Open access
Date
2021-04Type
- Conference Paper
ETH Bibliography
yes
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Abstract
We take a deep look into the behaviour of self-attention heads in the transformer architecture. In light of recent work discouraging the use of attention distributions for explaining a model’s behaviour, we show that attention distributions can nevertheless provide insights into the local behaviour of attention heads. This way, we propose a distinction between local patterns revealed by attention and global patterns that refer back to the input, and analyze BERT from both angles. We use gradient attribution to analyze how the output of an attention head depends on the input tokens, effectively extending the local attention-based analysis to account for the mixing of information throughout the transformer layers. We find that there is a significant mismatch between attention and attribution distributions, caused by the mixing of context inside the model. We quantify this discrepancy and observe that interestingly, there are some patterns that persist across all layers despite the mixing. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000496002Publication status
publishedExternal links
Book title
Proceedings of the 16th Conference of the European Chapter of the Association for Computational Linguistics: Main VolumePages / Article No.
Publisher
Association for Computational LinguisticsEvent
Organisational unit
03604 - Wattenhofer, Roger / Wattenhofer, Roger
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ETH Bibliography
yes
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