The complexity and non-linear dynamics of socio-motor phenomena underlying social interactions are often missed by observation methods that attempt to capture, describe, and rate the exchange in real time. Unknowingly to the rater, socio-motor behaviors of a dyad influence each other through implicit mirroring and shared cohesiveness that escape the naked eye. Implicit in their ratings nonetheless is the assumption that the other participant of the social dyad has an identical nervous system as that of the interlocutor, and that sensory-motor information is processed similarly by both agents’ brains. What happens when this is not the case? We here use the Autism Diagnostic Observation Schedule (ADOS) to formally study social dyadic interactions, at the macro- and micro-level of behaviors, by combining observation with digital data from wearables. We find that integrating subjective and objective data reveals fundamental new ways to improve standard clinical tools more generally into outcome measures of human behaviors and treatment effectiveness. This Supplementary Material contains the results from analyzing the gyroscope data in parallel with the results presented in the main paper from the linear acceleration data. Further the video (animation) explains the advantages of using a hybrid model of pencil and paper with digital biomarkers to advance clinical and basic research.