Modes of Information Transmission, in Complex Network Topologies, on the Stability of Cooperation Ivette C. Mart´ınez Grupo de Inteligencia Artificial Universidad Sim´ on Bol´ıvar, Venezuela Klaus Jaffe Departamento de Biolog´ıa de Organismos Universidad Sim´ on Bol´ıvar, Venezuela 1 Introduction Cooperative behavior is the base on which social behavior can emerge. Biologists, economists, computer scien- tists and physicists have all worked to further our understanding of human and animal cooperation. Yet different premises underlay these efforts. The main difference among them is the assumption that social behavior arrived through biological evolution among animals, and that culture and rational decision-making is a principal driver of the evolution of cooperation and sociality among humans (Richardson et al., 2004). Human cooperation seems to be molded by both, cultural and biological forces (Kurzban & Houser, 2005). Biological evolution, on the other hand, is thought to be based mainly on genetic information transmitted through genes from parents to offsprings. Nevertheless, using theories for biological evolution has provided a fertile ground to study the dynamics of pro- cesses governed by cultural evolution, such as human cooperation (Hammerstein, 2003) and economics (Nelson & Winter, 1982) Important differences exist between the dynamics of cultural evolution (Richardson et al., 2004) and bio- logical evolution (Nowak & Sigmund, 2004). Although both processes are often mixed up and lumped together when studying the evolution of cooperation, as done in (Nowak & Sigmund, 2005). One important feature differ- entiating systems driven by biological (BE) and cultural evolution (CE) is the direction of information transmis- sion. The transmission of information in BE is mainly vertical (heredity), and that in CE is horizontal (imitation of behavior of peers, including parents). This feature affects the dynamics of information transmission, and explains important differences in the dynamics between both types of evolution (Jaffe & Cipriani, 2006). Several mechanisms have been proposed to explain the emergence and maintenance of cooperation in biological terms. Hamilton (Hamilton, 1964) explains cooperation between relatives through “kin selection”; in which donor and recipient of a cooperative action are genetic relatives. among the mechanisms that have been proposed to explain cooperation between unrelated individuals we may recall: Direct reciprocity (Axelrod & Hamilton, 1981; Trivers, 1971), indirect reciprocity (Nowak & Sigmund, 1998), altruistic punishment (Fehr & Gachter, 2002), direct economics forces favoring cooperative groups (Jaffe, 2002a; Lehmann & Keller, 2006), and optimizing variance through assortative forces (Jaffe, 2002b; Ochoa & Jaffe, 2006).