the technique of reinforcement learning is concerned with the problem of finding suitable actions to take in a given situation in order to maximize a reward
Christopher M. Bishop - «Pattern Recognition and Machine Learning» (2006)
Reinforcement learning is an area of machine learning concerned with how software agents ought to take actions in an environment so as to maximize some notion of cumulative reward. Reinforcement learning is considered as one of three machine learning paradigms, alongside supervised learning and unsupervised learning.
en.wikipedia.org/wiki/Reinforcement_learning
In the context of reinforcement learning, an autonomous agent must learn to perform a task by trial and error, without any guidance from the human operator.