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Kaneko T, Matsumoto J, Lu W, Zhao X, Ueno-Nigh LR, Oishi T, Kimura K, Otsuka Y, Zheng A, Ikenaka K, Baba K, Mochizuki H, Nishijo H, Inoue KI, Takada M. Deciphering social traits and pathophysiological conditions from natural behaviors in common marmosets. Curr Biol 2024; 34:2854-2867.e5. [PMID: 38889723 DOI: 10.1016/j.cub.2024.05.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/15/2024] [Accepted: 05/17/2024] [Indexed: 06/20/2024]
Abstract
Nonhuman primates (NHPs) are indispensable animal models by virtue of the continuity of behavioral repertoires across primates, including humans. However, behavioral assessment at the laboratory level has so far been limited. Employing the application of three-dimensional (3D) pose estimation and the optimal integration of subsequent analytic methodologies, we demonstrate that our artificial intelligence (AI)-based approach has successfully deciphered the ethological, cognitive, and pathological traits of common marmosets from their natural behaviors. By applying multiple deep neural networks trained with large-scale datasets, we established an evaluation system that could reconstruct and estimate the 3D poses of the marmosets, a small NHP that is suitable for analyzing complex natural behaviors in laboratory setups. We further developed downstream analytic methodologies to quantify a variety of behavioral parameters beyond motion kinematics. We revealed the distinct parental roles of male and female marmosets through automated detections of food-sharing behaviors using a spatial-temporal filter on 3D poses. Employing a recurrent neural network to analyze 3D pose time series data during social interactions, we additionally discovered that marmosets adjusted their behaviors based on others' internal state, which is not directly observable but can be inferred from the sequence of others' actions. Moreover, a fully unsupervised approach enabled us to detect progressively appearing symptomatic behaviors over a year in a Parkinson's disease model. The high-throughput and versatile nature of an AI-driven approach to analyze natural behaviors will open a new avenue for neuroscience research dealing with big-data analyses of social and pathophysiological behaviors in NHPs.
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Affiliation(s)
- Takaaki Kaneko
- Center for the Evolutionary Origins of Human Behavior, Kyoto University, Inuyama, Aichi 484-8506, Japan.
| | - Jumpei Matsumoto
- Department of System Emotional Science, Faculty of Medicine, University of Toyama, Toyama 930-0194, Japan; Research Center for Idling Brain Science, University of Toyama, Toyama 930-0194, Japan
| | - Wanyi Lu
- Center for the Evolutionary Origins of Human Behavior, Kyoto University, Inuyama, Aichi 484-8506, Japan
| | - Xincheng Zhao
- Center for the Evolutionary Origins of Human Behavior, Kyoto University, Inuyama, Aichi 484-8506, Japan
| | - Louie Richard Ueno-Nigh
- Center for the Evolutionary Origins of Human Behavior, Kyoto University, Inuyama, Aichi 484-8506, Japan
| | - Takao Oishi
- Center for the Evolutionary Origins of Human Behavior, Kyoto University, Inuyama, Aichi 484-8506, Japan
| | - Kei Kimura
- Center for the Evolutionary Origins of Human Behavior, Kyoto University, Inuyama, Aichi 484-8506, Japan
| | - Yukiko Otsuka
- Center for the Evolutionary Origins of Human Behavior, Kyoto University, Inuyama, Aichi 484-8506, Japan
| | - Andi Zheng
- Center for the Evolutionary Origins of Human Behavior, Kyoto University, Inuyama, Aichi 484-8506, Japan
| | - Kensuke Ikenaka
- Department of Neurology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Kousuke Baba
- Department of Neurology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Hideki Mochizuki
- Department of Neurology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Hisao Nishijo
- Department of System Emotional Science, Faculty of Medicine, University of Toyama, Toyama 930-0194, Japan; Research Center for Idling Brain Science, University of Toyama, Toyama 930-0194, Japan; Faculty of Human Sciences, University of East Asia, Shimonoseki, Yamaguchi 751-8503, Japan
| | - Ken-Ichi Inoue
- Center for the Evolutionary Origins of Human Behavior, Kyoto University, Inuyama, Aichi 484-8506, Japan
| | - Masahiko Takada
- Center for the Evolutionary Origins of Human Behavior, Kyoto University, Inuyama, Aichi 484-8506, Japan; Department of Neurology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan.
