Machine Learning for Humans, Part 5: Reinforcement Learning

In supervised learning, training data comes with an answer key from some godlike "supervisor". If only life worked that way! In reinforcement learning (RL) there's no answer key, but your reinforcement learning agent still has to decide how to act to perform its task. In the absence of existing training data, the agent learns from experience. It collects the training examples ("this action was good, that action was bad") through trial-and-error as it attempts its task, with the goal of maximizing long-term reward.