The Size of the Stag Determines the Level of Cooperation

2021 ◽  
Author(s):  
Eric Schnell ◽  
Robin Schimmelpfennig ◽  
Michael Muthukrishna
Keyword(s):  
Population Growth ◽  
Population Size ◽  
Carrying Capacity ◽  
Large Scale ◽  
Growth Dynamics ◽  
Stag Hunt ◽  
Low Levels

ABSTRACTIn the last 12,000 years, human societies have scaled up from small bands to large states of millions and even billions. Many modern societies and even groups of societies cooperate on large-scale projects with relatively low levels of conflict, but the scale and intensity of cooperation varies dramatically between societies. Here we attempt to formalize dynamics that may be driving this rapid increase in cooperation and the differences we see between societies. Our model extends an N-person stag hunt to include population growth dynamics, “stags” with different sized payoffs, and competition for these stags. An increasing number of cooperators is required to access larger stags. The payoff from these stags in turn increases carrying capacity, which increases competition for the stag. As population size increases, new cooperative thresholds are attainable, and as population size shrinks, previously attainable thresholds fall out of reach. Among other predictions, we show that when a new threshold is accessible to a population, the level of cooperation will increase to reach this threshold. However, when the next threshold is out of reach, cooperation decreases as individuals refrain from costly cooperation, preferring a smaller stag. This model offers a framework for understanding the rapid increase in the scale of human cooperation and decline of violence, differences between societies, and challenges to future cooperation.

scholarly journals Noise-Induced Transitions in a Population Growth Model Based on Size-Dependent Carrying Capacity

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Neeme Lumi ◽  
Ain Ainsaar ◽  
Romi Mankin
Keyword(s):  
Population Growth ◽  
Population Size ◽  
Growth Model ◽  
Carrying Capacity ◽  
Stochastic Dynamics ◽  
Exact Analytical Solution ◽  
Probability Distributions ◽  
Stationary Probability Distribution ◽  
Size Dependent ◽  
Stochastic Case

The stochastic dynamics of a population growth model with size-dependent carrying capacity is considered. The effect of a fluctuating environment on population growth is modeled as a multiplicative dichotomous noise. At intermediate values of population size the deterministic counterpart of the model behaves similarly to the Von Foerster model for human population, but at small and very large values of population size substantial differences occur. In the stochastic case, an exact analytical solution for the stationary probability distribution is found. It is established that variation of noise correlation time can cause noise-induced transitions between three different states of the system characterized by qualitatively different behaviors of the probability distributions of the population size. Also, it is shown that, in some regions of the system parameters, variation of the amplitude of environmental fluctuations can induce single unidirectional abrupt transitions of the mean population size.

Reduction of population growth in Tisbe holothuriae Humes (Copepoda : Harpacticoida) exposed to low cadmium concentrations

1986 ◽  
Vol 37 (4) ◽  
pp. 475 ◽  
Author(s):  
GW Brand ◽  
GJ Fabris ◽  
GH Arnott
Keyword(s):  
Population Growth ◽  
Population Size ◽  
Toxic Metals ◽  
Total Population ◽  
Cadmium Concentration ◽  
Male And Female ◽  
Total Population Size ◽  
Environmental Background ◽  
Laboratory Populations ◽  
Low Levels

Replicate laboratory populations of T. holothuriae initiated by founder females standardized in terms of reproductive status, age and environmental background were exposed to three levels of cadmium for 24 days and compared with untreated controls. At a cadmium concentration of 159 �g l-1 populations failed to increase and became virtually extinct, probably because of larval impairment. At concentrations of 2.3 and 40 �g l-1 population growth occurred but total population size (males plus females plus copepodids) and both male and female numbers were significantly reduced relative to controls. Knowledge of the response of harpacticoids to low levels of toxic metals therefore appears to be significant in developing an understanding of the effects of metals on marine ecosystems.

scholarly journals Population-Adjusted Egalitarianism

2021 ◽  
Author(s):  
Stéphane Zuber
Keyword(s):  
Economic Theory ◽  
Population Growth ◽  
Natural Resources ◽  
Population Size ◽  
Well Being ◽  
Allocation Of Resources ◽  
Trade Off ◽  
Optimal Population ◽  
Intertemporal Allocation ◽  
Low Levels

Egalitarianism focuses on the well-being of the worst-off person. It has attracted a lot of attention in economic theory, for instance when dealing with the sustainable intertemporal allocation of resources. Economic theory has formalized egalitarianism through the Maximin and Leximin criteria, but it is not clear how they should be applied when population size may vary. In this paper, I present possible justifications of egalitarianism when considering populations with variable sizes. I then propose new versions of egalitarianism that encompass many views on how to trade-off population size and well-being. I discuss some implications of egalitarianism for optimal population size. I first describe how population ethical views affects population growth. In a model with natural resources, I then show that utilitarianism always recommend a larger population for low levels of resources, but that this conclusion may not hold true for larger levels.

