Emergence of altruistic behavior with common words through natural selection

Abstract: How and why did human being acquire the ability of verbal communication? To consider the problem concerned with the origin of a verbal communication, we should consider why verbal communication brings a profit for the survival of individuals. In our previous study we examined the condition under which common words to express objects emerge among agents who pursue their own profit by computer simulations. The results indicated that the word which points out an object and a cooperative relation emerges, when agents can obtain more profit from the object by cooperation. However, neither a word nor a cooperative relation for non-profitable objects such as a predator was emerged. Then, what kind of environmental condition brings altruistic behaviors among agents? In the previous study the duplication and death of agents were determined by a comparative assessment. In this study we examine whether altruistic behavior with common words emerges without mutual mimicry of words among agents when agents are evaluated by an absolute assessment. The result suggests that selection of agents by absolute evaluation brings altruistic behaviors, however, stable cooperative behavior with common words emerges under only narrow range of selection pressure