Partial Identifiability in Inverse Reinforcement Learning For Agents With Non-Exponential Discounting

Fuente: arXiv
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Main Authors: Skalse, Joar, Abate, Alessandro
Format: Preprint
Published: 2024
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author Skalse, Joar
Abate, Alessandro
author_facet Skalse, Joar
Abate, Alessandro
contents The aim of inverse reinforcement learning (IRL) is to infer an agent's preferences from observing their behaviour. Usually, preferences are modelled as a reward function, $R$, and behaviour is modelled as a policy, $π$. One of the central difficulties in IRL is that multiple preferences may lead to the same observed behaviour. That is, $R$ is typically underdetermined by $π$, which means that $R$ is only partially identifiable. Recent work has characterised the extent of this partial identifiability for different types of agents, including optimal and Boltzmann-rational agents. However, work so far has only considered agents that discount future reward exponentially: this is a serious limitation, especially given that extensive work in the behavioural sciences suggests that humans are better modelled as discounting hyperbolically. In this work, we newly characterise partial identifiability in IRL for agents with non-exponential discounting: our results are in particular relevant for hyperbolical discounting, but they also more generally apply to agents that use other types of (non-exponential) discounting. We significantly show that generally IRL is unable to infer enough information about $R$ to identify the correct optimal policy, which entails that IRL alone can be insufficient to adequately characterise the preferences of such agents.
format Preprint
id arxiv_https___arxiv_org_abs_2412_11155
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Partial Identifiability in Inverse Reinforcement Learning For Agents With Non-Exponential Discounting
Skalse, Joar
Abate, Alessandro
Machine Learning
Artificial Intelligence
The aim of inverse reinforcement learning (IRL) is to infer an agent's preferences from observing their behaviour. Usually, preferences are modelled as a reward function, $R$, and behaviour is modelled as a policy, $π$. One of the central difficulties in IRL is that multiple preferences may lead to the same observed behaviour. That is, $R$ is typically underdetermined by $π$, which means that $R$ is only partially identifiable. Recent work has characterised the extent of this partial identifiability for different types of agents, including optimal and Boltzmann-rational agents. However, work so far has only considered agents that discount future reward exponentially: this is a serious limitation, especially given that extensive work in the behavioural sciences suggests that humans are better modelled as discounting hyperbolically. In this work, we newly characterise partial identifiability in IRL for agents with non-exponential discounting: our results are in particular relevant for hyperbolical discounting, but they also more generally apply to agents that use other types of (non-exponential) discounting. We significantly show that generally IRL is unable to infer enough information about $R$ to identify the correct optimal policy, which entails that IRL alone can be insufficient to adequately characterise the preferences of such agents.
title Partial Identifiability in Inverse Reinforcement Learning For Agents With Non-Exponential Discounting
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2412.11155