# Robotic Motion Learning Framework to Promote Social Engagement
## 2 System Design and Algorithms
### Experimental Setup  
For the experiment, each participant was directed to an unoccupied room containing a conference table equipped with a video camera, Microsoft Kinect, laptop, OP2, and seating for at least two people. The cords to power the equipment were hidden underneath the table to minimize participant distraction. The experimenter sat adjacent to the participant, with OP2 placed in between them on the table. The Kinect system was initialized and videotaping started. Participants engaged in a two-part \"Emotion Game\" with OP2. This layout can be seen below, in Figure 4.  
In the first half of the Emotion Game, OP2 introduced itself, using pre-recorded audio and gestures triggered by the experimenter. The participant was prompted by OP2 to perform three  
Figure 4: The experiment setup, consisting of a video camera (left), Kinect (behind robot), OP2, a laptop to operate OP2, and the informed consent packet. gestures: one \"exercise\" move, one \"emotion\", and one \"dance\" move. To ensure accurate data collection, each participant was asked to stand when demonstrating his or her moves. The angles of the participant's limbs during these gestures were tracked and recorded by the Kinect. Video footage of each participant's gestures was recorded to later be compared to the robot's reenactments. The participant was offered to return to a sitting position after completing the demonstrations. An interim-survey was completed by each participant after the first half of the emotion game. For each of its three sections, the participant was asked to answer Likert scale questions by assigning a numerical response to each prompt. The numerical scale ranged from 1-5, where \"1\" equated to \"Strongly Disagree\" and \"5\" equated to \"Strongly Agree\". The first section of the interim-survey examined the participant's interest in and comfort with current and new technology. This was intended to help the experimenter see if self-proclaimed technological expertise and exposure would affect how a participant reacted to OP2. The second section prompted the participant to comment on their initial impression of the robot. These 5 Likert scale questions guided the participant to comment on the appeal of the robot's demeanor, voice, word choice, and fluidity of movement, as well as whether he or she found the robot intimidating, to identify whether any of these factors were negatively impacting the participant's interaction. The third section of the interim-survey and the sole section of the forthcoming post-survey both focused on the participant's interaction with OP2, before and after the second half of the emotion game. The statements prompted the participant about his or her levels of comfort and enjoyment while interacting with the robot. The brief time required to complete the interim-survey allowed the experimenter to seamlessly train the motion learning algorithm for experimental group participants. Each participant then completed the second half of the Emotion Game. OP2 announced to the participant that it would reciprocate by demonstrating gestures to them. The participant's job was to identify which emotion the robot was attempting to articulate and display. The order of emotion primitives, listed earlier, appeared random but was kept consistent for all participants. However, OP2 performed an additional \"DMP move\" after the \"curiosity\" emotion primitive for experimental group participants. This \"DMP move\" was a DMP-learned reproduction of one of the participant's previous gestures from the first half. Experimental group participants were not given forewarning that the robot would include the imitative gesture. The participants' movements were tracked by the Kinect for posture analysis. Video footage was collected to track changes in emotional state, including mood contagion. Four dependent variables were tracked to determine where imitation increased social engagement during human-robot interaction: participant posture, facial emotional state, instances of mood contagion, and perception of robot autonomy.