  In spite of its relevance to the origin of complex networks, the interplay
between form and function and its role during network formation remains largely
unexplored. While recent studies introduce dynamics by considering rewiring
processes of a pre-existent network, we study network growth and formation by
proposing an evolutionary preferential attachment model, its main feature being
that the capacity of a node to attract new links depends on a dynamical
variable governed in turn by the node interactions. As a specific example, we
focus on the problem of the emergence of cooperation by analyzing the formation
of a social network with interactions given by the Prisoner's Dilemma. The
resulting networks show many features of real systems, such as scale-free
degree distributions, cooperative behavior and hierarchical clustering.
Interestingly, results such as the cooperators being located mostly on nodes of
intermediate degree are very different from the observations of cooperative
behavior on static networks. The evolutionary preferential attachment mechanism
points to an evolutionary origin of scale-free networks and may help understand
similar feedback problems in the dynamics of complex networks by appropriately
choosing the game describing the interaction of nodes.
