Evolution Commons^™

What Does Sentience Mean At The Neural Level?, Björn Brembs

Animal Sentience

Jonathan Birch's (2025) LSE criteria for sentience include motivational trade-offs, exemplified by C. elegansweighing hunger against desiccation risk. Yet once the neural circuit is known, this "trade-off" reduces to a single inhibitory synapse—an ‘elemental’ account discrediting the ‘molar’ one. My commentary illustrates the same discrepancy in Drosophila: dopaminergic ramping during courtship as it progressively suppresses threat-detecting neurons; so persistence past danger reflects recalibrated valuation rather than a weighed decision. As neurobiology increasingly discovers such discrepancies, all criteria resting on behavioral classifications risk being defined away without altering the behavior's validity.

Natural Behavior Vs. Subjective Experience In Fish Welfare Assessments, Ronald G. Oldfield

Animal Sentience

Several commentaries on the Oldfield & Bonano (2024) target article proposed that natural behavior should play a larger role in assessing the welfare of fishes in zoos and aquariums. However, the natural-behavior concept of animal welfare has been widely criticized because natural behaviors do not necessarily improve welfare, and unnatural behaviors do not necessarily reduce it. I review the three major concepts of animal welfare — physical health, natural behavior, and affect/feelings — and argue that behavior patterns, whether natural or otherwise, should be evaluated according to their effects on health and subjective experience. Using the affect/feelings concept and the …

I Lost My Number, Can I Have Yours? Body Image Satisfaction With Sexually Dimorphic Traits Is Associated With Men's Dating Anxiety And Confidence, David A. Frederick, Tania A. Reynolds, Nikoline L. Smart, Justin R. Garcia, David A. Puts

Psychology Faculty Articles and Research

Evolutionary scientists posit that sexual selection processes caused males to develop sexually dimorphic traits to aid them during intrasexual competition and increase their likelihood of being chosen as mates. Evolutionary social sciences have extensively examined women's preferences for traits such as muscle mass and voice pitch, reasoning that these traits serve as cues of men's ability to provide direct benefits (e.g., resources) and indirect (genetic) benefits passed on to offspring. At the same time, body image researchers have extensively focused on the social causes and consequences of men's dissatisfaction with their muscularity and body fat. We connected these two research …

Awe As Signpost: An Argument For The Consistency Of Lewis’S “Joy” And Psychological Awe, Audrey Hendricks

Senior Honors Theses

C.S. Lewis’s Surprised by Joy details Lewis’s autobiographical apologetic for the existence of God through his experiences of “Joy,” a technical term invented by Lewis. Upon close study, his experiences of Joy contain many similarities to psychological awe. This investigation compares Lewis’s Joy with psychological awe using the Awe Experience Scale (AWE-S) to determine consistency. Lewis’s Joy was found to be consistent with all six criteria of the AWE-S in addition to other recognized psychological characteristics of awe. In addition to qualitative consistency, this review also argues for the teleological consistency of the two concepts, contending for a Christian teleological …

Aggression And Fish Welfare: Challenges And Opportunities, Christine M. Soper, Peter D. Dijkstra

Animal Sentience

Oldfield & Bonano’s (2024) [O&B] target article discusses the wellbeing and sociality of bony fishes. Many fish species, such as cichlids, are not only social but territorial. Aggression is normal, but territorial aggression in a captive environment can have a negative impact on welfare. Aggression-related injuries and deaths are prevalent in pet stores as well as research settings. We discuss the need to develop effective methods to minimize the negative consequences of aggression.

The Evolution Of Self-Awareness In Conscious Organisms, Robert A. Dielenberg

Journal of Conscious Evolution

Self-awareness in conscious organisms remains an enduring puzzle for philosophers and neuroscientists. This paper proposes a tripartite evolutionary model tracing its emergence through three sequential types: the sensory self (primitive egocentric, valence-tagged awareness of sensory states), the bodily self (external objectification of the body as a distinct entity, evidenced by mirror self-recognition in select species), and the cognitive self (internal objectification of the mind enabling recursive self-transformation). Adopting a monist framework, the model treats consciousness as the biological substrate of delayed neural apperception (the “Delayed Present”), within which selves emerge as increasingly sophisticated models. It distinguishes non-human metacognition—implicit, online regulation—from …

