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Glowacki L, McDermott R. Key individuals catalyse intergroup violence. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210141. [PMID: 35369758 DOI: 10.1098/rstb.2021.0141] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Intergroup violence is challenging to understand: why do individuals cooperate to harm members of other groups when they themselves may be killed or injured? Despite progress in understanding the evolutionary and proximate mechanisms that underlie violence, we still have little insight into the processes that lead to the emergence of coalitionary aggression. We argue that an overlooked component is the presence of individuals who have a crucial role in initiating violence. In instigating intergroup violence, these key individuals may expect to face lower costs, receive greater benefits, or garner benefits that have a greater value to them than others. Alternatively, key individuals may be motivated by individual traits such as increased boldness, propensity for aggression or exploratory behaviour. Key individuals catalyse the emergence of coalitionary violence through one of several processes including altering the costs and benefits that accrue to others, paying a greater share of the startup costs, signalling privileged knowledge, or providing coordination, among other factors. Here we integrate diverse lines of empirical research from humans and non-human animals demonstrating that inter-individual variation is an important factor in the emergence of intergroup violence. Focusing on the role of key individuals provides new insights into how and why violence emerges. This article is part of the theme issue 'Intergroup conflict across taxa'.
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Affiliation(s)
| | - Rose McDermott
- Political Science, Brown University, Providence, RI, USA
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2
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Garfield ZH, Syme KL, Hagen EH. Universal and variable leadership dimensions across human societies. EVOL HUM BEHAV 2020. [DOI: 10.1016/j.evolhumbehav.2020.07.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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3
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Making ‘my’ problem ‘our’ problem: Warfare as collective action, and the role of leader manipulation. THE LEADERSHIP QUARTERLY 2020. [DOI: 10.1016/j.leaqua.2019.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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4
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Wiessner P. Collective Action for War and for Peace: A Case Study among the Enga of Papua New Guinea. CURRENT ANTHROPOLOGY 2019. [DOI: 10.1086/702414] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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5
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Elephant Crop Damage: Subsistence Farmers’ Social Vulnerability, Livelihood Sustainability and Elephant Conservation. SUSTAINABILITY 2018. [DOI: 10.3390/su10103572] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
African elephants (Loxodonta africana) induce considerable crop damage risks, shocks and stresses on subsistence farmers at the wildlife-agriculture interface. In this study, we explored the social dimensions of human-elephant interactions in the wildlife-agrarian landscape. The study aimed at unraveling the associated hazardous conditions and nature of the subsistence farmers’ social vulnerability and practices with respect to elephant crop damage, subsistence farmers’ livelihoods, and elephant conservation. Applying qualitative thematic content analysis, the sustainable livelihood framework (SLF) and additive generalized linear models (GLMs), this study revealed that the status of relational social capital influences human-elephant conflict (HEC) management and subsistence farmers’ responses, regardless of the farmers’ social learning and environmental values about the social-ecological system. The strengthening of multiple local stakeholder participation, institutional governance and access to livelihoods assets are needed for human food security and elephant conservation. Adoption of more effective nuanced crop protection counter-measures against elephants at farm level is urgently needed.
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6
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Mirville MO, Ridley AR, Samedi J, Vecellio V, Ndagijimana F, Stoinski TS, Grueter CC. Factors influencing individual participation during intergroup interactions in mountain gorillas. Anim Behav 2018. [DOI: 10.1016/j.anbehav.2018.08.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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7
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Singh M, Wrangham R, Glowacki L. Self-Interest and the Design of Rules. HUMAN NATURE-AN INTERDISCIPLINARY BIOSOCIAL PERSPECTIVE 2018; 28:457-480. [PMID: 28840481 DOI: 10.1007/s12110-017-9298-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Rules regulating social behavior raise challenging questions about cultural evolution in part because they frequently confer group-level benefits. Current multilevel selection theories contend that between-group processes interact with within-group processes to produce norms and institutions, but within-group processes have remained underspecified, leading to a recent emphasis on cultural group selection as the primary driver of cultural design. Here we present the self-interested enforcement (SIE) hypothesis, which proposes that the design of rules importantly reflects the relative enforcement capacities of competing parties. We show that, in addition to explaining patterns in cultural change and stability, SIE can account for the emergence of much group-functional culture. We outline how this process can stifle or accelerate cultural group selection, depending on various social conditions. Self-interested enforcement has important bearings on the emergence, stability, and change of rules.