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2
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Crespi BJ. The Roots of Science, Technology, Engineering, and Mathematics: What Are the Evolutionary and Neural Bases of Human Mathematics and Technology? BRAIN, BEHAVIOR AND EVOLUTION 2024; 99:1-12. [PMID: 38368855 DOI: 10.1159/000537908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 02/15/2024] [Indexed: 02/20/2024]
Abstract
INTRODUCTION Neural exaptations represent descent via transitions to novel neural functions. A primary transition in human cognitive and neural evolution was from a predominantly socially oriented primate brain to a brain that also instantiates and subserves science, technology, and engineering, all of which depend on mathematics. Upon what neural substrates and upon what evolved cognitive mechanisms did human capacities for science, technology, engineering, and mathematics (STEM), and especially its mathematical underpinnings, emerge? Previous theory focuses on roles for tools, language, and arithmetic in the cognitive origins of STEM, but none of these factors appears sufficient to support the transition. METHODS In this article, I describe and evaluate a novel hypothesis for the neural origins and substrates of STEM-based cognition: that they are based in human kinship systems and human maximizing of inclusive fitness. RESULTS The main evidence for this hypothesis is threefold. First, as demonstrated by anthropologists, human kinship systems exhibit complex mathematical and geometrical structures that function under sets of explicit rules, and such systems and rules pervade and organize all human cultures. Second, human kinship underlies the core algebraic mechanism of evolution, maximization of inclusive fitness, quantified as personal reproduction plus the sum of all effects on reproduction of others, each multiplied by their coefficient of relatedness to self. This is the only "natural" equation expected to be represented in the human brain. Third, functional imaging studies show that kinship-related cognition activates frontal-parietal regions that are also activated in STEM-related tasks. In turn, the decision-making that integrates kinship levels with costs and benefits from alternative behaviors has recently been shown to recruit the lateral septum, a hub region that combines internal (from the prefrontal cortex, amygdala, and other regions) and external information relevant to social behavior, using a dedicated subsystem of neurons specific to kinship. CONCLUSIONS Taken together, these lines of evidence suggest that kinship systems and kin-associated behaviors may represent exaptations for the origin of human STEM.
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Affiliation(s)
- Bernard J Crespi
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
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Dunbar RIM. The social brain hypothesis - thirty years on. Ann Hum Biol 2024; 51:2359920. [PMID: 38994897 DOI: 10.1080/03014460.2024.2359920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2024] [Accepted: 05/20/2024] [Indexed: 07/13/2024]
Affiliation(s)
- Robin I M Dunbar
- Department of Experimental Psychology, University of Oxford, Oxford, UK
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4
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Bruner E. Cognitive archaeology, and the psychological assessment of extinct minds. J Comp Neurol 2024; 532:e25583. [PMID: 38289186 DOI: 10.1002/cne.25583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 12/21/2023] [Accepted: 01/09/2024] [Indexed: 02/01/2024]
Abstract
Evolutionary anthropology relies on both neontological and paleontological information. In the latter case, fields such as paleoneurology, neuroarchaeology, and cognitive archaeology are supplying new perspectives in prehistory and neuroscience. Cognitive archaeology, in particular, investigates the behaviors associated with extinct species or cultures according to specific psychological models. For example, changes in working memory, attention, or visuospatial integration can be postulated when related behavioral changes are described in the archaeological record. However, cognition is a process based on different and partially independent functional elements, and extinct species could hence have evolved distinct combinations of cognitive abilities or features, based on both quantitative and qualitative differences. Accordingly, differences in working memory can lead to more conceptual or more holistic mindsets, with important changes in the perception and management of the mental experience. The parietal cortex is particularly interesting, in this sense, being involved in functions associated with body-tool integration, attention, and visual imaging. In some cases, evolutionary mismatches among these elements can induce drawbacks that, despite their positive effects on natural selection, can introduce important constraints in our own mental skills. Beyond the theoretical background, some hypotheses can be tested following methods in experimental psychology. In any case, theories in cognitive evolution must acknowledge that, beyond the brain and its biology, the human mind is also deeply rooted in body perception, in social networks, and in technological extension.
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Affiliation(s)
- Emiliano Bruner
- Centro Nacional de Investigación sobre la Evolución Humana, Burgos, Spain
- Alzheimer's Centre Reina Sofia-CIEN Foundation-ISCIII, Madrid, Spain
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5
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Dunbar RIM. The origins and function of musical performance. Front Psychol 2023; 14:1257390. [PMID: 38022957 PMCID: PMC10667447 DOI: 10.3389/fpsyg.2023.1257390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 09/29/2023] [Indexed: 12/01/2023] Open
Abstract
Music is widely recognised as a human universal, yet there is no agreed explanation for its function, or why and when it evolved. I summarise experimental evidence that the primary function of musicking lies in social bonding, both at the dyadic and community levels, via the effect that performing any form of music has on the brain's endorphin system (the principal neurohormonal basis for social bonding in primates). The many other functions associated with music-making (mate choice, pleasure, coalition signalling, etc) are all better understood as derivative of this, either as secondary selection pressures or as windows of evolutionary opportunity (exaptations). If music's function is primarily as an adjunct of the social bonding mechanism (a feature it shares with laughter, feasting, storytelling and the rituals of religion), then reverse engineering the problem suggests that the capacity for music-making most likely evolved with the appearance of archaic humans. This agrees well with anatomical evidence for the capacity to sing.
