Effects of Colored LEDs in Robotic Storytelling on Storytelling Experience and Robot Perception

Social robots can use biomimetic modalities such as gestures to convey emotions. The use of colored light for emotion expression is also possible, but rarely explored. In this paper, colored LEDs are used in addition to contextual gestures to communicate emotions in robotic storytelling. Results show that adding colored light to the storytelling did not improve the recipients' transportation into the story. Their cognitive absorption was significantly decreased. The users' perception of the NAO robot was not influenced by colored lights except for animacy which was higher using only white LEDs. Problems might have been mismatches between colors and emotions, the lack of emotional gestures, and the too small light emission from NAO's eye LEDs. Since smart rooms lighting can affect the users' whole visual field, they could enhance emotional effects. Thus, future studies should investigate the integration of a robotic storyteller in smart rooms allowing for smart light control.