Anne Fleur Kortekaas-Rijlaarsdam

CHAPTER 6 126 MPH effects The main effect of entry level was significant ( t (177.7)=12.10, p <.001, d =.29, showing that within the ADHD group entry level was predictive of the finally achieved math level. The main effect of condition was significant ( t (157.8)=2.6, p =.008, d =.25, indicating that children in the ADHD group performed better on the math task in the motivation condition compared to the neutral condition. The main effect of treatment was not significant ( t (161.9)=1.04, p =.298) when entry level was taken into account, indicating that MPH did not improve math performance over and above entry level performance, independent of condition. Interaction between Rewarded Feedback and MPH There was no treatment*condition interaction ( t (157.8)=-.51, p =.609) when entry level was taken into account, indicating that MPH did not affect the ability to profit from a motivational condition on a math task. Rewarded feedback resulted in +.59 higher achieved math level during placebo and MPH treatment resulted in +.57 higher entry level compared to placebo. Together, rewarded feedback and MPH treatment resulted in an increase in achieved math level of 1.03 (from 7.00 with placebo in the neutral condition to 8.03 with MPH in the motivation condition). This difference was significant ( t (62)=4.25, p <.001, d =.54), implying that the combination of rewarded feedback and MPH treatment resulted in better math performance than either treatment alone. Achieved math level and entry level were not influenced by medication sequence (placebo versus active medication), thus ruling out carryover effects (all p s>.50). D I SCUSS I ON Our results illustrated the positive effects of a motivational condition on math performance. The finding that rewarded feedback improved math performance in both children with ADHD and TD children, emphasizes the potential educational value of simple, task related positive feedback coupled to small rewards on math performance. This finding is in line with previous findings of positive effects of feedback and reward on math performance in TD children (Dihoff et al., 2004; Luwel et al., 2011; Narciss & Huth, 2006) and is in line with theories about the effects of positive feedback, intrinsic motivation and task persistence on task interest and performance (Deci et al., 1999). These results are promising, as this type of rewarded feedback (a smile from the teacher, a praise or applause or thumbs up, a sticker) is the type that is most commonly given by teachers. Further, on the longer term (in actual classrooms), the use of reward and feedback may further increase motivation to learn, increase feelings of self-