Key points are not available for this paper at this time.
Peter L. Callero, Judith A. Howard, Jane A. Piliavin, Helping Behavior as Role Behavior: Disclosing Social Structure and History in the Analysis of Prosocial Action, Social Psychology Quarterly, Vol. 50, No. 3 (Sep., 1987), pp. 247-256
Callero et al. (Tue,) studied this question.