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Full-Text Articles in Life Sciences

Multiple Ways To Implement And Infer Sentience, Nicolas Rouleau, Michael Levin Jul 2023

Multiple Ways To Implement And Infer Sentience, Nicolas Rouleau, Michael Levin

Animal Sentience

Segundo-Ortin & Calvo’s (S&C’s) thorough review of “plant neurobiology” presents evidence supporting the possibility of plant sentience. They make a compelling case that plants anticipate, assess risk, cooperate, mimic, and pursue goals, as do their animal counterparts. S&C point out that there is a double standard: behavioural patterns associated with subjective experiences in humans are considered valid for inferring cognition in non-human animals but not in diverse other systems including plants. We argue that cognitive functions, including sentience, can potentially be achieved by very different systems and their disparate substrates. We offer some context from the basal cognition literature and …


Plant Sentience: Not Now, Maybe Later?, Helen Tiffin Jul 2023

Plant Sentience: Not Now, Maybe Later?, Helen Tiffin

Animal Sentience

Segundo-Ortin’s target article provides compelling evidence for physiological and behavioral complexity in plants, bringing us closer to a recognition of some kind of plant cognition – but it does not as yet offer firm grounds for inferring sentience (feeling) in plants, The recent history of the scientific demonstration and recognition of animalsentience in invertebrates, for example, does not entirely rule out the possibility that further research might provide support for plant sentience. Should this ever turn out to be the case, the ethical problems raised are not insurmountable, and would not threaten the now proven case for animal sentience


Limits To Sentience, Donald M. Broom Jun 2023

Limits To Sentience, Donald M. Broom

Animal Sentience

There are many parallels between cellular function in animals and plants. Plants can have complex interactions with their environments. But they lack a central nervous system, which is a prerequisite for sentience (the capacity to feel). In my view the suggestion that plants are sentient is not only empirically incorrect but potentially harmful to the efforts to protect the welfare of sentient beings.


Disentangling Sentience From Developmental Plasticity, Jonathan Birch May 2023

Disentangling Sentience From Developmental Plasticity, Jonathan Birch

Animal Sentience

Plants, like animals, display remarkable developmental plasticity, inviting the metaphorical use of terms like “decision” and “choice”. In the animal case, this is not taken to be evidence of sentience, because sentience is a complex product of development, not something that guides it. We should apply the same standards when evaluating the evidence in plants. It is hard to overstate the contrast with the case of invertebrates such as octopuses, where pain markers that were originally developed for use in mammals have been clearly demonstrated and plausible neural substrates for sentience have been identified.


The Elephant In The Garden, Ila France Porcher May 2023

The Elephant In The Garden, Ila France Porcher

Animal Sentience

The other commentators on Chapman & Huffman (2018) have pointed out in different ways that despite our biological nature, there is a widespread tendency for humans to believe that we are not only superior to animals, but that we are not animals at all. Alongside our denial of animal sentience and cognition, this has resulted in the denial of our own instinctive natures. It is this denial that is our error, for it is only by understanding our true natural heritage that we can begin to change the runaway path we are on.


Plant Sentience: "Feeling" Or Biological Automatism?, Andrea Mastinu Apr 2023

Plant Sentience: "Feeling" Or Biological Automatism?, Andrea Mastinu

Animal Sentience

Sentience refers to the ability of an organism to have subjective experiences such as sensations, emotions and awareness. Whereas some animals, including humans, are widely recognized as sentient, the question of whether plants are sentient is still debated among scientists, philosophers, and ethicists. Over the past 20 years, many scientists such as Trewavas, Baluška, Mancuso, Gagliano, and Calvo have reported interesting discussions about memory, behavior, communication, and intelligence in plants. However, the reported conclusions have not convinced the entire scientific community. In this commentary, I would like to focus on two critical aspects related to sentience: cognition and emotion


Plant Sentience: Bias And Promise, Sidney Carls-Diamante Apr 2023

Plant Sentience: Bias And Promise, Sidney Carls-Diamante

Animal Sentience

Whichever side of the debate one chooses, plant sentience is a fertile research area that challenges received views and assumptions, generates novel insights, and suggests new ways that felt states might arise. My commentary discusses methodological and philosophical implications.


From Animal To Plant Sentience: Is There Credible Evidence?, Leonard Dung Apr 2023

From Animal To Plant Sentience: Is There Credible Evidence?, Leonard Dung

Animal Sentience

Segundo-Ortin & Calvo argue that plants have a surprisingly varied and complex behavioral repertoire. Which of these behavioral capacities are credible indicators of sentience? If we use the standards of evidence common in discussions of animal sentience, the behavioral capacities reviewed are insufficient evidence of sentience. Even if some putative indicators of animal sentience are present in plants, it is not clear whether what we should conclude is that plants are sentient or that those indicators are inadequate.


