The Impact of Altruism on the Efficiency of Atomic Congestion Games

Caragiannis, Ioannis; Kaklamanis, Christos; Kanellopoulos, Panagiotis; Kyropoulou, Maria; Papaioannou, Evi

doi:10.1007/978-3-642-15640-3_12

Cited by 29 publications

(90 citation statements)

References 19 publications

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“…1 Our general framework makes it an easy observation that 1 The altruism model of Caragiannis et al [2010] differs from ours in a slight technicality discussed in Section 3 (see Remark 3.2). Therefore, various bounds we cite here are stated differently in Caragiannis et al [2010].…”

Section: Our Contributions and Resultsmentioning

confidence: 98%

“…(1) For atomic congestion games with linear cost functions, Caragiannis et al [2010] derived a tight bound of 5+4α 2+α…”

Section: Our Contributions and Resultsmentioning

confidence: 99%

“…Caragiannis et al [2010] studied a nearly identical model of altruism in atomic congestion games. Several of our present results and models generalize results of Caragiannis et al [2010], and we discuss them in more detail in the corresponding sections of this article.…”

Section: Subsequent Workmentioning

confidence: 99%

See 2 more Smart Citations

Altruism and Its Impact on the Price of Anarchy

Chen

Keijzer

Kempe

et al. 2014

ACM Trans. Econ. Comput.

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We study the inefficiency of equilibria for congestion games when players are (partially) altruistic. We model altruistic behavior by assuming that player i's perceived cost is a convex combination of 1 − α i times his direct cost and α i times the social cost. Tuning the parameters α i allows smooth interpolation between purely selfish and purely altruistic behavior. Within this framework, we study primarily altruistic extensions of (atomic and nonatomic) congestion games, but also obtain some results on fair cost-sharing games and valid utility games.We derive (tight) bounds on the price of anarchy of these games for several solution concepts. Thereto, we suitably adapt the smoothness notion introduced by Roughgarden and show that it captures the essential properties to determine the robust price of anarchy of these games. Our bounds show that for atomic congestion games and cost-sharing games, the robust price of anarchy gets worse with increasing altruism, while for valid utility games, it remains constant and is not affected by altruism.However, the increase in the price of anarchy is not a universal phenomenon: For general nonatomic congestion games with uniform altruism, the price of anarchy improves with increasing altruism. For atomic and nonatomic symmetric singleton congestion games, we derive bounds on the pure price of anarchy that improve as the average level of altruism increases. (For atomic games, we only derive such bounds when cost functions are linear.) Since the bounds are also strictly lower than the robust price of anarchy, these games exhibit natural examples in which pure Nash equilibria are more efficient than more permissive notions of equilibrium.

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Section: Our Contributions and Resultsmentioning

confidence: 98%

“…(1) For atomic congestion games with linear cost functions, Caragiannis et al [2010] derived a tight bound of 5+4α 2+α…”

Section: Our Contributions and Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Altruism and Its Impact on the Price of Anarchy

Chen

Keijzer

Kempe

et al. 2014

ACM Trans. Econ. Comput.

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“…Already for these simple models it has been observed in a series of papers [5,7,8] that altruistic behavior can actually be harmful in the sense that the price of anarchy may increase as players become more altruistic. This observation served as a starting point for the investigations conducted in this paper.…”

Section: Introductionmentioning

confidence: 99%

“…All these models are special cases of the one studied here. Among these articles, the inefficiency of equilibria in the presence of altruistic/spiteful behavior was studied for various games in [5,[7][8][9]14]. After its introduction in [22], the smoothness framework has been adapted in various directions [23][24][25], including an extension to a particular model of altruism in [8], which constitutes a special case of the altruistic games considered here.…”

Section: Introductionmentioning

confidence: 99%

Inefficiency of Games with Social Context

et al. 2015

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Abstract. The study of other-regarding player behavior such as altruism and spite in games has recently received quite some attention in the algorithmic game theory literature. Already for very simple models, it has been shown that altruistic behavior can actually be harmful for society in the sense that the price of anarchy may increase as the players become more altruistic. In this paper, we study the severity of this phenomenon for more realistic settings in which there is a complex underlying social structure, causing the players to direct their altruistic and spiteful behavior in a refined player-specific sense (depending, for example, on friendships that exist among the players). Our findings show that the increase in the price of anarchy is modest for congestion games and minsum scheduling games, whereas it is drastic for generalized second price auctions.

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The Impact of Tribalism on Social Welfare

Han

Soloviev

Wang

2019

Algorithmic Game Theory

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We explore the impact of mutual altruism among the players belonging to the same set -their tribe -in a partition of all players in arbitrary strategic games upon the quality of equilibria attained. To this end, we introduce the notion of a τ -tribal extension of an arbitrary strategic game, in which players' subjective cost functions are updated to reflect this, and the associated Price of Tribalism, which is the ratio of the social welfare of the worst Nash equilibrium of the tribal extension to that of the optimum of social welfare. We show that in a well-known game of friendship cliques, network contribution games as well as atomic linear congestion games, the Price of Tribalism is higher than the Price of Anarchy of either the purely selfish players or fully altruistic players (i.e. ones who seek to maximise the social welfare). This phenomenon is observed under a variety of equilibrium concepts. In each instance, we present upper bounds on the Price of Tribalism that match the lower bounds established by our example.

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The Impact of Altruism on the Efficiency of Atomic Congestion Games

Cited by 29 publications

References 19 publications

Altruism and Its Impact on the Price of Anarchy

Altruism and Its Impact on the Price of Anarchy

Inefficiency of Games with Social Context

The Impact of Tribalism on Social Welfare

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