5,132 readers of the German weekly, "Die Zeit", participated in a three-person bargaining experiment. In our data analysis we focus on (1) the influence of age, gender, profession and medium chosen for participation and (2) the external validity of student behaviour (inside and outside the lab). We find that older participants and women care more about equal distributions and that Internet users are more self-regarding than those using mail or fax. Decisions made by students in the lab are rather similar to those made by participants in the newspaper experiment, indicating a high degree of external validity of student data. Copyright 2007 The Author(s). Journal compilation Royal Economic Society 2007.