Evaluation of Out of Africa hypotheses by means of agent-based modeling

According to the Out of Africa theory early hominins originated in Africa subsequently dispersing into Eurasia. At least two dispersal events are documented, during which Pleistocene hominins left the African continent. Out of Africa 1 refers to the early hominin dispersal prior to Homo sapiens (e.g. Homo erectus/ergaster) while Out of Africa 2 deals with the dispersal of H. sapiens. Many hypotheses try to explain why early hominins dispersed beyond the African continent. Suggested causes include factors such as climate, geography, vegetation, demography, competition, ecology and cognition. However, no attempt has been made yet to model the hypotheses' mechanisms explicitly in order to compare them on a quantitative scale. We therefore explore the potential of agent-based modeling. An agent-based model consists of the acting entities, the so-called agents, an environment and rules of interaction among them. We analyzed the most common Out of Africa hypotheses and systematically formalized them by aid of an agent-based modeling framework. Our results show that the most common Out of Africa hypotheses can be attributed to at least four different scenarios. We refer to the scenarios as environmental, demographic, resource driven, ecology and cognition based scenarios. Our study provides a framework that helps designing agent-based models with respect to the dispersal of early hominins out of the African continent.