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Full-Text Articles in Ecology and Evolutionary Biology

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


Animal Communication And Sentience, Catia Correia-Caeiro, Katja Liebal Jun 2023

Animal Communication And Sentience, Catia Correia-Caeiro, Katja Liebal

Animal Sentience

Segundo-Ortin & Calvo (S&C) argue for sentience in plants on the basis of several studies of what they describe as "cognitive abilities" in plants. As other commentaries (e.g., Brooks Pribac, 2023; Damasio & Damasio, 2023; ten Cate, 2023) have pointed out, however, there is some misuse of several concepts, and a lack of evidence for sentience. We try to clarify three questions in S&C’s discussion: (1) How is communication defined and conceptualised in animal research? (2) Is plant communication comparable to animal communication? (3) Is communication (or the process we see in plants) a good basis for inferring sentience in …


Associative Learning: Unmet Criterion For Plant Sentience, Luigi Baciadonna, Catherine Macri, Martin Giurfa May 2023

Associative Learning: Unmet Criterion For Plant Sentience, Luigi Baciadonna, Catherine Macri, Martin Giurfa

Animal Sentience

In a thought-provoking target article, Segundo-Ortin & Calvo (S&C) discuss the possibility that plants are sentient, focusing on a series of capacities normally attributed only to human and nonhuman animals. S&C propose learning as a marker for sentience. We review studies reporting associative learning in plants and find that they either lack essential controls or fail to produce replicable results. The capacity to learn has not yet been demonstrated in plants, so it cannot be used to support the hypothesis that plants are sentient. Further studies are needed. But agnosticism about sentience should not deter us from investigating unexpected new …


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.


Complex Floral Behavior Of An Angiosperm Family, Tilo Henning, Moritz Mittelbach May 2023

Complex Floral Behavior Of An Angiosperm Family, Tilo Henning, Moritz Mittelbach

Animal Sentience

Segundo-Ortin & Calvo provide a comprehensive overview of the many aspects of plant behavior examined to date. In our view, multiple lines of evidence make it difficult to deny plant sentience. We add further evidence to support the conclusion that plants are sentient organisms. As in animals, the behavior of plants can be seen and studied as an evolutionary trait, subject to and a consequence of increasing complexity in the interactions of plants with their environment. Our example is the evolution of floral behavior in Loasaceae, where complex patterns of stamen movement have co-evolved in interaction with specialized pollinators.


Sensing Is A Far Cry From Sentience, Antonio Damasio, Hanna Damasio Apr 2023

Sensing Is A Far Cry From Sentience, Antonio Damasio, Hanna Damasio

Animal Sentience

The hypothesis that plants might be sentient confuses the notion of sentience (or consciousness) with that of sensing. Sentience/consciousness implies feeling, experience, and subjectivity. Sensing does not. Plants can sense/detect and even respond appropriately in the absence of any sentience/consciousness.


Plant Sentience: The Burden Of Proof, Jon Mallatt, David G. Robinson, Michael R. Blatt, Andreas Draguhn, Lincoln Taiz Apr 2023

Plant Sentience: The Burden Of Proof, Jon Mallatt, David G. Robinson, Michael R. Blatt, Andreas Draguhn, Lincoln Taiz

Animal Sentience

Segundo-Ortin & Calvo’s (2023) target article takes a less speculative and more evidence-based approach to plant sentience than did previous works promoting that idea. However, it retains many of the idea’s longstanding difficulties such as starting from a false dichotomy (plants must be either hardwired or sentient), not accepting the full burden of proof for an extraordinary claim, confusingly redefining accepted cognitive terms, implying cell consciousness, not adopting the most parsimonious explanations for plant behaviors, and downplaying all the counterevidence. We advise rectifying these problems before plant sentience can become a full-fledged scientific domain.


Plant Sentience: A Hypothesis Based On Shaky Premises, Carel Ten Cate Apr 2023

Plant Sentience: A Hypothesis Based On Shaky Premises, Carel Ten Cate

Animal Sentience

Plants may produce fascinating behavioural phenomena for which the label ‘cognitive process’ may be applicable, at least by some definitions. Segundo-Ortin & Calvo (2023) base their hypothesis that plants might be sentient on the premise of demonstrated presence of cognitive complexity. However, the way phenomena are ascribed, and how the term ‘cognitive’ is used by Segundo-Ortin & Calvo, deviates from the common practice in studies of animal cognition, implying greater complexity than seems justified. It thus provides a questionable basis for attributing sentience to plants.


