Evaluating interactional synchrony in full-body interaction with autistic children

Interactional synchrony, the spontaneous coordination of movements during interaction, is increasingly considered important in research on the development of non-verbal communication by autistic children. There is evidence that interventions using embodied interaction technologies to support interactional synchrony are possible, but we do not have a shared framework in Human-Computer Interaction (HCI) for designing and evaluating such systems. We discuss existing measurement and evaluation tools used in experimental psychology and consider how the prevalent approach could be adapted to naturalistic HCI study contexts, with input from domain experts. We report on an exploratory case study evaluating a full-body interactive musical system with a group of ten autistic children. We provide methodological recommendations for the evaluation of future systems focusing on interactional synchrony, highlight limitations of current measurement tools and suggest mitigations.