On his fantastic website PainScience.com, Paul Ingram has an article “Pain is Weird“.
It’s a great article, which I’d recommend reading. (You can also see my articles on chronic pain here and here)
But is pain actually weird?
Perception is Weird
In the article, Ingram cites the following quote:
Pain is an opinion on the organism’s state of health rather than a mere reflective response to an injury. There is no direct hotline from pain receptors to ‘pain centers’ in the brain. There is so much interaction between different brain centers, like those concerned with vision and touch, that even the mere visual appearance of an opening fist can actually feed all the way back into the patient’s motor and touch pathways, allowing him to feel the fist opening, thereby killing an illusory pain in a nonexistent hand.
Phantoms in the brain, by VS Ramachandran and Sandra Blakeslee
The patient being referred to was suffering from “phantom limb pain” – he was in agony from the feeling of a permanently clenched fist in a hand that had been amputated.
With a clever arrangement of mirrors, Ramachandran created the illusion that the man’s amputated arm was restored — a sort of “virtual” limb. The mere appearance
Pain is Weird, Paul Ingram
of his phantom hand opening and closing normally cured his agonizing “spasms.” He felt better because of the illusion that he was better – because he thought he was better.
That does seem pretty weird.
But when you dig into it, all forms of perception are in fact pretty damn strange!
We are under the illusion that we simply “experience the world as it is”. That we see, hear, touch, taste and smell things as they are, but the research shows that this is far from what actually happens.
So while it’s true that “pain is an opinion”, perhaps so is everything else.
Top Down vs Bottom Up
The traditional view is of pain as a “damage meter” – Trauma is inflicted; nerve endings in the tissue detect the damage and relay it to the brain.
Science has shown this to be an overly simplistic model however.
Sensory information detected by nociceptors is indeed relayed to the brain via nerves (interoception), but it is neither sufficient on its own, nor necessarily has to be present, for the brain to generate the experience of pain.
The brain also gathers information from lots of other areas – proprioception (info about the body’s posture and position), exteroception (what you can see, hear, etc), cognition (expectations, beliefs, emotional state, etc).
Whether or not you experience the sensation of pain or not depends upon your brain’s opinion of all this information combined.
In much the same way, the traditional view of vision is that it works like a video camera, that hearing works like a microphone, and so on. But again science has shown these to be very bad analogies for how perception actually works.
While the eyes, ears, nose, tongue and skin do of course collect sensory data and pass it to the brain, the images, sounds, smells, tastes and sensations that we experience are produced in the brain, and draw heavily on lots of other data such as past experiences, expectations, beliefs, mood and emotions.
Sailing a sheep across the ocean
If you are a native English speaker, a sheep is very obviously a cute (and delicious) wooly ruminant, and a ship is a large sea faring vessel. If you are French however, they sound like exactly the same word.
That may seem hard to believe if you don’t speak any other languages, but if you start to learn French you’ll soon find it works both ways – dessus (on top of) and dessous (under), sound (at least to me) like exactly the same word. At least with sheep and ship you usually have context to go on…
Ou?
Finding the cat on the mat
Dessus
Dessous?
Non! Dessus!
To a French person these two seemingly identical words sound as different as sheep and ship to us.
How can this be?
The same sound waves are falling into our eardrums and causing the same oscillations in our tiny ear bones. Why is it that different nationalities hear the same sounds differently?
Ship / sheep, and dessus / dessous, are what are known in linguistics as “minimal pairs”.
In phonology, minimal pairs are pairs of words or phrases in a particular language, spoken or signed, that differ in only one phonological element, such as a phoneme, toneme or chroneme, and have distinct meanings.
https://en.wikipedia.org/wiki/Minimal_pair
These words cause problems for foreign language learners when one or both of the sounds don’t exist in your native language.
As a baby, you learn to recognise (and reproduce) all the phonemes of your language – these are the finite number of sounds that can be combined to make all words. There are 44 in English (there are more sounds than letters as combinations can produce new sounds – the ee in sheep for example as opposed to the e in Shep the Sheepdog’s name).
Humans are capable of producing an infinite number of different sounds however, as just tiny movements of the tongue or lips, or restricting or changing the flow of air will alter the sound significantly. Because of this, there can be quite a lot of regional variation in how these sounds are produced – accents – or even just person to person.
Your “oo” is probably different from my “oo” (unless yer a Yorkshire type an’all), but it’s in roughly the same ballpark, and far removed from either of our “aa” sounds. Now try slowly and smoothly going aaaaoooooaaaaoooo. You’ll hear it’s a fluid continuum with a kind of no man’s land in between. You’ve been hearing oos and aas since the day you were born, and while there’s variation between mine and yours, they are clearly on the oo end of the spectrum. When your brain hears something oo like, it sorts it into a bucket marked oo. An English brain has 44 phoneme buckets (it doesn’t really, this is an analogy, bare with me…).
When you start learning a new language as an adult. Your brain initially keeps using the same buckets – they’re the only buckets it has for the time being. In many cases the buckets work just fine, there are lots of shared sounds between many languages – particularly ones with common roots and shared history such as in Western Europe.
