In 1969, David Lewis used the nascent theory of games to argue that semantic meaning can be conve... more In 1969, David Lewis used the nascent theory of games to argue that semantic meaning can be conventional. Imagine a situation in which the world can be in one of two states. An agent, the sender, observes the actual state and then sends a message to a second agent, the receiver. The receiver cannot directly observe the state but does perform some action after observing the sender’s message. Both players are paid off if and only if the receiver performs an action appropriate for the state of the world. Lewis noted that if, for example, signal A is sent only in state one, and the receiver responds to signal A by performing the action appropriate for state one, then it looks like signal A has come to mean something like ‘state one has occurred’ or ‘perform the action appropriate for state one’. However, because Lewis was limited to techniques available at the time, he was unable to provide a thorough account of how agents adopt conventions. In single chapters of earlier books, Skyrms ([1996], [2004]) introduced an approach for joining Lewis’s signalling game with modern approaches to game theory, namely, those based on evolutionary dynamics and theories of Brit. J. Phil. Sci. 64 (2013), 883–887
We use evolutionary game theory to study the evolution of harming behavior (spite) in settings in... more We use evolutionary game theory to study the evolution of harming behavior (spite) in settings involving both tags and (anti-)correlated interaction. Our results show an interesting interaction between these mechanisms. The presence of tags shows that pure spite is less likely to evolve when theoretically expected, but that conditional spite is more likely than expected. Moreover, we identify a novel tag-based equilibrium where spite occurs within but not between groups. We discuss implications for the evolution of spite, punishment, and the methodological approach of using exogenous parameters to represent (anti-)correlated interactions.
Recent models using simple signaling games provide a theoretical setting for investigating the ev... more Recent models using simple signaling games provide a theoretical setting for investigating the evolutionary connection between signaling and behavioral plasticity. These models have shown that plasticity is typically eliminated in common-interest signaling games. In many real cases of signaling, however, interests do not align. Here, I present a model of the evolution of plasticity in signaling games and consider games of common, opposed, and partially aligned interests. I find that the setting of partial common interest is most conducive to the evolution of plasticity. Plastic individuals succeed by learning when to deceive others and when to trust others’ signals.
Spite, the shady relative of altruism, involves paying a fitness cost to inflict a cost on some r... more Spite, the shady relative of altruism, involves paying a fitness cost to inflict a cost on some recipient. Here, we investigate a density dependent dynamic model for the evolution of spite in populations of changing size. We extend the model by introducing a dynamic carrying capacity. Our analysis shows that it is possible for unconditionally spiteful behavior to evolve without population structure in any finite population. In some circumstances spiteful behavior can contribute to its own stability by limiting population growth. We use the model to show that there are differences between spite and altruism, and to refine Hamilton's original argument about the insignificance of spite in the wild. We also discuss the importance of fixing the measure of fitness to classify behaviors as selfish or spiteful.
We examine contemporary game-theoretic accounts of ownership as a convention. New results from dy... more We examine contemporary game-theoretic accounts of ownership as a convention. New results from dynamic networks complicate matters, suggesting that if ownership is conventional, it should not be as prevalent as it seems to be. In fact, such models reveal a tendency toward antiownership norms. The value of resources may be crucial: low stakes lead to conventional ownership, but ownership norms rarely evolve; high stakes lead to a predominance of ownership at the cost of its conventionality. We argue that conventional ownership norms can originate in nonconventional ways and discuss some philosophical implications.
There are circumstances in which we want to predict a series of interrelated events. Faced with s... more There are circumstances in which we want to predict a series of interrelated events. Faced with such a prediction task, it is natural to consider logically inconsistent predictions to be irrational. However, it is possible to find cases where an inconsistent prediction has higher expected accuracy than any consistent prediction. Predicting tournaments in sports provides a striking example of such a case and I argue that logical consistency should not be a norm of rational predictions in these situations.
Journal of Experimental and Theoretical Artificial Intelligence, Sep 1, 2012
ABSTRACT Equilibrium concepts in game theory can be justified as the outcomes of some plausible l... more ABSTRACT Equilibrium concepts in game theory can be justified as the outcomes of some plausible learning rules. Some scholars have sought a deeper kind of justification arguing that learning rules which do not find equilibria of a game will not be evolutionarily successful. This article presents and examines a model of evolving learning rules. The results are mixed for learning rules that lead to equilibria, showing that they are often successful, but not strongly stable. It is also shown that evolved learning rules, when taken in isolation, may not lead to equilibria. This is a case of reflexive modelling; where game theoretic models are used to assess other features of game theory. I argue that it is possible for reflexive modelling to provide a weak form of justification, but that it falls short in this case.
