Key points are not available for this paper at this time.
Bella M. DePaulo, John Tang, William Webb, Claudia Hoover, Kerry Marsh, Carol Litowitz, Age Differences in Reactions to Help in a Peer Tutoring Context, Child Development, Vol. 60, No. 2 (Apr., 1989), pp. 423-439
DePaulo et al. (Sat,) studied this question.