Augmenting Zero-Shot Dense Retrievers with Plug-in Mixture-of-Memories

Suyu Ge, Chenyan Xiong, Corby Rosset, Arnold Overwijk, Jiawei Han, Paul Bennett


Abstract
In this paper we improve the zero-shot generalization ability of language models via Mixture-Of-Memory Augmentation (MoMA), a mechanism that retrieves augmentation documents from multiple information corpora (external memories), with the option to “plug in” unseen memory at inference time. We develop a joint learning mechanism that trains the augmentation component with latent labels derived from the end retrieval task, paired with hard negatives from the memory mixture. We instantiate the model in a zero-shot dense retrieval setting by augmenting strong T5-based retrievers with MoMA. With only T5-base, our model obtains strong zero-shot retrieval accuracy on the eighteen tasks included in the standard BEIR benchmark, outperforming some systems with larger model sizes. As a plug-in-play model, our model can efficiently generalize to any unseen corpus, meanwhile achieving comparable or even better performance than methods relying on target-specific pretraining. Our analysis further illustrates the necessity of augmenting with mixture-of-memory for robust generalization, the benefits of augmentation learning, and how MoMA utilizes the plug-in memory at inference time without changing its parameters. Our code can be found at https://github.com/gesy17/MoMA.
Anthology ID:
2023.emnlp-main.111
Volume:
Proceedings of the 2023 Conference on Empirical Methods in Natural Language Processing
Month:
December
Year:
2023
Address:
Singapore
Editors:
Houda Bouamor, Juan Pino, Kalika Bali
Venue:
EMNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1796–1812
Language:
URL:
https://aclanthology.org/2023.emnlp-main.111
DOI:
10.18653/v1/2023.emnlp-main.111
Bibkey:
Cite (ACL):
Suyu Ge, Chenyan Xiong, Corby Rosset, Arnold Overwijk, Jiawei Han, and Paul Bennett. 2023. Augmenting Zero-Shot Dense Retrievers with Plug-in Mixture-of-Memories. In Proceedings of the 2023 Conference on Empirical Methods in Natural Language Processing, pages 1796–1812, Singapore. Association for Computational Linguistics.
Cite (Informal):
Augmenting Zero-Shot Dense Retrievers with Plug-in Mixture-of-Memories (Ge et al., EMNLP 2023)
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PDF:
https://aclanthology.org/2023.emnlp-main.111.pdf
Video:
 https://aclanthology.org/2023.emnlp-main.111.mp4