 Stress and early adversity have been found to influence immune function via enhanced expression of the conserved transcriptional response to adversity CTRA genetic profile. Expression of this genetic profile was reduced in adults who completed a prosocial behavior intervention. This project aims to implement this intervention in adolescents. 90 high school students will be recruited and assigned to one of three groups 30group. Participants will either conduct 3 acts of kindness for themselves, conduct 3 acts of kindness for others, or report about their day 3 times per week for 4 weeks. During this intervention, they will receive text messages 3 days per week instructing them to complete their respective act. Participants will provide a brief description of this act that evening, as well as complete brief surveys at the end of the week for each week of the intervention. Participants will come into the lab twice, once before and once after the 4-week intervention. During these lab sessions participants will complete survey measures, have their heart rate measured, and have a blood draw conducted by a trained phlebotomist. Participants parents will also complete a brief survey to provide demographic information and an idea of what prosocial behaviors participants witnessed in their home. We will use these data to assess the effects of prosocial behavior on health and the psychological mechanisms underlying these effects. At the second study visit, participants will be given the opportunity to donate part of their study payment to a charity to measure prosociality. Any donations will be vetted with the psychology departments accounting group prior to making any donations in the universitys name. Scott Monatlik, Director, Tax and Information Practices, at or 310 794-6724 will be contacted and information regarding the appropriate steps to take to ensure that the donation is made to an acceptable charity prior to any donations. Actual helping behavior donations is measured to provide an ecologically valid experimental evaluation of prosociality rather than traditional metrics of computerized, fictional giving. Conceptual frameworks from developmental and health psychology guide the hypothesis that prosocial behavior will influence adolescents. 