Altruism has both an evolutionary and a psychological meaning. As the term is used in evolutionary theory, a trait is deemed altruistic if it reduces the fitness of the actor and enhances the fitness of someone else. In its psychological sense, the thesis that we have altruistic ultimate motives asserts that we care about the welfare of others, not just as a means of enhancing our own well-being, but as an end in itself. In Unto Others (hereafter UO), we consider (...) both evolutionary altruism (Part I) and psychological altruism (Part II) from an evolutionary perspective. We propose a multilevel selection theory to explain how altruism can evolve from group selection, based on Darwin’s solution to the problem. Our presentation of multilevel selection theory expands the range of topics beyond altruism in other respects as well. In Part I1 of UO, we evaluate the arguments, both conceptual and empirical, that philosophers and psychologists have advanced in an attempt to choose between psychological egoism and motivational pluralism. We conclude that these arguments are inconclusive. (shrink)

Philosophers and social scientists have recently turned to Lewis sender–receiver games to provide an account of how lexical terms can acquire meaning through an evolutionary process. However, the evolution of meaning is contingent on both the particular sender–receiver game played and the choice of evolutionary dynamic. In this paper I explore some differences between models that presume an infinitely large and randomly mixed population and models in which a finite number of agents communicate with their neighbors in a social network. (...) My results show that communication with neighbors is more conducive to the evolution of meaning than communication with strangers. Additionally, I show that the behavior of the system is highly dependent on the topological structure of the social network. I argue that a specific class of networks—small world graphs—is especially conducive to the evolution of meaning. This is because small world graphs have a short characteristic path length while still maintaining a high degree of correlation between neighbors. Since many actual social networks, such as friendship networks and nervous systems, are conjectured to be small world structures, these results indicate that these networks are quite hospitable to the efficient evolution of meaning. (shrink)

Public reason theories are characterized by three conditions: constructivism, representation, and stability. Constructivism holds that justification does not rely on any antecedent moral or political values outside of the procedure of agreement. Representation holds that the reasons for the choice in the model must be rationally explicable to real agents outside the model. Stability holds that the principles chosen in the procedure should be stable upon reflection, especially in the face of diversity in a pluralistic society. Choice procedures that involve (...) at least two-stages with different information, as Rawls’s theory does, will be path-dependent and not meet the condition of representation since it will not be globally coherent. Attempts to solve this problem without eliminating the segmentation of choice in the procedure will run afoul of constructivism or stability. This problem is instructive because it highlights how public reason theories must evolve in the face of increased concerns about diversity. (shrink)

The partial cooperation displayed by subjects in the Centipede Game deviates radically from the predictions of traditional game theory. Even standard, infinite population, evolutionary settings have failed to provide an explanation for this behavior. However, recent work in finite population evolutionary models has shown that such settings can produce radically different results from the standard models. This paper examines the evolution of partial cooperation in finite populations. The results reveal a new possible explanation that is not open to the standard (...) models and gives us reason to be cautious when employing these otherwise helpful idealizations. *Received January 2007; revised November 2007. †To contact the author, please write to: Department of Logic and Philosophy of Science, University of California, 3151 Social Science Plaza A, Irvine, CA 92697-5100; e-mail: [email protected]. (shrink)

Pre‐play signals that cost nothing are sometimes thought to be of no significance in interactions which are not games of pure common interest. We investigate the effect of pre‐play signals in an evolutionary setting for Assurance, or Stag Hunt, games and for a Bargaining game. The evolutionary game with signals is found to have dramatically different dynamics from the same game without signals. Signals change stability properties of equilibria in the base game, create new polymorphic equilibria, and change the basins (...) of attraction of equilibria in the base game. Signals carry information at equilibrium in the case of the new polymorphic equilibria, but transient information is the basis for large changes in the magnitude of basins of attraction of equilibria in the base game. These phenomena exemplify new and important differences between evolutionary game theory and game theory based on rational choice. (shrink)

There are two fundamental problems for instituting a social contract. The first is cooperating to produce a surplus; the second is deciding how to divide this surplus. I represent each problem by a simple paradigm game, a Stag Hunt game for cooperating to produce a surplus, and a bargaining game for its division. I will discuss these simple games in isolation, and end by discussing their composition.