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Affiliation(s)
- Robin I. M. Dunbar
- Department of Experimental Psychology, University of Oxford, Radcliffe Quarter, Oxford, United Kingdom
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Dunbar RIM, Shultz S. Four errors and a fallacy: pitfalls for the unwary in comparative brain analyses. Biol Rev Camb Philos Soc 2023; 98:1278-1309. [PMID: 37001905 DOI: 10.1111/brv.12953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 03/17/2023] [Accepted: 03/17/2023] [Indexed: 04/03/2023]
Abstract
Comparative analyses are the backbone of evolutionary analysis. However, their record in producing a consensus has not always been good. This is especially true of attempts to understand the factors responsible for the evolution of large brains, which have been embroiled in an increasingly polarised debate over the past three decades. We argue that most of these disputes arise from a number of conceptual errors and associated logical fallacies that are the result of a failure to adopt a biological systems-based approach to hypothesis-testing. We identify four principal classes of error: a failure to heed Tinbergen's Four Questions when testing biological hypotheses, misapplying Dobzhansky's Dictum when testing hypotheses of evolutionary adaptation, poorly chosen behavioural proxies for underlying hypotheses, and the use of inappropriate statistical methods. In the interests of progress, we urge a more careful and considered approach to comparative analyses, and the adoption of a broader, rather than a narrower, taxonomic perspective.
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Affiliation(s)
- Robin I M Dunbar
- Department of Experimental Psychology, Anna Watts Building, University of Oxford, Oxford, OX2 6GG, UK
| | - Susanne Shultz
- Department of Earth and Environmental Sciences, Michael Smith Building, University of Manchester, Manchester, M13 9PT, UK
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7
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Lau AR, Cunningham AD, Bales KL. Pairing status and stimulus type predict responses to audio playbacks in female titi monkeys. Front Ecol Evol 2023; 11:1145205. [PMID: 38584610 PMCID: PMC10997360 DOI: 10.3389/fevo.2023.1145205] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2024] Open
Abstract
Some paired primates use complex, coordinated vocal signals to communicate within and between family groups. The information encoded within those signals is not well understood, nor is the intricacy of individuals' behavioral and physiological responses to these signals. Considering the conspicuous nature of these vocal signals, it is a priority to better understand paired primates' responses to conspecific calls. Pair-bonded titi monkeys (Plecturocebus cupreus) sing duets comprised of the male and female's long call. Here, we use a playback study to assess female titi monkeys' responses to different vocal stimuli based on the subject's pairing status. Six adult female titi monkeys participated in the study at two timepoints--pre-pairing and post-pairing. At each timepoint, subjects underwent three distinct playbacks--control recording, male solo vocalization, and pair duet. Behaviors such as locomotion and vocalizations were scored during and after the playback, and cortisol and androgen values were assessed via a plasma blood sample. Female titi monkeys attended more to social signals compared to the control, regardless of pairing status. However, in the time immediately following any playback type, female titi monkeys trilled more and spent a greater proportion of time locomoting during pre-pairing timepoints (compared to post-pairing). Female titi monkeys' behavioral responses to social audio stimuli, combined with subjects' increases in cortisol and androgens as paired individuals, imply female titi monkeys attend and respond to social signals territorially.
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Affiliation(s)
- Allison R. Lau
- Graduate Group in Animal Behavior, University of California, Davis, One Shields Avenue, Davis, CA, 95616
- California National Primate Research Center, University of California, Davis, Davis, CA, 95616
| | - Ashley D. Cunningham
- Department of Psychology, University of California, Davis, One Shields Avenue, Davis, CA, 95616
| | - Karen L. Bales
- Graduate Group in Animal Behavior, University of California, Davis, One Shields Avenue, Davis, CA, 95616
- California National Primate Research Center, University of California, Davis, Davis, CA, 95616
- Department of Psychology, University of California, Davis, One Shields Avenue, Davis, CA, 95616
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, One Shields Avenue, Davis, CA 95616
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8
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Dunbar R. Why did doctrinal religions first appear in the Northern Subtropical Zone? EVOLUTIONARY HUMAN SCIENCES 2023; 5:e15. [PMID: 37587936 PMCID: PMC10427489 DOI: 10.1017/ehs.2023.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 05/01/2023] [Accepted: 05/02/2023] [Indexed: 08/18/2023] Open
Abstract
Doctrinal religions that involve recognised gods, more formal theologies, moral codes, dedicated religious spaces and professional priesthoods emerged in two phases during the Neolithic. Almost all of these appeared in a narrow latitudinal band (the northern Subtropical Zone). I suggest that these developments were the result of a need to facilitate community bonding in response to scalar stresses that developed as community sizes increased dramatically beyond those typical of hunter-gatherer societies. Conditions for population growth (as indexed by rainfall patterns and the difference between pathogen load and the length of the growing season) were uniquely optimised in this zone, creating an environment of ecological release in which populations could grow unusually rapidly. The relationship between latitude, religion and language in contemporary societies suggests that the peculiar characteristics of the northern (but not the southern) Subtropical Zone were especially favourable for the evolution of large scale religions as a way of enforcing community cohesion.
