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Journal Articles

Benefits from grouping and cooperative hunting among Ache hunter-gatherers: Insights from an agent-based foraging model

Janssen, M.A. and K. Hill

2014 Human Ecology 42 (6): 823-835.


We develop an agent-based model of foraging behavior based on ecological parameters of the environment and prey characteristics measured in the Mbaracayu Reserve Paraguay. We then compare estimated foraging behavior from our model to the ethnographically observed behavior of Ache hunter–gatherers who inhabit the region and show a close match for daily harvest rates, time allocation, and species composition of prey. The model allows us to explore the implications of social living, cooperative hunting, variation in group size and mobility, under Ache-like ecological conditions. Simulations show that social living decreases daily risk of no food, but cooperative hunting has only a modest effect on mean harvest rates. Analysis demonstrates that bands should contain 7–8 hunters who move nearly every day in order to achieve the best combination of average harvest rates and low probability of no meat in camp.

Keywords: Optimal foraging theory; Agent-based modeling


Experimental platforms for behavioral experiments on social-ecological systems

Janssen, M.A., A. Lee, and T. Waring

2014 Ecology and Society 19 (4): 20.


Recently, there has been an increased interest in using behavioral experiments to study hypotheses on the governance of social-ecological systems. A diversity of software tools are used to implement such experiments. We evaluated various publicly available platforms that could be used in research and education on the governance of social-ecological systems. The aims of the various platforms are distinct, and this is noticeable in the differences in their user-friendliness and their adaptability to novel research questions. The more easily accessible platforms are useful for prototyping experiments and for educational purposes to illustrate theoretical concepts. To advance novel research aims, more elaborate programming experience is required to either implement an experiment from scratch or adjust existing experimental software. There is no ideal platform best suited for all possible use cases, but we have provided a menu of options and their associated trade-offs.

Keywords: education; lab experiments; research; software


The effect of constrained communication and limited information in governing a common resource

Janssen, M.A., M. Tyson, and A. Lee

2014 International Journal of the Commons  8(2): 617-635.


Allowing resource users to communicate in behavioural experiments on commons dilemmas increases the level of cooperation. In actual common pool resource dilemmas in the real world, communication is costly, which is an important detail missing from most typical experiments. We conducted experiments where participants must give up harvesting opportunities to communicate. The constrained communication treatment is compared with the effect of limited information about the state of the resource and the actions of the other participants. We find that despite making communication costly, performance of groups improves in all treatments with communication. We also find that constraining communication has a more significant effect than limiting information on the performance of groups.

Keywords: common pool resource, conditional cooperation, costly communication, lab experiments, limited information


The effect of social preferences on the evolution of cooperation in public good games

Janssen, M.A., M. Manning and O. Udiani

2014 Advances in Complex Systems 17(3/4): 1450015.


Human societies are unique in the level of cooperation among non-kin. Evolutionary models explaining this behavior typically assume pure strategies of cooperation and defection. Behavioral experiments, however, demonstrate that humans are typically conditional co-operators who have other-regarding preferences. Building on existing models on the evolution of cooperation and costly punishment, we use a utilitarian formulation of agent decision making to explore conditions that support the emergence of cooperative behavior. Our results indicate that cooperation levels are significantly lower for larger groups in contrast to the original pure strategy model. Here, defection behavior not only diminishes the public good, but also affects the expectations of group members leading conditional co-operators to change their strategies. Hence defection has a more damaging effect when decisions are based on expectations and not only pure strategies.

Keywords: Public good games; group selection; other-regarding preferences; conditional cooperation


A computational Model Library for publishing model documentation and code

Rollins, N.D., C.M. Barton, S. Bergin, M.A. Janssen and A. Lee

2014  Environmental Modelling and Software 61: 59-64.


We present a repository for disseminating the computational models associated with publications in the social and life sciences. The number of research projects using computational models has been steadily increasing but the resulting publications often lack model code and documentation which hinders replication, verification of results and accumulation of knowledge. We have developed an open repository, the CoMSES Net Computational Model Library, to address this problem. Submissions to the library can be original models accompanying publications or replications of previous studies. Researchers can request that their models undergo a certification process that verifies that the model code successfully compiles and runs and that it follows documentation best practices. Models that pass the certification process are assigned persistent URLs and identifiers. We present the basic components of our repository, discuss our initial experiences with the library, and elaborate on future steps in the development of this cyberinfrastructure.