How does Sober-Wilson group selection explain the possibility of the evolution of altruism, as modeled by cooperation in the Prisoner’s Dilemma? The essential point is that if the parameters of the model are just right, group structure can generate positive correlation of interactions between cooperators. If positive correlation is strong enough, cooperation can evolve; if not it cannot. This is true whether the positive correlation is generated by a group selection model or in some other way.

We use game theoretic models to take an in-depth look at the dynamics of discrimination and academic collaboration. We find that in collaboration networks, small minority groups may be more likely to end up being discriminated against while collaborating. We also find that discrimination can lead members of different social groups to mostly collaborate with in-group members, decreasing the effective diversity of the social network. Drawing on previous work, we discuss how decreases in the diversity of scientific collaborations might negatively (...) affect the progress of epistemic communities. (shrink)

Intersectionality theory explores the special sorts of disadvantage that arise as the result of occupying multiple disadvantaged demographic categories. One significant methodological problem for the quantitative study of intersectionality is the difficulty of acquiring data sets large enough to produce significant results when one is looking for intersectional effects. For this reason, we argue, simulation methods may be particularly useful to this branch of theorizing because they can generate precise predictions and causal dependencies in a relatively cheap way, and can (...) thus guide future empirical work. We illustrate this point through models which show that intersectional oppression can arise under conditions where social groups are disadvantaged in the emergence of bargaining norms. As we show, intersectional disadvantage can arise even when actors from all social categories are completely identical in terms of preferences and abilities. The conditions necessary to derive such disadvantage are relatively minimal. And when actors behave in ways that reflect stronger intersectional identities, the potential for disadvantage increases. (shrink)

Bruner shows that in cultural interactions, members of minority groups will learn to interact with members of majority groups more quickly—minorities tend to meet majorities more often as a brute fact of their respective numbers—and, as a result, may come to be disadvantaged in situations where they divide resources. In this paper, we discuss the implications of this effect for epistemic communities. We use evolutionary game theoretic methods to show that minority groups can end up disadvantaged in academic interactions like (...) bargaining and collaboration as a result of this effect. These outcomes are more likely, in our models, the smaller the minority group. They occur despite assumptions that majority and minority groups do not differ with respect to skill level, personality, preference, or competence of any sort. Furthermore, as we will argue, these disadvantaged outcomes for minority groups may negatively impact the progress of epistemic communities. (shrink)

Bruner shows that in cultural interactions, members of minority groups will learn to interact with members of majority groups more quickly—minorities tend to meet majorities more often as a brute fact of their respective numbers—and, as a result, may come to be disadvantaged in situations where they divide resources. In this paper, we discuss the implications of this effect for epistemic communities. We use evolutionary game theoretic methods to show that minority groups can end up disadvantaged in academic interactions like (...) bargaining and collaboration as a result of this effect. These outcomes are more likely, in our models, the smaller the minority group. They occur despite assumptions that majority and minority groups do not differ with respect to skill level, personality, preference, or competence of any sort. Furthermore, as we will argue, these disadvantaged outcomes for minority groups may negatively impact the progress of epistemic communities. (shrink)

Recent years have seen increased interest in the question of whether it is possible to provide an evolutionary game-theoretic explanation for certain kinds of social norms. I sketch a proof of a general representation theorem for a large class of evolutionary game-theoretic models played on a social network, in hope that this will contribute to a greater understanding of the long-term evolutionary dynamics of such models, and hence the evolution of social norms.

Applications of game theory to moral philosophy are impededby foundational issues and troublesome examples. In the first part of this paper,questions are raised about the appropriate game-theoretical frameworks for applications to moralphilosophy and about the proper interpretations of the theoretical devices employed inthese frameworks. In the second part, five examples that should be of particular interest to thoseinterested in the connections between ethics and game theory are delineated and discussed. Thefirst example comprises games in which there is an outcome unanimously (...) preferred to the``solution'' of the game, appropriately defined. The second comprises games whose solution callsfor different players to employ different strategies. The third comprises games whosesolution calls for players to adopt mixed strategies. The fourth comprises games whose solutionrequires players to cycle among a variety of strategies. The fifth comprises games whose solutionrequires players to discriminate in morally inappropriate ways. (shrink)

