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arXiv · 2310.07325

An Adversarial Example for Direct Logit Attribution: Memory Management in GELU-4L

Jett Janiak·Can Rager·James Dao·Yeu-Tong Lau
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Abstract

Prior work suggests that language models manage the limited bandwidth of the residual stream through a "memory management" mechanism, where certain attention heads and MLP layers clear residual stream directions set by earlier layers. Our study provides concrete evidence for this erasure phenomenon in a 4-layer transformer, identifying heads that consistently remove the output of earlier heads. We further demonstrate that direct logit attribution (DLA), a common technique for interpreting the output of intermediate transformer layers, can show misleading results by not accounting for erasure.

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Jett Janiak, Can Rager, James Dao, Yeu-Tong Lau. 2023-10-11. An Adversarial Example for Direct Logit Attribution: Memory Management in GELU-4L. https://doi.org/10.18653/v1%2F2024.blackboxnlp-1.15

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