Systematics Of Disk-Winged Bats (Thyroptera), Courtney L. Klumpp

Capstone Showcase

This thesis investigates the evolutionary relationships among disk-winged bats in the genus Thyroptera, a small group of Neotropical bats known for the adhesive suction disks on their wings and feet that allow them to roost inside tightly rolled leaves. The distinctive morphology and behavior of these bats have not been extensively documented, and their phylogenetic relationships remain only partially resolved. The goal of this research is to better understand how these species are related to one another and to determine whether the five recognized species of Thyroptera form a single monophyletic group. To address this question, morphological and genetic …

Both Studying And Protecting Octopuses “On Their Own Terms”, Jennifer Jacquet, Janelle Kaz, Becca Franks, Christine Webb

Animal Sentience

Cephalopods – indeed, all animals – “must be seen on their own terms,” with respect for their autonomy and their ecological imperatives. This will provide greater scientific insight along with a more ethical and accurate understanding of minds beyond our own.

Cephalopod Consciousness On “Their Own Terms”: Who Are “They”?, Willa M. Lane, Victor Ajuwon, Nicola S. Clayton

Animal Sentience

Mather’s call to consider cephalopods’ consciousness “on their own terms” raises the question of the extent to which cephalopods can be considered a homogenous group. While coloeoid cephalopods share traits that strongly distinguish them from other molluscs and invertebrates, they show vast ecological and morphological diversity, with implications for the design of empirical investigations of consciousness. Extending Mather’s argument, we apply Birch et al.’s (2020) five-dimensional model to compare octopus, cuttlefish, squid, and nautilus. This comparison shows that even within a graded rather than categorical framework, putative consciousness profiles depend on which taxa are included in discussions of “cephalopod consciousness.” …

The Term Consciousness And Impressive Evidence For Cephalopod Awareness, Donald M. Broom

Animal Sentience

Mather presents comprehensive evidence of cephalopod cognitive ability and of a high level of awareness. The importance of taking account of the biological functioning and adaptations to the living environment is emphasised. An argument is presented that it is better to limit the use of the word conscious to ‘not unconscious’ and to use awareness in relation to the various levels of cognitive functioning.

The Consciousness Inherent In Chasing Your Tail, Sergio M. Pellis Dr.

Animal Sentience

Who is conscious and how do we know? Complexity in behavior and cognition is certainly a clue that cannot be ignored in identifying this trait, and as Mather’s target article shows, it is hard not to imagine consciousness arising in cephalopods. But how complex is complex? An alternative may be gleaned from the fact that all living things rely on negative feedback to navigate their worlds, and this requires all sentient beings knowing what is to be stabilized in reflection to themselves. If so, consciousness is a universal trait.

Cephalopod Consciousness: Asking The Right Questions, Gordon Burghardt

Animal Sentience

Jennifer Mather has provided a comprehensive and fascinating overview of the various cognitive accomplishments of cephalopods and their sensory, behavioral, and neurophysiological attributes. The advances in our understanding of a clade that has been separated from vertebrate evolution by well over half a billion years is a testament to advances in both methodology and the questions we now feel free to address. Mather embeds her review in the issue of consciousness, which is certainly a perennial issue in mental evolution, going back to Romanes and earlier. I argue that the term “consciousness” has such a checkered history and is used …

Dental Microwear And Diets Of Late Miocene Primates From Rudabánya, Hungary, Peter S. Ungar, Anna K. Wilcox, David R. Begun

School of Dentistry Faculty Publications

Objectives: This study focuses on a dental microwear texture analysis of European pliopithecids and dryopithecins from the Miocene primate site of Rudabánya, Hungary. The goal is to determine whether these taxa, found in part together in the same deposits, differed in their food preferences, or at least consumed, on a daily basis, in a manner that might have facilitated sympatry. Materials and Methods: Here we report on a molar surface texture analysis of all available fossil primates from Rudabánya that preserve antemortem microwear. This includes both Anapithecus hernyaki (n = 14) and Rudapithecus hungaricus (n = 5, including one from …

