Exploring Non-Causal Reasoning in LLMs Through the Lens of Chain-of-Thought
Introduction
LLMs have established prominence across a broad spectrum of complex problem-solving tasks. The adoption of the Chain of Thought (CoT) strategy has been a significant advancement, purportedly enhancing reasoning capabilities in these models. Contrary to the intuitive expectation associating correct CoTs with correct answers, empirical evidence suggests a surprising disjunction between them. Our paper scrutinizes this phenomenon through causal analysis, aiming to unearth the Structural Causal Model (SCM) LLMs implicitly adopt, contrasting it with human reasoning frameworks.
The Non-Causal Link Between CoT and Correct Answers
The examination of LLM performance across various tasks, employing both direct answering and CoT methodologies, unveils an inconsistent impact of CoT on accuracy. Notably, the presence of correct answers following incorrect CoTs, and vice versa, underscores a potential disconnect in the LLMs’ reasoning pathway. This discrepancy casts doubt on the presumption that LLMs engage in sequential causal reasoning analogous to human thought processes.
Demonstrating Causal Relationships in LLM Reasoning
Adopting cause-effect interventions, our analysis significantly contributes to the discourse by identifying varying implied SCMs across distinct tasks and models. Specifically, our findings categorize these causal structures into four definitive types, with "full connection" and "common cause" being prevalent among the examined tasks. This variance underscores the nuance within LLM reasoning capabilities and the influence of factors such as in-context learning and fine-tuning methodologies on the established causal links.
Implications on LLM Training and Reasoning
Our investigation sheds light on the profound impact of commonly deployed techniques in LLM training, including in-context learning, supervised fine-tuning, and reinforcement learning from human feedback. These methods, while proven to enhance task performance, do not consistently fortify the causal relationship between CoT and the resultant answers. This revelation poses essential considerations for future LLM training paradigms and underscores the necessity of adopting mechanisms that genuinely enhance reasoning capabilities.
Future Directions
The dissection of CoT through causal analysis presents a nascent but pivotal approach toward understanding and advancing LLM reasoning faculties. Future explorations might explore the granular aspects of reasoning processes, possibly incorporating other reasoning strategies and considering a broader task scope. Moreover, tweaking LLM training methodologies to align more closely with ideal causal reasoning structures remains an open avenue for research.
Conclusion
In summary, our paper accentuates the intricate landscape of LLM reasoning, marked by non-causal reasoning patterns and influenced by prevalent training techniques. By pioneering the causal analysis of CoT in LLMs, we hope to pave the way for further research aimed at cultivating more reliable and transparent LLM reasoning processes.