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Full-Text Articles in Life Sciences

Sentience In Decapods: Difficulties To Surmount, Michael L. Woodruff Jan 2022

Sentience In Decapods: Difficulties To Surmount, Michael L. Woodruff

Animal Sentience

In the target article Crump et al. present 8 criteria to assess whether decapods experience pain. Four of these -- sensory integration, motivational trade-offs, flexible self-protection, and associative learning -- could be used to assess sentience in general. In this commentary I discuss difficulties with using these criteria to provide evidence of sentience in decapods, particularly if this evidence is to change public opinion and policies. These difficulties are lack of evidence, the potential to eventually explain the neurobiological basis of the behaviors chosen as criteria, thereby eliminating any explanatory work for sentience, and the reluctance to bring animals that …


The Reality And Prevalence Of Animal Sentience, Antonio Damasio Jan 2022

The Reality And Prevalence Of Animal Sentience, Antonio Damasio

Animal Sentience

Rowan et al use findings from neurobiology, clinical neurology, and general biology to argue for the extensive presence of sentience in animals, but they are wisely cautious concerning when in the phylogenetic scale that emergence occurred.


Defending Human Difference By Raising The Bar, Joe Gough Jan 2022

Defending Human Difference By Raising The Bar, Joe Gough

Animal Sentience

Chapman & Huffman (C&H) offer a theory of why we humans want to believe that we are different: to justify our cruelty to animals. This commentary offers further supporting evidence of this and examines more closely what the claim that humans are ‘different’ amounts to. It also considers some methodological issues in animal psychology closely related to C&H ‘s theory. These problems result from a common strategy for defending hypotheses about human difference.


Intuition And The Invertebrate Dogma, Jonathan Balcombe Jan 2020

Intuition And The Invertebrate Dogma, Jonathan Balcombe

Animal Sentience

Just as intuition, fueled by hubris, led us to exclude insects from moral consideration, so intuition can lead to the opposite conclusion. Observed insect behavior, combined with scientific support for insect consciousness summarized in Mikhalevich & Powell’s target article, and bolstered by the Precautionary Principle, all militate against completely denying moral status to insects.


The Perfecting Of The Octopus, Ila France Porcher Jan 2019

The Perfecting Of The Octopus, Ila France Porcher

Animal Sentience

Cephalopods split away from the phylogenetic tree about half a billion years ago, and octopus evolution has been accelerated by an extremely low survival rate. This helps explain why this unusual animal presents qualities found in no other. It has a radially organized nervous system with a processing centre for each of its eight tentacles. Yet, although this might suggest that each tentacle has its own centre of consciousness, it remains just one animal, with one mouth to feed, and one life to lose, and it behaves as if it is centrally controlled. Its capacity for a range of intelligent …


Cephalopods Are Best Candidates For Invertebrate Consciousness, Jennifer A. Mather, Claudio Carere Jun 2018

Cephalopods Are Best Candidates For Invertebrate Consciousness, Jennifer A. Mather, Claudio Carere

Jennifer Mather, PhD

Insects might have been the first invertebrates to evolve sentience, but cephalopods were the first invertebrates to gain scientific recognition for it.


If It Looks Like A Duck: Fish Fit The Criteria For Pain Perception, Julia E. Meyers-Manor Jan 2018

If It Looks Like A Duck: Fish Fit The Criteria For Pain Perception, Julia E. Meyers-Manor

Animal Sentience

Whereas we have denied the experience of pain to animals, including human babies, the evidence is becoming clearer that animals across a variety of species have the capacity to feel pain (Bellieni, 2012). As converging findings are collected from pain studies and the study of cognition, it is becoming harder to deny that fish are among the species that do feel pain.


Pain In Fish: Evidence From Peripheral Nociceptors To Pallial Processing, Michael L. Woodruff Jan 2018

Pain In Fish: Evidence From Peripheral Nociceptors To Pallial Processing, Michael L. Woodruff

Animal Sentience

The target article by Sneddon et al. (2018) presents convincing behavioral and pharmacological evidence that ray-finned fish consciously perceive noxious stimuli as painful. One objection to this interpretation of the evidence is that the fish nervous system is not complex enough to support the conscious experience of pain. Data that contradict this objection are presented in this commentary. The neuroanatomy and neurophysiology of the fish nervous system from the peripheral nerves to the pallium is able to support the sentient appreciation of pain.