Field Journal: The Excluded Middle, Carrie E. Kouts

Masters Theses

What does it look like to engage with organisms and landscapes at the periphery of anthropocentric value structures? How does one break the internalized myth that the “built” environment is excluded from the natural world? When does a hyper-mobile and hyper-commodified society confront the exponential crisis of animal death? Within this series of journal entries, field notes, collection observations, weird prose, and sensory musings, one will find questions on the nature of being human and the complex narratives of care we encounter in a world shared with more-than-humans. Each handwritten vignette and photograph from daily life weaves a non-linear and …

Cost-Effective Solutions For High-Throughput Enzymatic Dna Methylation Sequencing, Amy Longtin, Marina M. Watowich, Baptiste Sadoughi, Rachel M. Petersen, Sarah F. Brosnan, Kenneth Buetow, Qiuyin Cai, Cayo Biobank Research Unit, Vanderbilt University, Michael D. Gurven, James P. Higham, Heather M. Highland, Yi-Ting Huang, Hillard Kaplan, Thomas S. Kraft, Yvonne A. L. Lim, Jirong Long, Amanda D. Melin, Michael J. Montagne, Jamie Roberson, Kee Seong Ng, Michael L. Platt, India A. Schneider-Crease, Jonathan Stieglitz, Benjamin C. Trumble, Vivek Venkataraman, Ian J. Wallace, Jie Wu, Noah Snyder-Mackler, Angela Jones, Alexander G. Bick, Amanda J. Lea

ESI Publications

Characterizing DNA methylation patterns is important for addressing key questions in evolutionary biology, development, geroscience, and medical genomics. While costs are decreasing, whole-genome DNA methylation profiling remains prohibitively expensive for most population-scale studies, creating a need for cost-effective, reduced representation approaches (i.e., assays that rely on microarrays, enzyme digests, or sequence capture to target a subset of the genome). Most common whole genome and reduced representation techniques rely on bisulfite conversion, which can damage DNA resulting in DNA loss and sequencing biases. Enzymatic methyl sequencing (EM-seq) was recently proposed to overcome these issues, but thorough benchmarking of EM-seq combined with …

Functional Morphology Of The Primate Knee And Its Implications For Hominin Bipedal Mechanics, Catherine K. Miller

Dartmouth College Ph.D Dissertations

Bipedal locomotion is central to the human condition, having shaped our evolutionary trajectory since its early emergence in the hominin lineage. Despite its importance, key questions remain about its origins and evolutionary trajectory. While many studies have focused on locomotor-related anatomies, comparatively less attention has been paid to the knee joint – a structure critical to the primate locomotor repertoire. This dissertation aims to clarify the form-function relationship of the knee in extant primates to better infer the locomotor behaviors of Miocene hominoids and Plio-Pleistocene hominins. To address these questions, this research employs a multifaceted analytical approach, integrating linear measurements, …

Maggot Mass Effect On The Development And Survival Of Forensic Blow Flies, Akomavo Fabrice Gbenonsi

School of Natural Resources: Dissertations, Theses, and Student Research

Forensic entomology scientists use blow flies' developing patterns to estimate the postmortem interval (PMI). However, larval aggregations produce metabolic heat, resulting in complex microclimates that may change growth timetables. This study investigates how larval density and associated temperature changes affect the development and survival of two forensically essential blow fly species, Lucilia sericata and Calliphora vicina.

This study examined how larval density and associated thermal profiles affect the development of both blow fly species. Using a split-plot design, we tested four larval densities at 25°C and 30°C, with temperature gradients measured via thermocouple at four mass positions three times …

Quantified Lives: Data, Bias, And The Cost Of Categorization, Colin F. Geraghty

Dissertations, Theses, and Capstone Projects

This project critically examines how statistical methods and data visualization have historically been used to categorize, rank, and control human populations. By exploring the works of key figures like Francis Galton, Karl Pearson, and R.A. Fisher, it traces the evolution of categorization frameworks from their eugenic roots to modern applications in artificial intelligence and global metrics like the World Happiness Report. Through interactive visualizations and historical analysis, the project invites users to question the legitimacy of these frameworks and reflect on their impact on society. At its core, this work emphasizes the need to move beyond rigid classification systems, challenging …

