Motor interference between Humans and Humanoid Robots: Effect of Biological and Artificial Motion

If humanoid robots are to become commonplace in our society, it is important to understand how they are perceived by humans. An influent model in social cognitive neuroscience posits that in human face-to-face interaction, the observation of another individual performing an action facilitates the execution of a similar action, and interferes with the execution of different action. In one interference experiment, null interference was reported when subjects observed an industrial robotic arm moving at a constant velocity perform an incongruent task, suggesting that this effect may be specific to interacting with other humans. This experimental paradigm was adapted to investigate how humanoid robots interfere with humans. Subjects performed rhythmic arm movements while observing either a human agent or humanoid robot performing either congruent or incongruent movements with comparable kinematics. The variance of the executed movements was used as a measure of the amount of interference in the movements. In a previous report, we reported that in contrast to the robotic arm, the humanoid robot caused a significant increase of the variance of the movement during the incongruent condition. In the present report we investigate the effect of the movement kinematics on the interference. The humanoid robot moved either with a biological motion, based on a realistic model of human motion, or with an artificial motion. We investigated the variance of the subjects' movement during the incongruent condition, with the hypothesis that it should be reduced for the artificial movement in comparison to the biological movement. We found a significant effect of the factors defining the experimental conditions, congruency and type of movements' kinematics, on the subjects' variation. Congruency was found to have the expected effect on the area, but the increase in incongruent conditions was only significant when the robot movements followed biological motion. This result implies that motion is a significant factor for the interference effect