(with Heidi Colleran) “We propose to implement a lab-in-the-field study on the island of Malekula, Vanuatu, to investigate cooperation within a heterogenous society. Vanuatu, per capita the most linguistically diverse country on earth, provides a perfect case in multiculturalism featuring unique variation in regional, tribal, religious, and linguistic group markers but a high degree of homogeneity in other socio-economic determinants of human behavior. Building on extensive ethnographic work, we adapt standard behavioral games to the specifics of the field site allowing for novel insights on multiple competing identities, research that is only possible in such a society where not only multiple identities exist but where they also matter differently in different contexts. To this end, we elicit with whom individuals prefer to interact, their choices, and their beliefs about others’ behavior while varying the salience of one or another of the existing multi-level identities. While Vanuatu represents a rather unique environment, inferences from a society where diversity is enshrined in various aspects of life will be crucial to understand the effects of identities in a more and more diverse world.”