Components Of Evolutionary Psychology Are Falsifiable, But Does That Make It A Good Theory? Commentary On Costello Et Al. (2025), David S. Moore

Pitzer Faculty Publications and Research

At the center of narrow evolutionary psychology’s theory lies the assumption that many human behavioral mechanisms evolved via natural selection. Although some components of this theory are falsifiable, its Lakatosian framework protects its core assumptions from falsifiability, even though most human behaviors probably do not require evolutionary explanations. Crucially, falsifiability is a necessary but insufficient quality of a good scientific theory, and the value of narrow evolutionary psychology (NEP) can be questioned on other grounds. NEP holds that only natural selection can create complex, functional adaptations, but natural selection is not a creative force; this process merely functions as a …

Learning In Nonleafcutting Fungus-Gardening Ants, Elizabeth D. Boshers

Biology Theses

Social complexity influences learning and other cognitive behaviors, but for insects, this influence is not well understood. Delayed rejection is an aversive learning behavior previously studied exclusively in leafcutting ant species, the most socially complex of the fungus-gardening ants. Fungus-gardening ants are unique in that they do not directly consume the material they forage, using it instead as substrate to cultivate a symbiotic fungus on which the ants are obligately dependent. Here, I attempt to induce delayed rejection in several fungus-gardening ant species that exhibit a range of social complexity, then compare the characteristics of delayed rejection behavior among species. …

Précis Of The Edge Of Sentience: Risk And Precaution In Humans, Other Animals, And Ai, Jonathan Birch

Animal Sentience

We often face grave practical decisions that seem to hinge on whether a system is sentient. This family of cases includes invertebrate animals, people who are unresponsive after brain injury, fetuses, neural organoids, and now AI technologies. We must decide what to do despite ongoing disagreement about the nature of sentience. In our state of uncertainty, we should pragmatically transform the question from “Is it sentient?” to “Is it a sentience candidate, an investigation priority, or neither?”. When a system is a sentience candidate, it is negligent to fail to consider precautions. We should instead evaluate precautions for their proportionality …

Endocrine Responses To Two Distinct Foraging Contexts In The Bonobo (Pan Paniscus), Lauren Mitchell

Master's Theses

In gregarious animals, a social structure characterized by female dominance is relatively rare. However, bonobos (Pan paniscus), one of the two species most closely related to humans, are characterized by partial female dominance, with females forming close social bonds. In contrast, chimpanzees (Pan troglodytes), a close relative of the bonobo, are characterized by strong male-male bonding and social dominance with female chimpanzees lacking close social bonds. There is a lack of consensus concerning the reasons for these behavioral differences in Pan, specifically, the physiological processes responsible for female dominance in bonobos. The role of hormones …

What Is It Like To Be A Diplomat? Reflections On Donald Griffin And Emotion, Oliver H. Turnbull

Animal Sentience

This commentary addresses three aspects of Donald Griffin’s work: (1) his thoughts beyond cognition, on emotion; (2) his views on the earliest origins of mind, including primitive forms of consciousness; and (3) his diplomatic use of memorable phrases to facilitate change.

Communication In Noise Is The Window On Cognition, R. Haven Wiley

Animal Sentience

As Griffin surmised, communication is the window on cognition, but as shown here, only if it is noisy. This commentary is an invitation to consider the full implications of the evolution of noisy communication. A combination of Information Theory, Signal Detection Theory, and Natural Selection, in a unified theory of the evolution of communication, reveals that noise is inevitable. All organisms are thus decision makers. Perception, thought, freedom of decision, self-awareness, metabolism, and natural selection all share the consequences of signals in noise. A full understanding of each requires attention to the errors of receivers. Griffin’s hunch is correct with …

Understanding The Welfare Of Aquarium Fish, Paul Rose

Animal Sentience

Bony fishes (Osteichthyes) are prevalent in public and domestic aquaria, yet evidence-based welfare practices exist for only a limited number of species. Oldfield & Bonano’s (O&B’s) target article highlights critical questions about the wellbeing and sociality of Osteichthyes. Advancing research on their biology, physiology, psychology, and behavior is essential to develop and validate welfare measures, ensuring guidelines for welfare-focused housing and husbandry.

