From Slavin (2009): "Intrinsic incentive: An aspect of an activity that people enjoy and, therefore, find motivating" (p. 312).

Lepper and colleagues (1973) found that "promising extrinsic rewards for an activity that is intrinsically interesting might undermine intrinsic interest by inducing children to expect a reward for doing what they had previously done for nothing" (p. 313). This may only be true for younger students.

Other research found that "the use of rewards more often increases intrinsic motivation especially when rewards are contingent on the quality of performance rather than on mere participation in an activity, when the rewards are seen as recognition of competence" (p. 313-314).

Intrinsic motivation can be enhanced by arousing interest, maintaining curiosity, using a variety of interesting presentation modes, and helping students set their own goals (p. 314-316).