It would be difficult to come up with a more frequently confused concept in psychology than reinforcement and punishment. In fact, “reinforcement” and “punishment” aren’t difficult to understand on their own: Reinforcement simply means any means of increasing or encouraging the designated behavior; punishment is any means of inhibiting or decreasing the designated behavior.
It was only when B.F. Skinner devised the “positive” and “negative” descriptors that he became the bane of college students for generations to come. Rather than “positive” and “negative,” things would have been much simpler if he had used the terms “by adding” and “by removing.”
The easiest concept to remember is “positive reinforcement.” If you want to train a rat to push a lever, you can reward it by offering a food pellet every time the lever is pressed. The rat will learn very quickly to push the lever. This is positive reinforcement, or “reinforcement by adding.”
But people quickly become confused by the term “negative reinforcement.” It’s much easier to understand if you think of it as “reinforcement by removing.” If the behavior you want to reinforce is pushing a lever, you can also train the rat by removing something when the lever is pushed. For example you could play an annoying sound, and pushing the lever could stop the sound. The rat will quickly learn to press the lever whenever the sound is played. This is negative reinforcement, or “reinforcement by removing.”
Things get trickier when you talk about punishment, or decreasing a behavior. What is “positive punishment”? It’s punishment by adding, remember? Suppose you want to train a rat to stay in one corner of his cage. You could play the annoying sound whenever it is in the wrong part of the cage. This is exactly the way “invisible fences” for dogs work: a sensor on the dog’s collar detects the electrical current from the buried wire and plays a high-frequency sound whenever the dog crosses it. Eventually the dog learns to stay in its yard and out of the neighbor’s flower bed. This is positive punishment, or “punishment by adding.”
And what about negative punishment? That’s probably the trickiest concept of all. What would “punishment by removing” be? Well, think again about training the rat to stay in one corner. You could attach electrodes to its brain and give it a pleasurable electrical stimulation. Then when it left its corner, you could remove the stimulation — that’s punishment for going to the wrong spot in the cage. With a nice enough stimulation, such as simulating sex, it wouldn’t take long to get the rat to stay in its corner all the time. You could also think of this as positive reinforcement: you’re rewarding the rat for the desired behavior of staying in its corner. However, the two concepts are different. You couldn’t in any way say that the first example of providing food when a rat presses a lever is “negative punishment.”
Each of these can be effective methods of training, but positive reinforcement seems to get all the good press. Why is that? When used correctly, positive reinforcement can indeed be extremely effective. Rats learn very quickly to press the correct lever if it always results in a food reward; you can even train them to press a lever dozens of times to get a single food pellet. It can also be a great way to teach your kids good behavior: if you give a young child a sticker every time she brushes her teeth, she’ll do a lot of tooth-brushing.
Punishment, meanwhile — especially positive punishment — is discouraged in most child-rearing advice books. Why? If it’s effective for training rats and dogs, won’t kids learn in the same way? The problem is that children live in a much more complex social environment than dogs and rats. You want your child to stay in his seat at the restaurant, but you also want to talk to your friends. From your perspective, yelling at him when he gets out of his chair is punishment, but from his perspective, that’s the only time you’re talking to him. While he may not like being yelled at, he prefers it to being ignored, so from the child’s perspective, you’re not punishing him for getting out of his seat, you’re reinforcing that behavior. It would probably be better to reward him for staying in his seat by including him in the conversation, or letting him play with a favorite toy if he stays seated. (Though this second option is problematic because the ultimate goal is for children to stay in their seats and not play with toys in restaurants. Maybe you should just get a baby sitter.)
But there are times when punishment is really the only effective way to train your kids. You don’t want to use a reward schedule as the only way to prevent dangerous behavior like running into traffic: one mistake can be tragic, and you can’t practically reward your child every time she doesn’t run out into the street. A time-out when she doesn’t listen to your warnings or heads in the wrong direction is probably more effective.
Though it sounds “cruel,” we have often found very negative punishment to be very effective. If Jim and Nora were fighting over a toy, the quickest way to get them to stop fighting was simply to remove the toy (“punishment by removing”). It didn’t take long for them to learn that trying to get a toy by stealing it from your sibling was not effective!