Cited by 575Speech and dialogue systemsTopic ModelingInformation Retrieval and Search Behavior

Retrieval Augmentation Reduces Hallucination in Conversation

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Shuster, Kurt, Poff, Spencer, Chen, Moya, Kiela, Douwe, Weston, Jason·2021·Findings of the Association for Computational Linguistics: EMNLP 2021

Abstract

Despite showing increasingly human-like conversational abilities, state-of-the-art dialogue models often suffer from factual incorrectness and hallucination of knowledge (Roller et al., 2021).In this work we explore the use of neural-retrieval-in-the-loop architectures -recently shown to be effective in open-domain QA (Lewis et al., 2020b; Izacard and Grave, 2021b) -for knowledge-grounded dialogue, a task that is arguably more challenging as it requires querying based on complex multi-turn dialogue context and generating conversationally coherent responses.We study various types of architectures with multiple components -retrievers, rankers, and encoder-decoders -with the goal of maximizing knowledgeability while retaining conversational ability.We demonstrate that our best models obtain state-of-the-art performance on two knowledge-grounded conversational tasks.The models exhibit open-domain conversational capabilities, generalize effectively to scenarios not within the training data, and, as verified by human evaluations, substantially reduce the well-known problem of knowledge hallucination in state-of-the-art chatbots. * Equal ContributionThe following is a conversation with an AI assistant.The assistant is helpful, creative, clever, and very friendly.Human: Hello, who are you?AI: I am an AI created by OpenAI.How can I help you today?Human: Tell me about Kyunghyun

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  • Long-context strategies and retrieval-augmented generation techniques have improved LLMs' memory in handling long-term tasks.

    “Although long-context strategies (Bertsch et al., 2024) and retrieval-augmented generation techniques (Shuster et al., 2021) have improved LLMs' memory in handling long-term tasks, these text-based memory methods face significant limitations in terms of token count, computational cost, and inference time (Zhang et al., 2024).”

    From Evaluating the Long-Term Memory of Large Language Models (2025) · cites this paper as Shuster et al., 2021

    The Introduction and Discussion (page numbers unavailable in our copy) report that retrieval-augmented models improve performance in knowledge-grounded, multi-turn dialogue. They do not establish that these techniques improve LLMs’ memory on long-term tasks; the paper’s reference to retrieval used “as a memory” appears in Related Work, not as its own finding. (LLM, conf=0.82)

    Experimental — accuracy not yet measured
  • Deep learning based NLG generation is prone to hallucinate unintended text, which degrades system performance and fails to meet user expectations in many real-world scenarios.

    “However, it is also apparent that deep learning based generation is prone to hallucinate unintended text, which degrades the system performance and fails to meet user expectations in many real-world scenarios.”

    From Survey of Hallucination in Natural Language Generation (2023) · cites this paper as [121]

    The Introduction says that even large dialogue models generate plausible but factually incorrect statements, and the Conclusion calls this an important problem. The human-evaluation section treats hallucination as an aspect of model performance. Our copy does not establish that it fails user expectations in many real-world scenarios. (LLM, conf=0.82)

    Experimental — accuracy not yet measured
  • Human evaluation is still one of the most commonly used approaches for evaluating hallucinations in NLG due to the challenging and imperfect nature of current automatic evaluation.

    “Due to the challenging and imperfect nature of the current automatic evaluation of hallucinations in NLG, human evaluation [226, 233] is still one of the most commonly used approaches.”

    From Survey of Hallucination in Natural Language Generation (2023) · cites this paper as [233]

    Section 4.2.1 describes human annotation of hallucinations in conversational responses, and Section 5 says standard dialogue metrics are insufficient to capture hallucination. The paper does not establish that human evaluation is one of the most commonly used approaches across NLG. (LLM, conf=0.84)

    Experimental — accuracy not yet measured
  • RAG systems improve factual consistency and provide traceable evidence for generated responses.

    “RAG systems improve factual consistency and provide traceable evidence for generated responses (Shuster et al., 2021;Gao et al., 2023).”

    From Improving Amharic Information Retrieval with Translative and Multi-Agent Debate Retrieval Augmented Generation (2026) · cites this paper as Shuster et al., 2021

    Section 4.2.1 reports that retrieval-augmented models had dramatically lower hallucination rates in human evaluations, supporting improved factuality in the studied conversations. The same section says evaluators were shown a retrieved document to help interpret where a response’s knowledge came from, but it does not establish that RAG systems generally provide traceable evidence for their generated responses. Page numbers are unavailable in our copy. (LLM, conf=0.84)

    Experimental — accuracy not yet measured
  • The efficacy of long-context LLMs and RAG techniques in very long-term dialogues remains unexplored.

    “Despite advancements in longcontext large language models (LLMs) and retrieval augmented generation (RAG) techniques, their efficacy in very long-term dialogues remains unexplored.”

    From Evaluating Very Long-Term Conversational Memory of LLM Agents (2024) · cites this paper as Shuster et al., 2021

    The Introduction (page unavailable) says RAG had not yet been applied to open-domain knowledge-grounded dialogue, supporting a narrower claim about a gap in prior research. The paper then evaluates RAG on multi-turn dialogue; it does not establish that the efficacy of long-context LLMs or RAG in very long-term dialogues remains unexplored. (LLM, conf=0.80)

    Experimental — accuracy not yet measured

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Cited by

Sorted by citations

Authors
Shuster, K., Poff, S., Chen, M., Kiela, D., & Weston, J.
Affiliations
Meta (United States) (US)
Venue
Findings of the Association for Computational Linguistics: EMNLP 2021
Published
2021
Pages
3784-3803
OpenAlex
W3155807546
Cited by
575
References
16
Citations by year
2026: 148 · 2025: 166 · 2024: 105 · 2023: 84 · 2022: 54 · 2021: 18
FWCI
30.14
Type
conference paper
Language
en
Open access
Licence
cc-by
Locations
Findings of the Association for Computational Linguistics: EMNLP (Findings of EMNLP) (publishedVersion, cc-by)
Topics
  • Physical Sciences › Computer Science › Artificial Intelligence › Speech and dialogue systems
  • Physical Sciences › Computer Science › Artificial Intelligence › Topic Modeling
  • Physical Sciences › Computer Science › Information Systems › Information Retrieval and Search Behavior
Keywords
retrieval-augmented generation, knowledge-grounded dialogue, neural retrieval, rankers, encoder-decoder architecture, chatbots, factual accuracy, multi-turn dialogue, open-domain conversation

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