Motivation brought to the test: Successful retrieval practice is modulated by mastery goal orientation and external rewards

We investigated how learners' motivation impacts the testing effect for complex study materials. High mastery goal orientation was expected to weaken the effect, while external rewards for successful retrieval practice were expected to strengthen it. Two experiments (N = 191) compared restudy, retrieval practice, and retrieval practice with external reward in a between-subject design. We assessed delayed retention after 1 week. Both experiments revealed a testing effect. Learners' mastery goal orientation moderated the effect in both experiments. It was strong in students with low mastery goal orientation and absent in those with high mastery goal orientation. The external reward failed to enhance the testing effect in Experiment 1, but boosted it in Experiment 2 with more specific criteria for “successful retrieval practice.” In Experiment 2, the reward increased students' retrieval practice effort, improving delayed retention. These results suggest that students' motivation to practice retrieval and to restudy are important boundary conditions for the testing effect.