publicaciones seleccionadas artículo Payments for Ecosystem Services and Motivational Crowding in Colombia's Amazon Piedmont 2019 Prosocial Behavior and Subjective Insecurity in Violent Contexts: Field Experiments 2016 documento de trabajo Ending Ecoservices Payments Does Not Crow Out Lab-in-the Field Forest Conservation 2022 Effects of Ending Payments for Ecosystem Services: removal does not crowd prior conservation out 2020