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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, as yet, weaker for other infraorders, such as penaeid shrimps, highlighting important research gaps. Having demonstrated our framework’s application to decapod crustaceans, we hope that future research will apply it to other taxa.

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Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Author Biography

Andrew Crump, Research Officer, LSE, works on the Foundations of Animal Sentience project and specializes in invertebrate sentience. He previously completed a PhD in Biological Sciences at Queen’s University Belfast. Website

Heather Browning, Research Officer, LSE, works on the Foundations of Animal Sentience project and specializes in animal welfare. She previously completed a PhD in Philosophy at the Australian National University. Alongside her academic career, Browning has worked as a zookeeper and animal welfare officer. Website

Alexandra Schnell, Research Fellow, Darwin College, University of Cambridge, focuses on comparing cognitive abilities, such as learning and memory, in diverse taxa including cephalopods and corvids. Website

Charlotte Burn, Associate Professor, RVC, specializes in the mechanisms and motivations behind animal behaviour, animal perceptual abilities, and how to make concrete improvements to animal welfare. She is also Deputy Head of the RVC’s Animal Welfare Science and Ethics Group. Website

Jonathan Birch, Associate Professor, LSE, is the Principal Investigator on the Foundations of Animal Sentience project, a five-year Horizon 2020 project investigating animal sentience. Website





Article Thread

Crump, Andrew; Browning, Heather; Schnell, Alex; Burn, Charlotte; and Birch, Jonathan (2022) Sentience in decapod crustaceans: A general framework and review of the evidence. Animal Sentience 32(1)

Solms, Mark (2022) Truly minimal criteria for animal sentience. Animal Sentience 32(2)

Reber, Arthur S; Baluska, Frantisek; and Miller, William B, Jr. (2022) Of course crustaceans are sentient: But there's more to the story. Animal Sentience 32(3)

Jablonka, Eva and Ginsburg, Simona (2022) Pain sentience criteria and their grading. Animal Sentience 32(4)

Tye, Michael (2022) Crustacean Pain. Animal Sentience 32(5)

Ng, Yew Kwang (2022) No need for certainty in animal sentience. Animal Sentience 32(6)

Brown, Culum (2022) Fine-tuning the criteria for inferring sentience. Animal Sentience 32(7)

Souza Valente, Cecilia de (2022) Decapod sentience: broadening the framework. Animal Sentience 32(8)

Gorman, Richard (2022) What might decapod sentience mean for policy, practice, and public?. Animal Sentience 32(9)

Irvine, Elizabeth (2022) Independence, weight and priority of evidence for sentience. Animal Sentience 32(10)

Woodruff, Michael L (2022) Sentience in decapods: Difficulties to surmount. Animal Sentience 32(11)

Burrell, Brian D (2022) Emotional component of pain perception in the medicinal leech?. Animal Sentience 32(12)

Comstock, Gary (2022) Pain in Pleocyemata, but not in Dendrobranchiata?. Animal Sentience 32(13)

Walters, Edgar T (2022) Strong inferences about pain in invertebrates require stronger evidence. Animal Sentience 32(14)

Levin, Michael (2022) Generalizing frameworks for sentience beyond natural species. Animal Sentience 32(15)

Montemayor, Carlos (2022) Distinguishing epistemic and moral grounds for legal protection. Animal Sentience 32(16)

Andrews, Kristin (2022) Does the sentience framework imply all animals are sentient?. Animal Sentience 32(17)

Abramson, Charles I and Calvo, Paco (2022) Unresolved issues of behavioral analysis in invertebrates. Animal Sentience 32(18)

Briffa, Mark (2022) Sentience in decapods: an open question. Animal Sentience 32(19)

Butlin, Patrick (2022) Sentience criteria to persuade the reasonable sceptic. Animal Sentience 32(21)

de Waal, Frans B. M. (2022) Sentience as part of emotional lives. Animal Sentience 32(22)

Brown, Simon A. B. (2022) How much of a pain would a crustacean “common currency” really be?. Animal Sentience 32(23)

Mallatt, Jon and Feinberg, Todd E, MD (2022) Decapod sentience: Promising framework and evidence. Animal Sentience 32(24)

Kakrada, Eva and Colombo, Michael (2022) Extending the null hypothesis to invertebrate pain sentience. Animal Sentience 32(25)

Key, Brian and Brown, Deborah (2022) Lack of imagination can bias our view of animal sentience. Animal Sentience 32(26)

Cooper, Jonathan J.; Tinarwo, Ambrose; and Ventura, Beth A (2022) Decapods as food, companions and research animals: Legal impact of ascribing sentience. Animal Sentience 32(27)

Gibbons, Matilda and Chittka, Lars (2022) A framework for evaluating evidence of pain in animals. Animal Sentience 32(28)

Elwood, Robert W. (2022) Pros and cons of a framework for evaluating potential pain in decapods. Animal Sentience 32(29)

Veit, Walter (2022) Integrating evolution into the study of animal sentience. Animal Sentience 32(30)

Crump, Andrew; Browning, Heather; Schnell, Alex; Burn, Charlotte; and Birch, Jonathan (2022) Animal sentience research: Synthesis and proposals. Animal Sentience 32(31)

Montemayor, Carlos (2023) Jurisprudence and animal protection. Animal Sentience 32(32)