Negative reinforcement is "one of the most consistently misunderstood principles of behaviour."- Cooper, Heron and Heward (2007, p.255)
Negative reinforcement occurs when something already present is removed (taken away) as a result of a person's behaviour, creating a favourable outcome for that person. Basically, when a person's behaviour leads to the removal of something that was unpleasant to that person then negative reinforcement is occuring.
The term "stimulus" would be used within Applied Behaviour Analysis to describe the "something" that is taken away or removed. The stimulus could be anything, for example a person, a noise, a feeling, an emotion or an object.
Technically, for negative reinforcement to occur, the person must engage in the behaviour that created the favourable outcome more frequently in the future (Miltenberger, 2008).
A good way to remember the meaning of the “negative” in negative reinforcement is to think of it in relation to mathematics. When you see a negative symbol in math then it means subtraction.
When you see the term negative used with reinforcement then think of something being subtracted.
Consider someone taking a shower to remove a bad smell; you could say taking the shower led to the subtraction of the bad smell or said another way, taking the shower was negatively reinforced by the removal (subtraction) of the bad smell.
Example One: Turning off a light at night time (Iwata & Smith, 2007).
For arguments sake we’ll say you want the light off at night so you can sleep. By turning off the light you are removing it or “subtracting” it. The light was already present before you pressed the switch to turn it off and once you pressed the switch the light was gone. This removal of light is something that you wanted and so you are more likely to press the light switch at night time in future.
Your behaviour of pressing the switch is negatively reinforced by the removal of the light. Remember that when something is taken away (the light) as a result of your behaviour (pressing the light switch) and it being taken away will lead you to engage in that behaviour again (pressing the light switch every time you go to bed) then negative reinforcement has occurred.
Example Two: Using earplugs to remove an annoying noise.
Mary’s husband Mike sometimes snores during the night and she can’t sleep through it when he does. When Mary is woken by Mike’s snoring she has learned that putting in earplugs blocks out the noise and she can no longer hear his snoring. Every time he now snores she puts in the earplugs – thus there is an increase in this behaviour of putting in earplugs.
Before Mary put in her earplugs, there was an aversive stimulus present – Mike’s snoring – these earplugs then blocked out this stimulus (snoring) or you could say it was removed. Mary’s use of earplugs has been strengthened because they remove this aversive stimulus and so negative reinforcement has occurred.
Take note that negative reinforcement is not a bad thing, in fact it's a good thing and to make this point we suggest you read our examples of negative reinforcement.
This belief that negative reinforcement is a bad thing is understandable given the word "negative" is used; this has led to the term being very misunderstood (Cooper, et al 2008).
Negative reinforcement is the opposite of positive reinforcement. Since positive reinforcement means “reward” then negative reinforcement means “punishment”.
It’s true that positive reinforcement is often just called “reward” but it’s also possible to say that negative reinforcement “rewards” for engaging in a behaviour. A basic example of how negative reinforcement is rewarding can be seen by how a college student gets rid of some “body odour” by taking a shower.
This college student, Steve, hasn’t had a shower in about a month and now notices he’s starting to give off a pretty awful smell. This smell is pretty aversive and so he decides to have a shower. After taking the shower the smell is gone and so his behaviour of having a shower was negatively reinforced with the removal of the smell.
In the example above, the smell is already present so he then takes a shower that makes the smell go away; because the shower got rid of the smell there is an increased likelihood that he will take a shower again when he needs to get rid of his body odour in the future.
Positive reinforcement, on the other hand, is when something that is not already present in an environment is added when a person engages in a behaviour and the behaviour that led to this addition will also increase (Cooper, Heron, & Heward, 2007).
Continuing with Steve’s showering; when he steps into the shower there is no water coming out of the shower-head, he then turns on the hot-water tap (faucet) and water comes out. In this case, his behaviour of turning on the hot-water tap was positively reinforced with the addition of hot-water.
So you can hopefully now see how both positive and negative reinforcement are “rewarding” or in another way, how the outcomes from both forms of reinforcement are favourable. Removing an unwanted smell occurred through negative reinforcement and this was a good outcome for the student because he wanted the smell gone – he wasn’t punished for having a shower!
It is important to remember that the outcomes (consequences) from both positive and negative reinforcement are favourable and so the behaviours that led to the reinforcement are more likely to occur again in the future.
In contrast, punishment occurs when the outcomes from engaging in a behaviour are not favourable and so the behaviours that led to the punishment will reduce in the future. For example, if you put your hand in the fire and get burned you’re unlikely to do it again in the future, so there won’t be an increase in this type of behaviour.
Negative reinforcement is when someone engages in a “negative” or “bad” behaviour and gets something from it.
Another example might best dispel this one too . A parent and child are grocery shopping. When they pass the sweet section the child grabs a big bag of sweets and throws them into the trolley. The parent takes them out and tells the child to put them back. The child flops on the ground and starts screaming because he wants the sweets. The parent notices people staring at them and to stop the child’s tantrum gives in and allows him to have the sweets.
This boy’s behaviour could be termed “negative” and therefore it may seem like the tantrum (his behaviour) was negatively reinforced with sweets. However, his behaviour was actually positively reinforced because he was given the sweets!
Remember that positive reinforcement is when your behaviour gets you something that you wanted but that was not already present. The boy didn’t have sweets so he threw a tantrum (behaviour) and this tantrum got him sweets. Negative reinforcement is when something that is already present is taken away as a result of behaviour and it’s removal was something that you wanted (remember Steve’s bad smell?).
