Do you think tarantulas are sentient? Why/why not?

[Feral]

I did see what you posted, but did you read what I wrote? As in "feel pain in a meaningful way" - A tarantula could not easily throw off a leg if it felt pain similar to what a human would feel if a limb were suddenly amputated - it would go into shock. They may feel something, but not the massive pain we would feel. I've also seen film of a grasshopper continue to eat grass as if nothing was happening while a mantis was eating its body - if it were really in pain why would it continue normal behavior like eating?

You're not arguing against me, you're arguing against science. The data has already been proven, peer reviewed, and accepted. Are you going to say science is wrong?

Inverts aren't humans. They have vastly different anatomies and physiologies. You have to look at each creature for what it actually is.
You're making unverified assumptions about thier physiology. You can't really assume that a body that has that kind of regenerative, inherent ability would feel pain or would go into shock after the leg is autoamputated because you don't know how the neural system is arranged. It could well be that, since the body is designed to do that naturally, they have evolved a built-in shut off for the pain neurons. Or it could be that you have what's called human observer bias, where you're expecting an animal to show signs of distress in a mammalian-like way that you can relate to and understand, but the invert way of expressing pain may be something entirely alien and unrecognizable to us. Or it could be any number of things.

But regardless, that's all moot because they have measured, in studies, inverts' reactions to hypersensitization, acute pain, and chronic pain. They've already quantified the effect pain has on the inverts by observing physical reactions to painful stimuli, how it changes their behaviors afterwards, and how they react to re-stimulation of the painful area. It's all measurable data, numbers. It's all in the links provided, read the material.

 

[Feral]

I strongly suggest reading this. Not many publications as reputable as this other than maybe “nature”. It puts the entire discussion to rest.

https://advances.sciencemag.org/content/5/7/eaaw4099

That is the study that the article I posted earlier was based on. Besides the content being the same, you can compare the names of the scientists, etc. and see.

I thought the article was actually very accurate and well written, so I thought lay people would find it more accessible. But I always appreciate the true source, can't go wrong there!

 

[DrGilman]

Just went back and read the one you posted. I agree it’s very well written. I have a subscription to Science and Nature and JAMA as I am in the medical profession and I trust them usually before any other sources. I try and check them before I go elsewhere especially since science journalism can sometimes be so misleading. On the other hand I agree that original source science publications can be intimidating sometimes and locked behind paywalls. That’s part of the trouble with science illiteracy. It’s refreshing to see people back to their statements with credible sources. Cheers to you on that.

 

[Feral]

Thank you! That actually really means a seriously big, big heap to me... And it's even more fitting for today than you might know! Thank you!

Thank you for the publication recommendation, I'll try to remember to go poke around SaN and JAMA. I get too absurdly happy about a good nerd-out.
My feelings are... kinda inversely proportional? concerning paywalls. lol

It's lovely to have minds here who are lively, agile, and not hesitant to get way into the nit and/or grit. Welcome, I'm sure you'll be an asset!

 

[SonsofArachne]

You're not arguing against me, you're arguing against science. The data has already been proven, peer reviewed, and accepted. Are you going to say science is wrong?

Actually, as any scientist will tell you, science is proven wrong all the time. That's how science works. But that's neither here nor there as I wasn't arguing that you, or science, was wrong. I was pointing out some instances where pain in invertebrates would appear to be either very muted or non-existent. As far the pain study you cited it does not claim that inverts experience pain in the exact same way we do or that inverts all have the same levels of sensitivity, so it does not explain away the examples I gave. If someone could show me a study that proves a spider is in agony when it drops a leg, or a grasshopper somehow continues eating while being in excruciating pain from being eaten, I would definitely be interested in finding out how that works.

 

[DrGilman]

Actually, as any scientist will tell you, science is proven wrong all the time. That's how science works. But that's neither here nor there as I wasn't arguing that you, or science, was wrong. I was pointing out some instances where pain in invertebrates would appear to be either very muted or non-existent. As far the pain study you cited it does not claim that inverts experience pain in the exact same way we do or that inverts all have the same levels of sensitivity, so it does not explain away the examples I gave. If someone could show me a study that proves a spider is in agony when it drops a leg, or a grasshopper somehow continues eating while being in excruciating pain from being eaten, I would definitely be interested in finding out how that works.

