Baby schema in human-robot physical interaction: Influence of baby likeness in a communication robot on caregiving behavior

One huge societal problem faced by nursing homes in aging countries like Japan is easing the loneliness, anxiety, reluctance in communication and related problems caused by dementia. Innovative methods are required to address this problem, which is aggravated by an acute shortage of care-providing staff. The use of such traditional management methods as physical or medical treatment must be intensified. Baby-like robots are increasingly being introduced into nursing homes as companions. The multiple infant traits in baby-like robots (multimodal infant features) can trigger the baby schema effect, which increases the desire of seniors to interact with their environments and triggers caregiving behaviors. However, to the best of our knowledge, no research has systematically analyzed how multimodal infant features trigger the baby schema—not to mention how adequately they do so. In this work, we first investigated how the appearance and the voice design of baby-like robots trigger the baby schema. 41 healthy adults between the age of 20–50 interacted with baby-like robots that had five different forms. 21 interacted with robots that had a voice function of real infant voices, and the remaining 20 interacted with robots without any voice. The participants rated the robots based on their baby likeness, their degree of fun to play with, and their degree of easy to play with. During the experiment, we video-recorded the number of caregiving and non-caregiving behaviors done with five different kinds of robot to evaluate the degree of the baby schema triggered in the participants. The multimodal infant features increased the baby schema effect, although non-linearly. The baby schema triggers a threshold beyond which the reality of the infant features exceeds it, and the increase of caregiving behavior will be lessened. This study provides a guideline for the design of current and future baby-like robots and a methodology for studying baby schema and caregiving behaviors in an ethical, safe, and controlled environment without actual infants.