What Can Plant Science Learn From Animal Nervous Systems?, Luiz Pessoa Apr 2023

What Can Plant Science Learn From Animal Nervous Systems?, Luiz Pessoa

Animal Sentience

I welcome Segundo-Ortin & Calvo’s (2023) call for a rigorous science of plant behavior and physiology. My commentary addresses three points drawn from the literature on animal brains that could help elucidate the possibility of cognition and sentience in plants: (1) the presumed requirement of a centralized brain; (2) centralization of control versus heterarchical organization; and (3) connecting plant research with research on animal nervous systems.


Plant Sentience And The Case For Ethical Veganism, Josh Milburn Apr 2023

Plant Sentience And The Case For Ethical Veganism, Josh Milburn

Animal Sentience

Does the possibility of plant sentience pose a problem for ethical veganism? It has not yet been demonstrated that plants are sentient (i.e., that they can feel). Moreover, even if it were demonstrated that plants could feel, it would also have to be demonstrated that they can feel the affectively “valenced” feelings that are ethically significant, such as pain and fear, rather than just neutral sensations such as darker/lighter, or wetter/drier. Finally, if plants could feel valenced feelings, veganism would likely still be the ethical option, on the principle of causing the least harm.


Plants Detect And Adapt, But Do Not Feel, Paul C. Struik Apr 2023

Plants Detect And Adapt, But Do Not Feel, Paul C. Struik

Animal Sentience

Plant sentience is a hot topic in scientific and popular media. There are moral reasons to respect both the service of plants to humanity and their natural integrity as creatures playing their own significant role in a complex ecosystem. However, to infer that plants have certain cognitive capacities that are present also in certain human and nonhuman animals calls for scientific rigor beyond mere analogy. The unique capacities of plants identified by Segundo-Ortin & Calvo are not necessarily linked to sentience. Nor is it likely that sentience is an evolutionary trait that is present to some extent in all living …


Insentient “Cognition”?, Stevan Harnad Mar 2023

Insentient “Cognition”?, Stevan Harnad

Animal Sentience

A sentient state is a state that it feels like something to be in. Cows have them, cars don’t. Cognitive capacities are a subset of behavioral capacities. Not all behavioral capacities are cognitive (but the distinction is fuzzy). Might the difference have something to do with whether the behaver is sentient?


Plant Sentience Revisited: Sifting Through The Thicket Of Perspectives, Paco Calvo, Miguel Segundo-Ortin Jan 2023

Plant Sentience Revisited: Sifting Through The Thicket Of Perspectives, Paco Calvo, Miguel Segundo-Ortin

Animal Sentience

In our target article (Segundo-Ortin & Calvo 2023), we proposed the intriguing possibility of plant sentience, drawing parallels with non-human animal studies. This response aims to sift through the rich thicket of perspectives offered by our commentators. To do so, we assess the risks of employing double standards, as well as the tendencies of anthropomorphizing and zoomorphizing in plant studies. We also emphasize the need for clarity in linguistic and conceptual terms, examine the neurophysiological evidence for plant sentience, and discuss the ethical implications of such recognition.


Defining And Exploring Animal Sentience, Andrew N. Rowan, Joyce M. D'Silva Mrs, Ian J.H. Duncan, Nicholas Palmer Jan 2023

Defining And Exploring Animal Sentience, Andrew N. Rowan, Joyce M. D'Silva Mrs, Ian J.H. Duncan, Nicholas Palmer

Animal Sentience

One of the commentaries on the target article notes that "animal sentience" is difficult to define operationally. This response to the commentaries develops a working, usable definition of animal sentience and examines the relationships between animal emotions and sentience.


Plant Sentience? Between Romanticism And Denial: Science, Miguel Segundo-Ortin, Paco Calvo Jan 2023

Plant Sentience? Between Romanticism And Denial: Science, Miguel Segundo-Ortin, Paco Calvo

Animal Sentience

A growing number of non-human animal species are being seriously considered as candidates for sentience, but plants are either forgotten or explicitly excluded from these debates. In our view, this is based on the belief that plant behavior is hardwired and inflexible and on an underestimation of the role of plant electrophysiology. We weigh such assumptions against the evidence to suggest that it is time to take seriously the hypothesis that plants, too, might be sentient. We hope this target article will serve as an invitation to investigate sentience in plants with the same rigor as in non-human animals.


