Word Importance Explains How Prompts Affect Language Model Outputs

Fuente: arXiv
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Autori principali: Hackmann, Stefan, Mahmoudian, Haniyeh, Steadman, Mark, Schmidt, Michael
Natura: Preprint
Pubblicazione: 2024
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author Hackmann, Stefan
Mahmoudian, Haniyeh
Steadman, Mark
Schmidt, Michael
author_facet Hackmann, Stefan
Mahmoudian, Haniyeh
Steadman, Mark
Schmidt, Michael
contents The emergence of large language models (LLMs) has revolutionized numerous applications across industries. However, their "black box" nature often hinders the understanding of how they make specific decisions, raising concerns about their transparency, reliability, and ethical use. This study presents a method to improve the explainability of LLMs by varying individual words in prompts to uncover their statistical impact on the model outputs. This approach, inspired by permutation importance for tabular data, masks each word in the system prompt and evaluates its effect on the outputs based on the available text scores aggregated over multiple user inputs. Unlike classical attention, word importance measures the impact of prompt words on arbitrarily-defined text scores, which enables decomposing the importance of words into the specific measures of interest--including bias, reading level, verbosity, etc. This procedure also enables measuring impact when attention weights are not available. To test the fidelity of this approach, we explore the effect of adding different suffixes to multiple different system prompts and comparing subsequent generations with different large language models. Results show that word importance scores are closely related to the expected suffix importances for multiple scoring functions.
format Preprint
id arxiv_https___arxiv_org_abs_2403_03028
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Word Importance Explains How Prompts Affect Language Model Outputs
Hackmann, Stefan
Mahmoudian, Haniyeh
Steadman, Mark
Schmidt, Michael
Artificial Intelligence
Computation and Language
I.2.7; I.5.2
The emergence of large language models (LLMs) has revolutionized numerous applications across industries. However, their "black box" nature often hinders the understanding of how they make specific decisions, raising concerns about their transparency, reliability, and ethical use. This study presents a method to improve the explainability of LLMs by varying individual words in prompts to uncover their statistical impact on the model outputs. This approach, inspired by permutation importance for tabular data, masks each word in the system prompt and evaluates its effect on the outputs based on the available text scores aggregated over multiple user inputs. Unlike classical attention, word importance measures the impact of prompt words on arbitrarily-defined text scores, which enables decomposing the importance of words into the specific measures of interest--including bias, reading level, verbosity, etc. This procedure also enables measuring impact when attention weights are not available. To test the fidelity of this approach, we explore the effect of adding different suffixes to multiple different system prompts and comparing subsequent generations with different large language models. Results show that word importance scores are closely related to the expected suffix importances for multiple scoring functions.
title Word Importance Explains How Prompts Affect Language Model Outputs
topic Artificial Intelligence
Computation and Language
I.2.7; I.5.2
url https://arxiv.org/abs/2403.03028