Behaviorism is a systematic approach to understand the behavior of humans and other animals. It assumes that all behaviors are either reflexes produced by a response to certain stimuli in the environment, or a consequence of that individual's history. During the first half of the twentieth century, John B. Watson devised methodological behaviorism, which rejected introspective methods and sought to understand behavior by only measuring observable behaviors and events. It was not until the 1930s that B. F. Skinner suggested that private events, including thoughts and feelings, should be subjected to the same controlling variables as observable behavior.

The work of Skinner was rooted in a view that classical conditioning was far too simplistic to be a complete explanation of complex human behavior. He believed that the best way to understand behavior is to look at the causes of an action and its consequences. He called this approach operant conditioning. Operant conditioning is a method of learning that occurs through rewards and punishments for behavior. Through operant conditioning, an individual makes an association between a particular behavior and a consequence. Reinforcement and punishment are the core tools through which operant behavior is modified. Positive reinforcement and negative reinforcement increase the probability of a behavior that they follow, while positive punishment and negative punishment reduce the probability of behavior that they follow.

Behavior modification is a set of therapies based on operant conditioning. The main principle comprises changing environmental events that are related to a person's behavior. For example, the reinforcement of desired behaviors and ignoring or punishing undesired ones. There are different types of positive reinforcements. Primary reinforcement is when a reward strengths a behavior by itself. Secondary reinforcement is when something strengthens a behavior because it leads to a primary reinforcer. Examples of behavior modification therapy include token economy and behavior shaping. Token economy is a system in which targeted behaviors are reinforced with tokens (secondary reinforcers) and later exchanged for rewards (primary reinforcers). As a mom of three kids, I used token economy intuitively at home and realized that it is widely adapted in early childhood education. While my kids grow older, I noticed approaches involve more introspective work lead them find their own strength and go further in the long run.