Pain behaviour: what is it and what do we do about it?


I’m re-reading Fordyce’s classic Behavioral Methods for Chronic Pain and Illness and once again I’m struck by how many of the concepts he introduced and systematically investigated are either mis-interpreted and ignored in our current approaches to helping people with persistent pain. Today I’ll explore just a tiny portion of what Fordyce described.

Pain behaviour refers to all the observable actions we do in relation to experiencing pain (NB some people include thoughts as well, but for today I’ll just focus on observable actions). There are roughly two groups of actions: those involuntary ones that we can call nocifensive responses that include reflex withdrawal underpinned by spinal reflexes but including brainstem circuits (see Barik, Hunter Thompson, Seltzer, Ghitani & Chesler, 2018); and those that are developed and shaped by learning (operant conditioning as well as social learning).

When I write about learning, I often have comments about this suggesting people have a choice about what they do, and that this learning must involve conscious awareness – the upshot of these comments is the idea that if we just tell someone that they’re doing something, information alone will be sufficient to change how often they’re doing it. Well, I don’t know about you, but if you’ve ever chewed your nails, changed your diet, decided to go on a social media diet, or do more exercise, you’ll know that there’s an enormous gap between knowing about and being able to follow through. So let me review some of the processes involved in learning and pain behaviour.

Pain behaviour probably has evolutionary significance. What we do when we’re sore acts as a signal to others, whether those actions are voluntary or involuntary. For example, while limping off-loads weight from the sore limb, it can also function to let other people know there’s something wrong. Groaning or sighing also lets people around us know that we’re not OK. Remembering that we’re a social species, being able to let others know that we need help – or not to do what we just did – means we’re more likely to receive attention, and also to warn others about potential danger. Of course, by eliciting help, we’re kinda obligated to help others when they do the same, which may be why when we see someone demonstrating prolonged pain behaviours we tend to feel annoyed: we might be asking ourselves “If they’re not going to reciprocate, why would I help? Dem’s the rules”

Now pain behaviour is also subject to learning principles. In other words, the specific behaviours we do develop in form and frequency depending on context. The underlying analysis goes like this: an antecedent is present (maybe it’s a particular person, location, or occasion), the behaviour occurs, then something in the environment/context occurs – and it’s this “something in the environment/context” that influences whether the behaviour is repeated, and/or the frequency of that behaviour. The easiest example of this is when you watch a three-year-old playing just a little distance from Mum and Dad. When she trips and falls, she’ll probably get up and brush herself down – and then you’ll see her look for Mum or Dad, and if they’re close enough, she’ll probably let out a bit of wail. In the context of Mum and Dad and her falling over, she’s learned that if she cries she’s likely to get a cuddle or some attention, and this is nice. In the absence of Mum and Dad, if she trips she’s less likely to cry because she’s not likely to get that cuddle. Clever huh?

So if that kind of learning occurs from the time we’re little, it’s easy to see how rapidly this pattern of behaving can become habitual, and when it’s habitual it’s unlikely to be something the child is aware she’s doing. Crying, or seeking attention, when we’re sore is something we’ve learned to do from an early age and while the form of that attention likely differs as we mature, the underlying mechanisms still apply (please don’t scream the place down when you go get your Covid vaccination! It’s OK for babies to cry, but not quite so socially appropriate for grown-ups to cry!).

How does the form of that behaviour change? It’s called “shaping” and it is something that occurs naturally through social learning, and it can also occur in a planned way. Take the example of the three-year-old falling and crying: crying is probably OK outdoors where there’s plenty of room and not too much attention being paid to the interactions between parents and child. Take that same behaviour indoors, perhaps in a supermarket or worse – a quiet waiting room – and it’s likely the parents will shush the child more quickly, and be a little more firm about any ongoing wailing. The context is different, the parents respond differently, and the child learns that it’s not OK to cry loudly where there are other people who might not approve. Over time children learn that in different contexts, different ways to attract attention are required. Clearly there’s more technical language we can use to describe this process, but for our purposes this is enough.

