The present experiment was based on an earlier fMRI study (Krebs et al., 2012), by using a very similar version of the paradigm with some adjustments related to electroencephalography (EEG) methodology (Fig. 1). A central grey fixation square (0.5°) and two placeholder frames, one in the left and right visual field (6° lateral from fixation and 6° below fixation), were continuously present on a black background throughout the experiment. Each trial started with a centrally presented arrow cue (400 ms duration) predicting the target location (left or right), as well as reward availability and task difficulty. With respect to reward likelihood, cue color was either green or blue, indicating whether a fast correct answer was going to be rewarded or not. In addition, white or black squares in the center of these arrows specified the difficulty (high or low) of the upcoming task trial. Colors predicting reward (green and blue) and task difficulty (white and black) were counterbalanced across participants. To enable links to some earlier studies in this attentional-cueing field (e.g., Grent-’t-Jong and Woldorff, 2007), catch cues trials were
