BERT Rankers are Brittle: A Study using Adversarial Document Perturbations

Research output: Chapter in book/report/conference proceedingConference contributionResearchpeer review

Authors

  • Yumeng Wang
  • Lijun Lyu
  • Avishek Anand

Research Organisations

External Research Organisations

  • Delft University of Technology
View graph of relations

Details

Original languageEnglish
Title of host publicationICTIR 2022
Subtitle of host publicationProceedings of the 2022 ACM SIGIR International Conference on the Theory of Information Retrieval
Pages115-120
Number of pages6
ISBN (electronic)9781450394123
Publication statusPublished - 25 Aug 2022
Event8th ACM SIGIR International Conference on the Theory of Information Retrieval, ICTIR 2022 - Virtual, Online, Spain
Duration: 11 Jul 202212 Jul 2022

Abstract

Contextual ranking models based on BERT are now well established for a wide range of passage and document ranking tasks. However, the robustness of BERT-based ranking models under adversarial inputs is under-explored. In this paper, we argue that BERT-rankers are not immune to adversarial attacks targeting retrieved documents given a query. Firstly, we propose algorithms for adversarial perturbation of both highly relevant and non-relevant documents using gradient-based optimization methods. The aim of our algorithms is to add/replace a small number of tokens to a highly relevant or non-relevant document to cause a large rank demotion or promotion. Our experiments show that a small number of tokens can already result in a large change in the rank of a document. Moreover, we find that BERT-rankers heavily rely on the document start/head for relevance prediction, making the initial part of the document more susceptible to adversarial attacks. More interestingly, we find a small set of recurring adversarial words that when added to documents result in successful rank demotion/promotion of any relevant/non-relevant document respectively. Finally, our adversarial tokens also show particular topic preferences within and across datasets, exposing potential biases from BERT pre-training or downstream datasets.

Keywords

    adversarial attack, bert, biases, neural networks, ranking

ASJC Scopus subject areas

Cite this

BERT Rankers are Brittle: A Study using Adversarial Document Perturbations. / Wang, Yumeng; Lyu, Lijun; Anand, Avishek.
ICTIR 2022 : Proceedings of the 2022 ACM SIGIR International Conference on the Theory of Information Retrieval. 2022. p. 115-120.

Research output: Chapter in book/report/conference proceedingConference contributionResearchpeer review

Wang, Y, Lyu, L & Anand, A 2022, BERT Rankers are Brittle: A Study using Adversarial Document Perturbations. in ICTIR 2022 : Proceedings of the 2022 ACM SIGIR International Conference on the Theory of Information Retrieval. pp. 115-120, 8th ACM SIGIR International Conference on the Theory of Information Retrieval, ICTIR 2022, Virtual, Online, Spain, 11 Jul 2022. https://doi.org/10.1145/3539813.3545122
Wang, Y., Lyu, L., & Anand, A. (2022). BERT Rankers are Brittle: A Study using Adversarial Document Perturbations. In ICTIR 2022 : Proceedings of the 2022 ACM SIGIR International Conference on the Theory of Information Retrieval (pp. 115-120) https://doi.org/10.1145/3539813.3545122
Wang Y, Lyu L, Anand A. BERT Rankers are Brittle: A Study using Adversarial Document Perturbations. In ICTIR 2022 : Proceedings of the 2022 ACM SIGIR International Conference on the Theory of Information Retrieval. 2022. p. 115-120 doi: 10.1145/3539813.3545122
Wang, Yumeng ; Lyu, Lijun ; Anand, Avishek. / BERT Rankers are Brittle : A Study using Adversarial Document Perturbations. ICTIR 2022 : Proceedings of the 2022 ACM SIGIR International Conference on the Theory of Information Retrieval. 2022. pp. 115-120
Download
@inproceedings{a9d999712b7249a58a5f9edc41864ec9,
title = "BERT Rankers are Brittle: A Study using Adversarial Document Perturbations",
abstract = "Contextual ranking models based on BERT are now well established for a wide range of passage and document ranking tasks. However, the robustness of BERT-based ranking models under adversarial inputs is under-explored. In this paper, we argue that BERT-rankers are not immune to adversarial attacks targeting retrieved documents given a query. Firstly, we propose algorithms for adversarial perturbation of both highly relevant and non-relevant documents using gradient-based optimization methods. The aim of our algorithms is to add/replace a small number of tokens to a highly relevant or non-relevant document to cause a large rank demotion or promotion. Our experiments show that a small number of tokens can already result in a large change in the rank of a document. Moreover, we find that BERT-rankers heavily rely on the document start/head for relevance prediction, making the initial part of the document more susceptible to adversarial attacks. More interestingly, we find a small set of recurring adversarial words that when added to documents result in successful rank demotion/promotion of any relevant/non-relevant document respectively. Finally, our adversarial tokens also show particular topic preferences within and across datasets, exposing potential biases from BERT pre-training or downstream datasets.",
keywords = "adversarial attack, bert, biases, neural networks, ranking",
author = "Yumeng Wang and Lijun Lyu and Avishek Anand",
note = "Funding Information: This work is partially supported by DFG Project AN 996/1-1. ; 8th ACM SIGIR International Conference on the Theory of Information Retrieval, ICTIR 2022 ; Conference date: 11-07-2022 Through 12-07-2022",
year = "2022",
month = aug,
day = "25",
doi = "10.1145/3539813.3545122",
language = "English",
pages = "115--120",
booktitle = "ICTIR 2022",

