Information Cascades and the Collapse of Cooperation

Abstract

in various types of structured communities newcomers choose their interaction partners by selecting a role-model and copying their social networks. participants in these networks may be cooperators who contribute to the prosperity of the community, or cheaters who do not and simply exploit the cooperators. For newcomers it is beneficial to interact with cooperators but detrimental to interact with cheaters. However, cheaters and cooperators usually cannot be identified unambiguously and newcomers' decisions are often based on a combination of private and public information. We use evolutionary game theory and dynamical networks to demonstrate how the specificity and sensitivity of those decisions can dramatically affect the resilience of cooperation in the community. We show that promiscuous decisions (high sensitivity, low specificity) are advantageous for cooperation when the strength of competition is weak; however, if competition is strong then the best decisions for cooperation are risk-adverse (low sensitivity, high specificity). Opportune decisions based on private and public information can still support cooperation but suffer of the presence of information cascades that damage cooperation, especially in the case of strong competition. our research sheds light on the way the interplay of specificity and sensitivity in individual decision-making affects the resilience of cooperation in dynamical structured communities. Cooperation is widespread in the real world and can be observed at different scales of biological organization, ranging from genes to multi-cellular organisms and socio-technological systems 1-4. However, cooperators pay a cost to benefit others. The extent to which cooperators can thrive within the system apparently contradicts the idea that only selfish behaviors are rewarded during competition between individuals. The resilience of cooperation has been approached in different domains 5 and evolutionary game theory 6-8 provides a framework for studying the evolution of cooperation among unrelated individuals. The Prisoner's Dilemma (PD) in particular has been widely employed for investigating the sustainability of cooperation. The prisoner's dilemma stresses the key point of the conflict of interest between what is best for the individual and what is best for the group, and thus creates a social dilemma. To solve the dilemma, several mechanisms have been suggested to facilitate the spreading of cooperation such as direct reciprocity, indirect reciprocity, kin selection, group selection, and graph selection or spatial reciprocity, etc. 2. Much work has been dedicated to the spreading of cooperation in structured populations and networks, where the promotion of cooperation is associated with the formation of cooperative clusters 9-12. In this paper we use evolutionary game theory to study a model of dynamical networks to understand how attachment choices cascade down the generations and lead, or not, to a collapse of cooperation. In this model, when a new node (newcomer) joins the network, i...

Opinion Diversity and the Resilience of Cooperation in Dynamical Networks

“…This paper aims to expand upon the work previously carried out by Yang et al [17]. The results presented in [17] demonstrate how the presence of public and private information available to nodes can affect which nodes they formed connections with.…”

“…This paper aims to expand upon the work previously carried out by Yang et al [17]. The results presented in [17] demonstrate how the presence of public and private information available to nodes can affect which nodes they formed connections with. In [17], potential neighbours that a newcomer can form connections with are limited to those that its chosen role model is currently connected to.…”

“…The results presented in [17] demonstrate how the presence of public and private information available to nodes can affect which nodes they formed connections with. In [17], potential neighbours that a newcomer can form connections with are limited to those that its chosen role model is currently connected to. Node prosperity is used by newcomers when selecting a role model, which can indicate which nodes are performing well.…”

“…These pieces of information are utilised as part of a newcomer's decision-making process to determine if it should form a connection with a potential neighbour. In this sense, the approach proposed in [17] and extended here is different from classical voter models [18]. In this case, individuals do not change their opinions based on the opinions of others, but rather use the available public and private information available to make a decision about connecting to potential partners.…”

“…In the model studied in [17], each node shares the same values when carrying out decision making, i.e., the same τ value used to perceive if a potential neighbour is trustworthy. However, it is likely that individuals within a network possess a more diverse range of opinions, some individuals are cautious whilst others are more trusting than their peers.…”