A Study Protocol for Assessing the Impact of Improvisation Training on Interpersonal Synchrony Across Age and Expertise (ImproSynchrony Project)

Background: Theatre improvisation provides a psychologically safe environment for practicing adaptive interpersonal behaviour, which can enhance interpersonal competence and reduce psychosocial stress. Interpersonal synchrony (IPS)—the temporal alignment of neural, cardiac, and behavioural activity during joint task performance—may represent a putative physiological mechanism underlying these beneficial effects. The Impro-Synchrony project aims to investigate whether IPS mediates the effects of improvisation training and to examine how IPS varies across age and levels of improvisation expertise. By combining neural, cardiac, behavioural, and self-report measures, the study aims to uncover the mechanisms through which improvisation training supports social functioning across the lifespan. Methods and analysis: The study is a 12-week controlled intervention study with a 12-month follow-up, designed to investigate the effects of improvisation training on IPS and social interaction competence across age groups (n = 200, ages 18–80). Prior to the intervention, differences in IPS will be examined by comparing groups of improvisation experts and novices. IPS will be assessed using electrophysiological measures (electroencephalography, EEG and electrocardiography, ECG), behavioural data (video recordings), self-reports, and qualitative data from learning diaries. These multimodal data will be collected at pretest, posttest, and follow-up to evaluate both immediate and long-term effects of the intervention. Discussion: The expected findings will clarify how improvisation training influences physiological and behavioural synchrony and social interaction quality. By including older adults, the study addresses a significant gap in improvisation research, with implications for enhancing social connectedness and mental health in ageing populations. The results will contribute to understanding how improvisation fosters empathy, cooperation, and effective interaction, offering practical insights for educators, policymakers, and practitioners.