Currenty I have a number of collaborations with colleagues at the various Dutch universities participating in the "Executive Brain" project, .University of Kent (social guilt hypothesis), University of Edinburgh and Michigan State University(the male warrior hypothesis), Bristol University (evolutionary psychology of intergroup relations), University of Oxford (social laughter), University of Pennsylvania (evolution of leadership), University of Minnesota (evolutionary psychology of environmental sustainability), and Washington State University (book on social dilemmas)

Current collaborators include: University of Kent (Roger Giner Sorolla; Edward Cartwright), the University of Edinburgh (Dominic Johnson), the University of Bristol (Justin Park, Ian Penton-Voak), the University of Oxford (Robin Dunbar), University of Pennsylvania (Rob Kurzban), Michigan State Unversity (carlos Navarrete), University of Minnesota (Vladas Griskevicius), University of Georgia (Sarah Brosnan), Strassbourg University (Ronald Noe),Washington State University (Craig Parks)