Computational Model Library

Evolution of Conditional Cooperation

Marco Janssen Miles Manning Oyita Udiani | Published Thu Aug 1 04:03:07 2013 | Last modified Fri May 13 22:07:23 2022

Cultural group selection model used to evaluate the conditions for agents to evolve who have other-regarding preferences in making decisions in public good games.

This paper introduces an experimental and exploratory approach, combining game theory and Genetic Algorithms to create a model to simulate evolutionary economic learning. The objective of this paper is to document the implementation of a genetic algorithm as a simulator for economic learning, then analyze how strategic behavior affects the evolution towards optimal outcomes, departing from different starting points and potentially transforming conflict into harmonious scenarios. For this purpose, the introduced construct aimed at allowing for the evaluation of different strategy selection methods and game types. 144 unique 2x2 games, and three distinct strategy selection rules: Nash equilibrium, Hurwicz rule and a Random selection method were used in this study. The particularity of this paper is that rather than changing the strategies themselves or player-specific features, the introduced genetic algorithm changes the games based on the player payoffs. The outcome indicated optimal player scenarios for both The Nash equilibrium and Hurwicz rules strategies, the first being the best performing strategy. The random selection method fails to converge to optimal values in most of the populations, acting as a control feature and reinforcing that strategic behavior is necessary for the evolutionary learning process. We documented also two additional observations. First, the games are often transformed in such a way that agents can coordinate their strategies to achieve a stable optimal equilibrium. And second, we observed the mutation of the populations of games into sets of fewer (repeating) isomorphic games featuring strong characteristics of previous games.

This model builds on the Armature distribution within the PaleoscapeABM model, which is itself a variant of the PaleoscapeABM available here written by Wren and Janssen, and.

This model aims to explore where and how much shellfish is discarded at coastal and non-coastal locations by daily coastal foraging. We use this model’s output to test the idea that we can confidently use the archaeological record to evaluate the importance of shellfish in prehistoric people’s diets.

The recognition that aquatic adaptations likely had significant impacts on human evolution triggered an explosion of research on that topic. Recognizing coastal foraging in the past relies on the archaeological signature of that behavior. We use this model to explore why some coastal sites are very intensely occupied and see if it is due to the shellfish productivity of the coast.

With this model, we investigate resource extraction and labor conditions in the Global South as well as implications for climate change originating from industry emissions in the North. The model serves as a testbed for simulation experiments with evolutionary political economic policies addressing these issues. In the model, heterogeneous agents interact in a self-organizing and endogenously developing economy. The economy contains two distinct regions – an abstract Global South and Global North. There are three interlinked sectors, the consumption good–, capital good–, and resource production sector. Each region contains an independent consumption good sector, with domestic demand for final goods. They produce a fictitious consumption good basket, and sell it to the households in the respective region. The other sectors are only present in one region. The capital good sector is only found in the Global North, meaning capital goods (i.e. machines) are exclusively produced there, but are traded to the foreign as well as the domestic market as an intermediary. For the production of machines, the capital good firms need labor, machines themselves and resources. The resource production sector, on the other hand, is only located in the Global South. Mines extract resources and export them to the capital firms in the North. For the extraction of resources, the mines need labor and machines. In all three sectors, prices, wages, number of workers and physical capital of the firms develop independently throughout the simulation. To test policies, an international institution is introduced sanctioning the polluting extractivist sector in the Global South as well as the emitting industrial capital good producers in the North with the aim of subsidizing innovation reducing environmental and social impacts.

BEGET Classic

Kristin Crouse | Published Mon Nov 11 07:30:59 2019 | Last modified Mon Nov 25 07:25:33 2019

BEGET Classic includes previous versions used in the classroom and for publication. Please check out the latest version of B3GET here, which has several user-friendly features such as directly importing and exporting genotype and population files.

The classic versions of B3GET include: version one and version three were used in undergraduate labs at the University of Minnesota to demonstrate principles in primate behavioral ecology; version two first demonstrated proof of concept for creating virtual biological organisms using decision-vector technology; version four was presented at the 2017 annual meeting at the American Association of Physical Anthropologists; version five was presented in a 2019 publication from the Journal of Human Evolution (Crouse, Miller, and Wilson, 2019).

Peer reviewed B3GET

Kristin Crouse | Published Thu Nov 14 20:07:16 2019 | Last modified Fri Dec 3 05:47:45 2021

B3GET simulates populations of virtual organisms evolving over generations, whose evolutionary outcomes reflect the selection pressures of their environment. The model simulates several factors considered important in biology, including life history trade-offs, investment in fighting ability and aggression, sperm competition, infanticide, and competition over access to food and mates. Downloaded materials include starting genotype and population files. Edit the these files and see what changes occur in the behavior of virtual populations!

View the B3GET user manual here.

Substitution of food products will be key to realising widespread adoption of sustainable diets. We present an agent-based model of decision-making and influences on food choice, and apply it to historically observed trends of British whole and skimmed (including semi) milk consumption from 1974 to 2005. We aim to give a plausible representation of milk choice substitution, and test different mechanisms of choice consideration. Agents are consumers that perceive information regarding the two milk choices, and hold values that inform their position on the health and environmental impact of those choices. Habit, social influence and post-decision evaluation are modelled. Representative survey data on human values and long-running public concerns empirically inform the model. An experiment was run to compare two model variants by how they perform in reproducing these trends. This was measured by recording mean weekly milk consumption per person. The variants differed in how agents became disposed to consider alternative milk choices. One followed a threshold approach, the other was probability based. All other model aspects remained unchanged. An optimisation exercise via an evolutionary algorithm was used to calibrate the model variants independently to observed data. Following calibration, uncertainty and global variance-based temporal sensitivity analysis were conducted. Both model variants were able to reproduce the general pattern of historical milk consumption, however, the probability-based approach gave a closer fit to the observed data, but over a wider range of uncertainty. This responds to, and further highlights, the need for research that looks at, and compares, different models of human decision-making in agent-based and simulation models. This study is the first to present an agent-based modelling of food choice substitution in the context of British milk consumption. It can serve as a valuable pre-curser to the modelling of dietary shift and sustainable product substitution to plant-based alternatives in Britain.

Prisoner's Tournament

Kristin Crouse | Published Wed Nov 6 05:39:54 2019 | Last modified Wed Dec 15 02:39:43 2021

This model replicates the Axelrod prisoner’s dilemma tournaments. The model takes as input a file of strategies and pits them against each other to see who achieves the best payoff in the end. Change the payoff structure to see how it changes the tournament outcome!

The Hawk-Dove Game

Kristin Crouse | Published Tue Nov 5 04:51:09 2019

This model simulates the Hawk-Dove game as first described by John Maynard Smith, and further elaborated by Richard Dawkins in “The Selfish Gene”. In the game, two strategies, Hawks and Doves, compete against each other, and themselves, for reproductive benefits. A third strategy can be introduced, Retaliators, which act like either Hawks or Doves, depending on the context.

Peer reviewed Vigilant sharing in a small-scale society

MARCOS PINHEIRO | Published Wed Jul 22 01:40:09 2020 | Last modified Wed Jul 29 02:03:28 2020

The model explores food distribution patterns that emerge in a small-scale non-agricultural group when sharing individuals engage in intentional consumption leveling with a given probability.

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