The Baldwin effect is a process by which learnt traits become gradually incorporated into the genome through a Darwinian mechanism. From its inception, the Baldwin effect has been regarded with skepticism. The objective of this paper is to relativize this assessment. Our contribution is two-fold. To begin with, we provide a taxonomy of the different arguments that have been advocated in its defense, and distinguish between three justificatory dimensions—feasibility, explanatory relevance and likelihood—that have been unduly conflated. Second, we sharpen the (...) debate by providing an evolutionary game theoretic perspective that is able to generalize previous results. The upshot of this paper is that the mechanism envisaged by Baldwin is less puzzling than commonly thought. (shrink)

Methodological individualism has a long, successful, and controversial track record in the social sciences. Its record in ecology is much shorter but proving as successful and controversial with so-called individual-based models. Distinctions and debates about methodological individualism in social sciences clarify the commitments of this general, individualistic approach to modeling ecological phenomena and show that there is a lot recommending it. In particular, a representational priority on individual organisms yields a cogent albeit deflationary account of ecological emergence and helps reveal (...) how quite disparate models and theories in ecology might be unified. (shrink)

What I call "strategic injustice" involves a set of formal and informal regulatory rules and conventions that often lead to grossly unfair outcomes for a class of individuals despite their resistance. My goal in this paper is to provide the necessary conditions for such injustices and for eliminating their instances from our social practices. To do so, I follow Peter Vanderschraaf's analysis of circumstances of justice and expand his account by embedding "asymmetric conflictual coordination games" that summarize fair division problems (...) in a dynamic social network. I use the network effect on such coordination games to explain the emergence of stable exploitative behavior and conventions by a class of individuals even in the presence of restraining efforts by others. I conclude that such unfair conventions are resilient to uncoordinated individual actions and interventions. In fact, maintaining a rough equality itself turns into another coordination problem. Finally, I show that something similar to a social movement that restructures the network of social relations is necessary to solve such coordination problems. (shrink)

Understanding the dynamics of information is crucial to many areas of research, both inside and outside of philosophy. Using computer simulations of three kinds of information, germs, genes, and memes, we show that the mechanism of information transfer often swamps network structure in terms of its effects on both the dynamics and the fitness of the information. This insight has both obvious and subtle implications for a number of questions in philosophy, including questions about the nature of information, whether there (...) is genetic information, and how to arrange scientific communities. (shrink)

Group-structured populations, of the kind prominent in discussions of multilevel selection, are contrasted with ‘neighbor-structured’ populations. I argue that it is a necessary condition on multilevel description of a selection process that there should be a nonarbitrary division of the population into equivalence classes (or an approximation to this situation). The discussion is focused via comparisons between two famous problem cases involving group structure (altruism and heterozygote advantage) and two neighbor-structured cases that resemble them. Conclusions are also drawn about the (...) role of correlated interaction in the evolution of altruism. 1 Introduction 2 Two Kinds of Population Structure 3 Objections and Replies 4 Particles on a Line 5 Conclusion Appendix: Neighborhoods and Selection CiteULike Connotea Del.icio.us What's this? (shrink)

Group-structured and neighbor-structured populations are compared, especially in relation to multilevel selection theory and evolutionary transitions. I argue that purely neighborstructured populations, which can feature the evolution of altruism, are not properly described in multilevel terms. The ability to “gestalt switch” between individualist and multilevel frameworks is then linked to the investigation of “major transitions” in evolution. Some explanatory concepts are naturally linked to one framework or the other, but a full understanding is best achieved via the use of both.

