The presence of a robot in a close relationship reduces the hormonal changes associated with pain in a laboratory setting

Abstract Human resources for healthcare management gradually fail to meet the demands because of an aging population. Pain is one of the most unpleasant sensations, and chronic pain is particularly difficult to manage. Loneliness is one of the key factors that worsens pain symptoms. Communication robots are used for smooth human communication. This study aimed to investigate whether communication robots would alter human pain perception via hormonal changes. Nineteen healthy participants experienced experimental pain before and after communicating with a robot named Moffly. Blood samples were collected to assess the hormonal levels. Pain was evaluated using the Short-form McGill Pain Questionnaire and Visual Analogue Scale. Furthermore, the participants’ mood and mental status were assessed by several questionnaires, including the Profile of Mood States 2nd Edition, Hospital Anxiety and Depression Scale, and Self-Rating Depression Scale. Subjective pain evaluation by the Visual Analogue Scale and the Short-form McGill Pain Questionnaire showed a significant decrease in pain in the robotic-communication condition than that in the control condition, accompanied by changes in the patterns of growth hormone, oxytocin, and estrogen. Depression and anxiety scores questionnaires also showed significant improvement after the experiment compared to before starting the experiment. The communication robots altered the participants’ pain perception, accompanied by changes in the growth hormone, oxytocin, dehydroepiandrosterone-sulfate, estrogen, and cortisol. Depression and anxiety improved after the intervention. This finding may reflect that not only humans but also robots can relieve human pain by suppressing factors that would exert a negative effect on pain perception, such as loneliness. Robots may be able to take over human functions, especially in the area of time-consuming cognitive behavioral therapy.