It is a misconception that science is constantly proven wrong, rather, science is constantly improved upon and without our prior knowledge (that with new knowledge becomes obsolete in comparison), we would be incapable of arriving at new information. You are making it a binary issue of "right" and "wrong" which is a common thing for people to do with most issues but we are hard pressed to find anything that exists which is truly binary. Science is simply transitory. Another common misstep is to anthropomorphize. It is only natural to perceive everything from our own perspective. This is called solipsism or known as the "other minds" theory in philosophy. As far as a grasshopper continuing to eat while being eaten, there are many electrical processes that continue to happen even after death in all living things. I would posit that this is similar, some sort of electrical movement or "auto pilot" system that is entirely unrelated to pain. I cannot find any research on that actual instance but based on what I do know and have read, that is my hypothesis regarding that phenomena. It's very interesting indeed and I would be curious to see if you find anything on it.

 

[SonsofArachne]

It is a misconception that science is constantly proven wrong, rather, science is constantly improved upon and without our prior knowledge (that with new knowledge becomes obsolete in comparison), we would be incapable of arriving at new information

This is what I was saying, just with more words. I certainly did not mean that "science is constantly proven wrong" You are misconstruing what I said.

Another common misstep is to anthropomorphize

Such as assuming pain experienced by an invertebrate would be similar to pain experienced by a human?

As far as a grasshopper continuing to eat while being eaten, there are many electrical processes that continue to happen even after death in all living things. I would posit that this is similar, some sort of electrical movement or "auto pilot" system that is entirely unrelated to pain.

It is just as likely, if not more so, that the grasshopper is not feeling pain, at least not as we know it. Eating is not a simple electrical process, a animal needs to select items that are eaten, implying that the grasshopper was continuing to go about it's normal routine, while being eaten, which leads to the conclusion that it wasn't experiencing what we (humans) know as pain.

 

[DrGilman]

I'm implying that perhaps what is perceived as eating is just a continuation of what the grasshopper was already doing when it started being consumed. I have not seen the video. I don't disagree with what you're saying and I think we are both on the same page for the most part but just dancing around each other.

 

[KenD]

It’s refreshing to see people back to their statements with credible sources. Cheers to you on that.

Indeed. Great job @Feral, your argumentation is impressive and your posts a joy to read.

 

[Vanessa]

I find it highly doubtful that tarantulas, or any other invertebrate, feel pain in any meaningful way. They will readily self-amputate a limb when said limb is trapped for a second or two. If they were able to feel pain from this it would be debilitating and defeat the purpose.

There are lots of lizards/reptiles who are capable of autotomy and who no doubt have an obvious response to painful stimuli. Pain itself is more to do with nerve endings communicating with the brain and, if those are severed biologically, then pain is not felt. It's the same way that a narcotic acts on our brains - it chemically severs the nerves from communicating pain to those receptors in our brains that allow us to act on it.
I would suggest that it is more likely that a tarantula can cut off the nerve responses that autotomy would result in, rather than there are no nerve responses at all.

 

[SonsofArachne]

There are lots of lizards/reptiles who are capable of autotomy and who no doubt have an obvious response to painful stimuli. Pain itself is more to do with nerve endings communicating with the brain and, if those are severed biologically, then pain is not felt. It's the same way that a narcotic acts on our brains - it chemically severs the nerves from communicating pain to those receptors in our brains that allow us to act on it.
I would suggest that it is more likely that a tarantula can cut off the nerve responses that autotomy would result in, rather than there are no nerve responses at all.

I'm not really suggesting that inverts don't feel something akin to pain, I just don't think they experience pain in the massive, shock-inducing way that humans do. I've seen way too many feeder roaches that were badly mangled continue on as if nothing were happening.

