Participatory simulations are conducted to improve our knowledge of human behaviors, to help in solving conflicts, to shape interaction protocols between humans and to teach some aspects of collective management. Agent-based participatory simulations differ from other kinds of participatory simulations including role playing games and experimental economics simulations. The control architecture of the agents, in these simulations, is more or less integrally replaced by a human player and the interactions between players are limited by the communication protocols designed for the agents, usually the exchange of electronic messages logged for further analysis. Such systems can be considered as ideal multi-agent systems featuring cognitive and intelligent agents. Previous work demonstrated that running this kind of simulations helps to design and improve multi-agent simulations. In this paper, we present a series of agent-based participatory experiments studying negotiation in an abstract case of common resource pool management. The roles were designed in such a way that conflicts should emerge during the negotiations. Observing the behavior of human players, we noticed the apparition of power relations between players. We observed that this power in negotiations was unrelated to any a priori dependence between agents or between roles but was instead drawn from strategies and, more surprisingly, this power was built on an emerging ontology.