Why Fine-Tuned Memories Still Struggle to Generalize

burny_tech · x · 2026-07-13

This paper examines a common phenomenon: LLMs can quickly memorize new facts during fine-tuning, but generalize poorly when multi-hop reasoning is required.

The author suggests the issue isn't "failure to learn knowledge," but a misalignment between knowledge and reasoning circuits. While facts exist inside the model, they don't reside in the layers actively involved in reasoning. By using self-patching to move appropriate hidden representations to the correct layers, the paper restored a significant portion of generalization ability; a simple heuristic recovered 58–75% of the oracle headroom.

Related event: Study Reveals Knowing-Using Gap in LLM Fine-Tuning(2 posts)→

Original post →

More from Models

Models channel →