 

[Feral]

I hypothesize that in addition to the probability of inherent pain sensation regulation in cases of auto-amputation and human observer bias as I previously mentioned, i think that in cases of trauma from external forces it's also of an matter of pain not interfering with primal instincts, like eating and ambulatory, as opposed to a matter of them experiencing the pain sensation more weakly.

And in an evolutionary way, it makes complete sense. The body would need to have the pain sensation to make sure the creature doesn't unnecessarily do anything to aggravate the injury or hamper healing. But the body would also need to make sure the individual continues on doing the things that increase its chance of surviving the painful episode, like moving, and promote healing, like eating. A creature isn't going to have a very high chance of pulling through an injury if it stops eating or stops moving, after all.

So maybe the nervous system is arranged so that pain is felt normally, but the base instincts just aren't impeded by a pain sensation.

Based on what science has proven concerning pain sensation, this is the most sensible hypothesis to explain what you're seeing, I think.

 

[Astron]

I would be really interested to hear whether you ascribe your tarantulas sentience, and more importantly, why or why not - what does your tarantula do (or not do) that makes you think it is sentient (or not sentient)? And why do you think such a behaviour is indicative of sentience (or its lack) in the first place? (I'd also love to see links to videos showing the behaviours in question, if you have them.)

By "sentient" I mean "subjectively experiencing one's information processing in some manner". This does not have to be as intense as humans do, and the kind may be radically different to the kind humans have (e.g. humans have a vibrant experience of visual stimuli in the form of e.g. colours, whereas tarantulas clearly process primarily vibrations, and humans have intense emotions relating to interpersonal bonds, such as love, while tarantulas are not really known for their social and affectionate natures) - but do you think they have *any* experience at all, regardless of how alien or basic?

To explain the contrast more: We strongly (and probably correctly) assume that a cat, dog or octopus has a subjective experience of what is happening to them, which is why hurting them for no reason is wrong - even though that experience is presumably vastly different from our own for a creature that has eight arms, and most of its brain inside them, or a creature for which scent is such a detailed sense.
On the other hand, a simple artificial intelligence that makes up an opponent in a computer game may detect and avoid obstacles and dangers, seek out and take up resources, respond to interactions with it in various ways, mimic human distress calls when hit and - for more advanced versions - even do some basic learning; stop responding to something if it happens over and over again without a threat manifesting, or map out an area. Similarly, a laptop can detect that it is overheating, and respond to this by using the fan more. But it isn't feeling anything, the heat may destroy it, and it registers this, but it doesn't hurt it, and we therefore do not need to feel bad for "killing" it.

Which of the two would you say is more like a tarantula? Do they operate like – very strange, and not particularly bright - cats? Or more like emotionless assassin robots that occasionally encounter situations they are not programmed to handle?

When a tarantula detects and avoids a noxious stimulus, do you think it also suffers pain/distress? When it is munching a cricket or digging around in proper substrate, do you think it experiences pleasure?
When you take the bark it is hiding beneath away in order to rehouse it, is it annoyed or frightened?
Have you ever seen your tarantula appearing confused, or curious? Or seemingly engrossed in or enjoying a particular sensation?
Why do you think they interact with pingpong balls the way they do, or allow themselves to be handled? Do you think they can be bored when just sitting around like pet rocks for weeks on end, or that they are agitated if they don't, because they prefer just chilling in their hiding places?
When someone keeps their tarantulas in bad conditions - e.g. a tiny enclosure with too little substrate, too little ventilation, no hiding place, too much humidity and parasites - do you think that person is being cruel, or do you criticise them for other reasons alone?

I'd really love to hear your thoughts.

Wow. Where do we start on all these points...

Going through all of the previous responses, there have been some fantastic discussions and articles on pain interpretation and response, which I've personally found as pretty illuminating.

I'm going to approach my answer from a slightly more existenstialist standpoint however (bear with me, it's not about to turn in that direction...)

