Behavior change support systems (BCSS) are computer-based systems that support individuals to form, alter or reinforce cognitions, emotions, attitudes or behaviors without using coercion or deception. A virtual reality therapy system is an example of BCSS. It supports change by providing individuals with relevant therapeutic experiences. For more than 15 years Delft University of Technology is studying how this technology can be used in treating people with a fear of heights or a fear of flying. In recent years, research has extended to the treatment of social phobia and PTSD.

Besides offering experiences, change support can also be offered by virtual health agents. These virtual agents can provide health information, motivate people to continue with their change process, but also help individuals to reflect on their goals and progress made. Understanding the effect and acceptance of the adaptive mechanisms underlying these behavior change support systems is a key computer science challenge.