}

Download

TY - GEN

T1 - BERT Rankers are Brittle

T2 - 8th ACM SIGIR International Conference on the Theory of Information Retrieval, ICTIR 2022

AU - Wang, Yumeng

AU - Lyu, Lijun

AU - Anand, Avishek

N1 - Funding Information: This work is partially supported by DFG Project AN 996/1-1.

PY - 2022/8/25

Y1 - 2022/8/25

N2 - Contextual ranking models based on BERT are now well established for a wide range of passage and document ranking tasks. However, the robustness of BERT-based ranking models under adversarial inputs is under-explored. In this paper, we argue that BERT-rankers are not immune to adversarial attacks targeting retrieved documents given a query. Firstly, we propose algorithms for adversarial perturbation of both highly relevant and non-relevant documents using gradient-based optimization methods. The aim of our algorithms is to add/replace a small number of tokens to a highly relevant or non-relevant document to cause a large rank demotion or promotion. Our experiments show that a small number of tokens can already result in a large change in the rank of a document. Moreover, we find that BERT-rankers heavily rely on the document start/head for relevance prediction, making the initial part of the document more susceptible to adversarial attacks. More interestingly, we find a small set of recurring adversarial words that when added to documents result in successful rank demotion/promotion of any relevant/non-relevant document respectively. Finally, our adversarial tokens also show particular topic preferences within and across datasets, exposing potential biases from BERT pre-training or downstream datasets.

AB - Contextual ranking models based on BERT are now well established for a wide range of passage and document ranking tasks. However, the robustness of BERT-based ranking models under adversarial inputs is under-explored. In this paper, we argue that BERT-rankers are not immune to adversarial attacks targeting retrieved documents given a query. Firstly, we propose algorithms for adversarial perturbation of both highly relevant and non-relevant documents using gradient-based optimization methods. The aim of our algorithms is to add/replace a small number of tokens to a highly relevant or non-relevant document to cause a large rank demotion or promotion. Our experiments show that a small number of tokens can already result in a large change in the rank of a document. Moreover, we find that BERT-rankers heavily rely on the document start/head for relevance prediction, making the initial part of the document more susceptible to adversarial attacks. More interestingly, we find a small set of recurring adversarial words that when added to documents result in successful rank demotion/promotion of any relevant/non-relevant document respectively. Finally, our adversarial tokens also show particular topic preferences within and across datasets, exposing potential biases from BERT pre-training or downstream datasets.

KW - adversarial attack

KW - bert

KW - biases

KW - neural networks

KW - ranking

UR - http://www.scopus.com/inward/record.url?scp=85138329521&partnerID=8YFLogxK

U2 - 10.1145/3539813.3545122

DO - 10.1145/3539813.3545122

M3 - Conference contribution

AN - SCOPUS:85138329521

SP - 115

EP - 120

BT - ICTIR 2022

Y2 - 11 July 2022 through 12 July 2022

ER -