Why Believing Something Will Hurt Makes It Hurt More


When you stub your toe, where does it hurt? In your foot, or in your head?


You certainly locate the pain in your foot; you don’t mistake it with a smack on the chin. But we all know that if some anaesthetist had dulled the connections between your extremities and your brain you wouldn’t feel a thing. Pain is, and can only be, something that happens in your mind.


And why do you hurt in your head? What possible purpose could the experience of pain have?


To draw away from the thing that’s hurting you? You don’t need to feel it to do that. In fact, you’ve probably pulled your foot away by the time you’re aware of the sting.


To warn you not to walk barefoot in the future? If so, it’s not very effective. And a near miss would do the trick just as well: why don’t you feel pain when you nearly stub your toe, which would be at least as useful?


In fact, pain and all other experiences serve a social purpose. We can talk about the things we feel, where we hurt, what we see. They’re part of our understanding of what others perceive of us: others infer that we’re hobbling because our toe hurts, and feeling the pain in our toe and being able to talk about it put us on the same page.


This social use of pain has some bizarre effects, and leads to some useful ways to reduce what we feel.


Researchers mildly hurt volunteers’ hands whilst showing them video clips in the position of their hands. When the video clip was of a hand with a needle puncturing the skin the participants claimed to hurt more than when the video was of a hand being prodded with a cotton bud.


This makes sense if our experience is social. If I saw somebody touching your hand with a cotton bud, I’d think you were mardy if you screamed in agony. You infer the same thing, and feel less pain.


In another, similar experiment, scientists burnt participants’ hands with a laser. When they told the volunteers that this would hurt a lot, they thought the pain was greater than when they expected a mild, warming sensation.


Pain is all in our heads. How much we think something will hurt affects how much it does hurt. Which is useful to know whether you’re dealing with a bee sting, a nettle rash, a vaccination – or a toe that is throbbing.


If you think it strange that people spend more time learning to drive than finding out how their own minds work, then read Chris Paley's Unthink (Amazon UK link).


Höfle et al. 2012

Brown et al. 2008