CEU Research on Boosting Cooperation with Higher-Order Interactions Published in Nature Human Behavior

A new study in Nature Human Behavior by CEU Department of Network and Data Science Assistant Professor Federico Battiston and a team of international colleagues sheds new light on the importance of social networks to understand prosocial behavior. Battiston’s research emerges from the inquiry: If a self-oriented option appears the most rewarding, why does one cooperate at all?

By applying ideas from the new theory of 'networks beyond pairwise interactions', Battiston and colleagues generalize the framework of evolutionary game theory on networks beyond dyadic games, proposing a new theory to boost cooperation in real, large and structured human societies.

Battiston notes that large-scale human cooperation is a fascinating puzzle from day-to-day interactions to greater endeavors such as volunteering to enlist for war. In such cases, humans routinely put aside individual interest in favor of a common good. Past pioneering work has shown the importance of kinship relations to sustain prosocial behavior in small-scale societies, showing that one is willing to pay a cost not only for one’s own benefit, but also for that of a person who shares one’s genes. This mechanism alone, however, is not able to provide a satisfactory answer to cooperative phenomena in much larger societies, such as organizations or nations. 

As one lives and cooperates in networks, a foundational pillar of large-scale cooperation is driven by the structure of one’s social relationships. Scientists have shown that repeated games between the same pairs of individuals support the creation of robust mutual interactions based on trust even among unrelated individuals, despite that the temptation to defect would prove to be more rewarding in a single individual round. The discovery of this mechanism almost 30 years ago, called network reciprocity, spurred significant further research at the boundary of evolutionary game theory and network science. Battiston expands on the idea that the exact architecture of one’s social network can significantly affect prosocial behavior. For instance, with a highly heterogenous distribution of social contacts, the increased clustering between individuals, or of shortcuts in the network can significantly boost cooperation in human populations.

To date, most investigations have focused so far on dilemmas where interactions are limited to pairs of individuals connected by the links of a network, such as the “prisoner's dilemma”. Battiston and colleagues go further, generalizing the framework of evolutionary game theory on networks beyond dyadic games, therefore becoming relevant to cases which occur at the level of groups. This is, for instance, the scenario of taxes for welfare state, which are beneficial from an individual perspective only if most individuals of a population are willing to contribute, and the numbers of free riders is limited. Such more complex dilemmas are typically described by public goods game. Traditional networks, intrinsically limited to dyadic interactions among agents fall short to provide an adequate representation of these 'higher-order' interactions, where larger groups of people interact. However, the use of different mathematical representations such as hypergraphs successfully capture the richness of these systems. In this way, Battiston and colleagues were able to formally describe the evolutionary dynamics of higher-order interactions, and unveil how going beyond the dyad can boost prosocial behavior in our society.

Read the new study in Nature Human Behavior, published on January 4, 2020, on boosting cooperation with higher-order interactions.