Figure 1.

Experimental set-up and proxemic analysis. (a) Participants sat diagonally on adjacent sides of a table with IMU sensors attached to their head and dominant hand. Two Kinect sensors tracked their movements from a distance. Sensors were attached to three host computers that were connected through a local area network. Experimenter sat in the corner of the room, started the tracking on Kinect host 1 using a wireless numeric keyboard and used the IMU host to insert timestamps at the beginning and the end of each trial. (b) We calculated the yaw angle (rotation around the vertical axis) for each participant in relation to the line connecting the heads. Thus, yaw angle of 0 would correspond to the participant looking at their partner. (c) We used the yaw angles to build a two-dimensional relational gaze histogram [22] where different parts of the plane are expected to correspond to different gaze behaviour (e.g. eye contact near the origin, shared attention around the centre of the plot, and other-oriented gaze near the edges).