20,535 research outputs found
Computational rationality and voluntary provision of public goods: an agent-based simulation model
The issue of the cooperation among private agents in realising collective goods has always raised problems concerning the basic nature of individual behaviour as well as the more traditional economic problems. The Computational Economics literature on public goods provision can be useful to study the possibility of cooperation under alternative sets of assumptions concerning the nature of individual rationality and the kind of interactions between individuals. In this work I will use an agent-based simulation model to study the evolution of cooperation among private agents taking part in a collective project: a high number of agents, characterised by computational rationality, defined as the capacity to calculate and evaluate their own immediate payoffs perfectly and without errors, interact to producing a public good. The results show that when the agents’ behaviour is not influenced either by expectations of others’ behaviour or by social and relational characteristics, they opt to contribute to the public good to an almost socially optimal extent, even where there is no big difference between the rates of return on the private and the public investment.Computational Economics; Agent-based models; Social Dilemmas; Collective Action; Public Goods
Learning to Reach Agreement in a Continuous Ultimatum Game
It is well-known that acting in an individually rational manner, according to
the principles of classical game theory, may lead to sub-optimal solutions in a
class of problems named social dilemmas. In contrast, humans generally do not
have much difficulty with social dilemmas, as they are able to balance personal
benefit and group benefit. As agents in multi-agent systems are regularly
confronted with social dilemmas, for instance in tasks such as resource
allocation, these agents may benefit from the inclusion of mechanisms thought
to facilitate human fairness. Although many of such mechanisms have already
been implemented in a multi-agent systems context, their application is usually
limited to rather abstract social dilemmas with a discrete set of available
strategies (usually two). Given that many real-world examples of social
dilemmas are actually continuous in nature, we extend this previous work to
more general dilemmas, in which agents operate in a continuous strategy space.
The social dilemma under study here is the well-known Ultimatum Game, in which
an optimal solution is achieved if agents agree on a common strategy. We
investigate whether a scale-free interaction network facilitates agents to
reach agreement, especially in the presence of fixed-strategy agents that
represent a desired (e.g. human) outcome. Moreover, we study the influence of
rewiring in the interaction network. The agents are equipped with
continuous-action learning automata and play a large number of random pairwise
games in order to establish a common strategy. From our experiments, we may
conclude that results obtained in discrete-strategy games can be generalized to
continuous-strategy games to a certain extent: a scale-free interaction network
structure allows agents to achieve agreement on a common strategy, and rewiring
in the interaction network greatly enhances the agents ability to reach
agreement. However, it also becomes clear that some alternative mechanisms,
such as reputation and volunteering, have many subtleties involved and do not
have convincing beneficial effects in the continuous case
Partner Selection for the Emergence of Cooperation in Multi-Agent Systems Using Reinforcement Learning
Social dilemmas have been widely studied to explain how humans are able to
cooperate in society. Considerable effort has been invested in designing
artificial agents for social dilemmas that incorporate explicit agent
motivations that are chosen to favor coordinated or cooperative responses. The
prevalence of this general approach points towards the importance of achieving
an understanding of both an agent's internal design and external environment
dynamics that facilitate cooperative behavior. In this paper, we investigate
how partner selection can promote cooperative behavior between agents who are
trained to maximize a purely selfish objective function. Our experiments reveal
that agents trained with this dynamic learn a strategy that retaliates against
defectors while promoting cooperation with other agents resulting in a
prosocial society.Comment:
Towards simulated morality systems: Role-playing games as artificial societies
Computer role-playing games (RPGs) often include a simulated morality system as a core design element. Games' morality systems can include both god's eye view aspects, in which certain actions are inherently judged by the simulated world to be good or evil, as well as social simulations, in which non-player characters (NPCs) react to judgments of the player's and each others' activities. Games with a larger amount of social simulation have clear affinities to multi-agent systems (MAS) research on artificial societies. They differ in a number of key respects, however, due to a mixture of pragmatic game-design considerations and their typically strong embeddedness in narrative arcs, resulting in many important aspects of moral systems being represented using explicitly scripted scenarios rather than through agent-based simulations. In this position paper, we argue that these similarities and differences make RPGs a promising challenge domain for MAS research, highlighting features such as moral dilemmas situated in more organic settings than seen in game-theoretic models of social dilemmas, and heterogeneous representations of morality that use both moral calculus systems and social simulation. We illustrate some possible approaches using a case study of the morality systems in the game The Elder Scrolls IV: Oblivion
Player agency in interactive narrative: audience, actor & author
The question motivating this review paper is, how can
computer-based interactive narrative be used as a constructivist learn-
ing activity? The paper proposes that player agency can be used to
link interactive narrative to learner agency in constructivist theory,
and to classify approaches to interactive narrative. The traditional
question driving research in interactive narrative is, ‘how can an in-
teractive narrative deal with a high degree of player agency, while
maintaining a coherent and well-formed narrative?’ This question
derives from an Aristotelian approach to interactive narrative that,
as the question shows, is inherently antagonistic to player agency.
