does that mean it carries a transferable representation of the computation? ...

June 17, 2026 · 17 min · Zelina
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How Sparse is Your Thought? Cracking the Inner Logic of Chain-of-Thought Prompts

TL;DR for operators Chain-of-thought prompting is often sold as a window into model reasoning. This paper is more useful because it treats CoT as something less mystical and more testable: a prompt-induced change in internal representations.1 The researchers train sparse autoencoders on hidden activations from two Pythia models solving GSM8K math problems under CoT and NoCoT prompts. They then patch CoT-derived sparse features into NoCoT runs and ask a sharper question: does inserting those internal features increase the log-probability of the correct answer? ...

August 1, 2025 · 16 min · Zelina