Source-Aware Training Enables Knowledge Attribution in Language Models

TL;DR

This paper introduces source-aware training for large language models, enabling them to cite their pretraining sources, which improves transparency and interpretability without significantly affecting performance.

Contribution

It proposes a novel training method that associates source identifiers with knowledge in LLMs, allowing for faithful source attribution during response generation.

Findings

Enables LLMs to cite pretraining sources accurately

Minimal impact on model perplexity compared to standard training

Highlights importance of data augmentation for attribution

Abstract

Large language models (LLMs) learn a vast amount of knowledge during pretraining, but they are often oblivious to the source(s) of such knowledge. We investigate the problem of intrinsic source citation, where LLMs are required to cite the pretraining source supporting a generated response. Intrinsic source citation can enhance LLM transparency, interpretability, and verifiability. To give LLMs such ability, we explore source-aware training -- a recipe that involves (i) training the LLM to associate unique source document identifiers with the knowledge in each document, followed by (ii) an instruction-tuning stage to teach the LLM to cite a supporting pretraining source when prompted. Source-aware training borrows from existing pretraining/fine-tuning frameworks and requires minimal changes to the model architecture or implementation. Through experiments on synthetic data, we demonstrate that our training recipe can enable faithful attribution to the pretraining data without a substantial impact on the model's perplexity compared to standard pretraining. Our findings also highlight the importance of pretraining data augmentation in achieving attribution. Code and data available here: \url{https://github.com/mukhal/intrinsic-source-citation}