The US has over 7 million individuals with intellectual and developmental disabilities (I/DD). I/DD are a set of disabilities that negatively affect an individual's ability to learn, reason, solve problems, and learn social or life skills. Examples of I/DD include Down Syndrome, Williams Syndrome, and Autism. A significant number of people with I/DD have experienced trauma at some point in their lives, which can cause them to experience a lot of negative side effects, such as depression, grief, and anxiety; further, these feelings might be triggered during everyday life events. This means that people with I/DD need therapy or other help to deal with their trauma. However, there are not enough therapists who are trained to help this community. The research for this project will design virtual reality (VR) worlds that help traumatized adults with I/DD to help themselves. The idea is not to provide them therapy—that requires a professional—but to use the power of VR to help adults with I/DD take their attention away from negative thoughts when they are triggered. Ideas that will come out of this research have the potential to develop coping approaches for everyone, including people without I/DD, by creating readily accessible VR-based tools for self-regulation. <br/><br/>This project will design VR-mediated technologies that empower adults with I/DD to engage in independent post-trauma self-regulation (PTSR) to cope with the negative effects of trauma. The novelty of this work stems from leveraging the notion of trauma-informed care from the field of social work to the design of human-centered technology in the domain of VR technologies for self-regulation. The main idea behind trauma-informed care is to consider the role of trauma and its lingering effects in the lives of individuals who have experienced it, using that awareness to design care practices to avoid situations that retraumatize or trigger them. The project aims to perform trauma-informed care-based design of VR technologies for self-regulation by: (1) understanding how adults in the I/DD community engage in PTSR; (2) understanding to what extent VR environments are accessible to the I/DD community, which heretofore has not been systematically explored; (3) co-designing and prototyping with adults with I/DD a VR-mediated PTSR application; and (4) conducting a two-month pilot study to evaluate the usability, accessibility, and user experience of the prototype. The research will result in the dissemination of recommendations for building accessible self-regulation and VR experiences for adults with I/DD, as well as a case study of applying trauma-informed care to technology design.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.