The main concern in designing a robotic interface for children with Autism Spectrum Disorder (ASD) is the degree of life-like appearance. Therapeutic robots are designed in various forms; anthropomorphic robots that highly resemble human beings, non-anthropomorphic robots that either appear like animals or cartoon-like characters, and non-biomimetic robots that do not look like any kind of living species (Cabibihan et al., 2013). Social interactions are challenging for children with ASD; therefore, researchers have compared anthropomorphic and non-anthropomorphic robotic designs to observe which design generates more positive feedback. Research has indicated that designs that do not resemble human beings evoke more social responses (Robins et al., 2006). Also, robots that resemble animals or cartoon-like characters lead to more stimulation (Duquette et al., 2008; Michaud et al., 2003). Moreover, experiments have noted that non-biomimetic robots received positive feedback from children with ASD as well (Robins et al., 2007; Michaud et al., 2003). Further work has suggested that non- anthropomorphic and non-biomimetic robot designs may permit the emphasizing of social signals by producing more noticeable cues, and restricting distractions to gather attention for desired social signals (Scassellati et al., 2012). However, anthropomorphic robots may be utilized in particular circumstances, for instance if aiming for a better generalization of acquired skills, because in the case of anthropomorphic robot design, children with ASD may comprehend social interactions more clearly. Besides, the robot should be perceived as a mechanical entity, not as a human being (Cabibihan et al., 2013). On the other hand, extremely machine-like robots may cause attention loss because the child may be interested more in the mechanical aspects of the robot than in interacting with the robot (Kozima et al., 2007). A proper degree of life-like appearance should be achieved to ensure that the robot is not so anthropomorphic that the child is intimidated and that the robot is not so machine-like that the child becomes more attracted to inspecting mechanical components (Kozima & Nakagawa, 2006).
Utilizing robotic systems provides convenient, sheltered, expectable, and consistent conditions, in contrast to everyday social interactions, which are unpredictable and uncontrollable. In robotic systems, interaction complexity can be determined and progressively advanced (Robins et al., 2004c). Considering that individuals with ASD suffer from excessive stimulation (Johnson & Myers, 2007), eliminating superfluous social cues may be beneficial in helping individuals with ASD process social signals (Scassellati et al., 2012). Children with ASD favor simple designs, modest appearance, and foreseeable circumstances while interacting with a toy (Ferrara & Hill, 1980). Robins et al., (2004c) developed interactive robotic systems that support essential communication and social interaction abilities in the Aurora Project. In the scope of the Aurora Project, a robot called Robota is utilized which is a 45 cm high humanoid robotic toy comprised of commercial doll components (head, arms, and legs) (Billard, 2003). Robins et al., (2004c) compared the interaction level and response of the children with ASD while interacting with two separate versions of the robot. In the first version, the robot was clothed to resemble a human, and in the second version, the robot was dressed with a plain white cloth covering all features of its face (Robins et al., 2004c). After comparing these two circumstances, Robins et al. (2004c) observed that children with ASD exhibited a preference to interact with the plain second version of the robot.
Visual engagement is crucial in maintaining the attention of the children with ASD (Cabibihan et al., 2013). A robot containing highly bright components may result in the over stimulation of the child. Moreover, children with ASD are interested in distinctive forms, lights, and spinning mechanical components (Michaud at al., 2003). Also, robot design should not permit sharp corners and the use of ropes (Cabibihan et al., 2013). Interacting with robots is less complicated compared to human interaction, which makes robots more attractive for children with ASD. Thus, the appearance of the robot should not immensely resemble that of a human since the attention of children with ASD may diminish (Robins et al., 2007). Facial expressions of the robot should be simple, and unnecessary forms like eyelashes and eyebrows should be avoided to improve simplicity (Cabibihan et al., 2013). Generally, children with ASD avoid eye contact. However some children have been observed to be interested in making eye contact (Robins et al., 2009), which creates an opportunity to provoke the making and
preserving of eye contact. Still, this attribute should be customizable since it highly depends on the child (Robins et al., 2007). In terms of safety, the design of the robot should avoid sharp corners and sudden motions since children with ASD may behave incompliantly or unpredictably. Also, the robot should be designed so as to minimize the possibility of malfunction. The child may have a tantrum and throw the robot, so the robot should be designed to be firm and able to resist strong impacts (Cabibihan et al., 2013).
Numerous robots have utilized motion to gather attention of the children. Objects in motion tend to attract the attention of children with ASD. Therefore, designing robots to be mobile may become highly beneficial (Cabibihan et al., 2013). Children with ASD have exhibited a preference to engage with mobile robots instead of passive robots (Dautenhahn, 2003). Michaud et al. (2003) indicated that children with ASD displayed positive feedback towards mobile robots. Rewards based on achievements are also encouraging for children with ASD; the accurate completion of a task should be rewarded since positive feedback has been demonstrated to be greatly constructive (Robins et al., 2007). Rewards to encourage children may be presented in a sensory form, for example illuminating the robot or playing songs, because children with ASD are encouraged and attracted by these types of rewards (Michaud et al., 2003). Providing options during the child-robot interaction may increase attention and enable sufficient learning. Making choices enables the child to be more in control, and thus more interested in the interaction. For instance, allowing the child decide between illuminating the robot and playing songs as a reward for achievement may increase the engagement of the child (Robins et al., 2007).
Children’s perceptions of a robot are highly significant and to comprehend children’s opinions about the appearance of robots Woods (2006) conducted a study with 159 children. In the experiment children assessed 40 images of robots via filling a questionnaire about the appearance, personality, and emotions of every robot. Relying on the empirical data gathered from the research, Woods (2006) suggested a set of design rules for the robots that interact with children:
“Robots should have cartoon-like features, exaggerated facial features, a female gender and be brightly colored for positive behaviors. Robots should have realistic
features, less clear facial features, and be dully colored to depict negative behaviors. The whole appearance of a robot should be considered at the outset of the design phase rather than focusing on specific aspects such as the face. Robots for children should not be designed to look completely human-like, unless they are perfect replicas, indistinguishable of humans.” (Woods, 2006, p.1413)
Li et al., (2010) examined the influence of robot appearance and a user’s cultural background on the engagement, perceived attractiveness, and response of the user. The results indicated a positive correlation between interaction level and the perceived attractiveness of the robot. The study also revealed cultural differences in approaches and interaction levels of the users when they encounter a service robot. Korean and Chinese users regarded social robots that they have encountered as being more attractive and experienced greater engagement with the robot than German users (Li et al., 2010). Users perceived the machine-like robot to be less pleasant than the zoomorphic (animal- like) robot. According to Li et al. (2010), active interaction increases robots’ perceived appeal and trustworthiness. Finally, Li et al. (2010) suggested increasing the time and amount of the human-robot interaction to enhance engagement and likeability.