Fish Sentience, Consciousness, And Ai, Ila France Porcher Jan 2018

Fish Sentience, Consciousness, And Ai, Ila France Porcher

Animal Sentience

The systematic criticism of articles providing evidence that fish and invertebrates can feel pain is discussed. Beliefs are known to be stronger than evidence in the human mind, and could generate this outcry, while from another perspective, the criticisms appear as a territorial move by fishermen against a perceived threat to their domain. The scientific inconsistency in which consciousness is granted to machines but not to fish and invertebrates, purely due to political bias, is pointed out. No basis exists for denying sentience to any life form as long as science is ignorant of the nature and source of consciousness.


Studying Dog Emotion Beyond Expression And Without Concern For Feeling, Peter F. Cook Jan 2017

Studying Dog Emotion Beyond Expression And Without Concern For Feeling, Peter F. Cook

Animal Sentience

Studies of dog emotion have focused on the expression of social emotion, either because this is taken to suggest human-like feeling states in dogs or because it has been the most accessible signal of dog emotional processing. I argue for an approach grounded in affective neuroscience, relying on direct measures of physiology across different contexts. This work may be particularly fertile in exploring social emotion in the dog, not because dogs necessarily share human emotional states, but because they are unique in having likely evolved to fit a human social niche.


Animal Models, Agendas And Sentience, Thomas Creson Jan 2017

Animal Models, Agendas And Sentience, Thomas Creson

Animal Sentience

Woodruff’s target article on teleost consciousness is a well-organized logical argument for considering the fish as a sentient being. This becomes more important for animal ethical discussion as the fish becomes a more important and legitimate animal model for investigating animal states and traits associated with higher levels of behavior such as learning and memory.


The Emotional Brain Of Fish, Sonia Rey Planellas Jan 2017

The Emotional Brain Of Fish, Sonia Rey Planellas

Animal Sentience

Woodruff (2017) analyzes structural homologies and functional equivalences between the brains of mammals and fish to understand where sentience and social cognition might reside in teleosts. He compares neuroanatomical, neurophysiological and behavioural correlates. I discuss current advances in the study of fish cognitive abilities and emotions, and advocate an evolutionary approach to the underlying basis of sentience in teleosts.


Similar Anatomy Does Not Imply Comparable Function, Jay R. Stauffer Jr. Jan 2017

Similar Anatomy Does Not Imply Comparable Function, Jay R. Stauffer Jr.

Animal Sentience

Woodruff concludes that ray-finned fishes (Actinopterygii) are sentient and that the pallium contributes to sentience in these fishes. He gives a detailed description of the pallium; however, he assumes that similar structures in fishes and tetrapods support similar behaviors, capabilities, and functions. I reject the premise that similarities in structure imply similarities in function. The fact that a selected species of fish may exhibit behaviors, reactions, and/or anatomy suggestive of sentience does not necessarily generalize to all teleosts.


Still Wondering How Flesh Can Feel, Gwen J. Broude Dec 2016

Still Wondering How Flesh Can Feel, Gwen J. Broude

Animal Sentience

Reber believes he has simplified Chalmers’s “hard problem” of consciousness by arguing that subjectivity is an inherent feature of biological forms. His argument rests on the related notions of continuity of mind and gradual accretion of capacities across evolutionary time. These notions need to be defended, not just asserted. Because Reber minimizes the differences in mental faculties among species across evolutionary time, it becomes easier to assert, and perhaps believe, that sentience is already present in early biological forms. The more explicit we are about the differences among these mental faculties and the differences across species, the less persuasive is …


Reber’S Caterpillar Offers No Help, Carl Safina Dec 2016

Reber’S Caterpillar Offers No Help, Carl Safina

Animal Sentience

Reber’s target article “Caterpillars, consciousness and the origins of mind” seems only to shift but not to address the question of where the mind is and how minds occur.



Resolving The Hard Problem And Calling For A Small Miracle, Arthur S. Reber Nov 2016

Resolving The Hard Problem And Calling For A Small Miracle, Arthur S. Reber

Animal Sentience

With the exception of the commentary by Key, the commentaries on Reber have a common feature: the commenters feel, with varying levels of enthusiasm, that there is at least some virtue in the core assumption of the Cellular Basis of Consciousness (CBC) theory that consciousness (or subjectivity or sentience) accompanies the earliest forms of life. The model has two important entailments: (a) it resolves the (in)famous Hard Problem by redirecting the search for the biochemical foundations of sentience away from human consciousness; and (b) it reduces the need for an emergentist miracle to a far simpler scale than is currently …


