This section in the Wiki analyzes social behavior. Although other organisms are social, we humans are uniquely social, living in large groups of distantly-related yet cooperating individuals, and in our reliance on culture for survival. Theories of Cultural Evolution are the extension of evolutionary theory to cultural change. Since our capacity for culture evolved genetically, and genetic evolution has not stopped, genetic and cultural evolution operate simultaneously, demanding a theory of Genetic-Cultural Coevolution.
Of course, the main advantage in living in a social group is the opportunity for Cooperation. Traditionally this is regarded as so obvious as to often go unstated. A controversial aspect of evolutionary theory as applied to culture is its use to explain and predict various forms of conflict (failure to cooperate.) We do not see this viewpoint as in any way undermining the virtue or predominance of cooperation; what we do see is a subtle argument that the maintenance of cooperation is more difficult than often supposed, and that numerous aspects both of human instinct and culture work together to make this cooperation possible.
Of course, the main advantage in living in a social group is the opportunity for Cooperation.