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(We routinely do experiments and thus, these pages show the most relevant ones. Click at the end of each page to move to the next/previous one)

Behavioral patterns behind the demise of the commons

Behavioral patterns behind the demise
of the commons

Common-pool resources require a dose of self-restraint to ensure sustainable exploitation, but this has often proven elusive in practice. To understand why, and characterize behaviors towards ecological systems in general, we devised a social dilemma experiment in which participants gain profit from harvesting a virtual forest vulnerable to overexploitation. Out of 16 Chinese and 15 Spanish player groups, only one group from each country converged to the forest’s maximum sustainable yield.
All other groups were overzealous, with about half of them surpassing or on the way to surpass a no-recovery threshold. Computational-statistical analyses attribute such outcomes to an interplay between three prominent player behaviors, two of which are subject to decision-making «inertia» that causes near blindness to the resource state. These behaviors, being equally pervasive among players from both nations, imply that the commons fall victim to behavioral patterns robust to confounding factors such as age, education, and culture.

M. Jusup, F. M. Cardoso, C. Gracia Lazaro, L. Chen, Z. Wang, and Y. Moreno, “Robust behavioral patterns behind the demise of the commons”. Submitted for publication, preperint available upon request.

Trading in Complex Networks

Trading in Complex Networks

Global supply networks in agriculture, manufacturing, and services are a defining feature of the modern world. The efficiency and the distribution of surpluses across different parts of these networks depend on the choices of intermediaries. This paper conducts price formation experiments with human subjects located in large complex networks to develop a better understanding of the principles governing behavior. Our first finding is that prices are larger and that trade is significantly less efficient in small-world networks as compared to random networks.
Our second finding is that location within a network is not an important determinant of pricing. An examination of the price dynamics suggests that traders on cheapest — and hence active — paths raise prices while those off these paths lower them. We construct an agent-based model (ABM) that embodies this rule of thumb. Simulations of this ABM yield macroscopic patterns consistent with the experimental findings. Finally, we extrapolate the ABM on to significantly larger random and small-world networks and find that network topology remains a key determinant of pricing and efficiency.

F. M. Cardoso, C. Gracia-Lázaro, F. Moisan, S. Goyal, A. Sánchez, and Y. Moreno, “Trading in Complex Networks”. Submitted for publication, preperint available at the link below.

Onymity promotes cooperation in social dilemma experiments

Onymity promotes cooperation
in social dilemma experiments

One of the most elusive scientific challenges for over 150 years has been to explain why cooperation survives despite being a seemingly inferior strategy from an evolutionary point of view. Over the years, various theoretical scenarios aimed at solving the evolutionary puzzle of cooperation have been proposed, eventually identifying several cooperation-promoting mechanisms: kin selection, direct reciprocity, indirect reciprocity, network reciprocity, and group selection. Here, we report the results of repeated Prisoner’s Dilemma experiments with anonymous and onymous pairwise interactions among individuals.
We find that onymity significantly increases the frequency of cooperation and the median payoff per round relative to anonymity. Furthermore, we also show that the correlation between players’ ranks and the usage of strategies (cooperation, defection, or punishment) underwent a fundamental shift, whereby more prosocial actions are rewarded with a better ranking under onymity. Our findings prove that reducing anonymity is a valid promoter of cooperation, leading to higher payoffs for cooperators and thus suppressing an incentive–anonymity–that would ultimately favor defection.

Z. Wang, M. Jusup, R.-W. Wang, L. Shi, Y. Iwasa, Y. Moreno and J. Kurths, “Onymity promotes cooperation in social dilemma experiments”, Science Advances 3, e1601444 (2017).