Expressing emotions is essential for ensuring smooth communication between people. In the context of human-robot symbiosis, robots are also required to express emotions. Although one method of robot emotion expression involves using LEDs or other forms of light to display colors, considering the possibility of expressing emotions through clothing colors is also necessary. In this study, we developed a simple robot called the “Tilting Robot,” which only performs simple tilting motions to investigate whether changes in the robot’s clothing color would affect the expressed emotions. In the experiment, participants were divided into two groups: motion and posture groups. The motion group was shown videos of the robot’s motion whereas the posture group was shown still images of the robot’s posture. The results showed that the red clothing in the posture group significantly expressed anger, whereas the blue clothing in the motion group significantly expressed sadness. The rating for blue clothing was 4.04 ± 1.30, which was near “undecided.” This suggests that blue clothing does not necessarily intensify the emotion of sadness, but other clothing colors may weaken its expression. The rating for red clothing was 2.86 ± 1.06, which was lower than “undecided.” This suggests that red clothing may not express anger, but could give an impression of vitality.

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