In this example it was actually the parent’s behaviour that was negatively reinforced. The parent did not like the tantrum or the attention it was bringing (creating an aversive situation for the parent). This aversive situation was present before the parent allowed the child to have the sweets. After the parents behaviour (giving him the sweets) the boy stopped tantruming and so the aversive situation was gone (removed). Therefore the parent’s behaviour was negatively reinforced.
An important requirement for something to be termed “reinforcement” (whether positive or negative) is that the behaviour that led to the reinforcement must be strengthened or increased (Miltenberger, 2008).
Pretend that you notice a bad smell coming from your own body and you want it gone. You decide to stand on your head…but this doesn’t make the smell go away. In this case, your behaviour of standing on your head was not negatively reinforced with the removal of the smell.
The next time you have a smell and want it gone, you’re unlikely to stand on your head because doing this in the past was not reinforced by its removal. So in this case your behaviour of standing on your head is not strengthened and will not increase in the future and so negative reinforcement does not occur.
Now think of taking a shower to get rid of the smell. This shower will cause the smell to go away and so your behaviour of taking a shower will be negatively reinforced by the removal of the smell. Therefore, the next time you have a bad smell you’re more likely to take a shower again.
In this case, the behaviour of taking a shower is strengthened and there will be an increased future frequency of that behaviour. It can only be said that “reinforcement” has occurred when there will be an increase in the future frequency or strengthening of the behaviour (Iwata & Smith, 2007; Miltenberger, 2008).
Devlin, Leader, and Healy (2009) conducted a study to investigate whether a behavioural intervention or a sensory-based treatment would reduce self-injurious behaviour (SIB) in a 9-year-old boy diagnosed with autism. The researchers used a functional behaviour assessment to identify the functions maintaining the boy’s SIB. A functional assessment is basically a way of identifying why a person engages in a certain behaviour .
This assessment showed that he was engaging in self-injury because of negative reinforcement. The boy was engaging in self-injurious behaviour because every time he hit himself his teachers stopped the teaching sessions. To the boy, these teaching sessions were aversive and he didn’t want to be doing them, so he wanted to “escape” from them and had learned that by hitting himself the teachers would remove the aversive situation.
An aversive situation creates the desire to escape from it and if a certain behaviour allows you to escape from it you are more likely to engage in that behaviour again (negative reinforcement).
Let’s break it down a little more. The teaching session was being conducted (present before his self-injury), he then engaged in self-injury (behaviour) and the teachers stopped the teaching session. His self-injurious behaviour (SIB) was being negatively reinforced by the ending (removal) of the teaching sessions. Basically, this boy wanted to escape from having to do these academic tasks and he had learned that the consequence (outcome) of his SIB was that his teachers stopped asking him to do any school work.
Fortunately, the functional assessment identified this and allowed the researchers to develop an appropriate intervention to successfully reduce his SIB. The results of that study demonstrated ‘the effectiveness of a behavioural intervention over a sensory-based intervention in treating SIB’ (Devlin, Leader & Healy, 2009, p. 230).
Aversive stimuli (e.g. bad smell, noisy tantrums, snoring) generally create a desire to get away from them, i.e. escape. Typically, the term “escape” relates to the person leaving the aversive situation, like escaping from prison. However, the term is also used in relation to the removal of the aversive stimulus itself while you stay where you are.
Think of the bad smell example. You don’t walk away from the smell and leave it behind you. Instead you are stuck with it until you take a shower but the behaviour of taking the shower is still an attempt to escape from the aversive stimulus.
It’s important to note that there is a distinction between escape behaviour and avoidance behaviour (Miltenberger, 2008). Escape occurs when a behaviour removes an aversive stimulus that is already present while avoidance prevents the aversive stimulus from occurring in the first place. Note though that both escape and avoidance behaviour are still maintained by negative reinforcement (Iwata & Smith, 2007).
For example, the bad smell is already present so you then decide to take a shower which is an “escape”. Avoidance occurs when a behaviour prevents the aversive stimulus from “happening” in the first place. So if you know you start to smell from not showering then your behaviour of showering is likely to increase to prevent the smell from happening and this would be “avoidance”.The distinction comes down to whether the behaviour removes an already present aversive stimulus (escape) or prevents the occurrence of an aversive stimulus (avoidance).
Another example could be when you walk outside and the sun glare hurts your eyes. Because of the glare you decide to then put on sunglasses to escape from it but if you put the sun glasses on before you went outside in the sun then this would be avoiding the pain in the first place. In both cases, negative reinforcement maintains the behaviour of putting on the sun-glasses because it removes the glare of the sun.
Technically, it is possible to say that when negative reinforcement occurs then positive reinforcement is also occurring and vice-versa. Take the example of turning off the light at night time. If you look at it from the perspective of removing the light then negative reinforcement has occurred.
However, if you look at it from the perspective of adding darkness then positive reinforcement has occurred. The behaviour in both cases is the same (pressing the light switch) and the outcomes are the same too (light is removed and darkness is added) it just depends on how you look at it.
There have been a number of articles written about this (Michael, 1975) and recently the subject was discussed again in a number of published articles in the 2006 Spring edition of The Behaviour Analyst. All of these articles are freely available to read if you’re curiosity takes you there (scroll down to the bottom of that linked page to access those articles).