So, higher living creatures with complex nervous systems may have pain receptors?!
OH MY!
Am I the only one to read that and be amazed at how stupid we are? Do we really need to have studies and tests before we can grasp the basic concept that animals feel pain? Clearly I should have read the article first because the answer is in the first paragraph: Elwood was stumped. “It was the first time I ever considered the question,” he says.
The world is doomed.
No, you’re not the only one. For anyone who has watched invertebrates like crustaceans or cephalopods, I really think this would be very obvious, save that there was a preconception otherwise. But generally it seems strange to me that we still approach it as if there’s a line for suffering.
There’s a spectrum of more and more complex behavior, gradually moving through taxis, reflex, instinct, and more developed mental models, from sponges up through to the apes and whales, but without any sharp divisions. Why would anyone not expect response to injury to go through the same continuous spectrum?
Still kudos on this key point:
Denying that crabs feel pain because they don’t have the same biology is like denying they can see because they don’t have a visual cortex.
I’ve actually seen that basic argument here: in mammals a particular type of receptor is used in pain and another in reflex actions, and crustaceans use the second for everything, so none of it should count as real pain. As if the precise choice of chemical messenger truly dictates the ethological role, let alone our ethical approach to it.
I always thought the more important question was whether or not a given animal was capable of experiencing emotional/psychological suffering as a result of pain. Fruit flies can experience pain, last I heard, but that doesn’t stop me from swatting them or putting out a stale-wine trap.
Call me when they learned to be afraid melted butter.
Yeah, jackasses, because ALL creatures feel pain. And yes, animals feel “emotional” pain, too. You sound like you’re trying to justify that it’s ok that animals are harmed and killed everyday because they might not feel emotional pain. It’s been proven that elephants feel pain when one of their own dies, and they mourn. Other animals do, to. We’re not that fucking special to be the only creatures that experience pain and anguish.
I’m just wondering why the quotes around 'feel pain" here.
Because Lobsters, crabs, and insects don’t have an “I” so they don’t experience discomfort, they get “negative feedback from their neurons.”
If one wants to accept that as “feeling pain”, whether one is talking about fetuses or insects, is one’s own business, but it is rather more anarticle of faith than an matter of science.
Counterpoint: lobsters and crabs are also delicious.
To be fair nobody here is questioning that, though, or they wouldn’t be looking at invertebrates. And it’s entirely reasonable to surmise that some cases, like jellyfish or tapeworms let alone sponges or plants, have no capacity to mourn or dread, though they obviously respond to damage in their own way. Like I said, there’s a spectrum.
There’s a spectrum on that, too. Many mammals don’t have a sense of self in the same way people do, but I hope we’ve gotten to the point where everyone understands they feel pain in much the same fashion.
Lots of animals are delicious. 
There’s only some people who feel bad about eating them, but I hope nearly everyone would about boiling them alive. Which I think is the popular interest in this: they want to know whether it’s ok to watch lobsters struggle in the pot instead of killing them first. 
The prawn experiment isn’t conclusive. Put vinegar on a person’s tongue and they will try to get rid of the taste. But if the tongue is numbed first… The prawn’s antennae are one of it’s primary sensors; it is not surprising that they would want/need to keep them clear of contaminants, be they vinegar or mud. And if they are numbed, they are no going to be able to feel/sense the contaminant, and wouldn’t clean them as much.
Now, this is short article, so I suspect (hope) that he tested their reaction to things other than acetic acid, including things that would not be harmful to the animals, to see if those got the same reaction. But going just from this article, we can’t tell.
And then there is the whole discomfort-vs-pain question. I may not be in pain from it, but I’m still likely to move into the shade on a hot day. Still, I’m glad to see that someone is asking, and attempting to answer, the question.
I would think evolutionarily speaking, avoiding harm to your body is a pretty big win. This means you need a way of detecting harm and a way of avoiding/mitigating it. Thus, most things capable of motion should have some sense of pain–it’s their way of knowing that they shouldn’t mess with whatever they are messing with.
The fish that just wanders into jellyfish tentacles or anemones without feeling anything is not going to outcompete the one that knows how to avoid predators.
Do you feel sad when swatting mosquitos? They’re arthropods too, after all. This sort of thing can be carried too far. Bacteria and protists sense their environment and react to negative stimuli. By exactly the same argument to lobsters and crabs one can say they “feel pain”.
IIRC there are certain plants that will respond to stimuli and change behavior to avoid it. “Feeling Pain” as it were. Plants can’t do much about it though, on account of having no or very limited range of motion.
No, but that’s not because I imagine they can’t feel anything akin to pain, it’s that it’s not my main concern; I’d feel bad about setting up a device simply to try torturing them, but swatting seems a humane enough disposal. There are lots of animals, even mammals, I’m ok with killing under some circumstances, but care about how they are treated first. So I think your question is far aside of the point.
As for bacteria and protists, I’ll say again: there’s a spectrum of reactions. Crabs and lobsters are somewhere in the middle - and not necessarily the same place as mosquitos* - but I don’t imagine sharp lines. If you did want to draw one for “real pain”, though, I’m not sure what behavior or lack thereof would exclude them.
*As the article notes this is about ethology not phylogeny. You and a sea squirt are both chordates, but I wouldn’t make any judgments based on that.
Any word on crabs in nether regions?
Asking for a friend.
So wait now. Does that mean… if lobsters the size of elephants… were brushed with acetic acid… No, sorry you lost me.
Well, as far as I can prove, other human beings don’t have any “I” either. For example, you clearly are most likely just a product of my imagination, since there’s no scientific proof that you exist when I’m not paying attention to you.
Or, you know, just maybe, not everything needs scientific proof.
You’ve got it backwards. Lobster-sized elephants feel a scaled size pain when one of their own dies, and they just send a card.
