Volunteering leads to rock–paper–scissors dynamics in a public goods game

Abstract

Collective efforts are a trademark of both insect and human societies. They are achieved through relatedness in the former and unknown mechanisms in the latter. The problem of achieving cooperation among non-kin has been described as the 'tragedy of the commons', prophesying the inescapable collapse of many human enterprises. In public goods experiments, initial cooperation usually drops quickly to almost zero. It can be maintained by the opportunity to punish defectors or the need to maintain good reputation. Both schemes require that defectors are identified. Theorists propose that a simple but effective mechanism operates under full anonymity. With optional participation in the public goods game, 'loners' (players who do not join the group), defectors and cooperators will coexist through rock-paper-scissors dynamics. Here we show experimentally that volunteering generates these dynamics in public goods games and that manipulating initial conditions can produce each predicted direction. If, by manipulating displayed decisions, it is pretended that defectors have the highest frequency, loners soon become most frequent, as do cooperators after loners and defectors after cooperators. On average, cooperation is perpetuated at a substantial level.

Punish or perish? Retaliation and collaboration among humans

“…If players are told that they will be re-matched with the same co-players, or that their decisions will be made known, they often change their behaviour, obviously motivated by concerns for longer-lasting interactions or for reputation [50][51][52][53]. Similarly, if they can opt out of the Public Good game, or back into it, they base their decisions on the current state of the population and adapt rapidly [54]. Voluntary participation elicits a greater readiness to cooperate [55].…”

Payoff-based learning explains the decline in cooperation in public goods games

“…Different, and potentially more elaborate behavioural rules could be favoured in different scenarios allowing more behavioural flexibility [37,38].…”

Freedom, enforcement, and the social dilemma of strong altruism

“…(Only with this assumption does the joint effort turn into a venture.) In a finite population, cooperation evolves time and again, although it will then be quickly subverted by defection, which in turn gives way to non-participation (Hauert et al 2002a, b;Semmann et al 2003). If costly punishment of defectors is included in the game, then eventually one of the upsurges of cooperation will lead to a population dominated by punishers, and such a regime will last considerably longer before defectors invade again.…”