Within this approach, player agency must be restricted and manip-
ulated to maintain the narrative. Two alternative approaches based
on Brecht’s Epic Theatre and Boal’s Theatre of the Oppressed are
reviewed. If a Boalian approach to interactive narrative is taken the
conflict between narrative and player agency dissolves. The question
that emerges from this approach is quite different from the traditional
question above, and presents a more useful approach to applying in-
teractive narrative as a constructivist learning activity
Emergence of social networks via direct and indirect reciprocity
Many models of social network formation implicitly assume that network properties are static in steady-state. In contrast, actual social networks are highly dynamic: allegiances and collaborations expire and may or may not be renewed at a later date. Moreover, empirical studies show that human social networks are dynamic at the individual level but static at the global level: individuals' degree rankings change considerably over time, whereas network-level metrics such as network diameter and clustering coefficient are relatively stable. There have been some attempts to explain these properties of empirical social networks using agent-based models in which agents play social dilemma games with their immediate neighbours, but can also manipulate their network connections to
strategic advantage. However, such models cannot straightforwardly account for reciprocal behaviour based on reputation scores ("indirect reciprocity"), which is known to play an important role in many economic interactions. In
order to account for indirect reciprocity, we model the network in a bottom-up fashion: the network emerges from the low-level interactions between agents. By so doing we are able to simultaneously account for the effect of both direct reciprocity (e.g. "tit-for-tat") as well as indirect
reciprocity (helping strangers in order to increase one's reputation). This leads to a strategic equilibrium in the frequencies with which strategies are adopted in the population as a whole, but intermittent cycling over different strategies at the level of individual agents, which in turn gives rise to social networks which
are dynamic at the individual level but stable at the network level
Training and Turnover in Organizations
We present a two-level model of organizational training and agent production.
Managers decide whether or not to train based on both the costs of training
compared to the benefits and on their expectations and observations of the
number of other firms that also train. Managers also take into account the sum
of their employees' contributions and the average tenure length within their
organization. Employees decide whether or not to contribute to production based
on their expectations as to how other employees will act. Trained workers learn
over time and fold their increased productivity into their decision whether or
not to contribute. We find that the dynamical behavior at the two levels is
closely coupled: the evolution of the industry over time depends not only on
the characteristics of training programs, learning curves, and cost-benefit
analyses, but on the vagaries of chance as well. For example, in one case, the
double dilemma can be resolved for the industry as a whole and productivity
then increases steadily over time. In another, the organizational level dilemma
may remain unresolved and workers may contribute at fluctuating levels. In this
case the overall productivity stays low. We also find a correlation between
high productivity and low turnover and show that a small increase in training
rates can lead to explosive growth in productivity.Comment: 9 pages. Also available through anonymous ftp from parcftp.xerox.com
in the directory pub/dynamics as training.p
The Evolution of Altruism in Spatially Structured Populations
The evolution of altruism in humans is still an unresolved puzzle. Helping other individuals is often kinship-based or reciprocal. Several examples show, however, that altruism goes beyond kinship and reciprocity and people are willing to support unrelated others even when this is at a cost and they receive nothing in exchange. Here we examine the evolution of this "pure" altruism with a focus on altruistic teaching. Teaching is modeled as a knowledge transfer which enhances the survival chances of the recipient, but reduces the reproductive efficiency of the provider. In an agent-based simulation we compare evolutionary success of genotypes that have willingness to teach with those who do not in two different scenarios: random matching of individuals and spatially structured populations. We show that if teaching ability is combined with an ability to learn and individuals encounter each other on a spatial proximity basis, altruistic teaching will attain evolutionary success in the population. Settlement of the population and accumulation of knowledge are emerging side-products of the evolution of altruism. In addition, in large populations our simple model also produces a counterintuitive result that increasing the value of knowledge keeps fewer altruists alive.Altruism, Teaching, Knowledge Transfer, Spatially Structured Social Dilemmas
Diffusion processes in demographic transitions: a prospect on using multi agent simulation to explore the role of cognitive strategies and social interactions
Multi agent simulation (MAS) is a tool that can be used to explore the dynamics of different systems. Considering that many demographic phenomena have roots in individual choice behaviour and social interactions it is important that this behaviour is being translated in agent rules. Several behaviour theories are relevant in this context, and hence there is a necessity of using a meta-theory of behaviour as a framework for the development of agent rules. The consumat approach provides a basis for such a framework, as is demonstrated with a discussion of modelling the diffusion of contraceptives. These diffusion processes are strongly influenced by social processes and cognitive strategies. Different possible research lines are discussed which might be addressed with a multi-agent approach like the consumats.
Conformity-Driven Agents Support Ordered Phases in the Spatial Public Goods Game
We investigate the spatial Public Goods Game in the presence of
fitness-driven and conformity-driven agents. This framework usually considers
only the former type of agents, i.e., agents that tend to imitate the strategy
of their fittest neighbors. However, whenever we study social systems, the
evolution of a population might be affected also by social behaviors as
conformism, stubbornness, altruism, and selfishness. Although the term
evolution can assume different meanings depending on the considered domain,
here it corresponds to the set of processes that lead a system towards an
equilibrium or a steady-state. We map fitness to the agents' payoff so that
richer agents are those most imitated by fitness-driven agents, while
conformity-driven agents tend to imitate the strategy assumed by the majority
of their neighbors. Numerical simulations aim to identify the nature of the
transition, on varying the amount of the relative density of conformity-driven
agents in the population, and to study the nature of related equilibria.
Remarkably, we find that conformism generally fosters ordered cooperative
phases and may also lead to bistable behaviors.Comment: 13 pages, 5 figure
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