Do lobsters feel pain when they're boiled alive?
I just finished reading an archived article from the August 2004 issue of Gourmet magazine in which the recently deceased David Foster Wallace writes about the Maine Lobster Festival. Mr. Wallace raised a lot of interesting issues, mainly surrounding whether lobsters might feel pain when they are cooked (i.e., boiled) alive. Any insight on this topic would be helpful to me in coming to terms with the possibility of never indulging in lobster again. So, do they?
… "What are you going to do?" he cried.
"Boil the beast" she said, "what else?"
"But it's not dead" protested Belacqua "you can't boil it like that."
She looked at him in astonishment. Had he taken leave of his senses?
"Have sense" she said sharply, "lobsters are always boiled alive. They must be." She caught up the lobster and laid it on its back. It trembled. "They feel nothing" she said.
… She lifted the lobster clear of the table. It had about thirty seconds to live.
Well, thought Belacqua, it's a quick death, God help us all.
It is not.
— Samuel Beckett, "Dante and the Lobster" (1934)
It's a tricky one, Max, because pain is a subjective concept. Pain is how your brain responds to certain kinds of stimuli. As you might expect, lobsters have nerves and respond to sensation, but the question remains whether they can experience pain as we understand it. This is mostly a philosophical question, ultimately, but that hasn't stopped scientists from trying to figure out an answer.
Recently Stuart Barr and some of his colleagues at Queen's University Belfast published a study [abstract] on this very issue. (OK, they looked at prawns, not lobsters, but the same logic applies.) The study, titled "Nociception or Pain in a Decapod Crustacean?" [abstract], begins with the distinction outlined above, but makes it a bit more sciencey: "Nociception is the ability to perceive a noxious stimulus and react in a reflexive manner and occurs across a wide range of taxa. However, the ability to experience the associated aversive sensation and feeling, known as pain, is not widely accepted to occur in nonvertebrates." In other words, lots of animals respond to stimuli that could harm them, but we think those without spines don't feel it. How can we make this distinction? How can we operationalize pain?
Well, by doing things to invertebrates that would hurt a person and observing their responses. Mollusks, insects, annelids, and decapod crustaceans all show avoidance learning in response to electric shocks. And bee venom, which causes pain that most of us can attest to, will make a spider tear its own leg off. Barr et al. propose that in order to count as proof of pain, the animal's response must be nonreflexive; reduction of such response after analgesia is also evidence, they suggest, that what the animal is experiencing is pain. The authors designed an experiment in which prawns' antennae were pretreated with either the anesthetic benzocaine or salt water, as a placebo; the antennae then were variously pinched with a forceps or exposed to sodium hydroxide or acetic acid solutions. They found that following mechanical and chemical stimulation, the prawns engaged in prolonged sessions of rubbing or grooming their antennae; prawns who'd been anesthetized did less of this. Such responses were judged to be "more complex than a reflex action," and the fact that the rubbing and grooming were "directed specifically at the site of stimulation" was said to suggest that "higher processing is involved." These response patterns were similar to those shown by fish and other higher vertebrates. The authors' conclusion: prawns "fit criteria for pain."
But other scientists have questioned the validity of this method. Zoology and physiology professor James Rose says [pdf] that those who look to behavioral evidence for proof that an animal can experience pain are falling into the trap of anthropocentrism. "Humans [tend] to view other vertebrates as having mental states similar to our own. . . . This human tendency to attribute mental states to others is called 'theory of mind' and is probably the basis for our tendency to feel empathy toward other people." Rose says that using the human subjective experience as a model for animal experience is like using fish respiration as a model for mammal breathing. Instead he suggests focusing on neuroanatomical comparison, in accordance with "the most well-established principles of neuroscience: that neurobehavioral function, including sensory perception and psychological experience, are [sic] based on specific, identifiable properties of nervous system structure." Rose further suggests that the neocortex, which mammals have and lower species lack, is necessary for experiencing pain.
UK biologist Lynne Sneddon and her colleagues retorted [pdf] that it was Rose and his ilk who were being anthropocentric – by insisting that a feeling can only count as pain if it's experienced the way humans experience it. They argue in favor of the approach used by Barr: "If a noxious event has sufficiently adverse effects on behaviour and physiology in an animal and this experience is painful in humans, then it is likely to be painful in the animal." In response, Rose pointed out [pdf] that Sneddon's approach blurred the distinction between nociception and pain. He notes that the International Association for the Study of Pain defines pain as a "purely conscious experience." And it does: "An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage." And so we come full circle. The answer to the question of whether a lower organism can experience pain depends on how we define pain. As a recent article on the topic puts it: "It's debatable whether the debate will ever be resolved."