No Help On The Hard Problem, Derek Ball Nov 2016

No Help On The Hard Problem, Derek Ball

Animal Sentience

The hard problem of consciousness is to explain why certain physical states are conscious: why do they feel the way they do, rather than some other way or no way at all? Arthur Reber (2016) claims to solve the hard problem. But he does not: even if we grant that amoebae are conscious, we can ask why such organisms feel the way they do, and Reber’s theory provides no answer. Still, Reber’s theory may be methodologically useful: we do not yet have a satisfactory theory of consciousness, but perhaps the study of simple minds is a way to go about …


Unconscious Higher-Order Thoughts (Hots) As Pre-Reflective Self-Awareness?, Rocco J. Gennaro Nov 2016

Unconscious Higher-Order Thoughts (Hots) As Pre-Reflective Self-Awareness?, Rocco J. Gennaro

Animal Sentience

Rowlands argues that many nonhuman animals are “persons,” contrary to the prevailing orthodoxy which rests on a mistaken conception of the kind of self-awareness relevant to personhood. He argues that self-awareness bifurcates into two importantly different forms — reflective self-awareness and pre-reflective self-awareness — and that many animals can have the latter, which is sufficient for personhood. I agree that there is good reason to think that many animals can have pre-reflective self-awareness, but I think Rowlands is mistaken about its nature. His account runs the risk of leading to an infinite regress objection, and his notion of pre-reflective self-awareness …


Insects: Still Looking Like Zombies, Christopher S. Hill Oct 2016

Insects: Still Looking Like Zombies, Christopher S. Hill

Animal Sentience

In arguing that insect brains are capable of sentience, Klein & Barron rely heavily on Bjorn Merker’s claim that activity in the human mid-brain is sufficient for conscious experience. I criticize Merker’s claim by pointing out that the behaviors supported by midbrain activity are much more primitive than the ones that appear to depend on consciousness. I raise a similar objection to Klein & Barron’s contention that insect behaviors are similar to behaviors that manifest consciousness in human beings. The similarity is weak. I also respond to the related view that integrative activity in mid-brain structures is sufficient to explain …


How Could Consciousness Emerge From Adaptive Functioning?, Max Velmans Sep 2016

How Could Consciousness Emerge From Adaptive Functioning?, Max Velmans

Animal Sentience

The sudden appearance of consciousness that Reber posits in creatures with flexible cell walls and motility rather than non-flexible cells walls and no motility involves an evolutionary discontinuity. This kind of “miracle” is required by all “discontinuity” theories of consciousness. To avoid miraculous emergence, one may need to consider continuity theories, which accept that different forms of consciousness and material functioning co-evolve but assume the existence of consciousness to be primal in the way that matter and energy are assumed to be primal in physics.


Beginnings: Physics, Sentience And Luca, Carolyn A. Ristau Sep 2016

Beginnings: Physics, Sentience And Luca, Carolyn A. Ristau

Animal Sentience

According to Reber’s model, Cellular Basis of Consciousness (CBC), sentience had its origins in a unicellular organism and is an inherent property of living, mobile organic forms. He argues by analogy to basic physical forces which he considers to be inherent properties of matter; I suggest that they are instead the stuff of scientific investigation in physics. I find no convincing argument that sentience had to begin in endogenously mobile cells, a criterial attribute of the originator cell(s)for sentience according to CBC. Non-endogenously mobile cells, (i.e., plants or precursors) in a moving environment would suffice. Despite my concerns and the …


Subjective Experience In Insects: Definitions And Other Difficulties, Shelley Adamo Aug 2016

Subjective Experience In Insects: Definitions And Other Difficulties, Shelley Adamo

Animal Sentience

Whether insects have the potential for subjective experiences depends on the definition of subjective experience. The definition used by Klein & Barron (2016) is an unusually liberal one and could be used to argue that some modern robots have subjective experiences. From an evolutionary perspective, the additional neurons needed to produce subjective experiences will be proportionately more expensive for insects than for mammals because of the small size of the insect brain. This greater cost could weaken selection for such traits. Minimally, it may be premature to assume that small neuronal number is unimportant in determining the capacity for consciousness.


Bacteria And The Cellular Basis Of Consciousness, Michael L. Woodruff Aug 2016

Bacteria And The Cellular Basis Of Consciousness, Michael L. Woodruff

Animal Sentience

According to Reber’s theory, the Cellular Basis of Consciousness (CBC), sentience originates as bio-sensitivity in unicellular organisms. For this reason, Reber regards sentience as evolutionarily foundational. Many bacteria show chemotaxis and, thus, according to CBC, they are sentient. Analysis of the genetic mechanisms underlying bacterial chemotaxis indicates that sentience has no explanatory power in this case. Genetic analysis also fails to show species continuity underlying bio-sensitivity in bacteria and bio-sensitivity in species with nervous systems, so it does not seem that sentience is evolutionary foundational. CBC is rejected on these grounds.