Why do we care about this?

Pain behaviour is normal. It’s something we all do. Mostly it functions in a positive way. We signal to others that we need help, we protect the sore body part, and gradually we recover and resume normal life. In some contexts, though, the tendency to continue doing pain behaviours outlives its welcome. In persistent pain it’s particularly problematic, but it’s also problematic in acute pain situations.

Let’s take the example of the dreaded pain rating scale. The 0 = no pain to 10 = most severe pain I can imagine scale. In the context of an emergency room, being asked to rate pain is a quick and very practical way for clinicians to decide how severe the presumed injury/tissue damage is, whether the person needs analgesia, and whether they’re responding to it. Give a number less than 3 or 4 and you’re probably not going to get a lot of pain relief. Give a number closer to 10, and you’ll get something. Give a number greater than 10 and you may get raised eyebrows. In an experiment by Herta Flor (Flor, Knost & Birbaumer, 2002), participants were given an electric shock and asked to rate their pain intensity (also nociceptive detection threshold (aka pain threshold) and pain tolerance). After they’d rated their pain over several trials, they were given one of two conditions: one in which they were given smiley faces and money when their rating was higher than their average rating for the previous trials, and one in which they were given a sad smiley when their rating was lower than their average. Flor and colleagues found that those people who had been given positive smiley faces for higher pain ratings rated their pain intensity significantly higher than those who had been given neutral or negative smileys.

This experiment doesn’t reflect changes in pain intensity. And this is a critical point to note! The stimuli were the same across both groups. What changed was the response offered to participants after they rated their pain. In other words, behaviour associated with experiencing pain and the resultant rewards given for higher ratings was reinforced.

This experiment, along with a large number of others, is one reason why I don’t like pain intensity measures being taken at every treatment session. Pain intensity ratings are behaviours subject to the contingencies that all behaviour is subject to – people learn what to do, and they do it. And they’re unaware of this process.

We often rely on pain intensity ratings in both experimental studies and clinical practice. Unfortunately, while a numeric rating scale or visual analogue scale are quick and dirty, they’re not like a pain thermometer. We just don’t have an objective measure of pain intensity. And we forget this.

Where am I going with this?

A couple of points. I don’t think we can always influence a person’s experience of their pain. This means that we’re often needing to influence what they do about it – because prolonged distress and disability is not good for anyone. Given the social nature of our species, and the involuntary nature of our response to another person’s distress, we’re inclined to try to reduce distress by offering comfort. Nothing wrong with that except where it gets in the way of the person beginning to do things for themselves. As clinicians we need to reinforce actions a person does to increase their capabilities. We also need to limit our reinforcement of illness behaviour, and we need to do this with the consent of the person – being open about why we’re doing this. Remember people learn this stuff without knowing they’re learning it! This means that as clinicians we must stop judging people and what they do in response to pain. Pain behaviour is learned over a loooong time, and it’s reinforced in so many places. People don’t do pain behaviour on purpose. So we can’t judge people as being “non-copers” or having “exaggerated illness behaviour” – we can just gently show the person what happens, why it happens, and what the effect of that pattern of behaving is having on their life.

The second point is that we can’t treat pain ratings as Truth with a T, and think that we’re getting a pure measure of pain intensity – because rating pain on a scale is a behaviour, and it’s influenced in exactly the same way as all behaviours are. This doesn’t mean ignoring someone’s pain intensity – it just means we need to listen to what the person is trying to communicate.

Barik, A., Thompson, J. H., Seltzer, M., Ghitani, N., & Chesler, A. T. (2018). A Brainstem-Spinal Circuit Controlling Nocifensive Behavior. Neuron, 100(6), 1491-1503 e1493. doi: 10.1016/j.neuron.2018.10.037

Flor, Herta, Knost, Bärbel, & Birbaumer, Niels. (2002). The role of operant conditioning in chronic pain: an experimental investigation. Pain, 95(1), 111-118. doi: https://doi.org/10.1016/S0304-3959(01)00385-2

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