Emotional gambling task design. Participants observed their partner performing an emotional gambling task through a monitor displaying the task. Two boxes, labeled A and B (angle of field, 2.62° × 3.59°; interval between boxes, 2.76°), were displayed on each of their monitors. Each time their partner presses a button to choose either A or B, an emotional negative or positive image is presented 500 ms after the choice on only the partner’s monitor and simultaneously a sad or happy face symbol is presented on the participant’s monitor. Each valence (positive or negative) trial was performed 100 times, respectively, and a total of 200 images or face symbols were presented. EEG Amp = electroencephalogram amplifier; ERP = event-related potentials.