Robot Mediated Handholding Combined with a Mobile Video Call Makes the Users Feel Nearer and Closer

Combining a device that mediates social touch between people in remote locations with a video call can be expected to enhance the feeling of being in the same space (sense of space sharing) and social bonding with the remote partner. However, when the device is combined with a mobile phone video call, size inconsistency could occur between the device that acts as a substitute for the body part and the reduced video of the partner. In addition, when the device operates separately from a mobile phone in wireless communication, positional inconsistency also happens. This study developed a robotic hand-type social touch device and investigated whether it enhances the sense of space sharing and social bonding even though these inconsistencies occur. Experimental results revealed that the user's belief that the finger movements of the device were the partner's hand movement contributed to the sense of space sharing. The movements of the device according to the flow of conversation facilitated this belief; hence, the sense of space sharing increased in spite of the inconsistencies. Positional inconsistency was also found to have an adverse effect on social bonding. Positional consistency contributes to enhance social bonding because it visually facilitates the user's belief that the device is a substitute for the partner's body. Basically, the functions of the device, such as skin softness, body temperature, finger movements, and grip force, which enhance the reality of the touch sensation, could be effective in facilitating the user's beliefs. However, it was suggested that awareness of temperature does not always make positive contribution to the reality and could lead to eeriness.