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Affiliation(s)
- R.I.M. Dunbar
- Department of Experimental Psychology, University of Oxford, Radcliffe Observatory Quarter, Oxford OX2 6GG, UK
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9
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Kanaev IA. Entropy and Cross-Level Orderliness in Light of the Interconnection between the Neural System and Consciousness. ENTROPY (BASEL, SWITZERLAND) 2023; 25:418. [PMID: 36981307 PMCID: PMC10047885 DOI: 10.3390/e25030418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/01/2023] [Accepted: 02/20/2023] [Indexed: 06/18/2023]
Abstract
Despite recent advances, the origin and utility of consciousness remains under debate. Using an evolutionary perspective on the origin of consciousness, this review elaborates on the promising theoretical background suggested in the temporospatial theory of consciousness, which outlines world-brain alignment as a critical predisposition for controlling behavior and adaptation. Such a system can be evolutionarily effective only if it can provide instant cohesion between the subsystems, which is possible only if it performs an intrinsic activity modified in light of the incoming stimulation. One can assume that the world-brain interaction results in a particular interference pattern predetermined by connectome complexity. This is what organisms experience as their exclusive subjective state, allowing the anticipation of regularities in the environment. Thus, an anticipative system can emerge only in a regular environment, which guides natural selection by reinforcing corresponding reactions and decreasing the system entropy. Subsequent evolution requires complicated, layered structures and can be traced from simple organisms to human consciousness and society. This allows us to consider the mode of entropy as a subject of natural evolution rather than an individual entity.
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Affiliation(s)
- Ilya A Kanaev
- Department of Philosophy, Sun Yat-sen University, 135 Xingang Xi Rd, Guangzhou 510275, China
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10
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Dunbar RIM. Laughter and its role in the evolution of human social bonding. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210176. [PMID: 36126664 PMCID: PMC9489299 DOI: 10.1098/rstb.2021.0176] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 01/26/2022] [Indexed: 01/19/2023] Open
Abstract
In anthropoid primates, social grooming is the principal mechanism (mediated by the central nervous system endorphin system) that underpins social bonding. However, the time available for social grooming is limited, and this imposes an upper limit on the size of group that can be bonded in this way. I suggest that, when hominins needed to increase the size of their groups beyond the limit that could be bonded by grooming, they co-opted laughter (a modified version of the play vocalization found widely among the catarrhine primates) as a form of chorusing to fill the gap. I show, first, that human laughter both upregulates the brain's endorphin system and increases the sense of bonding between those who laugh together. I then use a reverse engineering approach to model group sizes and grooming time requirements for fossil hominin species to search for pinch points where a phase shift in bonding mechanisms might have occurred. The results suggest that the most likely time for the origin of human-like laughter is the appearance of the genus Homo ca 2.5 Ma. This article is part of the theme issue 'Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience'.
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Affiliation(s)
- R. I. M. Dunbar
- Department of Experimental Psychology, University of Oxford, Radcliffe Observatory Quarter, Oxford OX2 6GG, UK
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11
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Escribano D, Doldán-Martelli V, Cronin KA, Haun DBM, van Leeuwen EJC, Cuesta JA, Sánchez A. Chimpanzees organize their social relationships like humans. Sci Rep 2022; 12:16641. [PMID: 36198695 PMCID: PMC9534840 DOI: 10.1038/s41598-022-20672-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 09/16/2022] [Indexed: 12/05/2022] Open
Abstract
Human relationships are structured in a set of layers, ordered from higher (intimate relationships) to lower (acquaintances) emotional and cognitive intensity. This structure arises from the limits of our cognitive capacity and the different amounts of resources required by different relationships. However, it is unknown whether nonhuman primate species organize their affiliative relationships following the same pattern. We here show that the time chimpanzees devote to grooming other individuals is well described by the same model used for human relationships, supporting the existence of similar social signatures for both humans and chimpanzees. Furthermore, the relationship structure depends on group size as predicted by the model, the proportion of high-intensity connections being larger for smaller groups.
