In the year 2007 It was held the research project called “Measuring Trust, Trustworthiness and Pro-Sociality in Six Latin American Cities”: Bogotá, D.C, Buenos Aires, Caracas, Lima, Montevideo and San José de Costa Rica. The purpose of this study was to analyze the interaction between social exclusion and collective action in Latin America using a field experimental approach and examine some behavioral mechanisms and group outcomes regarding the possibilities for and limitations of collective action in groups. Specifically, it observed individuals facing problems of trust, collective action, and uncertainty under different levels of social heterogeneity and exclusion. The experimental setup was designed to measure individual attitudes in regard to Other-regarding preferences (Trust and reciprocity, cooperation and group formation), risk preferences (risk, ambiguity and loss aversion) and how the degree of group heterogeneity affects individual decisions and group outcomes. The set of experiments was based on four activities: a trust game, a public goods game, three games measuring individual attitudes in regard to risk, ambiguity, and losses, an a risk pooling game.