Abstract
BACKGROUND: Game theory enables the predictive study of the behavior of agents that recognize the mutual interdependence of their decisions and act rationally and strategically to maximize their own gains. In this paper, the extractivism of pequi (Caryocar coriaceum Wittm.) and fava d'anta (Dimorphandra gardneriana Tul.) in an area of common use of the semiarid region of northeastern Brazil is described as a model to illustrate a practical application of game theory in the interpretation of the phenomena analyzed in ethnobiological research. METHODS: Field research was conducted in the Araripe-Apodi National Forest. Semi-structured interviews were conducted with 55 informants recognized as knowledgeable and experienced in the extractivism of pequi and fava d'anta in the region. In the interviews, information that could contribute to the identification and understanding of the focal points of extractivism in the region was surveyed. Data were analyzed under an analytical/descriptive approach using the "content analysis" technique. RESULTS: There was a logic of competitive entrepreneurship around the commercial extractivism of pequi and fava d'anta in the region. Among the extractivists of pequi, one of the main collection rules refers to the prohibition of removing immature fruits by using sticks or shaking the branches. In the extractivism of fava d'anta, no specific rules have been established by collectors, but there is a predominant behavior of withdrawing all available fruits (pods) on a tree in a single visit. In an analysis guided by game theory, the collection decisions adopted by extractivists to maximize gain from the activity can be considered justifiable from the standpoint of economic rationality. CONCLUSIONS: The "game of extractivism" of pequi and fava d'anta operates under conditions similar to the "tragedy of the commons." In this game, the non-cooperative solution is converted to the Nash equilibrium. The approach used in this study contributed to the identification of strategies and solutions to problems arising from the extractivism of pequi and fava d'anta.