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Affiliation(s)
- Diego Escribano
- Grupo Interdisciplinar de Sistemas Complejos (GISC), Departamento de Matemáticas, Universidad Carlos III de Madrid, 28911, Leganés, Spain
| | - Victoria Doldán-Martelli
- Grupo Interdisciplinar de Sistemas Complejos (GISC), Departamento de Matemáticas, Universidad Carlos III de Madrid, 28911, Leganés, Spain
| | - Katherine A Cronin
- Animal Welfare Science Program, Lincoln Park Zoo, Chicago, IL, 60614, USA.,Lester E. Fisher Center for the Study and Conservation of Apes, Lincoln Park Zoo, Chicago, IL, 60614, USA
| | - Daniel B M Haun
- Department for Comparative Cultural Psychology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany.,Leipzig Research Centre for Early Child Development, Leipzig University, Jahnallee 59, 04109, Leipzig, Germany
| | - Edwin J C van Leeuwen
- Department for Comparative Cultural Psychology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany.,Animal Behaviour and Cognition, Department of Biology, University Utrecht, 3584 CH, Utrecht, The Netherlands
| | - José A Cuesta
- Grupo Interdisciplinar de Sistemas Complejos (GISC), Departamento de Matemáticas, Universidad Carlos III de Madrid, 28911, Leganés, Spain.,Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza, 50018, Zaragoza, Spain
| | - Angel Sánchez
- Grupo Interdisciplinar de Sistemas Complejos (GISC), Departamento de Matemáticas, Universidad Carlos III de Madrid, 28911, Leganés, Spain. .,Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza, 50018, Zaragoza, Spain.
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12
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Bzdok D, Dunbar RIM. Social isolation and the brain in the pandemic era. Nat Hum Behav 2022; 6:1333-1343. [PMID: 36258130 DOI: 10.1038/s41562-022-01453-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 08/24/2022] [Indexed: 11/08/2022]
Abstract
Intense sociality has been a catalyst for human culture and civilization, and our social relationships at a personal level play a pivotal role in our health and well-being. These relationships are, however, sensitive to the time we invest in them. To understand how and why this should be, we first outline the evolutionary background in primate sociality from which our human social world has emerged. We then review defining features of that human sociality, putting forward a framework within which one can understand the consequences of mass social isolation during the COVID-19 pandemic, including mental health deterioration, stress, sleep disturbance and substance misuse. We outline recent research on the neural basis of prolonged social isolation, highlighting especially higher-order neural circuits such as the default mode network. Our survey of studies covers the negative effects of prolonged social deprivation and the multifaceted drivers of day-to-day pandemic experiences.
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Affiliation(s)
- Danilo Bzdok
- The Neuro-Montreal Neurological Institute (MNI), McConnell Brain-Imaging Centre (BIC), Department of Biomedical Engineering, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
| | - Robin I M Dunbar
- Department of Experimental Psychology, University of Oxford, Oxford, UK.
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13
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Roberts SGB, Dunbar RIM, Roberts AI. Communicative roots of complex sociality and cognition: preface to the theme issue. Philos Trans R Soc Lond B Biol Sci 2022; 377:20220115. [PMID: 35934965 PMCID: PMC9358313 DOI: 10.1098/rstb.2022.0115] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 06/09/2022] [Indexed: 11/12/2022] Open
Abstract
Primates live in stable social groups in which they form differentiated relationships with group members and use a range of communication including facial expressions, vocalizations and gestures. However, how these different types of communication are used to regulate social interactions, and what cognitive skills underpin this communication, is still unclear. The aim of this special issue is to examine the types of cognitive skills underpinning the flexible and complex communication that is used to maintain the bonded social relationships found in primates and humans. This article is part of the theme issue 'Cognition, communication and social bonds in primates'.
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Affiliation(s)
- Sam G. B. Roberts
- School of Psychology, Liverpool John Moores University, Liverpool L3 3AF, UK
| | - Robin I. M. Dunbar
- Department of Experimental Psychology, University of Oxford, Oxford OX2 6GG, UK
| | - Anna I. Roberts
- Institute of Human Biology and Evolution, Adam Mickiewicz University, Poznan, Poland
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14
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Shultz S, Dunbar RIM. Socioecological complexity in primate groups and its cognitive correlates. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210296. [PMID: 35934968 PMCID: PMC9358314 DOI: 10.1098/rstb.2021.0296] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 04/21/2022] [Indexed: 11/12/2022] Open
Abstract
Characterizing non-human primate social complexity and its cognitive bases has proved challenging. Using principal component analyses, we show that primate social, ecological and reproductive behaviours condense into two components: socioecological complexity (including most social and ecological variables) and reproductive cooperation (comprising mainly a suite of behaviours associated with pairbonded monogamy). We contextualize these results using a meta-analysis of 44 published analyses of primate brain evolution. These studies yield two main consistent results: cognition, sociality and cooperative behaviours are associated with absolute brain volume, neocortex size and neocortex ratio, whereas diet composition and life history are consistently associated with relative brain size. We use a path analysis to evaluate the causal relationships among these variables, demonstrating that social group size is predicted by the neocortex, whereas ecological traits are predicted by the volume of brain structures other than the neocortex. That a range of social and technical behaviours covary, and are correlated with social group size and brain size, suggests that primate cognition has evolved along a continuum resulting in an increasingly flexible, domain-general capacity to solve a range of socioecological challenges culminating in a capacity for, and reliance on, innovation and social information use in the great apes and humans. This article is part of the theme issue 'Cognition, communication and social bonds in primates'.