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Affiliation(s)
- Manvir Singh
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA.
| | - Richard Wrangham
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Luke Glowacki
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
- Institute for Advanced Study in Toulouse, Toulouse, France
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8
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Seebacher F, Krause J. Physiological mechanisms underlying animal social behaviour. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0231. [PMID: 28673909 DOI: 10.1098/rstb.2016.0231] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/28/2017] [Indexed: 12/20/2022] Open
Abstract
Many species of animal live in groups, and the group represents the organizational level within which ecological and evolutionary processes occur. Understanding these processes, therefore, relies on knowledge of the mechanisms that permit or constrain group formation. We suggest that physiological capacities and differences in physiology between individuals modify fission-fusion dynamics. Differences between individuals in locomotor capacity and metabolism may lead to fission of groups and sorting of individuals into groups with similar physiological phenotypes. Environmental impacts such as hypoxia can influence maximum group sizes and structure in fish schools by altering access to oxygenated water. The nutritional environment determines group cohesion, and the increase in information collected by the group means that individuals should rely more on social information and form more cohesive groups in uncertain environments. Changing environmental contexts require rapid responses by individuals to maintain group coordination, which are mediated by neuroendocrine signalling systems such as nonapeptides and steroid hormones. Brain processing capacity may constrain social complexity by limiting information processing. Failure to evaluate socially relevant information correctly limits social interactions, which is seen, for example, in autism. Hence, functioning of a group relies to a large extent on the perception and appropriate processing of signals from conspecifics. Many if not all physiological systems are mechanistically linked, and therefore have synergistic effects on social behaviour. A challenge for the future lies in understanding these interactive effects, which will improve understanding of group dynamics, particularly in changing environments.This article is part of the themed issue 'Physiological determinants of social behaviour in animals'.
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Affiliation(s)
- Frank Seebacher
- School of Life and Environmental Sciences A08, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Jens Krause
- Department of Biology and Ecology of Fishes, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587 Berlin, Germany.,Faculty of Life Sciences Humboldt-Universität zu Berlin, Invalidenstrasse 42, 10115 Berlin, Germany
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9
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Christensen C, Radford AN. Dear enemies or nasty neighbors? Causes and consequences of variation in the responses of group-living species to territorial intrusions. Behav Ecol 2018. [DOI: 10.1093/beheco/ary010] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Affiliation(s)
| | - Andrew N Radford
- School of Biological Sciences, University of Bristol, Bristol, UK
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10
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Martin CF, Biro D, Matsuzawa T. Chimpanzees spontaneously take turns in a shared serial ordering task. Sci Rep 2017; 7:14307. [PMID: 29093539 PMCID: PMC5665892 DOI: 10.1038/s41598-017-14393-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 10/03/2017] [Indexed: 11/18/2022] Open
Abstract
Social coordination can provide optimal solutions to many kinds of group dilemmas, and non-human subjects have been shown to perform single actions successively or simultaneously with partners to maximize food rewards in a variety of experimental settings. Less attention has been given to showing how animals are able to produce multiple (rather than single) intermixed and co-regulated actions, even though many species’ signal transmissions and social interactions rely on extended bouts of coordinated turn-taking. Here we report on coordination behaviour in three pairs of chimpanzees (mother/offspring dyads) during an experimentally induced turn-taking scenario. Participants were given a “shared” version of a computer-based serial ordering task that they had previously mastered individually. We found that minimal trial-and-error learning was necessary for the participants to solve the new social version of the task, and that information flow was more pronounced from mothers toward offspring than the reverse, mirroring characteristics of social learning in wild chimpanzees. Our experiment introduces a novel paradigm for studying behavioural coordination in non-humans, able to yield insights into the evolution of turn-taking which underlies a range of social interactions, including communication and language.
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Affiliation(s)
| | - Dora Biro
- Department of Zoology, University of Oxford, Oxford, UK
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11
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Majolo B, Maréchal L. Between-group competition elicits within-group cooperation in children. Sci Rep 2017; 7:43277. [PMID: 28233820 PMCID: PMC5324140 DOI: 10.1038/srep43277] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 01/19/2017] [Indexed: 11/08/2022] Open
Abstract
Aggressive interactions between groups are frequent in human societies and can bear significant fitness costs and benefits (e.g. death or access to resources). During between-group competitive interactions, more cohesive groups (i.e. groups formed by individuals who cooperate in group defence) should out-perform less cohesive groups, other factors being equal (e.g. group size). The cost/benefit of between-group competition are thought to have driven correlated evolution of traits that favour between-group aggression and within-group cooperation (e.g. parochial altruism). Our aim was to analyse whether the proximate relationship between between-group competition and within-group cooperation is found in 3-10 years old children and the developmental trajectory of such a relationship. We used a large cohort of children (n = 120) and tested whether simulated between-group competition increased within-group cooperation (i.e. how much of a resource children were giving to their group companions) in two experiments. We found greater within-group cooperation when groups of four children were competing with other groups then in the control condition (no between-group competition). Within-group cooperation increased with age. Our study suggests that parochial altruism and in-group/out-group biases emerge early during the course of human development.
