Verifiable by Design: Aligning Language Models to Quote from Pre-Training Data

ACL ARR 2024 August Submission339 Authors

Abstract:

To trust the fluent generations of large language models (LLMs), humans must be able to *verify* their correctness against trusted, external sources. Recent efforts, such as providing citations via retrieved documents or post-hoc provenance, enhance verifiability but still provide no guarantees on their correctness. To address these limitations, we tackle the verifiability goal with a different philosophy: trivializing the verification process by developing models that quote verbatim statements from trusted sources in pre-training data. We propose Quote-Tuning, and demonstrate it is feasible to align LLMs to provide quoted statements from data memorized during pre-training. The core of Quote-Tuning is a fast membership inference function (Marone and Van Durme, 2023) that efficiently verifies
text against a trusted corpus. We leverage this tool to design a reward function to quantify quotes in model responses, which is then used to create a dataset for preference learning. Experimental results show that Quote-Tuning significantly increases verbatim quotes from high-quality pre-training documents by 55% to 130% relative to un-tuned models while maintaining response quality. Quote-Tuning also generalizes quoting to out-of-domain data, is applicable in different tasks, and provides additional benefits to truthfulness. Our method not only serves as a hassle-free method to increase quoting but also opens up avenues for improving LLM trustworthiness through better verifiability.

Paper Type: Long

Research Area: NLP Applications

Research Area Keywords: NLP Applications, Language Modeling, Generation

Contribution Types: NLP engineering experiment

Languages Studied: English

Submission Number: 339