Talk:Pain in crustaceans

Changes to subject of nociceptors
I have made some changes to the main text to reflect more recent findings on the presence of nociceptors in various animal groups, and added a link to a wikipage I uploaded recently Pain in invertebratesDrChrissy (talk) 13:30, 5 October 2011 (UTC)

Lead paragraph says nothing
I edited the lead paragraph to mention the two main arguments for and against. It was reverted. "Pain in crustaceans is a contentious issue. " says nothing. Bhny (talk) 21:29, 21 October 2013 (UTC)
 * But "pain in crustaceans is a contentious issue" is the most definitive statement that can be made on the topic. Even you are being contentious. --Epipelagic (talk) 23:21, 21 October 2013 (UTC)
 * It is a content free statement. The article has 2 main arguments as my edit summarized. If there is a third or fourth, then we could include those in the lead too.Bhny (talk) 23:49, 21 October 2013 (UTC)
 * In my opinion, the main argument is whether crustaceans experience only nociception, or are also able to experience pain (suffering). This distinction is imperative for lay people to understand and I believe the lead paras do this.  I'm afraid that your statement that the presence of opioid receptors indicates an ability to experience pain, is over-simplistic.  It has been stated that there are 7 criteria required to experience pain (explored in Pain in invertebrates).  These are-

1.Has a suitable nervous system and receptors 2.Physiological changes to noxious stimuli 3.Displays protective motor reactions that might include reduced use of an affected area such as limping, rubbing, holding or autotomy 4.Has opioid receptors and shows reduced responses to noxious stimuli when given analgesics and local anaesthetics 5.Shows trade-offs between stimulus avoidance and other motivational requirements 6.Shows avoidance learning 7.High cognitive ability and sentience
 * __DrChrissy (talk) 12:51, 22 October 2013 (UTC)


 * What is wrong with my edit summarizing the Opinion section in the lead? This has one argument for, and one against. Sure there are many steps to get to an opinion or conclusion but this is the lead and we can just put the conclusions and expand on that in the body of the article. At the moment there is nothing in the lead about what the contention is. Bhny (talk) 14:21, 22 October 2013 (UTC)
 * I have tweaked the lead paragraphs to make clearer what the contention is.__DrChrissy (talk) 15:30, 22 October 2013 (UTC)


 * thanks! Bhny (talk) 18:27, 2 May 2014 (UTC)

revisions to correct erroneous definition of nociceptors and regain NPOV in relevant sections
I was lead to this page by links from the fish pain page which was recently updated in a manner that in my opinion infringed Wikipedias Neutral Point of View (NPOV) policy (https://en.wikipedia.org/wiki/Wikipedia:Neutral_point_of_view). It was then apparent that some of the same people have been editing the pages on 'Pain" in crustaceans and invertebrates, with similar NPOV issues arising in some sections. There are also significant scientific issues with the "argument by analogy" concepts that have crept into these pages in recent edits by the same people.  Readers of these pages need to know how fraught argument by analogy is when applied to species that are so distantly related to humans as crustaceans, other invertebrates and fish, so they can make informed decisions on such matters rather than be fed biased opinion via wikipedia pages.

Edits included:

Introduction: To address this problem when assessing the capacity of other species to experience pain, argument by analogy is used.[1]

Inserted: However, it must also be remembered that argument by analogy is recognized as a very anthropomorphic way of assessing animal behaviours, and thus the method is scientifically incapable of providing sufficient evidence in support of human-like attributes, especially in animals that are not closely related to humans.

Lehman (1997). Anthropomorphism and scientific evidence for animal mental states. In : Mitchell et al (eds). Anthropomorphisms, Anecdotes and Animals State University of New York Press,  pp 104-116

Why ? Because laypeople/readers need to know this when you try to bring argument by analogy into the debate.

Edited: Specialists currently believe that all vertebrates can feel pain, and that certain invertebrates, like the octopus, might too

Replaced: SOME SCIENTISTS currently believe that all vertebrates can feel pain, and that certain invertebrates, like the octopus, might too….. HOWEVER, there is by no means scientific concensus on the matter and other scientists consider that pain perception is unlikely in both lower invertebrates (fish) and invertebrates (Rose et al. 2014, Key 2015).

Why ? The original paragraph implied all specialists (assume scientists ?) believe that all vertebrates feel pain – this is clearly a false and misleading statement, as evidenced by the supplied references. These references needed to be included to ensure Wikipedias NPOV policy is respected

Edited: Nociceptors, the neurones required for the sensation of pain,

Replaced: Nociceptors, the neurons that detect traumatic injury,  have been found in nematodes, annelids, molluscs[14] and in the arthropod, Drosophila,[15] despite earlier claims that nociceptors were absent in insects.

