Cited by 132Natural Language Processing TechniquesTopic ModelingSpeech Recognition and Synthesis

On Exposure Bias, Hallucination and Domain Shift in Neural Machine Translation

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Wang, Chaojun, Sennrich, Rico·2020·Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics

Abstract

The standard training algorithm in neural machine translation (NMT) suffers from exposure bias, and alternative algorithms have been proposed to mitigate this.However, the practical impact of exposure bias is under debate.In this paper, we link exposure bias to another well-known problem in NMT, namely the tendency to generate hallucinations under domain shift.In experiments on three datasets with multiple test domains, we show that exposure bias is partially to blame for hallucinations, and that training with Minimum Risk Training, which avoids exposure bias, can mitigate this.Our analysis explains why exposure bias is more problematic under domain shift, and also links exposure bias to the beam search problem, i.e. performance deterioration with increasing beam size.Our results provide a new justification for methods that reduce exposure bias: even if they do not increase performance on in-domain test sets, they can increase model robustness to domain shift.

Integrity signals

Registry

Crossref · 10.18653/v1/2020.acl-main.326

Cites

33 of 33 references verified0 citation errors · 0 not checkable

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  • In longform tasks, the hallucination problem can be exacerbated due to exposure bias.

    “Further, in longform tasks consisting of generating multiple sentences or paragraphs, the hallucination problem can be exacerbated due to the issue of exposure bias (Wang & Sennrich, 2020).”

    From Chain-of-Verification Reduces Hallucination in Large Language Models (2023) · cites this paper as Wang & Sennrich, 2020

  • Durmus et al. (2020) and Wang et al. (2020) suggested using QG and QA to identify factual inconsistencies in abstractive summaries, which is more Precision-oriented.

    “Durmus et al. (2020) and Wang et al. (2020) suggested using QG and QA to identify factual inconsistencies in abstractive summaries, which is more Precisionoriented.”
  • The QG-QA approach is based on the intuition that if a summary is consistent with its source, questions asked on the summary and the source should result in similar answers.

    “Their approach is based on the intuition that if a summary is consistent with its source, questions asked on the summary and the source should result in similar answers.”

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Authors
Wang, C., & Sennrich, R.
Affiliations
  • University of Edinburgh (GB)
  • University of Zurich (CH)
Corresponding author
Sennrich, Rico
Venue
Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics
Published
2020
Pages
3544-3552
ISSN
0736-587X (ISSN-L)
OpenAlex
W3035214886
Cited by
118
References
36
Citations by year
2026: 7 · 2025: 14 · 2024: 11 · 2023: 31 · 2022: 22 · 2021: 28 · 2020: 5
FWCI
8.21
Type
conference paper
Language
en
Open access
Licence
cc-by
Locations
  • Proceedings of the conference - Association for Computational Linguistics. Meeting (publishedVersion, cc-by)
  • Edinburgh Research Explorer (University of Edinburgh) (submittedVersion, cc-by)
  • Zurich Open Repository and Archive (University of Zurich) (submittedVersion, cc-by)
Funders
  • National Science Foundation
  • Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (176727)
  • Samsung
  • Engineering and Physical Sciences Research Council (EP/S001271/1)
Topics
  • Physical Sciences › Computer Science › Artificial Intelligence › Natural Language Processing Techniques
  • Physical Sciences › Computer Science › Artificial Intelligence › Topic Modeling
  • Physical Sciences › Computer Science › Artificial Intelligence › Speech Recognition and Synthesis
Keywords
exposure bias, hallucinations, domain shift, neural machine translation, beam search, spot size, model robustness, training algorithms

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