The two parts of pain

TIL: That what we think of as "pain" is actually two different things. The most basic sense is called nociception — a non-subjective reflex that drives lots of animals to pull away from dangerous things. Pain — actual pain — is what happens after nociception, and different individuals perceive it differently under different situations. So, for example, nociception is why you jerk your hand away from a hot stove. Pain is the feeling that helps you learn not to touch hot stoves again. Oh, and also, crabs might be capable of feeling both.


  1. There’s another part – fear.  When I was learning martial arts, I discovered that about 95% of pain is fear, and fear can be mastered.  The actual pain of getting punched is nothing next to the shock and terror.  This lesson was really useful today when the dentist gave me a filling.

    1. I discovered that about 95% of pain is fear

      I’ve discovered that 95% of pain is whatever the doctor does to fix it. Chopped my knee open with an ax – no pain. Got it sewed up – fucking owww! Broke a tooth in half – no pain. Got a crown – a month of misery. I’ve almost never experienced pain from an injury (and I’ve been to the ER about a dozen times) until the doctor has had at me.

        1. Definitely don’t want to date my dentist. The resident who sewed up my knee was totally hot. But if I wanted to date him, I didn’t need an ax wound as an excuse, since I worked with him every day.

  2. I’m always a little surprised by headlines like “Do crabs feel pain?” or “Do bees think?” At this point, shouldn’t anyone with a middle-school-level education (or whose ever kept a single pet) be aware that there is no special magic to human behavior?

  3. Of course, some people have no pain receptors to speak of and have to rely on the backup system to their nerves.

    And neither I nor my brother experience emotional distress as the result of pain.  Yank your arm out of its socket?  No prob.  Just push it back in and go about your business.  If I had a dime for every time I’ve heard idiot remarks like “but your arm can’t be broken because if it was you wouldn’t be telling me about it so calmly” followed by shocked and amazed X-ray technicians coming in with the news….

    1. Are you one of those people who can just casually throw up, rinse your mouth and be fine?

      1. My wife has been known to do that occasionally when she´s feeling sick from something she ate. Creeps me right the fuck out, but she feels fine afterwards.

        1. I had a friend who did it. If I have to throw up, there’s going to be moaning and groaning and gnashing of teeth for at least a day. Mostly, I guess, because I tend to dry heave for hours if I let myself throw up once. I’ve developed strong inhibitions against it for that reason.

      2. In my stupider days I mastered throwing up to be able to drink more, but that probably doesn’t count.

      1. It’s more often because they say that I shouldn’t have crawled over to the clinic but gotten an ambulance with that kind of wound because I could have passed out on the way over.  Well, pain *is* tiring but never immediately produces unconsciousness and anyway the wound is, more often than not, a couple of days old but I had errands to run and stuff.
        My doctor gave me shit for stomping around with broken bones in my foot for a couple of weeks so now I use the mnemonic “If in agony – assess (for structural damage)”.  My brother tied his company up in Workman’s Compensation paperwork for years because of the arm-socket incident.  He told them about it but they assumed some sort of hyperbole because of his deadpan delivery and didn’t send him to the doc right away.

    2.  I’ve got a poor pain response as well. In my case, I’ve now got cumulative joint damage because the “discomfort” of not shifting position makes me think things like “… I should probably move, but I’m so comfortable…” Probably one of my stupider thoughts.

      I nearly killed myself with appendicitis due to neglect, too. It certainly hurt like the blazes, but I wrote it off as the worlds worst period cramps and ignored it.

      Most of my insensitivity was learned, though – years of cluster migraines have given me a skewed perspective on “agony”. I now know to tell the triage nurse, when she asks me where it is on the pain scale, that I rate 10 as “cluster migraine”, 7 as “dislocated joint”, and that pain makes me dis-associative. Otherwise they don’t take me seriously :P

      1. Doctor:  how is your pain on a scale of one to ten, with ten being the worst pain you ever felt?
        Migraineur:  I get migraines pretty bad.  Everything else is a “one”.
        Doctor:  so you don’t really hurt very much right now?
        Migraineur:  It hurts like having both legs slowly torn off and the bloody stumps rubbed with rock salt, so it’s a “one”.

