Chain-of-Defensive-Thought: Structured Reasoning Elicits Robustness in Large Language Models against Reference Corruption

Abstract: Chain-of-thought prompting has demonstrated great success in facilitating the reasoning abilities of LLMs. In this work, we explore how these enhanced reasoning abilities can be exploited to improve the robustness of LLMs in tasks that are not necessarily reasoning-focused. In particular, we show how a wide range of LLMs exhibit significantly improved robustness against reference corruption using a simple method called chain-of-defensive-thought, where only a few exemplars with structured and defensive reasoning are provided as demonstrations. Empirically, the improvements can be astounding, especially given the simplicity and applicability of the method. For example, in the Natural Questions task, the accuracy of GPT-4o degrades from 60% to as low as 3% with standard prompting when 1 out of 10 references provided is corrupted with prompt injection attacks. In contrast, GPT-4o using chain-of-defensive-thought prompting maintains an accuracy of 50%.