# Synonyms

- Intent recognition
- Inverse optimal control
- Plan recognition

# Definition

Inverse reinforcement learning (inverse RL) considers the problem of extracting a reward function from observed (nearly) optimal behavior of an expert acting in an environment.

# Motivation and Background

The motivation for inverse RL is two fold:

- For many RL applications, it is difficult to write down an explicit reward function specifying how different desiderata should be traded off exactly. In fact, engineers often spend significant effort tweaking the reward function such that the optimal policy corresponds to performing the task they have in mind. For example, consider the task of driving a car well. Various desiderata have to be traded off, such as speed, following distance, lane preference, frequency of lane changes, distance from the curb, and so on. Specifying the reward function for the task of driving requires explicitly writing down the trade-off between these features.

Inverse RLâ€¦