From jumbled sounds and sights to higher order processes: Audio-visual sensitivity to intersensory synchrony in typical preschool development

Time proximity serves as a fundamental amodal cue, segmenting the array overlapping stimuli into distinct, multimodal Gestalts, thereby enabling accurate perception of both the inner and outer world. The ability to detect temporal alignment between sensory inputs, known as Sensitivity to Intersensory Synchrony (SIS), is hypothesized to underpin a developmental hierarchy. By enabling multisensory redundancy, SIS is thought to enhance perception, memory, learning, and motor functions. These, in turn, support higher-order processes such as Inhibitory Control and Self-Regulation, which are essential for shaping lifelong outcomes and well-being. Despite its significance, knowledge about the typical developmental trajectory of SIS remains limited, particularly as regards preschool years - a critical period for the development of SIS, Inhibitory Control, and Self-Regulation. This study addresses this gap by comparing SIS across three age groups in 305 neurotypical preschoolers (ages 3-6 years, mean age: 53.92 months; 152 females; 78.29% Italian) and exploring whether it supports Inhibitory Control and Self-Regulation. SIS was assessed using a preferential looking task with complex speech audio-visual stimuli. Inhibitory Control was measured through standardized tasks (NEPSY Visual Selective Attention, Flanker, Peg Tapping, and Go/No-go), while Self-Regulation was indirectly evaluated through the Strengths and Difficulties Questionnaire completed by teachers. Findings reveal higher SIS performance in preschoolers than previously reported, with age-related shifts in synchrony preferences based on modality order. SIS emerged as an embodied foundation of Self-Regulation, mediated by Inhibitory Control, particularly its Response Inhibition component - the ability to suppress automatic responses for goal-directed actions. The findings suggest links between SIS dysfunction and cognitive or behavioral outcomes and highlight the potential of bottom-up interventions targeting SIS to enhance broader developmental trajectories. Future studies should extend investigations to toddlerhood and early primary school years, employing longitudinal designs and eye-tracking tasks dynamically adapting to participants’ SIS to better capture individual variability.