A Brookings Institution Press and MIT Press publicationHow do social structures and group behaviors arise from the interaction of individuals In this groundbreaking study Joshua M. Epstein and Robert L. Axtell approach this ageold question with cuttingedge computer simulation techniques. Such fundamental collective behaviors as group formation cultural transmission combat and trade are seen to emerge from the interaction of individual agents following simple local rules.In their computer model Epstein and Axtell begin the development of a bottom up social science. Their program named Sugarscape simulates the behavior of artificial people agents located on a landscape of a generalized resource sugar. Agents are born onto the Sugarscape with a vision a metabolism a speed and other genetic attributes. Their movement is governed by a simple local rule look around as far as you can find the spot with the most sugar go there and eat the sugar. Every time an agent moves it burns sugar at an amount equal to its metabolic rate. Agents die if and when they burn up all their sugar. A remarkable range of social phenomena emerge. For example when seasons are introduced migration and hibernation can be observed. Agents are accumulating sugar at all times so there is always a distribution of wealth.Next Epstein and Axtell attempt to grow a protohistory of civilization. It starts with agents scattered about a twinpeaked landscape over time there is selforganization into spatially segregated and culturally distinct tribes centered on the peaks of the Sugarscape. Population growth forces each tribe to disperse into the sugar lowlands between the mountains. There the two tribes interact engaging in combat and competing for cultural dominance to produce complex social histories with violent expansionist phases peaceful periods and so on. The protohistory combines a number of ingredients each of which generates insights of its own. One of these ingredients is sexual reproduction. In som