Why ? Nociceptors do not detect pain, they are trauma receptors that relay information to the brain. Pain is an emotional response to nociception that is generated in certain parts of the brain in higher vertebrates. Pain is not

Nociception:

Added: However, it is important to remember that activity induced in the nociceptor and nociceptive pathways by a noxious stimulus is not pain, which is always a psychological state (Wall 1999)

Wall, P.D. (1999) Pain: neurophysiological mechanisms. In: Encyclopedia of Neuroscience (eds G. Adelman and B. Smith). Elsevier, Amsterdam, pp. 1565–1567.

why ? People need to know what nociception is, and that it is not pain. The additional information and reference helps laypeople to discriminate between nociception and pain, which was not clear in the original version.

Opinion section:

Added: However, In reviewing studies claiming to have demonstrated pain or consciousness in invertebrates, Mason (2011) condemned the use of many criteria such as problem solving, stimulus recognition, avoidance conditioning, or physiological stress responses. Other scientists have also noted that the research into invertebrate pain and awareness is beset with the same shortcomings that have undermined research with fishes: invalid criteria and measures for these states, as well as inflated interpretations, faith-based interpretations and HARKing (Hypothesizing after the facts are known (Browman and Skiftesvik 2011, Rose 2014)

Why ? To regain some balance rather than simply include one side of a debate in this section – failure to cite references to both sides of an argument infringes wikipedias policy on Neutral Point of View. https://en.wikipedia.org/wiki/Wikipedia:Neutral_point_of_view

Browman, H.I. and Skiftesvik, A.B. (2011) Welfare in aquatic organisms – is there some faith- based HARKing going on here? Diseases of Aquatic Organisms 94, 255–257.

Mason, G.J. (2011) Invertebrate welfare: where is the real evidence for conscious affective states? Trends in Ecology and Evolution 26, 212–213.

Rose JD, Arlinghaus R, Cooke SJ, Diggles BK, Sawynok W, Stevens ED, Wynne CDL (2014). Can fish really feel pain ? Fish and Fisheries 15: 97-133. . http://onlinelibrary.wiley.com/doi/10.1111/faf.12010/pdf 124.170.97.78 (talk) 07:08, 19 October 2015 (UTC)

Definition
I rewrote the definition sentence which I think was badly formulated for the following reasons. 1. it is not the pain of crustaceans that is "contentious" but the question of whether they experience pain and how. 2. I dont think it is accurate to say that the issue is "contentious" which suggests heated debate with some kind of emotional investment and polarization along ideological lines - I think it is more accurate to say that it is a matter of scientific debate. As with many questions in science it is simply not finally settled - that I think is different from an issue being contentious.·maunus · snunɐɯ· 22:00, 12 March 2016 (UTC)
 * Well your amended lead sentence, The question of whether crustaceans experience pain is a matter of scientific debate, unless significantly qualified, is just plain wrong. There are significant unresolved philosophical issues, quite aside from cultural and industry dissent with the issue. If what you say is now true then massive developments must have occurred in the literature which I cannot locate. Please provide the sources you base your sweeping assertion on (I assume you didn't just make it up all by yourself). --Epipelagic (talk) 00:35, 14 March 2016 (UTC)
 * I've been looking at the definition and compared this with how it is treated in a similar article, Animal consciousness. I feel they have it right over there.  It is stated what it is, and then indicated later about the controversy. Here, we start off defining the topic as a question, which immediately places us into problems of not really defining the article's subject matter.  I've re-drafted the opening sentences below. Comments welcome.
 * Pain is a complex mental state, with a distinct perceptual quality (nociception), but also associated with suffering, which is an emotional state. The existence of pain in crustaceans is contentious and a matter of scientific debate.
 * DrChrissy (talk) 17:17, 14 March 2016 (UTC)

External links modified
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added an additional paper of relevance to the scientific content of the page
Given that one of the references cited in this page is Elwood and Adams (2015), to retain a neutral point of view it is also important to cite the scientific literature that directly refutes the findings of Elwood and Adams (2015), so that readers can make informed decisions regarding the quality of the science being cited. Given that a response to Elwood and Adams has recently been published, I included this information as follows under the section entitled "Physiological responses"

"In their response to that study, a group of 13 researchers from around the world highlighted several critical flaws with the methods and conclusions of Elwood and Adams. These included the fact that the lactate levels measured were within the normal range measured for shore crabs, and that any increases in lactate in shocked crabs were most likely due to increased anaerobic activity caused by innervation of muscle and possible cessation of heart and respiratory movements bought about by the electric shocks.  Also, they pointed out that behavioural "activities that go beyond mere reflex responses" are inadequate criteria for pain.

I'm sure the gatekeepers of this page will appreciate me pointing these things out, as they are also committed to ensuring these sorts of pages present a non-biased, value neutral source of information............

Professor Pelagic (talk) 02:13, 25 April 2016 (UTC)
 * Worth noting the anonymous adjustments to the wording of the aforementioned edits which removed critical detailed information about the questionable study. Disappointing (but entirely predictable), that gatekeepers of this page saw fit to include only the original pro-pain article, but left it to others to include the response article containing feedback from scientists from around the world pointing out the fundamental scientific flaws in the original paper. Also worth noting the prior removal of previous reference to Rose et al. 2014 who point out the various inadequacies of invertebrate "pain" research. A neutral, non-biased approach in line with current scientific opinion on this topic would include such articles and give them more prominence so that readers can make more informed decisions about the subject matter.

