Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
We experimentally analyze cooperation in blended groups, where some group members stay together (partners) and others are switching groups (strangers). Our results reveal that teams consisting partly of members with strangers display a lower productivity compared to teams of permanent group members only. First, strangers cooperate less than partners in blended groups. Second, individual effort decisions increase with the number of group mates who are of the same type. This second effect holds for both strangers and partners and is neither driven by beliefs nor conditional willingness to cooperate. We argue that social identity plays a role here depending on group composition and the individuals’ role in a group.