Retrieval Augmentation Reduces Hallucination in Conversation (2104.07567v1)

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., 2020). 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, 2020) - 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.

Retrieval Augmentation as an Effective Strategy for Reducing Hallucination in Conversational AI

Introduction to Hallucination in Dialogue Systems

The phenomenon of hallucination, where conversational AI systems generate plausible but factually incorrect or unverifiable information, presents a significant challenge in the development of dialogue agents. Despite advancements in LLMs that enhance conversational fluency, these systems continue to suffer from inaccuracies and fabrications. The deployment of neural retrieval-in-the-loop architectures, particularly noted in open-domain Question Answering (QA), sheds light on a plausible mitigation route. This involves dynamically retrieving external documents to ground conversational responses in verifiable facts.

Retrieval-Augmented Architecture for Dialogue

This paper explores various retrieval-augmented neural architectures for dialogue, assessing their effectiveness in enhancing knowledgeability while preserving conversational coherence. Through comprehensive tests across multiple encoder-decoder frameworks, including BART and T5, the research delineates the advancements in mitigating knowledge hallucination through retrieval integration. The architectures underpinning this paper involve sophistications like Poly-encoders for nuanced document scoring, iterative retrieval tweaks for enhanced context relevance, end-to-end retriever training within the Fusion-in-Decoder (FiD) techniques, and dialogue-context adaptive retrieval mechanisms.

Significant Findings and Implications

The findings from extensive experiments on knowledge-grounded conversational datasets confirm that retrieval-augmented models, notably in state-of-the-art configurations, substantially diminish the frequency of hallucinated responses by over 60%. This decrement is notably more pronounced in scenarios involving unseen or out-of-distribution data. Implicitly, this emphasizes the models' adeptness at employing external knowledge sources for responses beyond the immediate scope of their trained parameters. The practical implications of these findings are vast, foreseeing improvements in chatbots and conversational AI's reliability, thereby enhancing user trust.

Theoretical Contributions and Future Directions

From a theoretical standpoint, this research enriches the understanding of retrieval-augmentation in dialogue systems, highlighting the nuanced interplay between retrieval mechanisms and generation capabilities in curbing hallucinations. The comparison among various retriever-enhancements and their differential impact on knowledge fidelity opens avenues for future explorations. Notably, the nuanced trade-offs between document quantity in retrieval and the quality of generated dialogue suggest intriguing future work in optimally balancing these aspects.

Moreover, the research underscores the potential of leveraging neural retrievers pre-trained on diverse datasets, marking a crucial step towards adaptive, context-aware retrieval mechanisms in dialogue systems. This invites further investigation into how different pre-training regimes and knowledge sources affect retrieval efficacy and, by extension, dialogue quality.

Concluding Remarks

In conclusion, retrieval augmentation stands out as a promising strategy for mitigating knowledge hallucination in conversational AI, substantiated by significant empirical evidence. This paper sets a foundational precedent for future endeavors aiming to refine the accuracy and reliability of dialogue systems, ensuring that these advancements translate into tangible benefits for end-users in real-world applications. The roadmap laid out by these findings not only prioritizes factual correctness in AI-generated dialogues but also aligns with the broader goals of making AI interactions more human-like, knowledgeable, and ultimately, more trustworthy.