Is Cortex Necessary?, Sean Allen-Hermanson Aug 2016

Is Cortex Necessary?, Sean Allen-Hermanson

Animal Sentience

A key contention of Klein & Barron (2016) is that consciousness does not depend on cortical structures. A critical appraisal suggests they have overestimated the strength of their evidence.


Cephalopods Are Best Candidates For Invertebrate Consciousness, Jennifer A. Mather, Claudio Carere Jul 2016

Cephalopods Are Best Candidates For Invertebrate Consciousness, Jennifer A. Mather, Claudio Carere

Animal Sentience

Insects might have been the first invertebrates to evolve sentience, but cephalopods were the first invertebrates to gain scientific recognition for it.


Caterpillars, Consciousness And The Origins Of Mind, Arthur S. Reber Jul 2016

Caterpillars, Consciousness And The Origins Of Mind, Arthur S. Reber

Animal Sentience

A novel framework for the origins of consciousness and mind, the Cellular Basis of Consciousness (CBC), is presented. The model is based on a simple, perhaps radical axiom: subjectivity is an inherent feature of particular kinds of organic form. Experiential states, including those denoted as "mind" and "consciousness," are present in the most primitive species. The model has several conceptual and empirical virtues, among them: (a) it (re)solves the problem of how minds are created by brains ─ also known as the "Hard Problem" (Chalmers 1995) ─ by revealing that the apparent difficulty results from a category error, (b) it …


Why Fish Do Not Feel Pain, Brian Key Jan 2016

Why Fish Do Not Feel Pain, Brian Key

Animal Sentience

Only humans can report feeling pain. In contrast, pain in animals is typically inferred on the basis of nonverbal behaviour. Unfortunately, these behavioural data can be problematic when the reliability and validity of the behavioural tests are questionable. The thesis proposed here is based on the bioengineering principle that structure determines function. Basic functional homologies can be mapped to structural homologies across a broad spectrum of vertebrate species. For example, olfaction depends on olfactory glomeruli in the olfactory bulbs of the forebrain, visual orientation responses depend on the laminated optic tectum in the midbrain, and locomotion depends on pattern generators …


Should Fish Feel Pain? A Plant Perspective, František Baluška Jan 2016

Should Fish Feel Pain? A Plant Perspective, František Baluška

Animal Sentience

Key (2016) claims fish that fish do not feel pain because they lack the necessary neuronal architecture: their responses to noxious stimuli, according to Key, are executed automatically without any feelings. However, as pointed out by many of his commentators, this conclusion is not convincing. Plants might provide some clues. Plants are not usually thought to be very active behaviorally, but the evidence suggests otherwise. Moreover, in stressful situations, plants produce numerous chemicals that have painkilling and anesthetic properties. Finally, plants, when treated with anesthetics, cannot execute active behaviors such as touch-induced leaf movements or rapid trap closures after localizing …


What Would The Babel Fish Say?, Monica Gagliano Jan 2016

What Would The Babel Fish Say?, Monica Gagliano

Animal Sentience

Starting with its title, Key’s (2016) target article advocates the view that fish do not feel pain. The author describes the neuroanatomical, physiological and behavioural conditions involved in the experience of pain in humans and rodents and confidently applies analogical arguments as though they were established facts in support of the negative conclusion about the inability of fish to feel pain. The logical reasoning, unfortunately, becomes somewhat incoherent, with the arbitrary application of the designated human criteria for an analogical argument to one animal species (e.g., rodents) but not another (fish). Research findings are reported selectively, and questionable interpretations are …


Fish Lack The Brains And The Psychology For Pain, Stuart W.G. Derbyshire Jan 2016

Fish Lack The Brains And The Psychology For Pain, Stuart W.G. Derbyshire

Animal Sentience

Debate about the possibility of fish pain focuses largely on the fish’s lack of the cortex considered necessary for generating pain. That view is appealing because it avoids relatively abstract debate about the nature of pain experience and subjectivity. Unfortunately, however, that debate cannot be entirely avoided. Subcortical circuits in the fish might support an immediate, raw, “pain” experience. The necessity of the cortex only becomes obvious when considering pain as an explicitly felt subjective experience. Attributing pain to fish only seems absurd when pain is considered as a state of explicit knowing.