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Full-Text Articles in Evolution

Pain-Capable Neural Substrates May Be Widely Available In The Animal Kingdom, Edgar T. Walters Jan 2016

Pain-Capable Neural Substrates May Be Widely Available In The Animal Kingdom, Edgar T. Walters

Animal Sentience

Neural and behavioral evidence from diverse species indicates that some forms of pain may be generated by coordinated activity in networks far smaller than the cortical pain matrix in mammals. Studies on responses to injury in squid suggest that simplification of the circuitry necessary for conscious pain might be achieved by restricting awareness to very limited information about a noxious event, possibly only to the fact that injury has occurred, ignoring information that is much less important for survival, such as the location of the injury. Some of the neural properties proposed to be critical for conscious pain in mammals …


How Not To Move The Line Drawn On Pain, Bjorn H. Merker Jan 2016

How Not To Move The Line Drawn On Pain, Bjorn H. Merker

Animal Sentience

In this second commentary I outline the inadequacy of Key's responses to the many peer critiques of his thesis that have so far appeared in Animal Sentience. I illustrate with examples drawn from his response to my first commentary.


Spinning Our Wheels And Deepening The Divide: Call For An Evidence-Based Approach To The Fish Pain Debate, Steven J. Cooke Jan 2016

Spinning Our Wheels And Deepening The Divide: Call For An Evidence-Based Approach To The Fish Pain Debate, Steven J. Cooke

Animal Sentience

There is vigorous ongoing debate about whether fish feel pain and have the capacity to suffer. The body of literature dedicated to the topic is increasing but what is particularly problematic is that the majority of the contributions represent opinion pieces and thus fall within the realm of advocacy. Many of the empirical research papers purporting that fish do or do not feel pain have problems with cavalier use of definitions, poor experimental design, or statistical/technical issues and tend to include advocacy statements in their interpretations. Rather than continuing to spin our wheels and deepen the divide, I would advocate …


Pain In Parallel, Peter Godfrey-Smith Jan 2016

Pain In Parallel, Peter Godfrey-Smith

Animal Sentience

Key's (2016) arguments against the view that fish feel pain can be shown to be fallacious by considering some damage-related behaviors in invertebrates. Pain may have different neural bases in different organisms, so the absence in fish of the cortical structures that might underlie pain in mammals does not settle the question of fish pain.


Pain In Fish: Weighing The Evidence, James D. Rose Jan 2016

Pain In Fish: Weighing The Evidence, James D. Rose

Animal Sentience

The target article by Key (2016) examines whether fish have brain structures capable of mediating pain perception and consciousness, functions known to depend on the neocortex in humans. He concludes, as others have concluded (Rose 2002, 2007; Rose et al. 2014), that such functions are impossible for fish brains. This conclusion has been met with hypothetical assertions by others to the effect that functions of pain and consciousness may well be possible through unknown alternate neural processes. Key's argument would be bolstered by consideration of other neurological as well as behavioral evidence, which shows that sharks and ray are fishes …


Nonverbal Indicators Of Pain, Simon Van Rysewyk Jan 2016

Nonverbal Indicators Of Pain, Simon Van Rysewyk

Animal Sentience

In discussing fish pain, Key (2016) privileges pain in humans — “the only species able to directly report on its feelings.” Human experience of pain is not necessarily best reflected by verbal self-report, however. Neural responses to noxious stimuli are influenced by individual differences and by context. Nonverbal pain displays such as facial expressions reflect part of the neural response to noxious stimuli. Most mammals have a specific facial grimace reflecting pain. If fish have a somatic expression of pain, the development of a reliable and accurate somatic pain scale specific to fish could make a contribution to the debate …


Anthropomorphic Denial Of Fish Pain, Lynne U. Sneddon, Matthew C. Leach Jan 2016

Anthropomorphic Denial Of Fish Pain, Lynne U. Sneddon, Matthew C. Leach

Animal Sentience

Key (2016) affirms that we do not know how the fish brain processes pain but denies — because fish lack a human-like cortex — that fish can feel pain. He affirms that birds, like fish, have a singly-laminated cortex and that the structure of the bird brain is quite different from that of the human brain, yet he does not deny that birds can feel pain. In this commentary we describe how Key cites studies that substantiate mammalian pain but discounts the same kind of data as evidence of fish pain. We suggest that Key's interpretations are illogical, do not …


Going Beyond Just-So Stories, Brian Key Jan 2016

Going Beyond Just-So Stories, Brian Key

Animal Sentience

Colloquial arguments for fish feeling pain are deeply rooted in anthropometric tendencies that confuse escape responses to noxious stimuli with evidence for consciousness. More developed arguments often rely on just-so stories of fish displaying complex behaviours as proof of consciousness. In response to commentaries on the idea that fish do not feel pain, I raise the need to go beyond just-so stories and to rigorously analyse the neural circuitry responsible for specific behaviours using new and emerging technologies in neuroscience. By deciphering the causal relationship between neural information processing and conscious behaviour, it should be possible to assess cogently the …


