A Bayesian Solution To The Imitation Gap

Fuente: arXiv
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Autori principali: Vuorio, Risto, Fellows, Mattie, Lu, Cong, Grislain, Clémence, Whiteson, Shimon
Natura: Preprint
Pubblicazione: 2024
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author Vuorio, Risto
Fellows, Mattie
Lu, Cong
Grislain, Clémence
Whiteson, Shimon
author_facet Vuorio, Risto
Fellows, Mattie
Lu, Cong
Grislain, Clémence
Whiteson, Shimon
contents In many real-world settings, an agent must learn to act in environments where no reward signal can be specified, but a set of expert demonstrations is available. Imitation learning (IL) is a popular framework for learning policies from such demonstrations. However, in some cases, differences in observability between the expert and the agent can give rise to an imitation gap such that the expert's policy is not optimal for the agent and a naive application of IL can fail catastrophically. In particular, if the expert observes the Markov state and the agent does not, then the expert will not demonstrate the information-gathering behavior needed by the agent but not the expert. In this paper, we propose a Bayesian solution to the Imitation Gap (BIG), first using the expert demonstrations, together with a prior specifying the cost of exploratory behavior that is not demonstrated, to infer a posterior over rewards with Bayesian inverse reinforcement learning (IRL). BIG then uses the reward posterior to learn a Bayes-optimal policy. Our experiments show that BIG, unlike IL, allows the agent to explore at test time when presented with an imitation gap, whilst still learning to behave optimally using expert demonstrations when no such gap exists.
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id arxiv_https___arxiv_org_abs_2407_00495
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A Bayesian Solution To The Imitation Gap
Vuorio, Risto
Fellows, Mattie
Lu, Cong
Grislain, Clémence
Whiteson, Shimon
Machine Learning
In many real-world settings, an agent must learn to act in environments where no reward signal can be specified, but a set of expert demonstrations is available. Imitation learning (IL) is a popular framework for learning policies from such demonstrations. However, in some cases, differences in observability between the expert and the agent can give rise to an imitation gap such that the expert's policy is not optimal for the agent and a naive application of IL can fail catastrophically. In particular, if the expert observes the Markov state and the agent does not, then the expert will not demonstrate the information-gathering behavior needed by the agent but not the expert. In this paper, we propose a Bayesian solution to the Imitation Gap (BIG), first using the expert demonstrations, together with a prior specifying the cost of exploratory behavior that is not demonstrated, to infer a posterior over rewards with Bayesian inverse reinforcement learning (IRL). BIG then uses the reward posterior to learn a Bayes-optimal policy. Our experiments show that BIG, unlike IL, allows the agent to explore at test time when presented with an imitation gap, whilst still learning to behave optimally using expert demonstrations when no such gap exists.
title A Bayesian Solution To The Imitation Gap
topic Machine Learning
url https://arxiv.org/abs/2407.00495