Preferential partner selection in an evolutionary study of Prisoner's Dilemma

Abstract

Partner selection is an important process in many social interactions, permitting individuals to decrease the risks associated with cooperation. In large populations, defectors may escape punishment by roving from partner to partner, but defectors in smaller populations risk social isolation. We investigate these possibilities for an evolutionary prisoner's dilemma in which agents use expected payoffs to choose and refuse partners. In comparison to random or round-robin partner matching, we find that the average payoffs attained with preferential partner selection tend to be more narrowly confined to a few isolated payoff regions. Most ecologies evolve to essentially full cooperative behavior, but when agents are intolerant of defections, or when the costs of refusal and social isolation are small, we also see the emergence of wallflower ecologies in which all agents are socially isolated. In between these two extremes, we see the emergence of ecologies whose agents tend to engage in a small number of defections followed by cooperation thereafter. The latter ecologies exhibit a plethora of interesting social interaction patterns. Partner selection is an important process in many social interactions, permitting individ uals to decrease the risks associated with cooperation. In large populations, defectors may escape punishment by roving from partner to partner, but defectors in smaller populations risk social isolation. We investigate these possibilities for an evolutionary prisoner's dilemma in which agents use expected payoffs to choose and refuse partners. In comparison to random or round-robin partner matching, we find that the average payoffs attained with preferential partner selection tend to be more narrowly confined to a few isolated payoff regions. Most ecologies evolve to essentially full cooperative behavior, but when agents are intolerant of defections, or when the costs of refusal and social isolation are small, we also see the emer gence of wallflower ecologies in which all agents are socially isolated. In between these two extremes, we see the emergence of ecologies whose agents tend to engage in a small number of defections followed by cooperation thereafter. The latter ecologies exhibit a plethora of interesting social interaction patterns. Disciplines

The prisoner’s dilemma on co-evolving networks under perfect rationality

“…Few, but promising works have brought forward research towards this end in the recent years: In [22], players keep a running average of payoffs obtained from each other player in a simulated tournament. These averages effectively determine whom to approach and whom to accept as co-player in the future.…”

Friendship, cliquishness, and the emergence of cooperation

“…Existing work on partner-choice models suggests that they have a number of advantages over the canonical formulation (Batali and Kitcher, 1995;de Vos et al, 2001;de Vos and Zeggelink, 1997;Hauk, 2001;Hayashi and Yamagishi, 1998;Peck, 1993;Sherratt and Roberts, 1998;Skyrms and Pemantle, 2000;Stanley et al, 1994). First, when partner choice is permitted, strategies can often rapidly achieve high levels of cooperation, even when the cooperative strategies are not initially common (Ashlock et al, 1996). Second, partner choice may resolve the problem of cyclical invasions in a changing ecology of strategies (de Vos et al, 2001;Sherratt and Roberts, 1998).…”

Chapter 21 ACE Models of Endogenous Interactions

“…Although the firms do not know anything about this, they immediately spot the difference in the value of advertising in the latter setup, avoiding it almost completely, whereas high signaling levels are reached in the standard version. Ashlock et al (1996): (threshold) expected payoff Ashlock et al (1996) study the effect of preferential partner selection in an evolutionary study of the prisoner's dilemma game. The Prisoner's Dilemma game studied is a standard two-player simultaneous-move game in which each player can decide to Cooperate or to Defect with the resulting payoffs being as follows: payoffs for mutual cooperation and mutual defection are 3 and 1 respectively, while a unilateral defector gets a payoff of 5, and the sucker payoff equals 0.…”

“…The time-structure of the ACE model of Ashlock et al (1996) is shown in Figure 9. For a given generation of agents, there are 150 rounds.…”

“…Riolo (1997) studies the effects and evolution of tag-mediated selection of partners in populations playing the Iterated Prisoner's Dilemma (IPD) game, analyzing exactly the same basic Prisoner's Dilemma (PD) game as Ashlock et al (1996).…”