Falsifying The Null Hypothesis That “Fish Do Not Feel Pain", Brian Key Jan 2016

Falsifying The Null Hypothesis That “Fish Do Not Feel Pain", Brian Key

Animal Sentience

The reader of Animal Sentience may surmise that because the weight of the commentaries on my target article, “Why fish do not feel pain,” is leaning towards not supporting my argument, it follows that the premise "fish do not feel pain" is incorrect. However, science does not prevail by popular opinion. History is plagued with numerous (and often widely accepted) examples of biological phenomena being explained by mysterious forces. In the absence of a mechanistic understanding, the many different guises of vitalism (the principle that life involves a vital energy) are often invoked to explain the unknown. Spurious …


An Invertebrate Perspective On Pain, Jennifer A. Mather Jan 2016

An Invertebrate Perspective On Pain, Jennifer A. Mather

Animal Sentience

Although Key (2016) argues that mammals feel pain and fish do not, from an invertebrate perspective, it is obvious that the pain experience is shared by animals from a number of different animal groups.


Sentience And Animal Welfare: New Thoughts And Controversies, Donald M. Broom Jan 2016

Sentience And Animal Welfare: New Thoughts And Controversies, Donald M. Broom

Animal Sentience

Sentience involves having some degree of awareness but awareness of self is not as complex as some people believe. Fully functioning vertebrate animals, and some invertebrates, are sentient but neither humans nor non-humans are sentient early in development or if brain-damaged. Feelings are valuable adaptive mechanisms and an important part of welfare but are not all of welfare so the term welfare refers to all animals, not just to sentient animals. We have much to learn about what non-human animals want from us, the functioning of the more complex aspects of their brains and of our brains and how we …


Cortex Necessary For Pain — But Not In Sense That Matters, Adam J. Shriver Jan 2016

Cortex Necessary For Pain — But Not In Sense That Matters, Adam J. Shriver

Animal Sentience

Certain cortical regions are necessary for pain in humans in the sense that, at particular times, they play a direct role in pain. However, it is not true that they are necessary in the more important sense that pain is never possible in humans without them. There are additional details from human lesion studies concerning functional plasticity that undermine Key’s (2016) interpretation. Moreover, no one has yet identified any specific behaviors that mammalian cortical pain regions make possible that are absent in fish.


Why Is Fish “Feeling” Pain Controversial?, E. Don Stevens Jan 2016

Why Is Fish “Feeling” Pain Controversial?, E. Don Stevens

Animal Sentience

In his excellent target article, Key (2016) develops a mechanistic argument in an attempt to show why it is unlikely that fish can “feel” pain or for that matter, “feel” anything. The topic is controversial and likely to achieve the goal of getting many hits for the inaugural issue of the new journal, Animal Sentience. In my view, the question is unlikely to be answered, for two reasons. First, because the proponents of the “fish feel pain” controversy are untrained and unskilled in the details and jargon of neurophysiology and/or neuroanatomy, and the opponents of the controversy, like Key, …


Fish Pain: A Painful Topic, Carl Safina Jan 2016

Fish Pain: A Painful Topic, Carl Safina

Animal Sentience

If fish cannot feel pain, why do stingrays have purely defensive tail spines that deliver venom? Stingrays’ ancestral predators are fish. And why do many fishes possess defensive fin spines, some also with venom that produces pain in humans? These things did not evolve just in case sentient humans would evolve millions of years later and then invent scuba. If fish react purely unconsciously to “noxious” stimuli, why aren’t sharp jabbing spines enough? Why also stinging venom?


How Welfare Biology And Commonsense May Help To Reduce Animal Suffering, Yew-Kwang Ng Jan 2016

How Welfare Biology And Commonsense May Help To Reduce Animal Suffering, Yew-Kwang Ng

Animal Sentience

Welfare biology is the study of the welfare of living things. Welfare is net happiness (enjoyment minus suffering). Since this necessarily involves feelings, Dawkins (2014) has suggested that animal welfare science may face a paradox, because feelings are very difficult to study. The following paper provides an explanation for how welfare biology could help to reduce this paradox by answering some difficult questions regarding animal welfare. Simple means based on commonsense could reduce animal suffering enormously at low or even negative costs to humans. Ways to increase the influence of animal welfare advocates are also discussed, focusing initially on farmed …


Is Sentience Only A Nonessential Component Of Animal Welfare?, Ian J.H. Duncan Jan 2016

Is Sentience Only A Nonessential Component Of Animal Welfare?, Ian J.H. Duncan

Animal Sentience

According to Broom (2014), animal welfare is a concept that can be applied to all animals, including single-celled organisms that are obviously not sentient. Such a stance makes it difficult to draw a connection between welfare and sentience, and that is the book’s downfall. Some excellent points are made about sentience and there are very good discussions on animal welfare. However, unless sentience is considered the essential component of welfare, any attempt to link the two phenomena will be unsuccessful — and that, indeed, is the case with this book.


Why Animal Welfarism Continues To Fail, Lori Marino Jan 2016

Why Animal Welfarism Continues To Fail, Lori Marino

Animal Sentience

Welfarism prioritizes human interests over the needs of nonhuman animals. Despite decades of welfare efforts other animals are mostly worse off than ever before, being subjected to increasingly invasive and harmful treatments, especially in the factory farming and biomedical research areas. A legal rights-based approach is essential in order for other animals to be protected from the varying ethical whims of our species.