Distributional reasoning in LLMs: Parallel Reasoning Processes in Multi-hop Reasoning

26 Sept 2024 (modified: 05 Feb 2025)Submitted to ICLR 2025EveryoneRevisionsBibTeXCC BY 4.0
Keywords: LLM, Multihop reasoning, Interpretability
TL;DR: An interpretable analysis of internal multi-hop reasoning processes in LLMs, taking into account the existence of parallel reasoning processes
Abstract: Large language models (LLMs) have shown an impressive ability to perform tasks believed to require "thought processes”. When the model does not document an explicit thought process, it's difficult to understand the processes occurring within its hidden layers, and to determine if this process can be referred to as reasoning. We introduce a novel and interpretable analysis of internal multi-hop reasoning processes in LLMs. We demonstrate that the prediction process for compositional reasoning questions can be modeled using a simple linear transformation between two semantic category spaces. We show that during inference, the middle layers of the network generate highly interpretable embeddings that represent a set of potential intermediate answers for the multi-hop question. We use statistical analyses to show that a corresponding subset of tokens is activated in the model's output, implying the existence of parallel reasoning paths. These observations hold true even when the model lacks the necessary knowledge to solve the task. Our findings can help uncover the strategies that LLMs use to solve reasoning tasks, offering insights into the types of thought processes that can emerge from artificial intelligence. Finally, we also discuss the implication of cognitive modeling of these results.
Supplementary Material: zip
Primary Area: interpretability and explainable AI
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Submission Number: 7422
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