Consequences of multiple simultaneous opportunities to exploit others’ efforts on free riding

Abstract

Individuals within a group do not all act in the same way: Typically, the investors (or producers) put efforts into producing resources while the free riders (or scroungers) benefit from these resources without contributing. In behavioral ecology, the prevalence of free riders can be predicted by a well-known game-theoretical model-the producer-scrounger (PS) model-where group members have the options to either search for resources (producers) or exploit the efforts of others (scroungers). The PS model has received some empirical support, but its predictions, surprisingly, are based on the strict assumption that only one resource can be exploited at a time.Yet, multiple simultaneous opportunities to exploit others' efforts should frequently occur in nature. Here, we combine analytic and simulation approaches to explore the effect of multiple simultaneous scrounging opportunities on tactic use. Our analyses demonstrate that scrounging rates should increase with the number of simultaneous opportunities. As such, the amount and spatial distribution (i.e., clumped vs. dispersed) of resources as well as the risk of predation are key predictors of scrounging behavior. Because scroungers contribute to reducing the speed of resource exploitation, the model proposed here has direct relevance to the exploitation and sustainability of renewable resources. K E Y W O R D Sevolutionary stable strategy, game theory, producer-scrounger game, simultaneous scrounging opportunities, stochastic effects

To produce or not to produce? Contrasting the effect of substance abuse in social decision-making situations

“…However, only a statistically significant correlation between the producer index and the RMM model was observed for the SUD group. This was expected since very few studies report close results to quantitative predictions [ 31 ] One of the reasons is that the RMM model does not consider the possibility of finding multiple patch zones [ 23 ]. In our task, as in natural conditions, the participants can simultaneously produce multiple patch zones.…”

“…Secondly, the Producer-Scrounger Game suggests that group members choose one of two mutually exclusive strategies, which in combination enable the group survival: (a) invest time searching for their resources (Produce), and (b) join a previously discovered patch zone (Scrounge). The Producer-Scrounger Game describes the optimal proportion of producers and scroungers within a group or responses that reaches an Evolutionarily Stable Strategy [ [21] , [22] , [23] ]. If all group members tended to scrounge, they wouldn't get the resources needed to survive, showing a non-optimal behavior; if all the group members tended to produce, they would not resist the arrival of a new member with a different strategy, also showing a non-optimal behavior.…”