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Affiliation(s)
- Bonaventura Majolo
- School of Psychology, University of Lincoln, Lincoln LN6 7TS, United Kingdom
| | - Laëtitia Maréchal
- School of Psychology, University of Lincoln, Lincoln LN6 7TS, United Kingdom
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12
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McAuliffe K, Wrangham R, Glowacki L, Russell AF. When cooperation begets cooperation: the role of key individuals in galvanizing support. Philos Trans R Soc Lond B Biol Sci 2016; 370:20150012. [PMID: 26503685 PMCID: PMC4633848 DOI: 10.1098/rstb.2015.0012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Life abounds with examples of conspecifics actively cooperating to a common end, despite conflicts of interest being expected concerning how much each individual should contribute. Mathematical models typically find that such conflict can be resolved by partial-response strategies, leading investors to contribute relatively equitably. Using a case study approach, we show that such model expectations can be contradicted in at least four disparate contexts: (i) bi-parental care; (ii) cooperative breeding; (iii) cooperative hunting; and (iv) human cooperation. We highlight that: (a) marked variation in contributions is commonplace; and (b) individuals can often respond positively rather than negatively to the contributions of others. Existing models have surprisingly limited power in explaining these phenomena. Here, we propose that, although among-individual variation in cooperative contributions will be influenced by differential costs and benefits, there is likely to be a strong genetic or epigenetic component. We then suggest that selection can maintain high investors (key individuals) when their contributions promote support by increasing the benefits and/or reducing the costs for others. Our intentions are to raise awareness in—and provide testable hypotheses of—two of the most poorly understood, yet integral, questions regarding cooperative ventures: why do individuals vary in their contributions and when does cooperation beget cooperation?
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Affiliation(s)
- Katherine McAuliffe
- Department of Psychology, Yale University, 2 Hillhouse Avenue, New Haven, CT 06520, USA Department of Human Evolutionary Biology, Harvard University, 11 Divinity Avenue, Cambridge, MA 02138, USA Department of Psychology, Boston College, Chestnut Hill, MA 02467, USA
| | - Richard Wrangham
- Department of Human Evolutionary Biology, Harvard University, 11 Divinity Avenue, Cambridge, MA 02138, USA
| | - Luke Glowacki
- Department of Human Evolutionary Biology, Harvard University, 11 Divinity Avenue, Cambridge, MA 02138, USA Program for Evolutionary Dynamics, Harvard University, 1 Brattle Square, Cambridge, MA 02138, USA
| | - Andrew F Russell
- Department of Human Evolutionary Biology, Harvard University, 11 Divinity Avenue, Cambridge, MA 02138, USA Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Treliever Road, Penryn, Cornwall TR10 9FE, UK
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13
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Gordon DS, Lea SEG. Who Punishes? The Status of the Punishers Affects the Perceived Success of, and Indirect Benefits From, “Moralistic” Punishment. EVOLUTIONARY PSYCHOLOGY 2016; 14:1474704916658042. [PMCID: PMC10480938 DOI: 10.1177/1474704916658042] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Accepted: 06/13/2016] [Indexed: 11/15/2023] Open
Abstract
“Moralistic” punishment of free riders can provide a beneficial reputation, but the immediate behavior is costly to the punisher. In Study 1, we investigated whether variation in status would be perceived to offset or mitigate the costs of punishment. One hundred and nineteen participants were presented with a vignette describing a punishment scenario. Participants predicted whether punishment would occur, how successful it would be, and indicated their attitude to the punisher. Participants believed only intervention by a high-status (HS) individual would be successful and that low-status (LS) individuals would not intervene at all. HS individuals predicted to punish successfully were seen as more formidable and likable. Study 2 investigated whether punishment was necessary to maintain an HS position. One hundred and seventeen participants were presented with a vignette describing a punishment scenario. Participants were asked to indicate whether they wished to be led by the punisher. HS individuals who did not punish were less likely to be chosen as leaders compared to HS punishers, whereas LS individuals who punished were no more or less likely to be chosen than nonpunishers. The results of both studies suggest that only HS individuals are expected to punish, likely because such a position offsets some of the costs of punishment. As a result, only HS individual can access the reputation benefits from punishment. Furthermore, an HS position may be dependent on the willingness to punish antisocial behavior. The ramifications that these results may have for the evolution of moralistic punishment are discussed.