Language Matters, Teya Brooks Pribac Jan 2023

Language Matters, Teya Brooks Pribac

Animal Sentience

The term sentience tends to be associated with affective valence along with affectively neutral sensory states. In the absence of evidence for affectively laden states in plants, the use of the term sentience in the exploration of plant sensory and behavioral complexity is misleading and ethically problematic for its potential to trivialize animal sentience.


Animal Sentience Science And Policy, Andrew Crump Jan 2022

Animal Sentience Science And Policy, Andrew Crump

Animal Sentience

Animal sentience research cannot be divorced from its ethical and political implications. For example, discovering which animals are sentient is vital for deciding which require welfare protection. Two legal case-studies illustrate the importance of scientists in such debates: the UK Animal Welfare (Sentience) Act 2022 had input from animal sentience researchers, whereas the US Animal Welfare Act 1966 did not. The former defined sentient animals much more plausibly than the latter. I accordingly argue that sentience researchers should inform policy, and that this is achievable without sacrificing scientific integrity.


Fine-Tuning The Criteria For Inferring Sentience, Culum Brown Jan 2022

Fine-Tuning The Criteria For Inferring Sentience, Culum Brown

Animal Sentience

“Sentience” means the capacity to feel, and feelings are private affairs. Sentience is hence extremely difficult to quantify in nonhuman animals. We have no direct means of determining whether an animal is sentient. Thus we rely on a series of indirect measures or criteria which collectively provide some level of confidence about the probability that an animal is sentient. Crump et al. propose a modified framework based on 8 criteria for estimating the likelihood of sentience in a target taxon. Whereas I very much like their proposed framework, I would suggest a couple of amendments that may improve it further: …


Unconscious Humans, Autonomous Machines And The Difficulty Of Knowing Which Animals Are Sentient, Marian Stamp Dawkins Jan 2022

Unconscious Humans, Autonomous Machines And The Difficulty Of Knowing Which Animals Are Sentient, Marian Stamp Dawkins

Animal Sentience

The framework proposed by Crump et al. still leaves much doubt about whether invertebrates such as crabs are sentient. For example, many complex behaviours - even in humans - occur without sentience. Also, simple machines could easily meet all of Crump et al.’s eight proposed criteria for sentience. Acknowledging the limitations of what we currently know about sentience is important both for formulating legislation correctly and for advancing scientific understanding of this most puzzling of biological phenomena.


Time To Stop Pretending We Don’T Know Other Animals Are Sentient Beings, Marc Bekoff Jan 2022

Time To Stop Pretending We Don’T Know Other Animals Are Sentient Beings, Marc Bekoff

Animal Sentience

Rowan et al.’s target article is an outstanding review of some of the history of the science of sentience, but one would have liked to see a much stronger “call to action.” We don’t need any more data to know that many other animals are sentient beings whose lives must be protected from harm in a wide variety of contexts. It is not anti-science to want more action on behalf of other animals right now.


Sentience In Decapod Crustaceans: A General Framework And Review Of The Evidence, Andrew Crump, Heather Browning, Alex Schnell, Charlotte Burn, Jonathan Birch Jan 2022

Sentience In Decapod Crustaceans: A General Framework And Review Of The Evidence, Andrew Crump, Heather Browning, Alex Schnell, Charlotte Burn, Jonathan Birch

Animal Sentience

We outline a framework for evaluating scientific evidence of sentience, focusing on pain experience. It includes eight neural and cognitive-behavioural criteria, with confidence levels for each criterion reflecting the reliability and quality of the evidence. We outline the rationale for each criterion and apply our framework to a controversial sentience candidate: decapod crustaceans. We have either high or very high confidence that true crabs (infraorder Brachyura) satisfy five criteria, amounting to strong evidence of sentience. Moreover, we have high confidence that both anomuran crabs (infraorder Anomura) and astacid lobsters/crayfish (infraorder Astacidea) meet three criteria—substantial evidence of sentience. The case is, …


Animal Sentience Research: Synthesis And Proposals, Andrew Crump, Heather Browning, Alex Schnell, Charlotte Burn, Jonathan Birch Jan 2022

Animal Sentience Research: Synthesis And Proposals, Andrew Crump, Heather Browning, Alex Schnell, Charlotte Burn, Jonathan Birch

Animal Sentience

Most commentaries on our target article broadly support our approach to evaluating evidence of animal sentience. In this Response, we clarify the framework’s purpose and address criticisms of our criteria. A recurring theme is that a framework to synthesise current evidence of sentience is not the same as an agenda for future directions in animal sentience research. Although future directions are valuable, our framework aims to evaluate existing evidence and inform animal welfare legislation.


