Pith. sign in

REVIEW 4 cited by

BERT Busters: Outlier Dimensions that Disrupt Transformers

Not yet reviewed by Pith; the record is open.

This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.

SPECIMEN: schema-true, not a live event

T0 review · schema-true

One-sentence machine reading of the paper's core claim.

pith:XXXXXXXX · record.json · timestamp

arxiv 2105.06990 v2 pith:PSQSOKGJ submitted 2021-05-14 cs.CL

BERT Busters: Outlier Dimensions that Disrupt Transformers

classification cs.CL
keywords pre-trainedtransformersberteffectmodelothertransformeracross
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved
0 comments
Share X Bluesky LinkedIn Reddit HN
read the original abstract

Multiple studies have shown that Transformers are remarkably robust to pruning. Contrary to this received wisdom, we demonstrate that pre-trained Transformer encoders are surprisingly fragile to the removal of a very small number of features in the layer outputs (<0.0001% of model weights). In case of BERT and other pre-trained encoder Transformers, the affected component is the scaling factors and biases in the LayerNorm. The outliers are high-magnitude normalization parameters that emerge early in pre-training and show up consistently in the same dimensional position throughout the model. We show that disabling them significantly degrades both the MLM loss and the downstream task performance. This effect is observed across several BERT-family models and other popular pre-trained Transformer architectures, including BART, XLNet and ELECTRA; we also show a similar effect in GPT-2.

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Forward citations

Cited by 4 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. Massive Activations Are Architecturally Robust: A Controlled Scratch/Commitment Residual Stream Test

    cs.LG 2026-06 unverdicted novelty 7.0

    In 160M and 290M parameter models, a new residual-stream split into scratch and protected channels causes massive activations to re-emerge in the protected decode channel, more concentrated on the start token.

  2. Eliciting Latent Predictions from Transformers with the Tuned Lens

    cs.LG 2023-03 accept novelty 7.0

    Training per-layer affine probes on frozen transformers yields more reliable latent predictions than the logit lens and enables detection of malicious inputs from prediction trajectories.

  3. LLM.int8(): 8-bit Matrix Multiplication for Transformers at Scale

    cs.LG 2022-08 conditional novelty 7.0

    LLM.int8() performs 8-bit inference for transformers up to 175B parameters with no accuracy loss by combining vector-wise quantization for most features with 16-bit mixed-precision handling of systematic outlier dimensions.

  4. A Comprehensive FP8 Training Recipe for Reasoning-Enhanced Language Models

    cs.CL 2025-09 conditional novelty 4.0

    A hybrid-granularity FP8 training recipe achieves near-lossless accuracy versus BF16 on reasoning benchmarks with up to 22% faster training and 14% lower memory.