This communication aims at discussing the interest of Sociology and Policy Science to answer research questions on the institutional economics research agenda on Ecosystem Services concept and on one of its tools: Payment for Environmental Services (PES). Through case studies at international level and in different countries (Costa Rica and Madagascar), we argue that policy transfer studies (PTS), Advocacy Coalition Framework (ACF), Path Dependency Framework (PDF) and Multiple Stream Framework (MSF) could provide a signif icant insight to understand PES program diffusion worldwide, form and characteristics of PES functioning in developing countries.