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


Stress: An Adaptive Problem Common To Plant And Animal Science, Özlem Yilmaz Apr 2023

Stress: An Adaptive Problem Common To Plant And Animal Science, Özlem Yilmaz

Animal Sentience

It is very hard to determine whether plants have “felt states,” but they do have specific states, such as stress, that depend on sensory input from their environment. Plants do not have neurons or brains, but they do have xylem and phloem, as well as many signalling molecules that are dynamically distributed in their bodies, enabling them to produce systemic responses to environmental stimuli. One common topic in plant and animal science that may or may not prove to involve sentience but that does involve the same molecules is stress.


Plants Lack The Functional Neurotransmitters And Signaling Pathways Required For Sentience In Animals, David G. Robinson, Michael R. Blatt, Andreas Draguhn, Lincoln Taiz, Jon Mallatt Apr 2023

Plants Lack The Functional Neurotransmitters And Signaling Pathways Required For Sentience In Animals, David G. Robinson, Michael R. Blatt, Andreas Draguhn, Lincoln Taiz, Jon Mallatt

Animal Sentience

We cannot agree with Segundo-Ortin and Calvo that plants are sentient organisms. We have critically examined several aspects of their target article, and find their claims are not supported by the published evidence. We address these claims in sections on whether plants have a ‘neurobiology’ analogous to that of animal nervous systems, including neurotransmitters and synaptic receptors that respond to anesthetics; and whether plant signaling resembles neural transmission. For the latter, we especially consider the unique way plants signal their responses to wounding. Although the plant vascular system has been compared to the animal nervous system, animal blood vessels would …


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.


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 …


Questions About Sentience Are Not Scientific But Cultural, Yoram Gutfreund Apr 2023

Questions About Sentience Are Not Scientific But Cultural, Yoram Gutfreund

Animal Sentience

Abstract: The findings of complex cognitive-like behaviours in plants are surprising and exciting. However, they do not provide a scientific reason for ascribing sentience to plants. The target article, in trying to provide evidence for sentience in plants, exposes the weakness of the science of animal consciousness in general. In this commentary, I try to explain why the scientific method is incapable of resolving the question of which organisms or systems are sentient.


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.


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.


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.


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.


Of Course Crustaceans Are Sentient: But There's More To The Story, Arthur S. Reber, Frantisek Baluska, William B. Miller Jr. Jan 2022

Of Course Crustaceans Are Sentient: But There's More To The Story, Arthur S. Reber, Frantisek Baluska, William B. Miller Jr.

Animal Sentience

We are in basic agreement with Crump et al. that animal welfare, particularly with regard to the experience of pain, is a topic of importance. However, we come to the issue from a different perspective, one in which all species are sentient and can feel pain. The implications of this theory are discussed.


No Need For Certainty In Animal Sentience, Yew Kwang Ng Jan 2022

No Need For Certainty In Animal Sentience, Yew Kwang Ng

Animal Sentience

This commentary supports Crump et al.’s (2022) point that where risks to welfare are severe, strong evidence of sentience is sufficient to warrant protecting welfare. Crump et al.’s eight criteria for sentience are also useful. Flexible decision-making (5) and flexible behaviour (6) are consistent with Ng (1995). The concession that the “no-need-for-sentience” proposition is unnecessary also strengthens the importance of the target article’s conclusions.


Decapod Sentience: Broadening The Framework, Cecilia De Souza Valente Jan 2022

Decapod Sentience: Broadening The Framework, Cecilia De Souza Valente

Animal Sentience

A framework for studying sentience in decapods is of great value, but how high a cost (in suffering) to each individual decapod (or any animal) is warranted for collecting scientific evidence of sentience? The lack of evidence for some of the target article’s proposed criteria surely results from the fact that research is focused mainly on biomedical studies, ecotoxicology, and commercial production, with decapod sentience and welfare seen as only a secondary research topic. I draw attention also to the possibility of a wider framework that includes all felt experiences, from suffering to pleasure.