Oolong: Investigating What Makes Transfer Learning Hard with Controlled Studies

Fuente: arXiv
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Auteurs principaux: Wu, Zhengxuan, Tamkin, Alex, Papadimitriou, Isabel
Format: Preprint
Publié: 2022
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author Wu, Zhengxuan
Tamkin, Alex
Papadimitriou, Isabel
author_facet Wu, Zhengxuan
Tamkin, Alex
Papadimitriou, Isabel
contents When we transfer a pretrained language model to a new language, there are many axes of variation that change at once. To disentangle the impact of different factors like syntactic similarity and vocabulary similarity, we propose a set of controlled transfer studies: we systematically transform the language of the GLUE benchmark, altering one axis of crosslingual variation at a time, and then measure the resulting drops in a pretrained model's downstream performance. We find that models can largely recover from syntactic-style shifts, but cannot recover from vocabulary misalignment and embedding matrix re-initialization, even with continued pretraining on 15 million tokens. %On the other hand, transferring to a dataset with an unaligned vocabulary is extremely hard to recover from in the low-data regime. Moreover, good-quality tokenizers in the transfer language do not make vocabulary alignment easier. Our experiments provide insights into the factors of cross-lingual transfer that researchers should most focus on when designing language transfer scenarios.
format Preprint
id arxiv_https___arxiv_org_abs_2202_12312
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Oolong: Investigating What Makes Transfer Learning Hard with Controlled Studies
Wu, Zhengxuan
Tamkin, Alex
Papadimitriou, Isabel
Computation and Language
When we transfer a pretrained language model to a new language, there are many axes of variation that change at once. To disentangle the impact of different factors like syntactic similarity and vocabulary similarity, we propose a set of controlled transfer studies: we systematically transform the language of the GLUE benchmark, altering one axis of crosslingual variation at a time, and then measure the resulting drops in a pretrained model's downstream performance. We find that models can largely recover from syntactic-style shifts, but cannot recover from vocabulary misalignment and embedding matrix re-initialization, even with continued pretraining on 15 million tokens. %On the other hand, transferring to a dataset with an unaligned vocabulary is extremely hard to recover from in the low-data regime. Moreover, good-quality tokenizers in the transfer language do not make vocabulary alignment easier. Our experiments provide insights into the factors of cross-lingual transfer that researchers should most focus on when designing language transfer scenarios.
title Oolong: Investigating What Makes Transfer Learning Hard with Controlled Studies
topic Computation and Language
url https://arxiv.org/abs/2202.12312