A Critical Evaluation of AI Feedback for Aligning Large Language Models

Fuente: arXiv
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Autori principali: Sharma, Archit, Keh, Sedrick, Mitchell, Eric, Finn, Chelsea, Arora, Kushal, Kollar, Thomas
Natura: Preprint
Pubblicazione: 2024
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author Sharma, Archit
Keh, Sedrick
Mitchell, Eric
Finn, Chelsea
Arora, Kushal
Kollar, Thomas
author_facet Sharma, Archit
Keh, Sedrick
Mitchell, Eric
Finn, Chelsea
Arora, Kushal
Kollar, Thomas
contents Reinforcement learning with AI feedback (RLAIF) is a popular paradigm for improving the instruction-following abilities of powerful pre-trained language models. RLAIF first performs supervised fine-tuning (SFT) using demonstrations from a teacher model and then further fine-tunes the model with reinforcement learning (RL), using feedback from a critic model. While recent popular open-source models have demonstrated substantial improvements in performance from the RL step, in this paper we question whether the complexity of this RL step is truly warranted for AI feedback. We show that the improvements of the RL step are virtually entirely due to the widespread practice of using a weaker teacher model (e.g. GPT-3.5) for SFT data collection than the critic (e.g., GPT-4) used for AI feedback generation. Specifically, we show that simple supervised fine-tuning with GPT-4 as the teacher outperforms existing RLAIF pipelines. More generally, we find that the gains from RLAIF vary substantially across base model families, test-time evaluation protocols, and critic models. Finally, we provide a mechanistic explanation for when SFT may outperform the full two-step RLAIF pipeline as well as suggestions for making RLAIF maximally useful in practice.
format Preprint
id arxiv_https___arxiv_org_abs_2402_12366
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A Critical Evaluation of AI Feedback for Aligning Large Language Models
Sharma, Archit
Keh, Sedrick
Mitchell, Eric
Finn, Chelsea
Arora, Kushal
Kollar, Thomas
Machine Learning
Artificial Intelligence
Computation and Language
Reinforcement learning with AI feedback (RLAIF) is a popular paradigm for improving the instruction-following abilities of powerful pre-trained language models. RLAIF first performs supervised fine-tuning (SFT) using demonstrations from a teacher model and then further fine-tunes the model with reinforcement learning (RL), using feedback from a critic model. While recent popular open-source models have demonstrated substantial improvements in performance from the RL step, in this paper we question whether the complexity of this RL step is truly warranted for AI feedback. We show that the improvements of the RL step are virtually entirely due to the widespread practice of using a weaker teacher model (e.g. GPT-3.5) for SFT data collection than the critic (e.g., GPT-4) used for AI feedback generation. Specifically, we show that simple supervised fine-tuning with GPT-4 as the teacher outperforms existing RLAIF pipelines. More generally, we find that the gains from RLAIF vary substantially across base model families, test-time evaluation protocols, and critic models. Finally, we provide a mechanistic explanation for when SFT may outperform the full two-step RLAIF pipeline as well as suggestions for making RLAIF maximally useful in practice.
title A Critical Evaluation of AI Feedback for Aligning Large Language Models
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2402.12366