Social behaviors, which are exemplified by mutualism, cooperation, or altruism, are widespread in the natural world and form the basis of human sociality. The aim of this project is to study several aspects of the evolutionary dynamics (Darwinian dynamics) of these behaviors from a theoretical perspective, by using mathematical models and computer simulations.Organisms are characterized by genotypes made of thousands of interacting genes (i.e., multilocus genotypes). But a social behavior, like any other behavior, is not determined by genotype alone. The behavior may also be learned socially (culturally transmitted), or learned individually by exploration during an individual's lifetime. Moreover, populations of individuals tend to be stratified and consist of several levels of interacting groups of individuals. The evolution of a social behavior is thus a complicated dynamical process, which involves multilocus genetics, multifactorial inheritance, and multilevel selection processes. This complexity is often neglected in current formalizations attempting to understand the evolution of social behaviors in humans and other species.The research proposes to study the evolution of social behaviors by trying to take this complexity into account. To that aim, models into three distinct but complementary directions will be developed. First, in order to improve our understanding of the selective pressure on genetically determined social behaviors, we will construct and analyze a series of multilocus models of social behaviors. Second, in order to improve our understanding of the interactions between the innate, socially learned and individually learned aspect of social behaviors, we will construct a series of gene-culture coevolutionary models of social and individual learning of social behaviors. Third, in order to improve our understanding of the transition from small-scale homogeneous social groups, to larger-scale stratified social groups, we will construct a series of models aiming at clarifying the role played by kinship ties, cultural transmission, and technological factors for the evolution of resource transfer between classes of individuals.Social behaviors have biological roots; and it is through the interaction of these behaviors with culture that social groups may have increased in their scale and complexity to the level that we observe today. By taking into account both genetic and cultural transmission, the different modeling parts of this research project is an attempt at providing a more unified and complete approach to understanding the evolution of sociality.