    3. My family has a bad habit of ignoring pain if it’s inconvenient.  The doctors get very upset if you show up at the emergency room when you’ve had a piece of glass in your eye all day long, or when you’ve had a collapsed lung for four days.

      My dad had a broken neck for at least 15 years, and probably longer.  He got an MRI and the med techs just completely freaked out, wanted to do emergency surgery.  Dad insisted on a second opinion, so they strapped him to a backboard and sent him across town to another MRI shop.  They said “yep, broken neck, prep the surgical theater” but Dad insisted on driving home because he had some odd job he wanted to get done for my mother first.  He didn’t get operated on until the next week, and then right after the operation he flew to England (with his head literally bolted into a stainless steel “crown”) to see his granddaughter.

      The interesting part about this is that we seem to have more pain receptors than most people.  For example I have pain-sensing nerves in my eyeballs, which is apparently somewhat unusual.  I’ve been stabbed in the eye a couple of times and had one of my eyes gouged out once (don’t worry, it went back in) and each time the doctors have expressed surprise when they found out that I can feel pain with the eyeball.  Made LASIK surgery no fun at all, I can tell you!

      I can’t ignore a migraine, though.  That’s a whole different order of pain than anything physical.

        1.  I wonder if people who have more pain receptors are forced to develop the ability to disregard physical pain, or if it’s part of the same genetic package.

  4. So crabs join the great realm of other delicious animals that we kill for food? I had a random realization a few weeks back that, for a large part of the animal kingdom, violent death is a very probable way to buy the farm. We’re a bit spoiled, but I’m happy to say that getting torn apart by predators isn’t likely to happen to me. I’ll leave my demise to whiskey and tobacco, like you’re supposed to do in America.

  5. Nonononononono.  Argh, this article just further complicates an already complicated tangle. (actually, Maggie’s description was great right up until she linked to that terrible article)

    The finding that crabs learn from an aversive experience is not evidence that they feel pain.  The misguided author of the linked piece seems to think that it is, but it ain’t.  Eric Kandel won a Nobel prize studying (among other things) a sort of fear-conditioning in invertebrates who learned to anticipate nociceptive stimuli.  He never argued that they were experiencing pain.

    The linked article suggests that the distinction between nociception and pain is long-term learning, but that isn’t true at all.  You can learn avoidance of nociceptive stimuli without pain.  Pain is a *psychological state that involves emotions*.  It might be useful to distinguish between three different things instead of two: nociception, *aversion*, and pain.

    Nociception is a particular signalling pathway that communicates potential peripheral tissue damage to the brain; it involves specific sensory receptors (including the ones that make you snatch your hand away from a hot stove).
    Aversion is the behavioral response to nociception and other aversive stimuli; the withdrawal or avoidance, either reflexive or learned, from noxious stimuli.
    Pain is a psychological/emotional response to nociception and other aversive stimuli that describes the subjective response to nociception.

    Everything that has a nervous system experiences aversion.
    Most, but not all, vertebrates experience nociception.
    The best evidence indicates that you need a cerebral cortex to experience pain.

    The crabs in this study exhibited learned aversion, which is not surprising in the least.  There is nothing there that addresses pain.

    1. It’s important that people understand the psychological/emotional component of pain. People tend to think of pain as a sensation. But people with intractable pain can have brain surgery that dampens the emotional component. If you ask these people if the pain is gone, they say no, it’s just as bad as before but it just doesn’t bother me as much. It’s also why opiates are addictive to people whose lives are filled with emotional pain–the circuits handling the response to physical pain and emotional pain are the same. 

    1. “pulsative” or “stinging”, one feels rather dull and, well, pulsating, the other more acute and sharp.

      1. Diffuse, sort of non-specific pain in a general area, vs very well defined pin-point pain is another way to divide the experiences up.

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