Albeit of subordinate priority, we also analyzed the ERPs elicited by the target stimuli. No significant differences between conditions were detected in the mean amplitudes of the early P1 and N1 components (all p-values>0.1). A significant interaction (F(1,21)=4.88, p=0.04) was obtained for the P2 component. This interaction is explained by a larger difference between high-difficulty and low-difficulty targets in reward trials (with a more positive wave for low-difficulty reward trials) compared to the same contrast for no-reward trials. However, this interaction effect related to P2 amplitude should be viewed as more exploratory considering that it would not survive a Bonferroni correction that takes all five ERP components into account that were analyzed here (resulting in a threshold of p<0.01). Subsequently, a more negative N2 deflection was observed for targets in no-reward trials, revealed by a main effect of reward (F(1,21)=11.31, p=0.003). The main effect of task difficulty (F(1,21)=1.61, p=0.22) and the interaction (F(1,21)<1) did not reach significance for these components. For the P3 component, a main effect of reward was observed (F(1,21)=23.65, p<0.001, see figure 4A), with a larger amplitude
