Aim 1: To test the behavioral effects of tDCS during social rejection. The first step will be to obtain behavioral effects of transcranial direct current stimulation (tDCS) during social rejection without functional magnetic resonance imaging (fMRI). Whereas previous studies used Cyberball (a computerized ball-tossing game that simulates social exclusion), we will use the Social Feedback Task. This task was created by Dr. Hsu to be more ethologically-relevant, has been shown to sustain negative moods during rejection and activates the right ventral lateral prefrontal cortex (rVLPFC) (preliminary fMRI data from 50 healthy controls in Dr. Hsu's previous study). Anodal tDCS will be applied over the right or left VLPFC to measure changes in mood during rejection and neutral conditions. Depending on results, alternate regions in separate subjects may also be stimulated: dorsolateral prefrontal cortex, insula, anterior cingulate cortex, pre-supplementary, and supplementary motor area [all regions may be right or left hemisphere]. All of these regions have been shown to be involved in emotion regulation. Questionnaires will be given before, during, and after the task to assess cognitive and emotional states.