Attention Sinks Induce Gradient Sinks: Massive Activations as Gradient Regulators in Transformers

Fuente: arXiv
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Main Authors: Chen, Yihong, Lin, Zhouchen, Yao, Quanming
Format: Preprint
Published: 2026
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author Chen, Yihong
Lin, Zhouchen
Yao, Quanming
author_facet Chen, Yihong
Lin, Zhouchen
Yao, Quanming
contents Attention sinks and massive activations are recurring and closely related phenomena in Transformer models. Existing explanations have largely focused on the forward pass, yet in pre-norm Transformers, large residual-stream norms play only an indirect forward role because sublayers operate on normalized inputs. We study this relationship from the perspective of backpropagation. Empirically and theoretically, we show that under causal masking, attention sinks can induce pronounced gradient concentration, which we term gradient sinks. Since the RMSNorm Jacobian attenuates gradients roughly in inverse proportion to input norm, massive activations can be understood as adaptive regulators of this localized gradient pressure during training. This interpretation predicts that attenuating sink-induced gradients should weaken massive activations. We test this prediction with V-scale, a modification that adjusts backpropagated gradients on the value path. In V-scale models, attention sinks are preserved, whereas massive activations are suppressed. These results identify gradient sinks as a backward-pass counterpart of attention sinks, and massive activations as an adaptive RMSNorm-mediated response that attenuates the resulting localized training pressure. Our code is available at https://anonymous.4open.science/r/GradientSinkCode-B309.
format Preprint
id arxiv_https___arxiv_org_abs_2603_17771
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Attention Sinks Induce Gradient Sinks: Massive Activations as Gradient Regulators in Transformers
Chen, Yihong
Lin, Zhouchen
Yao, Quanming
Machine Learning
Artificial Intelligence
Attention sinks and massive activations are recurring and closely related phenomena in Transformer models. Existing explanations have largely focused on the forward pass, yet in pre-norm Transformers, large residual-stream norms play only an indirect forward role because sublayers operate on normalized inputs. We study this relationship from the perspective of backpropagation. Empirically and theoretically, we show that under causal masking, attention sinks can induce pronounced gradient concentration, which we term gradient sinks. Since the RMSNorm Jacobian attenuates gradients roughly in inverse proportion to input norm, massive activations can be understood as adaptive regulators of this localized gradient pressure during training. This interpretation predicts that attenuating sink-induced gradients should weaken massive activations. We test this prediction with V-scale, a modification that adjusts backpropagated gradients on the value path. In V-scale models, attention sinks are preserved, whereas massive activations are suppressed. These results identify gradient sinks as a backward-pass counterpart of attention sinks, and massive activations as an adaptive RMSNorm-mediated response that attenuates the resulting localized training pressure. Our code is available at https://anonymous.4open.science/r/GradientSinkCode-B309.
title Attention Sinks Induce Gradient Sinks: Massive Activations as Gradient Regulators in Transformers
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2603.17771