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Affiliation(s)
- Susanne Shultz
- Department of Earth and Environmental Sciences, University of Manchester, Manchester, UK
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15
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Fichtel C, Kappeler PM. Coevolution of social and communicative complexity in lemurs. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210297. [PMID: 35934963 DOI: 10.1098/rstb.2021.0297] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The endemic lemurs of Madagascar (Lemuriformes: Primates) exhibit great social and communicative diversity. Given their independent evolutionary history, lemurs provide an excellent opportunity to identify fundamental principles in the coevolution of social and communicative traits. We conducted comparative phylogenetic analyses to examine patterns of interspecific variation among measures of social complexity and repertoire sizes in the vocal, olfactory and visual modality, while controlling for environmental factors such as habitat and number of sympatric species. We also examined potential trade-offs in signal evolution as well as coevolution between body mass or brain size and communicative complexity. Repertoire sizes in the vocal, olfactory and visual modality correlated positively with group size, but not with environmental factors. Evolutionary changes in social complexity presumably antedated corresponding changes in communicative complexity. There was no trade-off in the evolution of signals in different modalities and neither body mass nor brain size correlated with any repertoire size. Hence, communicative complexity coevolved with social complexity across different modalities, possibly to service social relationships flexibly and effectively in pair- and group-living species. Our analyses shed light on the requirements and adaptive possibilities in the coevolution of core elements of social organization and social structure in a basal primate lineage. This article is part of the theme issue 'Cognition, communication and social bonds in primates'.
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Affiliation(s)
- Claudia Fichtel
- Behavioral Ecology and Sociobiology Unit, German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, Göttingen 37077, Germany.,Leibniz-ScienceCampus Primate Cognition, Kellnerweg 4, 37077 Göttingen, Germany.,Department Anthropology/Sociobiology, University of Göttingen, Kellnerweg 6, 37077 Göttingen, Germany
| | - Peter M Kappeler
- Behavioral Ecology and Sociobiology Unit, German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, Göttingen 37077, Germany.,Leibniz-ScienceCampus Primate Cognition, Kellnerweg 4, 37077 Göttingen, Germany.,Department Anthropology/Sociobiology, University of Göttingen, Kellnerweg 6, 37077 Göttingen, Germany
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16
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Roberts AI, Roberts SGB. Intentional gesturing increases social complexity by allowing recipient's understanding of intentions when it is inhibited by stress. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210305. [PMID: 35934959 PMCID: PMC9358319 DOI: 10.1098/rstb.2021.0305] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 05/05/2022] [Indexed: 11/12/2022] Open
Abstract
Examining the links between intentional communication and social relationships provides insights into the cognitive skills needed to manage a differentiated set of social bonds. Great apes gesture intentionally, but how this intentionality relates to sociality is still unclear. Stress in the form of dominant audience members inhibits understanding of intentions, downgrading cognition to understanding of behaviour, but intentional communication may enable social bonding in stressful conditions. We examined the associations between gestural communication, sociality, stress and the outcome of interactions in wild chimpanzees. Social network size was positively associated with intentional but not non-intentional communication. When a dominant bystander was present with whom the recipient was weakly bonded, and gesturing was non-intentional, recipients produced avoidance response toward signallers to whom they were weakly bonded, indicating understanding of behaviour. Signallers used intentional gestures more frequently to recipients who were stressed, and intentional gestures evoked approach behaviour by the recipients, indicating understanding of intentionality. These results suggest that the presence of dominant bystanders is stressful, inhibiting understanding of intentionality. However, intentional gestures facilitate social bonding by allowing understanding of intentions. The cognitive skills underpinning intentional gestures may therefore play a key role in enabling primates to meet the demands of sociality. This article is part of the theme issue 'Cognition, communication and social bonds in primates'.
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Affiliation(s)
- Anna Ilona Roberts
- Institute of Human Biology and Evolution, Faculty of Biology, Adam Mickiewicz University, 61614, Poznan, Poland
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17
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Roberts SGB, Dunbar RIM, Roberts AI. Communicative roots of complex sociality and cognition: neuropsychological mechanisms underpinning the processing of social information. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210295. [PMID: 35934969 PMCID: PMC9358321 DOI: 10.1098/rstb.2021.0295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 04/08/2022] [Indexed: 11/12/2022] Open
Abstract
Primate social bonds are described as being especially complex in their nature, and primates have unusually large brains for their body size compared to other mammals. Communication in primates has attracted considerable attention because of the important role it plays in social bonding. It has been proposed that differentiated social relationships are cognitively complex because primates need to continuously update their knowledge about different types of social bonds. Therefore, primates infer whether an opportunity for social interaction is rewarding (valuable to individual goals) based on their knowledge of the social relationships of the interactants. However, exposure to distraction and stress has detrimental effects on the dopaminergic system, suggesting that understanding social relationships as rewarding is affected in these conditions. This paper proposes that complex communication evolved to augment the capacity to form social relationships during stress through flexibly modifying intentionality in communication (audience checking, response waiting and elaboration). Intentional communication may upregulate dopamine dynamics to allow recognition that an interaction is rewarding during stress. By examining these associations between complexity of communication and stress, we provide new insights into the cognitive skills involved in forming social bonds in primates and the evolution of communication systems in both primates and humans. This article is part of the theme issue 'Cognition, communication and social bonds in primates'.
