Affective feedback during a self-assessment test could help induce the learner to an optimal emotional state regarding the learning material. However, there is a lack of experimental evidence concerning the influence of affective feedback during a self-assessment test. This paper is a step towards this direction. The effect of achievement-based reward feedback on students' state and trait anxiety was examined. Ninety-two students participated in an experiment. Half of these students received an applause sound after a correct answer to a question. Results highlight gender differences concerning this emotional type of feedback.