Participants complete the Dynamic Emotional Identification Task, or DEIT (Wardle et al. 2012) following MDMA, oxytocin or placebo administration during which they identify emotional facial expressions presented on the screen. Participants completed this task once during each of the sessions. In the DEIT, 10 actors performed angry, fearful, sad, and happy expressions, for a total of 40 sequences, which were presented in random order. Each sequence consisted of 50 "frames" progressing from 0 to 100% emotional intensity at 2% steps, producing a color video of an emotional expression developing. Participants were instructed to "press the space bar as soon as you know what expression is being displayed." This ended the sequence and presented options of "angry," "fearful," "sad," and "happy." Perception of expressions was quantified as the intensity (0-100 %) of the face when the participant pressed the space bar for correctly identified sequences.