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Affiliation(s)
- Sam G. B. Roberts
- School of Psychology, Liverpool John Moores University, Liverpool L3 3AF, UK
| | - Robin I. M. Dunbar
- Department of Experimental Psychology, University of Oxford, Oxford OX2 6GG, UK
| | - Anna I. Roberts
- Institute of Human Biology and Evolution, Adam Mickiewicz University, Poznan, Poland
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18
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Pinacho-Guendulain B, Montiel-Castro AJ, Ramos-Fernández G, Pacheco-López G. Social complexity as a driving force of gut microbiota exchange among conspecific hosts in non-human primates. Front Integr Neurosci 2022; 16:876849. [PMID: 36110388 PMCID: PMC9468716 DOI: 10.3389/fnint.2022.876849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 05/16/2022] [Indexed: 11/13/2022] Open
Abstract
The emergent concept of the social microbiome implies a view of a highly connected biological world, in which microbial interchange across organisms may be influenced by social and ecological connections occurring at different levels of biological organization. We explore this idea reviewing evidence of whether increasing social complexity in primate societies is associated with both higher diversity and greater similarity in the composition of the gut microbiota. By proposing a series of predictions regarding such relationship, we evaluate the existence of a link between gut microbiota and primate social behavior. Overall, we find that enough empirical evidence already supports these predictions. Nonetheless, we conclude that studies with the necessary, sufficient, explicit, and available evidence are still scarce. Therefore, we reflect on the benefit of founding future analyses on the utility of social complexity as a theoretical framework.
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Affiliation(s)
- Braulio Pinacho-Guendulain
- Doctorado en Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana (UAM), Ciudad de México, Mexico
| | - Augusto Jacobo Montiel-Castro
- Department of Health Sciences, Metropolitan Autonomous University (UAM), Lerma, Mexico
- *Correspondence: Augusto Jacobo Montiel-Castro,
| | - Gabriel Ramos-Fernández
- Institute for Research on Applied Mathematics and Systems (IIMAS), National Autonomous University of Mexico (UNAM), Mexico City, Mexico
- Center for Complexity Sciences, National Autonomous University of Mexico, Mexico City, Mexico
| | - Gustavo Pacheco-López
- Department of Health Sciences, Metropolitan Autonomous University (UAM), Lerma, Mexico
- Gustavo Pacheco-López,
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19
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Coto ZN, Traniello JFA. Social Brain Energetics: Ergonomic Efficiency, Neurometabolic Scaling, and Metabolic Polyphenism in Ants. Integr Comp Biol 2022; 62:icac048. [PMID: 35617153 PMCID: PMC9825342 DOI: 10.1093/icb/icac048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/04/2022] [Accepted: 05/11/2022] [Indexed: 01/12/2023] Open
Abstract
Metabolism, a metric of the energy cost of behavior, plays a significant role in social evolution. Body size and metabolic scaling are coupled, and a socioecological pattern of increased body size is associated with dietary change and the formation of larger and more complex groups. These consequences of the adaptive radiation of animal societies beg questions concerning energy expenses, a substantial portion of which may involve the metabolic rates of brains that process social information. Brain size scales with body size, but little is understood about brain metabolic scaling. Social insects such as ants show wide variation in worker body size and morphology that correlates with brain size, structure, and worker task performance, which is dependent on sensory inputs and information-processing ability to generate behavior. Elevated production and maintenance costs in workers may impose energetic constraints on body size and brain size that are reflected in patterns of metabolic scaling. Models of brain evolution do not clearly predict patterns of brain metabolic scaling, nor do they specify its relationship to task performance and worker ergonomic efficiency, two key elements of social evolution in ants. Brain metabolic rate is rarely recorded and therefore the conditions under which brain metabolism influences the evolution of brain size are unclear. We propose that studies of morphological evolution, colony social organization, and worker ergonomic efficiency should be integrated with analyses of species-specific patterns of brain metabolic scaling to advance our understanding of brain evolution in ants.
