The developmental, individual-difference, relationship-based model (DIR), a theoretical and applied framework for comprehensive intervention, examines the functional developmental capacities of children in the context of their unique biologically based processing profile and their family relationships and interactive patterns. As a functional approach, it uses the complex interactions between biology and experience to understand behavior and articulates the developmental capacities that provide the foundation for higher order symbolic thinking and relating. During spontaneous 'floor time' play sessions, adults follow the child's lead utilizing affectively toned interactions through gestures and words to move the child up the symbolic ladder by first establishing a foundation of shared attention, engagement, simple and complex gestures, and problem solving to usher the child into the world of ideas and abstract thinking. This process is illustrated by a case example of a young boy on the autism spectrum interacting with his father during 'floor time' over a 3 year period.