Professor Pelagic (talk) 01:19, 29 April 2016 (UTC)


 * I'm not sure if this is just a general grumble that the article does not look the way you want it, or you have specific concerns. I also do not see any "anonymous adjustments" - this does not matter in any case as IP editors are anonymous but are perfectly allowed to edit here. If you have specific suggestions for changing content in this article, please could you make these. DrChrissy (talk) 14:55, 29 April 2016 (UTC)


 * And please keep your focus on content and drop your unhelpful, unfriendly, and uncollegiate aspersions. It is becoming very tiresome. You are just as much a "gatekeeper" of articles to do with pain in animals as anyone else here. Your own approach is at least as "biased" and "non-neutral" as anyone else you can point to. --Epipelagic (talk) 09:37, 30 April 2016 (UTC)

Insect nociceptors
It is inaccurate to say that insects do not have nociceptors, as the "Argument by Analogy" box implies. Drosophila melanogaster has nociceptors, and nociception in that species has been well-documented. Sega31098 (talk) 06:26, 8 May 2016 (UTC)

Length of lead
Please could you discuss which content should be removed so that the hat you have attached can be removed. DrChrissy (talk) 16:40, 19 July 2016 (UTC)
 * The lead was not too long at all so I removed the tag relative to policy. However the paragraph on pain measurements and definitions was somewhat off topic so I abbreviated it a bit and consolidated it with the other very short one sentence paragraphs.·maunus · snunɐɯ· 17:14, 19 July 2016 (UTC)

Use of language
When an expert (PhD or scientist with experience in a particular field) uses language understood only by their peers and within their own area of expertise, they are missing the 2nd half of the purpose of scientific study: sharing their knowledge with the rest of the world. This is also why I am against scientific journals that must be purchased in order to read the contents, but that's another matter.

The first paragraph and most of this article is written not for the layperson but for the scientific peer. By fiat, it excludes those who would/may benefit the most from the information in the article.

I would recommend re-writing this article using common layperson terminology. Reference to more complicated scientific terminology may be used sparingly and only if necessary.

I hold a PhD in Engineering myself. I have discovered that the layperson is far better off if the expert uses the same language they speak and understand. To put it more bluntly, stop trying to sound smart. It doesn't help anyone.

No offense to a layperson - I am a layperson on every subject myself, except the one subject I am an expert in. — Preceding unsigned comment added by 138.162.0.41 (talk) 13:46, 20 July 2016 (UTC)

Jellyfish?
We currently compare Earthworms, Insects, snails, Cephalopods, Fish, Amphibians, Reptiles, Birds, Mammals. Any chance we can include Jellyfish? I find them to be an interesting edge case because they have no brain but respond to stimuli. --Guy Macon (talk) 15:35, 9 September 2016 (UTC)
 * Interesting suggestion. I think some scientists would disagree about them not having a brain, although this probably depends on the definition used - and I suspect many might use the term ganglion.  I really don't know the literature on jellyfish, but I'll have a look and see if something can be made of it. DrChrissy (talk) 18:30, 9 September 2016 (UTC)

Varner's table
What exactly do all the question marks mean in the table in the "argument by analogy" section? That the information is unknown? Is "? / ✅" meant to mean "probably"? --McGeddon (talk) 20:07, 6 February 2017 (UTC)
 * The question marks generally mean that the attribute has not been investigated or the evidence is equivocal. The Table obviously needs a caption/explanation - I will have a look at this tomorrow. DrChrissy (talk) 00:58, 7 February 2017 (UTC)
 * Thanks! There are plenty of customisable cell-colour templates we can use here if you can get it down to a word or two. --McGeddon (talk) 18:05, 7 February 2017 (UTC)

The table make no sense. In same time cephalopods have nociceptors and brain linked, but it isn't sure if they have nociceptors. That is logical contradiction. Either they are all known or not know. 88.115.35.67 (talk) 22:53, 16 January 2018 (UTC)
 * I was concerned about this too so I went to Varner's text and his table has the same apparent flaw, it's not a transcription error that occurred here. However, the ? can stand for some species yes/some species no... perhaps the ? on nociceptors combined with the check on nociceptors connected to brain is meant to indicate that for all observed species with nociceptors they are also connected to the brain? 173.28.43.11 (talk) 07:06, 5 February 2020 (UTC)

Important New Reference
There is a new scientific review on the subject of pain in crustaceans -, see   https://academic.oup.com/icesjms/advance-article/doi/10.1093/icesjms/fsy058/5037899. Upon reading it I would suggest this page needs a thorough revision and update. I am surprised that this has not been done already.Professor Pelagic (talk) 11:21, 3 January 2019 (UTC)