When to Speak, When to Abstain: Contrastive Decoding with Abstention

Fuente: arXiv
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Hauptverfasser: Kim, Hyuhng Joon, Kim, Youna, Lee, Sang-goo, Kim, Taeuk
Format: Preprint
Veröffentlicht: 2024
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author Kim, Hyuhng Joon
Kim, Youna
Lee, Sang-goo
Kim, Taeuk
author_facet Kim, Hyuhng Joon
Kim, Youna
Lee, Sang-goo
Kim, Taeuk
contents Large Language Models (LLMs) demonstrate exceptional performance across diverse tasks by leveraging pre-trained (i.e., parametric) and external (i.e., contextual) knowledge. While substantial efforts have been made to enhance the utilization of both forms of knowledge, situations in which models lack relevant information remain underexplored. To investigate this challenge, we first present a controlled testbed featuring four distinct knowledge access scenarios, including the aforementioned edge case, revealing that conventional LLM usage exhibits insufficient robustness in handling all instances. Addressing this limitation, we propose Contrastive Decoding with Abstention (CDA), a novel training-free decoding method that allows LLMs to generate responses when relevant knowledge is available and to abstain otherwise. CDA estimates the relevance of both knowledge sources for a given input, adaptively deciding which type of information to prioritize and which to exclude. Through extensive experiments, we demonstrate that CDA can effectively perform accurate generation and abstention simultaneously, enhancing reliability and preserving user trust.
format Preprint
id arxiv_https___arxiv_org_abs_2412_12527
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle When to Speak, When to Abstain: Contrastive Decoding with Abstention
Kim, Hyuhng Joon
Kim, Youna
Lee, Sang-goo
Kim, Taeuk
Computation and Language
Large Language Models (LLMs) demonstrate exceptional performance across diverse tasks by leveraging pre-trained (i.e., parametric) and external (i.e., contextual) knowledge. While substantial efforts have been made to enhance the utilization of both forms of knowledge, situations in which models lack relevant information remain underexplored. To investigate this challenge, we first present a controlled testbed featuring four distinct knowledge access scenarios, including the aforementioned edge case, revealing that conventional LLM usage exhibits insufficient robustness in handling all instances. Addressing this limitation, we propose Contrastive Decoding with Abstention (CDA), a novel training-free decoding method that allows LLMs to generate responses when relevant knowledge is available and to abstain otherwise. CDA estimates the relevance of both knowledge sources for a given input, adaptively deciding which type of information to prioritize and which to exclude. Through extensive experiments, we demonstrate that CDA can effectively perform accurate generation and abstention simultaneously, enhancing reliability and preserving user trust.
title When to Speak, When to Abstain: Contrastive Decoding with Abstention
topic Computation and Language
url https://arxiv.org/abs/2412.12527