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Main Authors: Cohen, Michael K., Hutter, Marcus, Bengio, Yoshua, Russell, Stuart
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2410.06213
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author Cohen, Michael K.
Hutter, Marcus
Bengio, Yoshua
Russell, Stuart
author_facet Cohen, Michael K.
Hutter, Marcus
Bengio, Yoshua
Russell, Stuart
contents In reinforcement learning, if the agent's reward differs from the designers' true utility, even only rarely, the state distribution resulting from the agent's policy can be very bad, in theory and in practice. When RL policies would devolve into undesired behavior, a common countermeasure is KL regularization to a trusted policy ("Don't do anything I wouldn't do"). All current cutting-edge language models are RL agents that are KL-regularized to a "base policy" that is purely predictive. Unfortunately, we demonstrate that when this base policy is a Bayesian predictive model of a trusted policy, the KL constraint is no longer reliable for controlling the behavior of an advanced RL agent. We demonstrate this theoretically using algorithmic information theory, and while systems today are too weak to exhibit this theorized failure precisely, we RL-finetune a language model and find evidence that our formal results are plausibly relevant in practice. We also propose a theoretical alternative that avoids this problem by replacing the "Don't do anything I wouldn't do" principle with "Don't do anything I mightn't do".
format Preprint
id arxiv_https___arxiv_org_abs_2410_06213
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle RL, but don't do anything I wouldn't do
Cohen, Michael K.
Hutter, Marcus
Bengio, Yoshua
Russell, Stuart
Machine Learning
In reinforcement learning, if the agent's reward differs from the designers' true utility, even only rarely, the state distribution resulting from the agent's policy can be very bad, in theory and in practice. When RL policies would devolve into undesired behavior, a common countermeasure is KL regularization to a trusted policy ("Don't do anything I wouldn't do"). All current cutting-edge language models are RL agents that are KL-regularized to a "base policy" that is purely predictive. Unfortunately, we demonstrate that when this base policy is a Bayesian predictive model of a trusted policy, the KL constraint is no longer reliable for controlling the behavior of an advanced RL agent. We demonstrate this theoretically using algorithmic information theory, and while systems today are too weak to exhibit this theorized failure precisely, we RL-finetune a language model and find evidence that our formal results are plausibly relevant in practice. We also propose a theoretical alternative that avoids this problem by replacing the "Don't do anything I wouldn't do" principle with "Don't do anything I mightn't do".
title RL, but don't do anything I wouldn't do
topic Machine Learning
url https://arxiv.org/abs/2410.06213