Exploring the impact of background noise on fractal dynamics and complexity matching during social interaction

Everyday interaction relies on subtle behavioral adaptations that can be disrupted by environmental challenges such as background noise. This study examined the influence of background noise on the structure of postural variability, a hallmark of adaptive capacity, and complexity matching, an index of global interpersonal coordination. Twenty-two pairs of participants conversed under varying levels of background noise (53 – 92 dB SPL), while motion-tracking sensors captured their postural movements. As noise increased, participants exhibited more rigid and less adaptable dynamics. However, when standing, noise also covaried with increased complexity matching, reflecting enhanced global coupling. Finally, complexity matching was negatively associated with communication breakdowns, suggesting it may serve as a behavioral biomarker of successful interaction. These findings highlight the adaptive nature of human movement and underscore complexity matching as a key indicator of information exchange. Future research should explore the predictive value of complexity matching in indexing communication breakdowns prior to their occurrence.