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A Layer-wise Analysis of Supervised Fine-Tuning

2 Pith papers cite this work. Polarity classification is still indexing.

2 Pith papers citing it
abstract

While critical for alignment, Supervised Fine-Tuning (SFT) incurs the risk of catastrophic forgetting, yet the layer-wise emergence of instruction-following capabilities remains elusive. We investigate this mechanism via a comprehensive analysis utilizing information-theoretic, geometric, and optimization metrics across model scales (1B-32B). Our experiments reveal a distinct depth-dependent pattern: middle layers (20\%-80\%) are stable, whereas final layers exhibit high sensitivity. Leveraging this insight, we propose Mid-Block Efficient Tuning, which selectively updates these critical intermediate layers. Empirically, our method outperforms standard LoRA up to 10.2\% on GSM8K (OLMo2-7B) with reduced parameter overhead, demonstrating that effective alignment is architecturally localized rather than distributed. The code is publicly available at https://anonymous.4open.science/r/base_sft.

fields

cs.LG 2

years

2026 2

verdicts

UNVERDICTED 2

representative citing papers

Rotation-Preserving Supervised Fine-Tuning

cs.LG · 2026-05-08 · unverdicted · novelty 6.0

RPSFT improves the in-domain versus out-of-domain performance trade-off during LLM supervised fine-tuning by penalizing rotations in pretrained singular subspaces as a proxy for loss-sensitive directions.

citing papers explorer

Showing 2 of 2 citing papers.

  • Crafting Reversible SFT Behaviors in Large Language Models cs.LG · 2026-05-07 · unverdicted · none · ref 9 · internal anchor

    LCDD creates sparse carriers for SFT behaviors that SFT-Eraser can reverse, with ablations showing the sparse structure enables causal control.

  • Rotation-Preserving Supervised Fine-Tuning cs.LG · 2026-05-08 · unverdicted · none · ref 46 · internal anchor

    RPSFT improves the in-domain versus out-of-domain performance trade-off during LLM supervised fine-tuning by penalizing rotations in pretrained singular subspaces as a proxy for loss-sensitive directions.