42 research outputs found
Evolutionary establishment of moral and double moral standards through spatial interactions
Situations where individuals have to contribute to joint efforts or share
scarce resources are ubiquitous. Yet, without proper mechanisms to ensure
cooperation, the evolutionary pressure to maximize individual success tends to
create a tragedy of the commons (such as over-fishing or the destruction of our
environment). This contribution addresses a number of related puzzles of human
behavior with an evolutionary game theoretical approach as it has been
successfully used to explain the behavior of other biological species many
times, from bacteria to vertebrates. Our agent-based model distinguishes
individuals applying four different behavioral strategies: non-cooperative
individuals ("defectors"), cooperative individuals abstaining from punishment
efforts (called "cooperators" or "second-order free-riders"), cooperators who
punish non-cooperative behavior ("moralists"), and defectors, who punish other
defectors despite being non-cooperative themselves ("immoralists"). By
considering spatial interactions with neighboring individuals, our model
reveals several interesting effects: First, moralists can fully eliminate
cooperators. This spreading of punishing behavior requires a segregation of
behavioral strategies and solves the "second-order free-rider problem". Second,
the system behavior changes its character significantly even after very long
times ("who laughs last laughs best effect"). Third, the presence of a number
of defectors can largely accelerate the victory of moralists over non-punishing
cooperators. Forth, in order to succeed, moralists may profit from immoralists
in a way that appears like an "unholy collaboration". Our findings suggest that
the consideration of punishment strategies allows to understand the
establishment and spreading of "moral behavior" by means of game-theoretical
concepts. This demonstrates that quantitative biological modeling approaches
are powerful even in domains that have been addressed with non-mathematical
concepts so far. The complex dynamics of certain social behaviors becomes
understandable as result of an evolutionary competition between different
behavioral strategies.Comment: 15 pages, 5 figures; accepted for publication in PLoS Computational
Biology [supplementary material available at
http://www.soms.ethz.ch/research/secondorder-freeriders/ and
http://www.matjazperc.com/plos/moral.html
Constants in Future Cities and Regions
The paper resumes some of the conversations the authors had in three years of research, based on the review of best participatory planning practices worldwide. The case projects are selected and discussed with the protagonists across four leading issues: Simulation, Scenario and Visioning, Government and Governance, and Scale. The case-oriented discussion is a peculiarity of the book , contributing to give shape to future cities or regions. The aim is to build a critical thinking on how urban planning, policy and design issues are faced differently or similarly throughout every cases studied. The book include the description of computer models and media, socio-political experiments and professional practices which help communicating the future effects of different design, policy and planning strategies and schemes with a wide range of aims: from information, through consultation, towards active participation. The cases have confirmed that simulation tools can impact on local government and can drive new forms of "glocal" governance, shaping and implementing future plans and projects at different scale and time span. The following paragraphs will point at some of the constant thoughts the authors had around the selection and editing of the book's case studied and related issue
If cooperation is likely punish mildly: Insights from economic experiments based on the snowdrift game
Punishment may deter antisocial behavior. Yet to punish is costly, and the
costs often do not offset the gains that are due to elevated levels of
cooperation. However, the effectiveness of punishment depends not only on how
costly it is, but also on the circumstances defining the social dilemma. Using
the snowdrift game as the basis, we have conducted a series of economic
experiments to determine whether severe punishment is more effective than mild
punishment. We have observed that severe punishment is not necessarily more
effective, even if the cost of punishment is identical in both cases. The
benefits of severe punishment become evident only under extremely adverse
conditions, when to cooperate is highly improbable in the absence of sanctions.