All Living Organisms Are Sentient, Arthur S. Reber, Frantisek Baluska, William B. Miller Jr. Jan 2022

All Living Organisms Are Sentient, Arthur S. Reber, Frantisek Baluska, William B. Miller Jr.

Animal Sentience

We argue that all living organisms, from the simplest unicellular prokaryotes to Homo sapiens, have valenced experiences—feelings as states of preference—and are capable of cognitive representations. Bacteria can learn, form stable memories, and communicate, hence solve problems. Rowan et al.'s statement that "Subjective feelings are just that — subjective — and are available only to the animal (or human) experiencing them" is true but irrelevant. When we see a fish flopping about in the bottom of a boat we immediately recognize suffering without having a glimpse of the nature of piscine distress. Some controlled anthropomorphism can go a …


Legal Recognition Of Animal Sentience: The Case For Cautious Optimism, Jane Kotzmann Jan 2022

Legal Recognition Of Animal Sentience: The Case For Cautious Optimism, Jane Kotzmann

Animal Sentience

Rowan et al.’s target article provides a valuable indication of the work that was required to reach the point where animals are recognised as sentient in various laws. To ensure this work was not in vain, the language of sentience needs to be used as a moral currency to demand further cultural change involving greater human respect for animals.


The Science Of Animal Sentience And The Politics Of Animal Welfare Should Be Kept Separate, Marian Stamp Dawkins Jan 2022

The Science Of Animal Sentience And The Politics Of Animal Welfare Should Be Kept Separate, Marian Stamp Dawkins

Animal Sentience

Although linked historically by Rowan et al., the scientific study of animal sentience and political campaigns to improve animal welfare should be kept separate, for at least two reasons. First, the separation makes it clear that standards of evidence acceptable for ethical or political decisions on animal welfare can be lower than those required for a rigorously scientific approach to animal sentience. Second, it helps to avoid confirmatory bias in the form of giving undue weight to results that are in line with pre-conceived ideas and political views.


Revisiting Donald Griffin, Founder Of Cognitive Ethology, Carolyn A. Ristau Jan 2022

Revisiting Donald Griffin, Founder Of Cognitive Ethology, Carolyn A. Ristau

Animal Sentience

Donald Griffin’s writings, beginning with The Question of Animal Awareness (1976), strove to persuade scientists to study the possibility of animal sentience, the basis of Rowan et al.’s efforts to promote animal well-being. Facing great hostility (but also some acceptance) for his ideas, Griffin initially avoided animal welfare advocacy, fearing it would further undermine his efforts to gain recognition of animal sentience. In later years, however, he began to ponder the ethical implications of animal sentience, intending to study wild elephants’ communication and social behavior to better understand their experienced life and apply it to improving conservation methods. As he …


Pain Sentience Criteria And Their Grading, Eva Jablonka, Simona Ginsburg Jan 2022

Pain Sentience Criteria And Their Grading, Eva Jablonka, Simona Ginsburg

Animal Sentience

On the basis of the target article by Crump and colleagues, we suggest a more parsimonious scheme for evaluating the evidence for sentience. Since some of the criteria used by Crump et al. are not independent and some are uninformative we exclude some criteria and amalgamate others. We propose that evidence of flexible learning and prioritization, in conjunction with relevant data on brain organization, is sufficient for assigning pain-sentience to an animal and we suggest a scoring scheme based on four criteria.


Free Will And Animal Suicide, Sabina Schrynemakers Jan 2022

Free Will And Animal Suicide, Sabina Schrynemakers

Animal Sentience

David Peña-Guzmán presents two arguments against the view that because only humans have free will only humans can commit suicide: (1) nonhuman animals may possess free will, and (2) the libertarian notion of free will is incompatible with scientific explanation. The free will objection to animal suicide is indeed mistaken, but Peña-Guzmán’s criticism of the libertarian notion of free will seems misplaced. His target should instead be the assumption that free choices must be made consciously or self-reflectively or the assumption that freedom cannot come in degrees.


Truly Minimal Criteria For Animal Sentience, Mark Solms Jan 2022

Truly Minimal Criteria For Animal Sentience, Mark Solms

Animal Sentience

The criteria for determining animal sentience proposed in the target article are sensible but they lack an explicit functional justification for the focus on pain. This commentary provides an abbreviated account of the most basic functional principles that underpin animal sentience and articulates some minimal criteria for determining its presence.


Crustacean Pain, Michael Tye Jan 2022

Crustacean Pain, Michael Tye

Animal Sentience

This commentary discusses the target article’s methodology, the relevance of the claim that crustaceans lack a neocortex to the thesis that they feel pain, and the evaluation of the results of some trade-off experiments done with hermit crabs.