  Inclusive Fitness Theory (IFT) was proposed half a century ago by W.D.
Hamilton to explain the emergence and maintenance of cooperation between
individuals that allows the existence of society. Contemporary evolutionary
ecology identified several factors that increase inclusive fitness, in addition
to kin-selection, such as assortation or homophily, and social synergies
triggered by cooperation. Here we propose an Extend Inclusive Fitness Theory
(EIFT) that includes in the fitness calculation all direct and indirect
benefits an agent obtains by its own actions, and through interactions with kin
and with genetically unrelated individuals. This formulation focuses on the
sustainable cost/benefit threshold ratio of cooperation and on the probability
of agents sharing mutually compatible memes or genes. This broader description
of the nature of social dynamics allows to compare the evolution of cooperation
among kin and non-kin, intra- and inter-specific cooperation, co-evolution, the
emergence of symbioses, of social synergies, and the emergence of division of
labor. EIFT promotes interdisciplinary cross fertilization of ideas by allowing
to describe the role for division of labor in the emergence of social
synergies, providing an integrated framework for the study of both, biological
evolution of social behavior and economic market dynamics.
