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Main Authors: Niu, Jingcheng, Liu, Andrew, Zhu, Zining, Penn, Gerald
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2405.02421
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author Niu, Jingcheng
Liu, Andrew
Zhu, Zining
Penn, Gerald
author_facet Niu, Jingcheng
Liu, Andrew
Zhu, Zining
Penn, Gerald
contents We reassess the Knowledge Neuron (KN) Thesis: an interpretation of the mechanism underlying the ability of large language models to recall facts from a training corpus. This nascent thesis proposes that facts are recalled from the training corpus through the MLP weights in a manner resembling key-value memory, implying in effect that "knowledge" is stored in the network. Furthermore, by modifying the MLP modules, one can control the language model's generation of factual information. The plausibility of the KN thesis has been demonstrated by the success of KN-inspired model editing methods (Dai et al., 2022; Meng et al., 2022). We find that this thesis is, at best, an oversimplification. Not only have we found that we can edit the expression of certain linguistic phenomena using the same model editing methods but, through a more comprehensive evaluation, we have found that the KN thesis does not adequately explain the process of factual expression. While it is possible to argue that the MLP weights store complex patterns that are interpretable both syntactically and semantically, these patterns do not constitute "knowledge." To gain a more comprehensive understanding of the knowledge representation process, we must look beyond the MLP weights and explore recent models' complex layer structures and attention mechanisms.
format Preprint
id arxiv_https___arxiv_org_abs_2405_02421
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle What does the Knowledge Neuron Thesis Have to do with Knowledge?
Niu, Jingcheng
Liu, Andrew
Zhu, Zining
Penn, Gerald
Computation and Language
We reassess the Knowledge Neuron (KN) Thesis: an interpretation of the mechanism underlying the ability of large language models to recall facts from a training corpus. This nascent thesis proposes that facts are recalled from the training corpus through the MLP weights in a manner resembling key-value memory, implying in effect that "knowledge" is stored in the network. Furthermore, by modifying the MLP modules, one can control the language model's generation of factual information. The plausibility of the KN thesis has been demonstrated by the success of KN-inspired model editing methods (Dai et al., 2022; Meng et al., 2022). We find that this thesis is, at best, an oversimplification. Not only have we found that we can edit the expression of certain linguistic phenomena using the same model editing methods but, through a more comprehensive evaluation, we have found that the KN thesis does not adequately explain the process of factual expression. While it is possible to argue that the MLP weights store complex patterns that are interpretable both syntactically and semantically, these patterns do not constitute "knowledge." To gain a more comprehensive understanding of the knowledge representation process, we must look beyond the MLP weights and explore recent models' complex layer structures and attention mechanisms.
title What does the Knowledge Neuron Thesis Have to do with Knowledge?
topic Computation and Language
url https://arxiv.org/abs/2405.02421