1
|
Hunt KL, Patel M, Croft DP, Franks DW, Green PA, Thompson FJ, Johnstone RA, Cant MA, Sankey DWE. The evolution of democratic peace in animal societies. Nat Commun 2024; 15:6583. [PMID: 39097569 PMCID: PMC11297998 DOI: 10.1038/s41467-024-50621-5] [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: 10/20/2023] [Accepted: 07/17/2024] [Indexed: 08/05/2024] Open
Abstract
A major goal in evolutionary biology is to elucidate common principles that drive human and other animal societies to adopt either a warlike or peaceful nature. One proposed explanation for the variation in aggression between human societies is the democratic peace hypothesis. According to this theory, autocracies are more warlike than democracies because autocratic leaders can pursue fights for private gain. However, autocratic and democratic decision-making processes are not unique to humans and are widely observed across a diverse range of non-human animal societies. We use evolutionary game theory to evaluate whether the logic of democratic peace may apply across taxa; specifically adapting the classic Hawk-Dove model to consider conflict decisions made by groups rather than individuals. We find support for the democratic peace hypothesis without mechanisms involving complex human institutions and discuss how these findings might be relevant to non-human animal societies. We suggest that the degree to which collective decisions are shared may explain variation in the intensity of intergroup conflict in nature.
Collapse
Affiliation(s)
- K L Hunt
- Centre for Ecology and Conservation, Faculty of Environment, Science and Economy, University of Exeter, Penryn Campus, Cornwall, UK.
| | - M Patel
- Centre of Excellence for Data Science, Artificial Intelligence and Modelling and Department of Biology, University of Hull, Hull, UK
| | - D P Croft
- Centre for Research in Animal Behaviour, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK
| | - D W Franks
- Department of Biology and Department of Computer Science, University of York, York, UK
| | - P A Green
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, USA
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, RI, USA
| | - F J Thompson
- Centre for Ecology and Conservation, Faculty of Environment, Science and Economy, University of Exeter, Penryn Campus, Cornwall, UK
| | - R A Johnstone
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - M A Cant
- Centre for Ecology and Conservation, Faculty of Environment, Science and Economy, University of Exeter, Penryn Campus, Cornwall, UK
| | - D W E Sankey
- Centre for Ecology and Conservation, Faculty of Environment, Science and Economy, University of Exeter, Penryn Campus, Cornwall, UK.
- School of Natural and Environmental Science, Newcastle University, Newcastle upon Tyne, UK.
| |
Collapse
|
2
|
Glowacki L. The evolution of peace. Behav Brain Sci 2022; 47:e1. [PMID: 36524358 DOI: 10.1017/s0140525x22002862] [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] [Indexed: 12/23/2022]
Abstract
While some species have affiliative and even cooperative interactions between individuals of different social groups, humans are alone in having durable, positive-sum, interdependent relationships across unrelated social groups. Our capacity to have harmonious relationships that cross group boundaries is an important aspect of our species' success, allowing for the exchange of ideas, materials, and ultimately enabling cumulative cultural evolution. Knowledge about the conditions required for peaceful intergroup relationships is critical for understanding the success of our species and building a more peaceful world. How do humans create harmonious relationships across group boundaries and when did this capacity emerge in the human lineage? Answering these questions involves considering the costs and benefits of intergroup cooperation and aggression, for oneself, one's group, and one's neighbor. Taking a game theoretical perspective provides new insights into the difficulties of removing the threat of war and reveals an ironic logic to peace - the factors that enable peace also facilitate the increased scale and destructiveness of conflict. In what follows, I explore the conditions required for peace, why they are so difficult to achieve, and when we expect peace to have emerged in the human lineage. I argue that intergroup cooperation was an important component of human relationships and a selective force in our species history beginning at least 300 thousand years. But the preconditions for peace only emerged in the past 100 thousand years and likely coexisted with intermittent intergroup violence which would have also been an important and selective force in our species' history.
Collapse
Affiliation(s)
- Luke Glowacki
- Department of Anthropology, Boston University, Boston, MA, USA ://www.hsb-lab.org/
| |
Collapse
|
3
|
|
4
|
Sankey DWE, Hunt KL, Croft DP, Franks DW, Green PA, Thompson FJ, Johnstone RA, Cant MA. Leaders of war: modelling the evolution of conflict among heterogeneous groups. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210140. [PMID: 35369752 DOI: 10.1098/rstb.2021.0140] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
War, in human and animal societies, can be extremely costly but can also offer significant benefits to the victorious group. We might expect groups to go into battle when the potential benefits of victory (V) outweigh the costs of escalated conflict (C); however, V and C are unlikely to be distributed evenly in heterogeneous groups. For example, some leaders who make the decision to go to war may monopolize the benefits at little cost to themselves ('exploitative' leaders). By contrast, other leaders may willingly pay increased costs, above and beyond their share of V ('heroic' leaders). We investigated conflict initiation and conflict participation in an ecological model where single-leader-multiple-follower groups came into conflict over natural resources. We found that small group size, low migration rate and frequent interaction between groups increased intergroup competition and the evolution of 'exploitative' leadership, while converse patterns favoured increased intragroup competition and the emergence of 'heroic' leaders. We also found evidence of an alternative leader/follower 'shared effort' outcome. Parameters that favoured high contributing 'heroic' leaders, and low contributing followers, facilitated transitions to more peaceful outcomes. We outline and discuss the key testable predictions of our model for empiricists studying intergroup conflict in humans and animals. This article is part of the theme issue 'Intergroup conflict across taxa'.
Collapse
Affiliation(s)
- D W E Sankey
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK
| | - K L Hunt
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK
| | - D P Croft
- Centre for Research in Animal Behaviour, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QG, UK
| | - D W Franks
- Department of Biology and Department of Computer Science, University of York, York YO10 5DD, UK
| | - P A Green
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK.,Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA
| | - F J Thompson
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK
| | - R A Johnstone
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | - M A Cant
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK.,German Primate Centre, University of Göttingen, Göttingen 37077, Germany
| |
Collapse
|
5
|
Hosťovecký M, Riegert J, Pazda A, Prokop P. Skin Conductivity Responses to Images of War and Sports in Men and Women: An Evolutionary Perspective. ADAPTIVE HUMAN BEHAVIOR AND PHYSIOLOGY 2022. [DOI: 10.1007/s40750-022-00186-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|