In 1969, David Lewis used the nascent theory of games to argue that semantic meaning can be conve... more In 1969, David Lewis used the nascent theory of games to argue that semantic meaning can be conventional. Imagine a situation in which the world can be in one of two states. An agent, the sender, observes the actual state and then sends a message to a second agent, the receiver. The receiver cannot directly observe the state but does perform some action after observing the sender’s message. Both players are paid off if and only if the receiver performs an action appropriate for the state of the world. Lewis noted that if, for example, signal A is sent only in state one, and the receiver responds to signal A by performing the action appropriate for state one, then it looks like signal A has come to mean something like ‘state one has occurred’ or ‘perform the action appropriate for state one’. However, because Lewis was limited to techniques available at the time, he was unable to provide a thorough account of how agents adopt conventions. In single chapters of earlier books, Skyrms ([1996], [2004]) introduced an approach for joining Lewis’s signalling game with modern approaches to game theory, namely, those based on evolutionary dynamics and theories of Brit. J. Phil. Sci. 64 (2013), 883–887
We use evolutionary game theory to study the evolution of harming behavior (spite) in settings in... more We use evolutionary game theory to study the evolution of harming behavior (spite) in settings involving both tags and (anti-)correlated interaction. Our results show an interesting interaction between these mechanisms. The presence of tags shows that pure spite is less likely to evolve when theoretically expected, but that conditional spite is more likely than expected. Moreover, we identify a novel tag-based equilibrium where spite occurs within but not between groups. We discuss implications for the evolution of spite, punishment, and the methodological approach of using exogenous parameters to represent (anti-)correlated interactions.
Recent models using simple signaling games provide a theoretical setting for investigating the ev... more Recent models using simple signaling games provide a theoretical setting for investigating the evolutionary connection between signaling and behavioral plasticity. These models have shown that plasticity is typically eliminated in common-interest signaling games. In many real cases of signaling, however, interests do not align. Here, I present a model of the evolution of plasticity in signaling games and consider games of common, opposed, and partially aligned interests. I find that the setting of partial common interest is most conducive to the evolution of plasticity. Plastic individuals succeed by learning when to deceive others and when to trust others’ signals.
Spite, the shady relative of altruism, involves paying a fitness cost to inflict a cost on some r... more Spite, the shady relative of altruism, involves paying a fitness cost to inflict a cost on some recipient. Here, we investigate a density dependent dynamic model for the evolution of spite in populations of changing size. We extend the model by introducing a dynamic carrying capacity. Our analysis shows that it is possible for unconditionally spiteful behavior to evolve without population structure in any finite population. In some circumstances spiteful behavior can contribute to its own stability by limiting population growth. We use the model to show that there are differences between spite and altruism, and to refine Hamilton's original argument about the insignificance of spite in the wild. We also discuss the importance of fixing the measure of fitness to classify behaviors as selfish or spiteful.
We examine contemporary game-theoretic accounts of ownership as a convention. New results from dy... more We examine contemporary game-theoretic accounts of ownership as a convention. New results from dynamic networks complicate matters, suggesting that if ownership is conventional, it should not be as prevalent as it seems to be. In fact, such models reveal a tendency toward antiownership norms. The value of resources may be crucial: low stakes lead to conventional ownership, but ownership norms rarely evolve; high stakes lead to a predominance of ownership at the cost of its conventionality. We argue that conventional ownership norms can originate in nonconventional ways and discuss some philosophical implications.
There are circumstances in which we want to predict a series of interrelated events. Faced with s... more There are circumstances in which we want to predict a series of interrelated events. Faced with such a prediction task, it is natural to consider logically inconsistent predictions to be irrational. However, it is possible to find cases where an inconsistent prediction has higher expected accuracy than any consistent prediction. Predicting tournaments in sports provides a striking example of such a case and I argue that logical consistency should not be a norm of rational predictions in these situations.
Journal of Experimental and Theoretical Artificial Intelligence, Sep 1, 2012
ABSTRACT Equilibrium concepts in game theory can be justified as the outcomes of some plausible l... more ABSTRACT Equilibrium concepts in game theory can be justified as the outcomes of some plausible learning rules. Some scholars have sought a deeper kind of justification arguing that learning rules which do not find equilibria of a game will not be evolutionarily successful. This article presents and examines a model of evolving learning rules. The results are mixed for learning rules that lead to equilibria, showing that they are often successful, but not strongly stable. It is also shown that evolved learning rules, when taken in isolation, may not lead to equilibria. This is a case of reflexive modelling; where game theoretic models are used to assess other features of game theory. I argue that it is possible for reflexive modelling to provide a weak form of justification, but that it falls short in this case.
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