French people have an ee bucket. They use it to catch ee sound from words such as fille (fee), pile (peel). They don’t have an “i” bucket however (as in ship, kit), as i is not one of the French phonemes. When a French brain hears an English i, it chucks it in the nearest bucket available, the ee bucket. For this reason, ship is heard as sheep, chip as cheap, and spreadsheet could well be something done by a farmer rather than an accountant…
Predictive Coding
Hopefully the bucket analogy was useful. But please now completely forget it as it was actually a very bad one.
The reason being that it gives the impression that the brain waits for the sensory stimulus (in this case the vibration of the eardrum), analyses it, then sorts it into the most appropriate bucket.
The latest research indicates that this is not actually how perception works at all.
In fact, the brain preselects the phoneme bucket that it expects is going to be required in advance.
If you’re talking about sailing, your brain is going to go straight for the i bucket, because it’s unlikely you’re talking about a sheep lost at sea.
The brain works this way as it is much faster. Were it to wait and closely analyse every single piece of sensory information it received, your perception of the world would be lagging too far behind and you wouldn’t be able to react in a timely fashion.
The brain’s prediction models in your native tongue are generally very accurate, as they are based upon a lifetime’s worth of data and are constantly being error corrected. This doesn’t mean that they are infallible however, some simple priming as in the video below can significantly alter how you hear certain sounds:
It’s a kind of magic…
Magicians that use sleight of hand have been taking advantage of the predictive (and influenceable) nature of perception for centuries.
We tend to see what we expect to see (or not see what we don’t expect to see).
The world that you are now perceiving is the world that your visual system has predicted to be the present in the past.
GUSTAV KUHN, Psychologist and Magician
The quality on the video isn’t great unfortunately so it probably didn’t work, but if you’ve ever been dumbfounded by a good street magician there’s a good chance they were taking advantage of bugs in your predictive coding to get you to “see” things that weren’t there (or vice versa).
Now take a look at this video.
This one is very famous now so very probably you did see the gorilla, but again I’m sure you can think of numerous instances of when an object in your field of vision only becomes apparent to you after someone points it out. Once it has been pointed out, it’s hard to comprehend how you could possibly have missed it when it was right there in front of your eyes. The light from the object had been hitting your retina in exactly the same way before and after the cognitive change, but your subjective experience alters dramatically.
Is wine tasting a load of sheet?
There are those that would say that wine tasting is total bull.
In light of what we now know about perception, however, this is perhaps a little harsh.
The classic study that brought shame on sommeliers fooled professional wine tasters into describing the flavours of two identical glasses of white wine as completely different simply by adding some flavourless red dye to one of them.
“The wine’s color appears to provide significant sensory information, which misleads the subjects’ ability to judge flavor,” Brochet wrote of the results. “The observed phenomenon is a real perceptual illusion,” he added. “The subjects smell the wine, make the conscious act of odor determination and verbalize their olfactory perception by using odor descriptors. However, the sensory and cognitive processes were mostly based on the wine color.”
Frédéric Brochet
I don’t think, however, that you can draw the conclusion that there is zero objectivity involved in wine tasting based on this study. Yes, even professional wine tasters can be fooled, but that doesn’t mean they can’t differentiate between different wines under normal circumstances. (There’s also the possibility that fear of looking foolish drove them to describe the wines the way they did).
It is important, however, to recognise that beliefs and expectations have a huge impact upon how we taste and smell something. Is the wine expensive because it tastes better, or does it taste better because it’s expensive…?
It’s all in your head…
The cutting edge science shows that pain is a “biopsychosocial” phenomenon.
Unfortunately, this often appears to be misunderstood as scientists saying that pain is “psychosomatic”, that it is “all in your head”, and that you should either just get over it, or that there’s nothing you can do about it in terms of physical rehab.
But “biopsychosocial” is not a synonym for “psychosomatic”, and no leading pain expert is trying to say that all pain is all in your head – well, except in the way that EVERYTHING is all in your head, as hopefully the previous examples have illustrated.
Unfortunately, it’s very easy to misunderstand or strawman the case of the “pain science experts”.
By Original: Edward H. Adelson, vectorized by Pbroks13. – Own work, CC BY-SA 4.0, Link
A and B are clearly squares of different colours aren’t they?
By Original by Edward H. Adelson – File created by Adrian Pingstone, based on the original created by Edward H. Adelson, Copyrighted free use, Link
Guess again! It was all in your head…
Despite having the illusion revealed in the second image, if you go back to the first picture, you will still see the two squares as totally different shades.
While the reality that we perceive is produced within our own brain, and is shaped by our knowledge, emotions, experiences and beliefs, this doesn’t mean that you can consciously choose how and what you perceive.
Unfortunately, you can’t just decide not to feel pain, any more than you can decide to see the two squares as the same shade, or hear the difference between dessus and dessous.
The good news, however, is that unlike the optical illusion, there are steps you can take to, at the very least ameliorate the symptoms of chronic pain, and perhaps in some cases vanquish it altogether.
If you do suffer from chronic pain, check out my guide here. Though the article focuses on chronic back pain (from which I suffered personally), the principles can be applied to any chronic pain issue.
I also highly recommend the specific guides on Paul Ingram’s site Pain Science. There are guides for back pain, knee pain, neck pain and many more, all worth every penny (I resolved by lateral knee pain following his advice) and the book Better Movement by Todd Hargrove.
For a deeper dive into the latest scientific understandings of perception, check out the TED talk and Guardian Podcasts below with Anil Seth. A fascinating insight into just how feeble a grasp we have on reality!