Conditional strategies and the evolution of cooperation in spatial public goods games

Abstract

The fact that individuals will most likely behave differently in different situations begets the introduction of conditional strategies. Inspired by this, we study the evolution of cooperation in the spatial public goods game, where besides unconditional cooperators and defectors, also different types of conditional cooperators compete for space. Conditional cooperators will contribute to the public good only if other players within the group are likely to cooperate as well, but will withhold their contribution otherwise. Depending on the number of other cooperators that are required to elicit cooperation of a conditional cooperator, the latter can be classified in as many types as there are players within each group. We find that the most cautious cooperators, such that require all other players within a group to be conditional cooperators, are the undisputed victors of the evolutionary process, even at very low synergy factors. We show that the remarkable promotion of cooperation is due primarily to the spontaneous emergence of quarantining of defectors, which become surrounded by conditional cooperators and are forced into isolated convex "bubbles" from where they are unable to exploit the public good. This phenomenon can be observed only in structured populations, thus adding to the relevance of pattern formation for the successful evolution of cooperation.

Evolution of emotions on networks leads to the evolution of cooperation in social dilemmas

“…In particular, evolutionary games in networks, spurred on by the seminal discovery of spatial reciprocity [12] and, subsequently, * szolnoki.attila@ttk.mta.hu by the discovery that scale-free networks strongly facilitate the evolution of cooperation [13,14], are still receiving ample attention to this day [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34]. One of the most recent contributions to the subject concerns the assignment of cognitive skills to individuals that engage in evolutionary games in networks [35,[38][39][40][41]. The earliest forerunners to these advances can be considered strategies such as "tit for tat" [42] and Pavlov [43], many of which were already proposed during the seminal experiments performed by Axelrod [44] and which assume that individuals have cognitive skills that exceed those granted to them in the framework of classical game theory.…”

Conditional Cooperation and Framing Effects

“…Similarly, Gächter, Kölle, and Quercia (2017) [11] found that framing the public good game as a Maintenance or a Provision problem affects the elicited contribution profiles. 5 Different kinds of framing effects have been shown to affect contributions in public good games (e.g., Andreoni 1995 [14]; Ellingsen et al, 2012 [15]; Dufwenberg et al 2011 [16]; Fosgaard, Hansen,Wengström, 2014 [17]; Nikiforakis, 2010 [18]). For an extensive list of references, see Cartwright (2016) [19].…”

“…In his essay on experimenter demand effects, Zizzo (2010, p. 85) [8] argued that the FGF method could overestimate the fraction of conditional cooperators in their sample by making subjects "think that conditionality was important". Although Zizzo (2010) [8] focused primarily on 1 For some recent theoretical contributions on the evolution of conditional cooperation, see Szolnoki and Perc (2012) [5], Szolnoki and Perc (2013) [6] and Zhang and Perc (2016) [7]. the possibility that the strategy method "may have clued in subjects that the experiment was about conditionality", a similar argument could be made about the ordering of others' contributions.…”

“…4 Since changes in the presentation of the contribution table do not affect material incentives in the game, the experiment constitutes a test of framing effects. 5 The three treatments, in particular, evaluate the impact of simultaneity and ordering of the average contributions of others using a between-subject design. The ORDERED treatment uses the same frame as FGF.…”

Selection of the distributional rule as an alternative tool to foster cooperation in a Public Good Game

“…The wide literature in Experimental and Behavioral Economics try to understand the reason behind this behavior which seems to characterize human being. Using different kind of games such as Prisoner Dilemma, Ultimatum Game and Public Good Game, it has been shown that subjects do not behave as an homo oeconomicus but they are, on average, altruist in a bilateral game or they behave as an homo reciprocans in a multi-player setting (Szolnoki and Perc (2012), Tian et al (2016), Fehr and Gächter (1998)). …”