If we consider that "sentience is the capacity to feel, perceive, or experience subjectively", then we have our answer straight away. Our T's feel their surroundings, many of them redecorating their enclosures how they prefer. They perceive what is around them, in ways we can often only dream off (that roach ran where, and you still caught it?!). It seems like several of us have experienced the Pavlovian conditioning that comes from opening an enclosure for watering/feeding, and being greeted with a conditioned response (at least for certain species, some more than others!)

Which brings me nicely to my last point. Even amongst members of the same genus, and species, and even down to the same brood, there are differences in "personality". You can have an A.Chalcodes who is an absolute demon, and you can have an M.balfouri that's a placid kitten. Yet none of their 100+ siblings raised in exactly the same conditions exhibit the same behaviour.

So looping things back around to the original query; yes, I personally think they have at least a basic level of sentience

 

[viper69]

I find it highly doubtful that tarantulas, or any other invertebrate, feel pain in any meaningful way.

You're the guy that cheers when lobsters are dropped into hot water heh, I bet you built you a plank for them, like a pirate ship above a pot.

But for inverts.... octopus and their immediate relatives surely feel pain.

 

[SonsofArachne]

You're the guy that cheers when lobsters are dropped into hot water heh, I bet you built you a plank for them, like a pirate ship above a pot.

I went from thinking inverts experience pain differently than we do to a full-on Sadist - a bit of a leap, if you ask me

But for inverts.... octopus and their immediate relatives surely feel pain.

Again, pain - yes. The same way we experience it - doubtful. In some cephalopods the male's hectocotylus (sperm delivering arm) breaks off during sex. I'm pretty sure their sex drive would badly reduced if they felt pain the way we do. And before anybody says they must be able to shut off pain response to that arm, if that's true that would mean - They don't experience pain the way we do.

 

[RezonantVoid]

No, because I haven't had any of mine write me web messages yet

 

[DrGilman]

I went from thinking inverts experience pain differently than we do to a full-on Sadist - a bit of a leap, if you ask me



Again, pain - yes. The same way we experience it - doubtful. In some cephalopods the male's hectocotylus (sperm delivering arm) breaks off during sex. I'm pretty sure their sex drive would badly reduced if they felt pain the way we do. And before anybody says they must be able to shut off pain response to that arm, if that's true that would mean - They don't experience pain the way we do.

Our hairs fall out, our teeth fall out, we slowly shed our skin and replace it with new, etc. From an outsider studying us, we might look like we are losing body parts that cause us pain but we are fine.

 

[SonsofArachne]

Our hairs fall out, our teeth fall out, we slowly shed our skin and replace it with new, etc. From an outsider studying us, we might look like we are losing body parts that cause us pain but we are fine.

All these things you mention are way different than losing a limb. And for a "outsider" (alien, I assume) to believe losing these things would hurt us they would have to feel pain when they lose them, otherwise why would they assume we do? They would more likely assume we don't experience pain in the way they do, and they would be correct.

 

[DrGilman]

All these things you mention are way different than losing a limb. And for a "outsider" (alien, I assume) to believe losing these things would hurt us they would have to feel pain when they lose them, otherwise why would they assume we do? They would more likely assume we don't experience pain in the way they do, and they would be correct.

Just us calling them limbs is our language. What if we didn't call spider legs spider legs but rather we called them something totally unrelated to us. Something that didn't make us think losing one would hurt in the same way losing our leg would. A spider leg is in no way comparable to a human leg so it's pretty silly that we are even comparing them. That's the point I'm trying to make.

 

[SonsofArachne]

Just us calling them limbs is our language. What if we didn't call spider legs spider legs but rather we called them something totally unrelated to us. Something that didn't make us think losing one would hurt in the same way losing our leg would. A spider leg is in no way comparable to a human leg so it's pretty silly that we are even comparing them. That's the point I'm trying to make.

Okay, now this getting ridiculous. So you're saying that their legs aren't comparable to ours, but you still think they feel pain in the same way we do? And if you don't why do keep arguing? What's silly is trying to compare a mammals pain response to a invertebrates, which is what I've been trying to say.