" . . . it . . . was predicted that an interaction exists between social class and the nature of the incentive. Supecifically, it was believed that a nonmaterial incentive is as effective as a ...material incentive for middle-class Ss, whereas, for lower-class Ss a material incentive is more effective than a nonmaterial one." This belief was tested and results indicate that middle-class "children learn more quickly when given a nonmaterial incentive than when given a material incentive, while the reverse was true of lower-class children."
