Unobtrusive tracking of interpersonal orienting and distance predicts the subjective quality of social interactions

Interpersonal coordination of behavior is essential for smooth social interactions. Measures of interpersonal behavior, however, often rely on subjective evaluations, invasive measurement techniques or gross measures of motion. Here, we constructed an unobtrusive motion tracking system that enables detailed analysis of behavior at the individual and interpersonal levels, which we validated using wearable sensors. We evaluate dyadic measures of joint orienting and distancing, synchrony and gaze behaviors to summarize data collected during natural conversation and joint action tasks. Our results demonstrate that patterns of proxemic behaviors, rather than more widely used measures of interpersonal synchrony, best predicted the subjective quality of the interactions. Increased distance between participants predicted lower enjoyment, while increased joint orienting toward each other during cooperation correlated with increased effort reported by the participants. Importantly, the interpersonal distance was most informative of the quality of interaction when task demands and experimental control were minimal. These results suggest that interpersonal measures of behavior gathered during minimally constrained social interactions are particularly sensitive for the subjective quality of social interactions and may be useful for interaction-based phenotyping for further studies.

Methods
This data was collected using Kinect V2 sensors and Tinkerforge IMU Brick 2.0 inertial measurement units, and questionnaires. Gaze behaviors are manually annotated from video images saved by the Kinect sensors. Anonymous data derived from the Kinect and IMU tracking results is shared in preprocessed format due to limitations in the ethics approval for the study. Preprocessing steps applied to these intermediate data are included in the provided analysis script. Video images are not included in this dataset to preserve the privacy of our participants and to follow the requirements of the ethics approval.