Recent work on the evolution of social contracts and conventions has often used models of bargaining games, with reinforcement learning. A recent innovation is the requirement that every strategy must be invented either through through learning or reinforcement. However, agents frequently get stuck in highly-reinforced “traps” that prevent them from arriving at outcomes that are efficient or fair to the both players. Agents face a trade-off between exploration and exploitation, i.e. between continuing to invent new strategies and reinforcing strategies that (...) have already become highly reinforced by yielding high rewards. In this paper I systematically study the relationship between rates of invention and the efficiency and fairness of outcomes in two-player, repeated bargaining games. I use a basic reinforcement learning model with invention, and five variations of this model, designed introduce various forms of forgetting, to prioritize more recent reinforcement, or to maintain a higher rate of invention. I use computer simulations to investigate the outcomes of each model. Each models shows qualitative similarities in the relationship between the efficiency and fairness of outcomes, and the relative amount of exploration or exploitation that takes place. Surprisingly, there are often trade-offs between the efficiency and the fairness of the outcomes. (shrink)

Human beings are highly irrational, at least if we hold to an economic standard of ‘rationality’. Experimental economics studies the irrational behavior of human beings, with the aim of understanding exactly how our behavior deviates from the Homo economicus, as ‘rational man’ has been called. Insofar as philosophical theories depend upon rationality assumptions, experimental economics is the source of both problems and (at least potential) solutions to several philosophical issues. This article offers a programmatic and highly biased survey of some (...) of these issues, with the hope of convincing the reader that experimental economics is well-deserving of careful study by philosophers. (shrink)

Many societies have norms of equity – that those who make symmetric social contributions deserve symmetric rewards. Despite this, there are widespread patterns of social inequity, especially along gender and racial lines. It is often the case that members of certain social groups receive greater rewards per contribution than others. In this article, we draw on evolutionary game theory to show that the emergence of this sort of convention is far from surprising. In simple cultural evolutionary models, inequity is much (...) more likely to emerge than equity, despite the presence of stable, equitable outcomes that groups might instead learn. As we outline, social groups provide a way to break symmetry between actors in determining both contribution and reward in joint projects. (shrink)

Recently, philosophers have investigated the emergence and evolution of the social contract. Yet extant work is limited as it focuses on the use of simple behavioral norms in rather rigid strategic settings. Drawing on axiomatic bargaining theory, we explore the dynamics of more sophisticated norms capable of guiding behavior in a wide range of scenarios. Overall, our investigation suggests the utilitarian bargaining solution has a privileged status as it has certain stability properties other social arrangements lack.

At the very end of the 19th century, Gabriele Tarde wrote that all society was a product of imitation and innovation. This view regarding the development of society has, to a large extent, fallen out of favour, and especially so in those areas where the rational actor model looms large. I argue that this is unfortunate, as models of imitative learning, in some cases, agree better with what people actually do than more sophisticated models of learning. In this paper, I (...) contrast the behaviour of imitative learning with two more sophisticated learning rules (one based on Bayesian updating, the other based on the Nash-Brown-von Neumann dynamics) in the context of social deliberation problems. I show for two social deliberation problems, the Centipede game and a simple Lewis sender-receiver game, that imitative learning provides better agreement with what people actually do, thus partially vindicating Tarde. (shrink)

Cheap talk has often been thought incapable of supporting the emergence of cooperation because costless signals, easily faked, are unlikely to be reliable (Zahavi and Zahavi, 1997). I show how, in a social network model of cheap talk with reinforcement learning, cheap talk does enable the emergence of cooperation, provided that individuals also temporally discount the past. This establishes one mechanism that suffices for moving a population of initially uncooperative individuals to a state of mutually beneficial cooperation even in the (...) absence of formal institutions. (shrink)

A computer simulation runs a model generating a phenomenon under investigation. For the simulation to be explanatory, the model has to be explanatory. The model must be isomorphic to the natural system that realizes the phenomenon. This paper elaborates the method of assessing a simulation's explanatory power. Then it illustrates the method by applying it to two simulations in game theory. The first is Brian Skyrms's (1990) simulation of interactive deliberations. It is intended to explain the emergence of a Nash (...) equilibrium in a noncooperative game. The second is Skyrms's (2004) simulation of the evolution of cooperation. It is intended to explain cooperation in assurance games. The final section suggests ways of enhancing the explanatory power of these simulations. (shrink)

In this paper, completely uncoupled dynamics for n-player bargaining are proposed that mirror key behavioral elements of early bargaining and aspiration adjustment models. Individual adjustment dynamics are based on directional learning adjustments, solely driven by histories of own realized payoffs. Bargaining this way, all possible splits have positive probability in the stationary distribution of the process, but players will split the pie almost equally most of the time. The expected waiting time for almost equal splits to be played is quadratic.