scholarly journals Can we reestablish a self-sustaining population? A case study on reintroduced Crested Ibis with population viability analysis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yashuai Zhang ◽  
Fang Wang ◽  
Zhenxia Cui ◽  
Min Li ◽  
Xia Li ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Population Size ◽  
Carrying Capacity ◽  
Wild Population ◽  
Population Viability Analysis ◽  
Population Viability ◽  
Viability Analysis ◽  
Crested Ibis ◽  
Reintroduced Population

Abstract Background One of the most challenging tasks in wildlife conservation and management is clarifying which and how external and intrinsic factors influence wildlife demography and long-term viability. The wild population of the Crested Ibis (Nipponia nippon) has recovered to approximately 4400, and several reintroduction programs have been carried out in China, Japan and Korea. Population viability analysis on this endangered species has been limited to the wild population, showing that the long-term population growth is restricted by the carrying capacity and inbreeding. However, gaps in knowledge of the viability of the reintroduced population and its drivers in the release environment impede the identification of the most effective population-level priorities for aiding in species recovery. Methods The field monitoring data were collected from a reintroduced Crested Ibis population in Ningshan, China from 2007 to 2018. An individual-based VORTEX model (Version 10.3.5.0) was used to predict the future viability of the reintroduced population by incorporating adaptive patterns of ibis movement in relation to catastrophe frequency, mortality and sex ratio. Results The reintroduced population in Ningshan County is unlikely to go extinct in the next 50 years. The population size was estimated to be 367, and the population genetic diversity was estimated to be 0.97. Sensitivity analysis showed that population size and extinction probability were dependent on the carrying capacity and sex ratio. The carrying capacity is the main factor accounting for the population size and genetic diversity, while the sex ratio is the primary factor responsible for the population growth trend. Conclusions A viable population of the Crested Ibis can be established according to population viability analysis. Based on our results, conservation management should prioritize a balanced sex ratio, high-quality habitat and low mortality.

scholarly journals The dynamics of population by settlements in the Guba-Khachmaz economic-geographical region

2020 ◽  
Vol 3 ◽  
pp. 143-151
Author(s):  
Tural Bayramov ◽  
Keyword(s):  
Population Growth ◽  
Rural Population ◽  
Growth Dynamics ◽  
Living Standards ◽  
Geographical Region ◽  
Employment Rate ◽  
Social Survey ◽  
Rural And Urban ◽  
The Social ◽  
Dynamics Of Population

The article shows and analyzes the population growth dynamics in the Guba-Khachmaz economic-geographical region, the economic region’s urban and rural population. Its share of the population of Azerbaijan for the years 1990-2015 are shown in the tables and also analyzed. The population for rural and urban sectors and the indicators of rate are shown in the map for 2016-2017 years. Also, as a result of the social survey conducted in the region, the living standards of the population as well as the employment rate in the settlements were studied, and ways to mitigate problems were identified.

scholarly journals Ethnic Immigration Policy Implementation (1992- 2009)

2013 ◽  
pp. 109-117
Author(s):  
Shugatai Amangul
Keyword(s):  
National Identity ◽  
Population Growth ◽  
Policy Implementation ◽  
Population Size ◽  
International Migration ◽  
Immigration Policy ◽  
International Affairs ◽  
Migration Process ◽  
Economic Stability ◽  
Positive Effect

After Kazakhstan declared its independence, it became a large perform­er in the worldwide international migration process. The attraction of social and economic stability (with an increase in the level of liv­ing standard), stable ethno-demographic and population growth, no nationalist struggles as well as positive geopolitical situations, have lead to a huge flow of immigrants to Kazakhstan in the years since independence. In this study, I have suggested that results of the ethnic immigration policy include strengthening the national identity, creating a positive effect on the ethno-demographic outcomes, and increasing the number of the population size over the last nineteen years. DOI: http://dx.doi.org/10.5564/mjia.v0i17.87 Mongolian Journal of International Affairs, No.17 2012: 109-117

scholarly journals DYNAMIC STATE OF ECOSYSTEM CARRYING CAPACITY UNDER ISLAND URBANIZATION: A CASE STUDY OF PINGTAN ISLAND IN THE SOUTHEASTERN COAST OF CHINA

2020 ◽  
Vol 28 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Sheng Gao ◽  
Huihui Sun ◽  
Guangxi Cao ◽  
Lin Zhao ◽  
Runjie Wang ◽  
...  
Keyword(s):  
Sustainable Development ◽  
Carrying Capacity ◽  
Large Scale ◽  
Assessment Method ◽  
Dynamic State ◽  
Ecological Environment ◽  
The Sustainable Development ◽  
Rational Development ◽  
Pingtan Island

The assessment of ecological environment during the large-scale development of islands is a major topic in the study of current coastal islands. Choosing the appropriate assessment method to evaluate the suitability of carrying capacity of islands and making relevant suggestions are significant to the sustainable development of islands. Ecological footprint method is used to analyze the ecological carrying capacity of Pingtan Island (PI) from 2005 to 2016 for promoting the coordinated rational development and construction and ecological environment of the island. Although PI is in rapid urban development and construction, the island maintains secure and stable ecological conditions. PI is used as a research case to analyze the sustainable development of the ecological environment through the carrying capacity of the island ecosystem.

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