Relationship Development Intervention® (RDI) is a family-based, behavioral treatment designed to address autism’s core symptoms. Developed by psychologist Steven Gutstein, Ph.D., it builds on the theory that “dynamic intelligence” is key to improving quality of life for individuals with autism. Dr. Gutstein defines dynamic intelligence as the ability to think flexibly. This includes appreciating different perspectives, coping with change and integrating information from multiple sources (e.g. sights and sounds).