Negative reinforcement is a concept that is part of the theory of operant conditioning, a theory developed by psychologist B.F. Skinner. Negative reinforcement, positive reinforcement, punishment, and extinction are the four methods by which behavior is affected in this theory. Although many people associate this type of reinforcement with punishment, this is simply not true. Instead, this kind of conditioning serves to encourage a certain positive behavior by taking away a negative stimulus.
This concept is best illustrated with an example; A common one is a rat in a cage. When the rat is placed in the cage, it may receive a small electric shock, but if the rat presses a small lever, the electric shock stops. The electric shock is the negative stimulus, and when the lever is repeatedly pressed, the negative stimulus is removed. The rat quickly learns, through negative reinforcement, to press the lever and stop the shocks. It is not punishment; instead, it is an example of the removal of a negative stimulus leading to a desired behavior.
This may also occur if someone regularly gets stuck in traffic when going to work, for example. The traffic is the negative stimulus. If this hypothetical person learns that leaving for work earlier prevents getting stuck in traffic, and repeats this pattern with positive results, this is an example of negative reinforcement. This type of conditioning may be used in a number of situations, including in the home, in the classroom, or when training animals, among others.
Conversely, positive reinforcement is a similar concept but features the addition of a desired item rather than the removal of the negative stimulus. For instance, if a child completes all his homework, he might receive a sticker. The sticker is the example of positive reinforcement, because something is added rather than taken away, as in negative reinforcement.
Remember, punishment is not a type of negative reinforcement. Using the homework example again, if a child does not do his homework, he might be punished by staying inside for recess or by missing a class trip. The child will then associate the punishment with the action of not doing his homework, and will theoretically begin to do the homework to avoid punishment. Using these types of operant conditioning may help to affect behavior for the better; generally, it is believed that positive reinforcement is the most effective technique, but the negative variety of reinforcement can also be very effective in some situations, or with some personalities.