WP3 focuses on, matching mechanisms. Research considers the extent to which these mechanisms can be used to improve social cooperation between heterogenous agents in terms of public good provision and in the case of uncertainty. The mechanisms will be tested using experimental methods. In the framework of public good games, the mechanisms will be applied to certain situations of social dilemma. In the first stage of the game, agents are able to decide how great their personal, conditional contribution to the public good will be. In the second stage, the 'matching mechanism' will be enforced in order to alter the marginal prices of the public good. Agents will subsequently decide on a final private contribution to be made to the public good. The aim of the WP is to examine how far 'matching mechanisms' can be used in dynamic negotiation processes in order to foster social cooperation.