Figure 1

Schematic display of the experimental task setup during free task version and nonverbal task version. The experimenter was the designated interaction partner during the tasks and sat opposite of the participants. A monitor facing the participants displayed the stimuli. An Eyelink recorded participants’ eye movements, and the calibrated area included the interaction partner’s facial area and the stimuli. In the free task version, participants were free to choose how to convey the spatial information of the target stimulus to the partner. In the nonverbal task version, participants were instructed to press the space bar of a keyboard located in front of them and release it only for the pointing gesture. A video camera recorded all test runs, and the colored finger caps that participants wore on their index fingers were used to later extract the movement trajectories (see “Video analysis”).