Altruistic Versus Rational Behavior in a Public Good Game

This paper analyses an evolutionary version of the Public Good game of Eshel, Samuelson, and Shaked (1998) in which agents can choose between imitation and best-reply decision rules. We describe conditions under which altruistic and spiteful (maximizing) behavior arise: these conditions are established for any number of neighbors and any total number of agents in the population. Given mistake-free play, (short-run) outcomes are identical whether agents are constrained to employ an imitation rule only; or they can choose between imitation and best-reply rules. Given the possibility of mistakes, (long-run) outcomes vary across these two scenarios. The paper suggests how to provide public goods and gives an explanation of why we observe seemingly irrational cooperation - altruistic behavior - in the rational world.

On the Evolution of Preferences

A common feature of the literature on the evolution of preferences is that evolution favors nonmaterialistic preferences only if preference types are observable at least to some degree. We argue that this result is due to the assumption that in each state of the evolutionary dynamics some Bayesian Nash equilibrium is played. We show that under unobservability of preference types, conditional on selecting some self-confirming equilibrium as a rule for mapping preference into behavior, non-selfish preferences may be evolutionarily successful.evolution of preferences, altruism, learning, self-confirming equilibrium

Quality competition with motivated providers and sluggish demand

We study incentives for quality provision in markets where providers are motivated (semi-altruistic); prices are regulated and firms are funded by a combination of block grants and unit prices; competition is based on quality, and demand adjusts sluggishly. Health or education are sectors in which the mentioned features are the rule. We show that the presence of motivated providers makes dynamic competition tougher, resulting in higher steady-state levels of quality in the closed-loop solutions than in the benchmark open-loop solution, if the price is sufficiently high. However, this result is reversed if the price is sufficiently low (and below unit costs). Sufficiently low prices also imply that a reduction in demand sluggishness will lead to lower steady-state quality. Prices below unit costs will nevertheless be welfare optimal if the providers are sufficiently motivated.Quality competition; Differential games; Motivated agents.

Quality competition with motivated providers and sluggish demand

We study incentives for quality provision in markets where providers are motivated (semi-altruistic); prices are regulated and firms are funded by a combination of block grants and unit prices; competition is based on quality, and demand adjusts sluggishly. Health or education are sectors in which the mentioned features are the rule. We show that the presence of motivated providers makes dynamic competition tougher, resulting in higher steady-state levels of quality in the closed-loop solutions than in the benchmark open-loop solution, if the price is sufficiently high. However, this result is reversed if the price is sufficiently low (and below unit costs). Sufficiently low prices also imply that a reduction in demand sluggishness will lead to lower steady-state quality. Prices below unit costs will nevertheless be welfare optimal if the providers are sufficiently motivated.Quality competition; Differential games;Motivated agents

CSMA Local Area Networking under Dynamic Altruism

In this paper, we consider medium access control of local area networks (LANs) under limited-information conditions as befits a distributed system. Rather than assuming "by rule" conformance to a protocol designed to regulate packet-flow rates (e.g., CSMA windowing), we begin with a non-cooperative game framework and build a dynamic altruism term into the net utility. The effects of altruism are analyzed at Nash equilibrium for both the ALOHA and CSMA frameworks in the quasistationary (fictitious play) regime. We consider either power or throughput based costs of networking, and the cases of identical or heterogeneous (independent) users/players. In a numerical study we consider diverse players, and we see that the effects of altruism for similar players can be beneficial in the presence of significant congestion, but excessive altruism may lead to underuse of the channel when demand is low

Critical behavior in an evolutionary Ultimatum Game

Experimental studies have shown the ubiquity of altruistic behavior in human societies. The social structure is a fundamental ingredient to understand the degree of altruism displayed by the members of a society, in contrast to individual-based features, like for example age or gender, which have been shown not to be relevant to determine the level of altruistic behavior. We explore an evolutionary model aiming to delve how altruistic behavior is affected by social structure. We investigate the dynamics of interacting individuals playing the Ultimatum Game with their neighbors given by a social network of interaction. We show that a population self-organizes in a critical state where the degree of altruism depends on the topology characterizing the social structure. In general, individuals offering large shares but in turn accepting large shares, are removed from the population. In heterogeneous social networks, individuals offering intermediate shares are strongly selected in contrast to random homogeneous networks where a broad range of offers, below a critical one, is similarly present in the population.Comment: 13 pages, 7 figure

Cooperation, Punishment, Emergence of Government, and the Tragedy of Authorities

Under the conditions prevalent in the late Pleistocene epoch (small hunter-gatherer groups and frequent inter-group conflicts), coevolution of gene-related behavior and culturally transmitted group-level institutions provides a plausible explanation for the parochial altruistic and reciprocator traits of most modern humans. When, with the agricultural revolution, societies became larger and more complex, the collective nature of the monitoring and punishment of norm violators was no longer effective. This led to the emergence of new institutions of governance and social hierarchies. The transition from an egalitarian society and the acceptance of the new institutions may have been possible only if, in the majority of the population, the reciprocator trait had become an internalized norm. However, the new ruling class has its own dynamics, which in turn may lead to a new social crisis. Using a simple model inspired by previous work by Bowles and Gintis, these effects are studied here

Game theory of mind

This paper introduces a model of ‘theory of mind’, namely, how we represent the intentions and goals of others to optimise our mutual interactions. We draw on ideas from optimum control and game theory to provide a ‘game theory of mind’. First, we consider the representations of goals in terms of value functions that are prescribed by utility or rewards. Critically, the joint value functions and ensuing behaviour are optimised recursively, under the assumption that I represent your value function, your representation of mine, your representation of my representation of yours, and so on ad infinitum. However, if we assume that the degree of recursion is bounded, then players need to estimate the opponent's degree of recursion (i.e., sophistication) to respond optimally. This induces a problem of inferring the opponent's sophistication, given behavioural exchanges. We show it is possible to deduce whether players make inferences about each other and quantify their sophistication on the basis of choices in sequential games. This rests on comparing generative models of choices with, and without, inference. Model comparison is demonstrated using simulated and real data from a ‘stag-hunt’. Finally, we note that exactly the same sophisticated behaviour can be achieved by optimising the utility function itself (through prosocial utility), producing unsophisticated but apparently altruistic agents. This may be relevant ethologically in hierarchal game theory and coevolution