Analyses of the accuracy data yielded a main effect of reward (F(1,21)=14.03, p=0.001) with more correct responses for reward trials (M = 90 %, SD = 4 %) as compared with no-reward trials (M = 87 %, SD = 4 %). Unsurprisingly, accuracy was higher when the discrimination task was easy (M = 95 %, SD = 5 %) than when it was difficult (M = 81%, SD = 3 %; F(1,21)=234.38, p<0.001). No significant interaction of reward and task difficulty was found for task accuracy (F(1,21)=1.689, p=0.27). All these results are in line with the behavioral effects of the previous fMRI version of this task (Krebs et al., 2012).