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Affiliation(s)
- Zach N Coto
- Department of Biology, Boston University, Boston, MA 02215, USA
| | - James F A Traniello
- Department of Biology, Boston University, Boston, MA 02215, USA
- Graduate Program in Neuroscience, Boston University, Boston, MA 02215, USA
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20
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Dunbar RIM. Female Dispersion Is Necessary, but Not Sufficient, for Pairbonded Monogamy in Mammals. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.905298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Explanations for the evolution of social monogamy in mammals typically emphasise one of two possibilities: females are overdispersed (such that males cannot defend access to more than one female at a time) or males provide a service to the female. However, the first claim has never been formally tested. I test it directly at three levels using population-level data from primates and ungulates. First, I show that the females of monogamous genera do not have territories that are significantly larger, either absolutely or relatively, than those of polygynous genera. Second, using two indices of territorial defendability, I show that, given their typical day journey lengths, males of most monogamous species could easily defend an area large enough to allow them to monopolise as many as 5–10 females if they ranged solitarily. Finally, I use a model of male mate searching strategies to show that the opportunity cost incurred by pairbonded males is typically 5–10 times the reproductive success they actually obtain by being obligately monogamous. This suggests that the selection pressure dissuading them from pursuing a roving male strategy must be very considerable. At present, the evidence is undecided as to whether mitigating predation or infanticide risk is the primary function, but estimates of their impacts suggest that both are in fact plausible.
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21
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Lee PC. Groups, grouping and networks: dynamic unanswered questions for primatologists. Primates 2022; 63:187-193. [PMID: 35412094 DOI: 10.1007/s10329-022-00988-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 03/26/2022] [Indexed: 10/18/2022]
Affiliation(s)
- Phyllis C Lee
- Behaviour and Evolution Research Group and Scottish Primate Research Group, Psychology, Faculty of Natural Sciences, University of Stirling, Stirling, UK.
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22
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Barrett L, Henzi SP, Barton RA. Experts in action: why we need an embodied social brain hypothesis. Philos Trans R Soc Lond B Biol Sci 2022; 377:20200533. [PMID: 34957849 PMCID: PMC8710874 DOI: 10.1098/rstb.2020.0533] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The anthropoid primates are known for their intense sociality and large brain size. The idea that these might be causally related has given rise to a large body of work testing the 'social brain hypothesis'. Here, the emphasis has been placed on the political demands of social life, and the cognitive skills that would enable animals to track the machinations of other minds in metarepresentational ways. It seems to us that this position risks losing touch with the fact that brains primarily evolved to enable the control of action, which in turn leads us to downplay or neglect the importance of the physical body in a material world full of bodies and other objects. As an alternative, we offer a view of primate brain and social evolution that is grounded in the body and action, rather than minds and metarepresentation. This article is part of the theme issue 'Systems neuroscience through the lens of evolutionary theory'.
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Affiliation(s)
- Louise Barrett
- Department of Psychology, University of Lethbridge, Lethbridge, Canada
| | - S. Peter Henzi
- Department of Psychology, University of Lethbridge, Lethbridge, Canada
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23
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Kanaev IA. Evolutionary origin and the development of consciousness. Neurosci Biobehav Rev 2021; 133:104511. [PMID: 34942266 DOI: 10.1016/j.neubiorev.2021.12.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 12/04/2021] [Accepted: 12/19/2021] [Indexed: 10/19/2022]
Abstract
This review seeks to combine advances in anthropology and neuroscience to investigate the adaptive value of human consciousness. It uses an interdisciplinary perspective on the origin of consciousness to refute the most common fallacies in considering consciousness, particularly, disregarding the evolutionary origin of the subjective reality in looking for the neural correlates of consciousness and divorcing studies in neuroscience and behavioural sciences. Various explanations linked to consciousness in the field of neuroscience, supplemented with the theoretical explanation of an experience as an ongoing process of overlap between intrinsic neural dynamics and stimulation can be summarised as the stochastic dynamics of one's control system experienced by the individual in the form of subjective reality. This framework elaborates on the world-brain research program and lays foundation for the quantitative description of one's qualitative feelings and naturalistic science of consciousness. Furthermore, this study highlights the philosophical perspective of the inseparability between the physical correlates and the subjective reality contributing to the realistic ontology of conscious processes.
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Affiliation(s)
- Ilya A Kanaev
- School of Philosophy, Zhengzhou University, 100, Science Avenue, High Tech Zone, Zhengzhou, 450001, People's Republic of China.
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24
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Dunbar RIM, Shultz S. The Infertility Trap: The Fertility Costs of Group-Living in Mammalian Social Evolution. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.634664] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mammal social groups vary considerably in size from single individuals to very large herds. In some taxa, these groups are extremely stable, with at least some individuals being members of the same group throughout their lives; in other taxa, groups are unstable, with membership changing by the day. We argue that this variability in grouping patterns reflects a tradeoff between group size as a solution to environmental demands and the costs created by stress-induced infertility (creating an infertility trap). These costs are so steep that, all else equal, they will limit group size in mammals to ∼15 individuals. A species will only be able to live in larger groups if it evolves strategies that mitigate these costs. We suggest that mammals have opted for one of two solutions. One option (fission-fusion herding) is low cost but high risk; the other (bonded social groups) is risk-averse, but costly in terms of cognitive requirements.
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