Ontogenetic Biomechanics Of Tufted (Sapajus) And Untufted (Cebus) Capuchin Mandibles, Taylor A. Polvadore, Caitlin B. Yoakum, Parker M. Taylor, Megan A. Holmes, Myra F. Laird, Janine Chalk-Wilayto, Claudia Misue Kanno, Jose Americano De Oliveira, Claire E. Terhune

Anthropology Faculty Publications and Presentations

Objectives

Cortical bone geometry is commonly used to investigate biomechanical properties of primate mandibles. However, the ontogeny of these properties is less understood. Here we investigate changes in cortical bone cross-sectional properties throughout capuchin ontogeny and compare captive versus wild, semi-provisioned groups. Tufted capuchins (Sapajus spp.) are known to consume relatively hard/tough foods, while untufted capuchins (Cebus spp.) exploit less mechanically challenging foods. Previous research indicates dietary differences are present early in development and adult Sapajus mandibles can resist higher bending/shear/torsional loads.

Materials and methods

This study utilized microCT scans of 22 Cebus and 45 Sapajus from early …

Précis Of: "Birds, Bats And Minds: Tales Of A Revolutionary Scientist, Donald R. Griffin", Carolyn A. Ristau

Animal Sentience

Donald Griffin co-discovered bat sonar and founded the field of echolocation. He studied bird migration and founded Cognitive Ethology, the study of animal awareness and mental experiences. In all these endeavors, he faced hostile opposition. The biography (Ristau 2024) examines Griffin's life and the scientific explorations by him and others in these fields. This Précis emphasizes his arguments and supporting evidence for animal consciousness as well as his later research. Griffin considered the inhibiting assumptions made by scientists, including Cartesian views, the misunderstanding of innate behaviors, prejudice against lower animals, concern with violations of parsimony, and the assertions of the …

Wildlife Conservation: The Importance Of Individual Personality Traits And Sentience, Karen A. Owens, Gosia Bryja, Marc Bekoff

Animal Sentience

Individual differences in personality types within the same species have been studied much less than differences between species and populations. Personality differences are related to risk-taking and exploration, which in turn correlate with individuals' daily responses, decisions, and fitness. Bold and shy personality types can have different advantages and disadvantages under different social or environmental pressures. Analyzing personality differences has helped clarify how elk habituate to a well-populated area and how management strategies can be adapted to them. For wolves newly repatriated to Colorado, individual personality factors are likely to prove important for adapting to their new homes as well …

An Ecology Against The Right. Learning Uncertainty And Humility From Ecosystems, Pierre L. Ibisch, Mona Eikel-Pohen, Elias Iceman, Jake Snelling

Languages, Literatures, and Linguistics - All Scholarship

This article is a translation from the German to English. The title of the original is:

Ibisch, P.L. (2020): Eine Ökologie gegen rechts. Von Ökosystemen Unsicherheit und Demut lernen. In: Leitschuh, H., A. Brunnengräber, P.L. Ibisch, R. Loske, M. Müller, J. Sommer & E.-U. v. Weizsäcker (eds. J. Sommer, P.L. Ibisch, A. Brunnengräber): Ökologie und Heimat. Jahrbuch Ökologie 2021. Hirzel-Verlag, Stuttgart, 191-205.

An Exploration Of Factors Influencing Emerging Adults’ Decision-Making Regarding Family Intentionality, Samantha Mckee

Graduate Research Theses & Dissertations

The purpose of this mixed methods study was to gain an understanding of factors that may influence emerging adults’ decision-making regarding family intentionality. Specifically, it aimed to answer two research questions: 1) What factors influence an emerging adults’ decision-making regarding family intentionality? 2) Is there a correlation between the number of Adverse Childhood Experiences (ACEs) an individual has experienced and their desire to have children? This study also examined how ACEs are factored into the different systems of Bronfenbrenner’s Ecological Systems Theory and how they affect the child at each level. This study utilized a sequential quan-->QUAL design, combining …