B. F. Skinner’s most important work was the concept of operant conditioning. Essentially, operant conditioning is when someone learns a behavior as the result of the rewards and punishments associated with that behavior. Operant conditioning can be broken down into four types:
- Positive Reinforcement: This is when a behavior is strengthened and the probability of its recurring increases because a positive condition was the result.
- Negative Reinforcement: A behavior is strengthened as a result of avoiding or stopping a negative condition.
- Punishment: This occurs when a behavior is weakened and the probability of the behavior recurring decreases due to a negative condition being the result.
- Extinction: When a behavior is weakened because the result did not lead to a positive condition or a negative condition.
Positive and negative reinforcement will strengthen a particular behavior, making it more likely to occur, and punishment and extinction will weaken a particular behavior.
To see operant conditioning in action, B. F. Skinner performed a very simple experiment and invented the operant conditioning chamber, which is now often referred to as the Skinner Box.
- To conduct the experiment, begin by placing a hungry rat inside of the box. Every time the rat presses a lever inside the box, it will receive a pellet of food. The rat will soon come to learn that by pressing the lever, it will get food (a positive condition), and thus a behavior is strengthened by positive reinforcement.
- Next, place a rat into the box and then give it a slight electrical shock (a negative condition) to its feet. If the rat presses the lever, the shock will stop. Then send another slight electrical shock to the rat’s feet. Once again, when the rat presses the lever, the electrical shock stops. Every time the rat is given an electrical shock, the rat learns that in order to stop it, it must press the lever. This is an example of negative reinforcement, because the rat is learning a behavior in order to stop a negative condition.
- Place a rat into the box and give it a slight electrical shock (the negative condition) on its feet each time it presses the lever. The behavior of pressing the lever will be weakened because of the negative condition: this is an example of punishment.
- Now, place the rat into the box and do not give it food or an electrical shock whenever the lever is pressed. The rat will not associate a positive or negative condition to the behavior of pressing the lever, and thus this behavior will be weakened. This is an example of extinction.

In 1943, Skinner’s pregnant wife asked him to build a safer baby crib for their child. Always the inventor, Skinner created a heated crib that was enclosed with a plexiglass window and called it the Baby Tender. Skinner sent an article to Ladies’ Home Journal, and they printed the story as “Baby in a Box.” With the legacy of Skinner’s work in operant conditioning, a rumor spread that Skinner had used his experimental operant conditioning chamber on his own daughter and that it eventually drove her crazy to the point of suicide. These rumors, however, were completely false.