Comparison of Calculation Modes for Virtual Co-embodiment: Movement Average and Vector Summation

When two individuals control a virtual avatar simultaneously (virtual co-embodiment), their movement performance can, somewhat surprisingly, improve compared to when they control an avatar alone. This study investigated whether movement performance is affected by how individuals’ movements embody into an avatar: by averaging the positions of individual’s body parts or by summing the movement vector of each individual’s body parts. The experiment, in which participants reached a target with the avatar’s hand in these two types of co-embodiment, showed that the vector summation was more efficient in improving body movements than the position average.