From Balustrades to Pierre Vinken: Looking for Syntax in Transformer Self-Attentions

David Mareček, Rudolf Rosa


Abstract
We inspect the multi-head self-attention in Transformer NMT encoders for three source languages, looking for patterns that could have a syntactic interpretation. In many of the attention heads, we frequently find sequences of consecutive states attending to the same position, which resemble syntactic phrases. We propose a transparent deterministic method of quantifying the amount of syntactic information present in the self-attentions, based on automatically building and evaluating phrase-structure trees from the phrase-like sequences. We compare the resulting trees to existing constituency treebanks, both manually and by computing precision and recall.
Anthology ID:
W19-4827
Volume:
Proceedings of the 2019 ACL Workshop BlackboxNLP: Analyzing and Interpreting Neural Networks for NLP
Month:
August
Year:
2019
Address:
Florence, Italy
Venues:
ACL | BlackboxNLP | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
263–275
Language:
URL:
https://aclanthology.org/W19-4827
DOI:
10.18653/v1/W19-4827
Bibkey:
Cite (ACL):
David Mareček and Rudolf Rosa. 2019. From Balustrades to Pierre Vinken: Looking for Syntax in Transformer Self-Attentions. In Proceedings of the 2019 ACL Workshop BlackboxNLP: Analyzing and Interpreting Neural Networks for NLP, pages 263–275, Florence, Italy. Association for Computational Linguistics.
Cite (Informal):
From Balustrades to Pierre Vinken: Looking for Syntax in Transformer Self-Attentions (Mareček & Rosa, 2019)
Copy Citation:
PDF:
https://aclanthology.org/W19-4827.pdf