Sunday, August 26, 2012

Pain vs. suffering and animals vs. humans

People sometimes ask me whether I make a distinction between "pain" and "suffering." The answer is "yes, I do," although one reason this might not be clear is that I have the following quotation from George Orwell at the top of my page called "On the Seriousness of Suffering":
Nothing in the world was so bad as physical pain.
Katja Grace wrote a blog post based on this quote, and in the comments, I made the following clarification:

First, I don’t entirely agree with Orwell’s choice of words, but I included the quote as he wrote it for the sake of readability. In particular, as many have pointed out, what matters is not “pain” directly but “suffering,” i.e., the response that “this feels really awful and I want it to stop.” The commenters raised several examples where pain itself isn’t aversive: Pain asymbolia, masochism, people given morphine, etc., not to mention self-cutting and other things people do in order to release endorphins/opioids to make themselves feel better.
I would also omit Orwell’s word “physical,” because because mental pain can be just as bad.

Pain asymbolia is the most clear proof that pain and suffering are distinct, because unlike masochism where one can imagine that pleasure chemicals are merely outweighing pain signals, in pain asymbolia, the quale of pain itself is not aversive.

This suggests the broader question, What gives valence to qualia? I think the details of how this happens are largely unknown, but presumably there are brain processes which "paint" a suffering gloss onto experiences in the same way as certain brain processes paint a hedonic gloss onto pleasure. It's these painting operations that I count as suffering and that I want to reduce.

A related theme is the classic distinction between nociception and conscious pain. As Jane A. Smith explains in "A Question of Pain in Invertebrates":
Invertebrates, it seems, exhibit nociceptive responses analogous to those shown by vertebrates. They can detect and respond to noxious stimuli, and in some cases, these responses can be modified by opioid substances. However, in humans, at least, there is a distinction to be made between the "registering" of a noxious stimulus and the "experience" of pain. In humans, pain "may be seen as the response of the whole awake conscious organism to noxious stimuli, seated.., at the highest levels in the central nervous system, involving emotional and other psychological components" (Iggo, 1984). Experiments on decorticate mammals have shown that complex, though stereotyped, motor responses to noxious stimuli may occur in the absence of consciousness and, therefore, of pain (Iggo, 1984). Thus, it is possible that invertebrates' responses to noxious stimuli (and modifications of these responses) could be simple reflexes, occurring without the animals being aware of experiencing something unpleasant, that is, without "suffering" something akin to what humans call pain.
And from Antonio Damasio, The Feeling of What Happens, as excerpted here:
Would one or all of those neural patter[n]s of injured tissue be the same thing as knowing one had pain? And the answer is, not really. Knowing that you have pain requires something else that occurs after the neural patterns that correspond to the substrate of pain – the nociceptive signals – are displayed in the appropriate areas of the brain stem, thalamus, and cerebral cortex and generate an image of pain, a feeling of pain.
So when I ask whether insects might be able to suffer, I don't mean just whether they can react against physical injury and learn to avoid it in the future. I'm asking whether they can perceive this injury as something that is happening to them and that they want to have stopped. I agree that the jury is very much still out on this question. If it seems as though I believe otherwise, it's because I'm trying to track the expected value rather than the most likely point estimate.

Now, given that suffering is different from pain and that suffering can involve strong non-physical emotional components, does this mean animals matter less than we might think because they don't suffer in high-level mental ways?

First, it's unclear whether the claim is true that animals have substantially less sophisticated mentation, at least for "higher" animals like mammals. Animals show many of the psychopathologies that humans do and are used as models for depression when testing drugs. Elephants have death rituals. Crows appear to go sledding for fun. Marc Bekoff, Jonathan Balcombe, and other ethologists have written numerous books documenting the complex emotional lives of mammals, birds, fish, and even octopuses.

But, suppose it is true that non-human animals don't have a similar degree of psychological depth to their experiences. It's not obvious that this means they suffer less intensely. Maybe the brain applies normalization to its experiences, so that it can appropriately encode relative priorities of various drives without using excessive amounts of energy/storage. For example, say a mouse's suffering is between 0 and -10, while a human's would be between 0 and -50 due to emotional depth. However, maybe the human brain doesn't care about perfect granularity among all of the values between 0 and -50; it only needs a sufficient granularity to make the right tradeoffs, so it downplays the importance of physical pain. In other words, a physical pain that would have been -10 for the mouse might be -2 for the human, because the human has so much else to worry about. This is pure speculation, and I wouldn't rest my argument on this point, but it seems possible. This discussion also gets into philosophical issues about how we want to care about and measure emotional intensity, which lie beyond the scope of the current post.

Finally, what if animals do suffer less, even after taking account of the brain's normalization processes? Well, I guess I would ask, How much less do they suffer? I don't think it's orders of magnitude less, and if not, then the basic calculations showing that, at the margin, animal welfare takes priority over human welfare would remain. Suppose you were a chicken being scalded and drowned alive in a boiling defeathering tank. How much less bad would this experience be if you didn't have broader thoughts about the end of your life, the injustice of your situation, how much you'll miss your friends, etc.? I suspect that the raw physical pain would overwhelm these subsidiary thoughts during the moment, and even if not, I don't think the higher-level thoughts would be 10 times stronger than the raw pain.

Moreover, there are many times when humans may in fact suffer less because of their understanding of the situation. Humans enduring a bout of food poisoning can know that the agony will end after a day or two and can know that their friends and family will help them in the mean time. Animals going through the same experience may have no idea what's happening to them, whether it will end, or what will become of their lives.

The points discussed above are fascinating to ponder, and it's valuable to hear from other people which of their own experiences they've found most unpleasant. That said, we modern humans live extremely comfortable lives compared with factory-farmed or wild animals, so it isn't surprising that most of our worst memories may be of purely emotional injury. In any event, regardless of where we settle on the question of the relative magnitudes of animal and human pain, physical and psychological pain, I don't think it's likely to tip the balance of our calculations about where our dollars and hours will do the most good.