Keywords: Model archive; Open source; Computational modeling; Documentation; Agent-based modeling


Commuter’s Mode Choice as a Coordination Problem: A framed field experiment on traffic policy in Hyderabad, India

Chidambaram, B, M.A. Janssen, J. Rommel, and D. Zikos

2014 Transportation Research A: Policy and Practice 65:9-22.


All major Indian cities face a severe transport crisis, with the number of cars on the road increasing every day. Policy makers are trying to keep pace with this growth by supplying more roads, largely neglecting demand-side policy measures. We have developed an economic experiment to investigate behavioral responses of citizens to such measures. Drawing on a sample of 204 white-collar commuters from Hyderabad, India, we model mode choice as a coordination problem and analyze how bus subsidies, increased parking costs, and public information on preferential car use can affect mode choice. We find that pecuniary treatments are effective for shifting behavior towards socially more desirable outcomes and increasing total benefits. Mode choice is relatively unaffected by socio-economic variables like gender, education or income but is significantly affected by actual traffic behavior. We discuss limitations of the applied sampling, conclude with a critical evaluation of the strengths and weaknesses of economic experiments in transportation research, and offer an outlook on how further experimentation could enrich the policy debate.

Keywords: Coordination game; Experimental economics; Hyderabad; India; Mode switching; Public transport


Insights for managers from modeling species interactions across multiple scales in an idealized landscape

Schoon, M.L., J. Baggio, K. Salau and M.A. Janssen

2014 Environmental Modelling and Software 54(1):53-59.


In recent years there has been a shift in biodiversity efforts from protected areas to one of interlinked habitat patches across multiple land tenure types. Much work remains on how managers can intervene in such systems to achieve basic goals. We use an agent-based model of a metapopulation with predator–prey dynamics and density-dependent migration to examine theoretically the capacity of a manager to modify the ecosystem to achieve conservation goals. We explore management strategies aimed at maintaining one of two goals – local or global coexistence of species. To achieve their goal, the manager varies the connectivity between patches based on one of three strategies – the monitoring of predator, prey, or the vegetation carrying capacity of the patches. We find that strategies that lead to highest coexistence monitor mid-tier populations globally. Our goal is to use our model results to advance decision-making in conservation beyond protected areas, typical in today’s conservation.

Keywords: Conservation; Biodiversity; Population dynamics; Management; Adaptive management; Agent-based modeling


Book Chapters

Vulnerability of Social Norms to Incomplete Information

Janssen, M.A. and E. Ostrom

2014 In Complexity of Social Norms, edited by M. Xenitidou and B. Edmunds, pp. 161-173, Springer.


The ability of groups to self-govern their common pool resources is well documented (Ostrom, 1990). Whether common pool resources are fish stocks or freshwater or forest products, success of self-governance relates to the ability of appropriators to develop trust relationships, monitor and enforce agreements, and communicate among each other.


An Agent-based Model based on Field Experiments

Janssen, M.A.

2014 In Empirical agent-based-modelling - Challenges and Solutions: Volume 1: The Characterisation and Parameterisation of Empirical Agent-Based Models, edited by A. Smaigl and C. Barreteau, pp. 189-205, Springer.


This chapter described the empirical calibration of a theoretical model based on data from field experiments. Field experiments on irrigation dilemmas were performed to understand how resource users overcome asymmetric collective action problems. The fundamental problem facing irrigation systems is how to solve two related collective action problems: (1) the provision of the physical and ecological infrastructure necessary to utilize the resource (water), and (2) the irrigation dilemma where the relative positions of “head-enders” and “tail-enders” generate a sequential access to the resource itself (water). If actors act as rational, self-interested, agents, it is difficult to understand how irrigation infrastructure would ever be constructed and maintained by the farmers obtaining water from a system as contrasted to a government irrigation bureaucracy. Wittfogel (1957) argued that a central control was indispensable for the functioning of larger irrigation systems and hypothesized that some state-level societies have emerged as a necessary side-effect of solving problems associated with the use of large-scale irrigation.


Diffusion Dynamics of Electric Cars and Adaptive Policy: Towards an Empirical Based Simulation

Jager, W., M.A. Janssen and M. Bockarjova

2014 In Advances in Social Simulation, edited by  by B. Kamiński and G. Koloch, Advances in Intelligent Systems and Computing, 229: 259-270, Springer Berlin Heidelberg.


In this paper we apply the updated consumat approach to the case of diffusion of electric cars. We will discuss how data from a large sample can be used to parameterize a number of main behavioural drivers, and how these relate to behavioural processes. At this stage we explain how the data fit in the framework, and whereas a model is currently under development, first simulation results are to be available first during the ESSA conference.

Keywords: diffusion; electric cars; agent based modeling; human behavior; decision making; needs; consumat


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