## 7 Discussion  
As we have seen in the reviewed literature, there are two primary means of eliciting proper reactions from individuals with ASD, one using virtual reality technologies, and the other using social robotic technologies. The former typically relies on one or more avatars to serve as an agent to communicate with a participant, while the latter uses a robot. Virtual reality has two advantages over robotics: (1) both the avatar and the virtual scenes can be changed dynamically that fit the treatment scenarios, while a robot cannot easily change its appearance and the treatment environments cannot be changed easily; (2) the virtual reality based systems can be much cheaper than robots. Hence, unless the cost of robots is reduced drastically, virtually reality based systems could be more attractive to home-based uses. That said, robotic based solutions provide physical embodiment, which is not possible for virtual reality based systems. This advantage may lead to better generalization of skills learned in treatment sessions to the real-world scenarios, although this speculation has yet to be proven in clinical trials. For virtual reality based systems, even though it is desirable to render 3D views to a participant, which could potentially increase the treatment effectiveness and transferability to real-world skills, the use of head-mounted displays or virtual reality goggles might not be suitable for all individuals with ASD because some are more prone to cyber sickness. This concern is also applicable for wearable devices that take physiological data from a participant. Another observation is that the current autism studies have predominately focused on treatment programs that target a specific set of social skills. Although temporary improvements in social skills for individuals with ASD have been observed, it is doubtful such improvements can last and can be generalized. More importantly, such training programs do not address the psychological and emotion issues for individuals (especial for children and adolescents) with ASD. What is urgently needed for an individual with ASD is a life coach who he/she trusts, who shares the same interest with him/her with, who knows his/her emotions, and who is never upset no matter how badly he/she behaves. A recently granted patent describes a system that partially fulfill this goal [157]. This system provides an avatar-based mobile interface for an autism child to bound with the avatar character and to learn various lessons on social and emotional regulation skills. The system relies on the use of one or more therapist or parent to interact with an autism child. Essentially, the system presents an illusion that the child with ASD is interacting with an intelligent avatar who he/she feels comfortable interacting with while in reality he/she is communicating with an actual human being who he/she otherwise would be reluctant to communicate with. To help the participating parent or therapist, the system also provides carefully crafted prompts to guide him/her on how to properly interact with the child with ASD. We are currently also working on a system that aims to serve as a virtual life coach for children with ASD [158]. Several publications have reported so called closed-loop autonomous systems based on social robots or virtual avatars [135]. Unfortunately, such systems have achieved autonomy only for very specific scenarios. For example, in [135], the system is capable of assessing a very small set of imitation gestures made by a participant in realtime using predefined rules. This is far from the degree of autonomy needed to train children with ASD towards improved practical social skills. In [159], an ambitious design towards a virtual avatar that can autonomously respond to the participant's emotional reactions and action tendencies was presented. Unfortunately, the authors conceded that it is exceedingly difficult to model the participant accurately based on the limited information collected, including the frequency of touch (on the screen) and eye tracking.