To better understand memory processing during trauma, hydrocortisone and/or yohimbine (a stimulator of central norepinephrine) will be administered to healthy adults in two experiments in order to pharmacologically model the stress response. Following infusion, participants will hear a story with emotional and nonemotional segments in one experiment (N = 80) and emotional as well as nonemotional stimuli (faces and scenes) in another experiment (N = 80). It is predicted that relative to the placebo, hydrocortisone will impair memory for both emotional and nonemotional information, yohimbine will improve memory for both types of information, and the combination of hydrocortisone and yohimbine will enhance memory for emotional aspects and impair memory for the nonemotional segments of the story. Results from this study will permit a better understanding of how emotionally charged memories are encoded and will potentially lead to treatments to mitigate the psychological effects of traumatic exposure.