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Affiliation(s)
- David S. Gordon
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
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14
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Isakov A, Holcomb A, Glowacki L, Christakis NA. Modeling the Role of Networks and Individual Differences in Inter-Group Violence. PLoS One 2016; 11:e0148314. [PMID: 26828362 PMCID: PMC4735492 DOI: 10.1371/journal.pone.0148314] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 01/15/2016] [Indexed: 11/19/2022] Open
Abstract
There is significant heterogeneity within and between populations in their propensity to engage in conflict. Most research has neglected the role of within-group effects in social networks in contributing to between-group violence and focused instead on the precursors and consequences of violence, or on the role of between-group ties. Here, we explore the role of individual variation and of network structure within a population in promoting and inhibiting group violence towards other populations. Motivated by ethnographic observations of collective behavior in a small-scale society, we describe a model with differentiated roles for individuals embedded within friendship networks. Using a simple model based on voting-like dynamics, we explore several strategies for influencing group-level behavior. When we consider changing population level attitude changes and introducing control nodes separately, we find that a particularly effective control strategy relies on exploiting network degree. We also suggest refinements to our model such as tracking fine-grained information spread dynamics that can lead to further enrichment in using evolutionary game theory models for sociological phenomena.
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Affiliation(s)
- Alexander Isakov
- Department of Physics, Harvard University, Cambridge, Massachusetts, United States of America
| | - Amelia Holcomb
- Department of Mathematics, Yale University, New Haven, Connecticut, United States of America
| | - Luke Glowacki
- Department of Human Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America
- Program for Evolutionary Dynamics, Harvard University, Cambridge, Massachusetts, United States of America
| | - Nicholas A. Christakis
- Department of Sociology, Yale University, New Haven, Connecticut, United States of America
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, United States of America
- Yale Institute for Network Science, Yale University, New Haven, Connecticut, United States of America
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15
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Cronin KA, Acheson DJ, Hernández P, Sánchez A. Hierarchy is Detrimental for Human Cooperation. Sci Rep 2015; 5:18634. [PMID: 26692287 PMCID: PMC5155906 DOI: 10.1038/srep18634] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 11/20/2015] [Indexed: 11/09/2022] Open
Abstract
Studies of animal behavior consistently demonstrate that the social environment impacts cooperation, yet the effect of social dynamics has been largely excluded from studies of human cooperation. Here, we introduce a novel approach inspired by nonhuman primate research to address how social hierarchies impact human cooperation. Participants competed to earn hierarchy positions and then could cooperate with another individual in the hierarchy by investing in a common effort. Cooperation was achieved if the combined investments exceeded a threshold, and the higher ranked individual distributed the spoils unless control was contested by the partner. Compared to a condition lacking hierarchy, cooperation declined in the presence of a hierarchy due to a decrease in investment by lower ranked individuals. Furthermore, hierarchy was detrimental to cooperation regardless of whether it was earned or arbitrary. These findings mirror results from nonhuman primates and demonstrate that hierarchies are detrimental to cooperation. However, these results deviate from nonhuman primate findings by demonstrating that human behavior is responsive to changing hierarchical structures and suggests partnership dynamics that may improve cooperation. This work introduces a controlled way to investigate the social influences on human behavior, and demonstrates the evolutionary continuity of human behavior with other primate species.
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Affiliation(s)
- Katherine A Cronin
- Lincoln Park Zoo, Lester E. Fisher Center for the Study and Conservation of Great Apes, Chicago, IL 60614, USA.,Max Planck Institute for Psycholinguistics, Comparative Cognitive Anthropology Group, 6525 XD Nijmegen, The Netherlands
| | - Daniel J Acheson
- Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Penélope Hernández
- Universitat de València, ERI-CES, Departamento de Análisis Económico, Spain
| | - Angel Sánchez
- Universidad Carlos III de Madrid, Grupo Interdisciplinar de Sistemas Complejos (GISC), Departamento de Matemáticas, and Institute UC3M-BS of Financial Big Data, 28911 Leganés, Madrid, Spain.,Universidad de Zaragoza, Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), 50018 Zaragoza, Spain
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