Efficiency, Equality and Reciprocity in Social Preferences: A Comparison of Students and a Representative Population.

The debate between Engelmann and Strobel (2004, 2006) and Fehr, Naef, and Schmidt (2006) highlights the important question of the extent to which lab experiments on student populations can serve to identify the motivational forces present in society at large. We address this question by comparing the lab behavior of a student group and a non-student group, where the non-student group on all observable factors is almost identical to the representative adult population in Norway. All participants take part in exactly the same lab experiment. Our study shows that students may not be informative of the role of social preferences in the broader population. We nd that the representative participants differ fundamentally from students both in their level of selfishness and in the relative importance assigned to different moral motives. It is also interesting to note that while we do not find any substantial gender differences among the students, males and females in the representative group differ fundamentally in their moral motivation.