Gestures convey different physiological responses when performed toward and away from the body

We assessed the sympathetic and parasympathetic activation associated to the observation of Pantomime (i.e. the mime of the use of a tool) and Intransitive gestures (i.e. expressive) performed toward (e.g. a comb and "thinking") and away from the body (e.g. key and "come here") in a group of healthy participants while both pupil dilation (N = 31) and heart rate variability (N = 33; HF-HRV) were recorded. Large pupil dilation was observed in both Pantomime and Intransitive gestures toward the body; whereas an increase of the vagal suppression was observed in Intransitive gestures away from the body but not in those toward the body. Our results suggest that the space where people act when performing a gesture has an impact on the physiological responses of the observer in relation to the type of social communicative information that the gesture direction conveys, from a more intimate (toward the body) to a more interactive one (away from the body).We would like to thank Johanna Viana, Raphael Kroll and Alberto Villar for their precious help in the task construction and in the recruitment of participants. We also thank all the participants that entered the study. This work was funded by the French National Research Agency (ANR-11-EQPX-0023) and supported by European funds through the program FEDER SCV-IrDIVE. This study was partially conducted at the Psychology Research Centre (PSI/01662), University of Minho, and supported by the Portuguese Foundation for Science and Technology and the Portuguese Ministry of Science, Technology and Higher Education (UID/PSI/01662/2019), through the national funds (PIDDAC)