# Social Distance in Interactions between Children with Autism and Robots
## 3 Experiments  
As the robot communicating with children, we used NAO (see Figure 3). It is a small humanoid robot that walks on two legs independently and was developed by Aldebaran Robotics (currently SoftBank Robotics). This robot is used in therapy for the elderly and children with autism, and as a programming tool in many educational institutions and research facilities. The height of the robot is 574 mm, which is sufficient for playing touch game with children. It speaks numerous languages, including Japanese. It has seven touch sensors on his head, hands, and feet, which were used in our experiment [39]. This robot was controlled by the Wizard of Oz (WoZ) technique in this study. The cameras were inserted into the face of robot, but we used the data collected by a high-resolution webcam (full HD 1080p) that recorded from behind the robot. This was because the robot needed to continue moving for the games, and the resolution was too low to run the detection programs discussed in Section 2. In total, 15 children with ASD (age: 4-14 (\(M=9.3\), \(SD=3.9\)), including 2 girls and 13 boys) participated in the trials. Two interactive movement sessions were conducted in consultation with the occupational therapists. _Touch Body Game_[40] and _Dancing with Me_[41], designed in our previous work, proved that the robot-play therapy helped children with ASD to improve their prosocial behavior. As shown in Figure 4, in all trials, either the caregiver or the therapist played the games together with the child. Figure 3: NAO robot movements during _Dance with NAO_. Figure 2: Flowchart of Program A and Program B. Selection of face range and low-pass filter phases are added in Program B. Before starting the experiment, the researcher explained the protocol of the experiment to the caregiver or therapist, and child. After the explanation, the participants entered the play room and followed what the [PERSON] asked to do. While they interacted with [PERSON] in the play room, the WoZ operator controlled the [PERSON] and collected the webcam data in the hidden room. The _Touch Body Game_ was used to investigate whether a child with autism had a solid understanding of body parts. The children were asked by the robot to touch specific body parts. Five questions were asked at 30 s intervals. For example, [PERSON] says, \"Please touch the top of your head slowly\", and waits 30 s. When the child touches the specified part, [PERSON] praises the child and moves to the next question. If the response is wrong, [PERSON] will say \"Please try again\". If there is no response from the child, [PERSON] automatically moves on to the next question after 30 s. The sensors and bumpers of the body parts used were the head, left hand, right hand, left foot, and right foot, in that order. During _Dance with NAO_, autistic children danced with [PERSON] to theme songs from popular animation shows, \"Yokaitaiso Daiichi\" and \"Head, Shoulders, Knees, and Toes\". Here, [PERSON] jumped along with the participants. Each song was played for 90 s, as it would on TV. When the song begins, [PERSON] says, \"Follow me and dance with me\". The dance imitates the actual dance of \"Yokaitaiso Daiichi\" and \"Head, Shoulders, Knees, and Toes\" with the head and arms swinging to the rhythm. All these interactions were recorded with the webcam (see Figure 5). The social responsiveness scale (SRS) was used to measure the strength of autistic traits in the children [42]. The total scores of SRS were converted to T scores, and they represented the level of the autism traits. Symptatic traits of autism were considered severe when the T score was 76 or higher; a score between 66 and 75 was considered moderate. T scores of 60 to 65 represented mild autism traits, and 59 and lower T scores indicated typical levels [42,43]. SRS has five treatment subscales: social awareness, social communication, social cognition, social motivation, and restricted interests and repetitive behavior.