Put simply, reinforcement learning is a machine learning technique that involves training an artificial intelligence agent through the repetition of actions and associated rewards.
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A reinforcement learning agent experiments in an environment, taking actions and being rewarded when the correct actions are taken. Over time, the agent learns to take the actions that will maximize its reward. That’s a quick definition of reinforcement learning, but taking a closer look at the concepts behind reinforcement learning will help you gain a better, more intuitive understanding of it.
Reinforcement In Psychology
The term “reinforcement learning” is adapted from the concept of reinforcement in psychology. For that reason, let’s take a moment to understand the psychological concept of reinforcement. In the psychological sense, the term reinforcement refers to something that increases the likelihood that a particular response/action will occur. This concept of reinforcement is a central idea of the theory of operant conditioning, initially proposed by the psychologist B.F. Skinner. In this context, reinforcement is anything that causes the frequency of a given behavior to increase. If we think about possible reinforcement for humans, these can be things like praise, a raise at work, candy, and fun activities.
In the traditional, psychological sense, there are two types of reinforcement. There’s positive reinforcement and negative reinforcement. Positive reinforcement is the addition of something to increase a behavior, like giving your dog a treat when it is well behaved. Negative reinforcement involves removing a stimulus to elicit a behavior, like shutting off loud noises to coax out a skittish cat.
Positive and Negative Reinforcement In Machine Learning
Positive reinforcement increases the frequency of a behavior while negative reinforcement decreases the frequency. In general, positive reinforcement is the most common type of reinforcement used in reinforcement learning, as it helps models maximize the performance on a given task. Not only that but p[positive reinforcement leads the model to make more sustainable changes, changes which can become consistent patterns and persist for long periods of time.
In contrast, while negative reinforcement also makes a behavior more likely to occur, it is used for maintaining a minimum performance standard rather than reaching a model’s maximum performance. Negative reinforcement in reinforcement learning can help ensure that a model is kept away from undesirable actions, but it can’t really make a model explore desired actions.
Training A Reinforcement Agent
When a reinforcement learning agent is trained, there are four different ingredients or states used in the training: initial states (State 0), new state (State 1), actions, and rewards.
Imagine that we are training a reinforcement agent to play a platforming video game where the AI’s goal is to make it to the end of the level by moving right across the screen. The initial state of the game is drawn from the environment, meaning the first frame of the game is analyzed and given to the model. Based on this information, the model must decide on an action. […]