If cooperation is likely, mild punishment is not less effective and leads to
higher average payoffs, and is thus the much preferred alternative. Presented
results suggest that the positive effects of punishment stem not only from
imposed fines, but may also have a psychological background. Small fines can do
wonders in motivating us to chose cooperation over defection, but without the
paralyzing effect that may be brought about by large fines. The later should be
utilized only when absolutely necessary.Comment: 15 pages, 6 figures; accepted for publication in PLoS ON
Interdependent network reciprocity in evolutionary games
Besides the structure of interactions within networks, also the interactions between networks are of the outmost
importance. We therefore study the outcome of the public goods game on two interdependent networks that are
connected by means of a utility function, which determines how payoffs on both networks jointly influence the
success of players in each individual network. We show that an unbiased coupling allows the spontaneous
emergence of interdependent network reciprocity, which is capable to maintain healthy levels of public
cooperation even in extremely adverse conditions. The mechanism, however, requires simultaneous formation of
correlated cooperator clusters on both networks. If this does not emerge or if the coordination process is
disturbed, network reciprocity fails, resulting in the total collapse of cooperation. Network interdependence can
thus be exploited effectively to promote cooperation past the limits imposed by isolated networks, but only if the
coordination between the interdependent networks is not disturbe
Constants in Future Cities and Regions
The paper resumes some of the conversations the authors had in three years of research, based on the review of best participatory planning practices worldwide. The case projects are selected and discussed with the protagonists across four leading issues: Simulation, Scenario and Visioning, Government and Governance, and Scale. The case-oriented discussion is a peculiarity of the book , contributing to give shape to future cities or regions. The aim is to build a critical thinking on how urban planning, policy and design issues are faced differently or similarly throughout every cases studied. The book include the description of computer models and media, socio-political experiments and professional practices which help communicating the future effects of different design, policy and planning strategies and schemes with a wide range of aims: from information, through consultation, towards active participation. The cases have confirmed that simulation tools can impact on local government and can drive new forms of “glocal” governance, shaping and implementing future plans and projects at different scale and time span. The following paragraphs will point at some of the constant thoughts the authors had around the selection and editing of the book’s case studied and related issues
How Natural Selection Can Create Both Self- and Other-Regarding Preferences, and Networked Minds
Biological competition is widely believed to result in the evolution of
selfish preferences. The related concept of the `homo economicus' is at the
core of mainstream economics. However, there is also experimental and empirical
evidence for other-regarding preferences. Here we present a theory that
explains both, self-regarding and other-regarding preferences. Assuming
conditions promoting non-cooperative behaviour, we demonstrate that
intergenerational migration determines whether evolutionary competition results
in a `homo economicus' (showing self-regarding preferences) or a `homo
socialis' (having other-regarding preferences). Our model assumes spatially
interacting agents playing prisoner's dilemmas, who inherit a trait determining
`friendliness', but mutations tend to undermine it. Reproduction is ruled by
fitness-based selection without a cultural modification of reproduction rates.
Our model calls for a complementary economic theory for `networked minds' (the
`homo socialis') and lays the foundations for an evolutionarily grounded theory
of other-regarding agents, explaining individually different utility functions
as well as conditional cooperation
Punishment in Public Goods games leads to meta-stable phase transitions and hysteresis
The evolution of cooperation has been a perennial problem in evolutionary
biology because cooperation can be undermined by selfish cheaters who gain an
advantage in the short run, while compromising the long-term viability of the
population. Evolutionary game theory has shown that under certain conditions,
cooperation nonetheless evolves stably, for example if players have the
opportunity to punish cheaters that benefit from a public good yet refuse to
pay into the common pool. However, punishment has remained enigmatic because it
is costly, and difficult to maintain. On the other hand, cooperation emerges
naturally in the Public Goods game if the synergy of the public good (the
factor multiplying the public good investment) is sufficiently high. In terms
of this synergy parameter, the transition from defection to cooperation can be
viewed as a phase transition with the synergy as the critical parameter. We
show here that punishment reduces the critical value at which cooperation
occurs, but also creates the possibility of meta-stable phase transitions,
where populations can "tunnel" into the cooperating phase below the critical
value. At the same time, cooperating populations are unstable even above the
critical value, because a group of defectors that are large enough can
"nucleate" such a transition. We study the mean-field theoretical predictions
via agent-based simulations of finite populations using an evolutionary
approach where the decisions to cooperate or to punish are encoded genetically
in terms of evolvable probabilities. We recover the theoretical predictions and
demonstrate that the population shows hysteresis, as expected in systems that
exhibit super-heating and super-cooling. We conclude that punishment can
stabilize populations of cooperators below the critical point, but it is a
two-edged sword: it can also stabilize defectors above the critical point.Comment: 22 pages, 9 figures. Slight title change, version that appears in
Physical Biolog
Correlation of Positive and Negative Reciprocity Fails to Confer an Evolutionary Advantage: Phase Transitions to Elementary Strategies
Economic experiments reveal that humans value cooperation and fairness. Punishing unfair behavior is therefore common, and according to the theory of strong reciprocity, it is also directly related to rewarding cooperative behavior. However, empirical data fail to confirm that positive and negative reciprocity are correlated. Inspired by this disagreement, we determine whether the combined application of reward and punishment is evolutionarily advantageous. We study a spatial public goods game, where in addition to the three elementary strategies of defection, rewarding, and punishment, a fourth strategy that combines the latter two competes for space. We find rich dynamical behavior that gives rise to intricate phase diagrams where continuous and discontinuous phase transitions occur in succession. Indirect territorial competition, spontaneous emergence of cyclic dominance, as well as divergent fluctuations of oscillations that terminate in an absorbing phase are observed. Yet, despite the high complexity of solutions, the combined strategy can survive only in very narrow and unrealistic parameter regions. Elementary strategies, either in pure or mixed phases, are much more common and likely to prevail. Our results highlight the importance of patterns and structure in human cooperation, which should be considered in future experiments