ADAM: Dense Retrieval Distillation with Adaptive Dark Examples

Chongyang Tao, Chang Liu, Tao Shen, Can Xu, Xiubo Geng, Binxing Jiao, Daxin Jiang


Abstract
To improve the performance of the dual-encoder retriever, one effective approach is knowledge distillation from the cross-encoder ranker. Existing works prepare training instances by pairing each query with one positive and a batch of negatives. However, most hard negatives mined by advanced dense retrieval methods are still too trivial for the teacher to distinguish, preventing the teacher from transferring abundant dark knowledge to the student through its soft label. To alleviate this issue, we propose Adam, a knowledge distillation framework that can better transfer the dark knowledge held in the teacher with adaptive dark examples. Different from previous works that only rely on one positive and hard negatives as candidate passages, we create dark examples that all have moderate relevance to the query by strengthening negatives and masking positives in the discrete space. Furthermore, as the quality of knowledge held in different training instances varies as measured by the teacher’s confidence score, we propose a self-paced distillation strategy that adaptively concentrates on a subset of high-quality instances to conduct our dark-example-based knowledge distillation to help the student learn better. We conduct experiments on two widely-used benchmarks and verify the effectiveness of our method.
Anthology ID:
2024.findings-acl.692
Volume:
Findings of the Association for Computational Linguistics ACL 2024
Month:
August
Year:
2024
Address:
Bangkok, Thailand and virtual meeting
Editors:
Lun-Wei Ku, Andre Martins, Vivek Srikumar
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
11639–11651
Language:
URL:
https://aclanthology.org/2024.findings-acl.692
DOI:
10.18653/v1/2024.findings-acl.692
Bibkey:
Cite (ACL):
Chongyang Tao, Chang Liu, Tao Shen, Can Xu, Xiubo Geng, Binxing Jiao, and Daxin Jiang. 2024. ADAM: Dense Retrieval Distillation with Adaptive Dark Examples. In Findings of the Association for Computational Linguistics ACL 2024, pages 11639–11651, Bangkok, Thailand and virtual meeting. Association for Computational Linguistics.
Cite (Informal):
ADAM: Dense Retrieval Distillation with Adaptive Dark Examples (Tao et al., Findings 2024)
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PDF:
https://aclanthology.org/2024.findings-acl.692.pdf