Processing speed deficits: A missing link in understanding individual variation in children's interval timing skills?

The goal of this study was to explore the possible moderating and mediating roles of processing speed in children's interval timing performance. Nine- to 11-year-old children (N = 103; 53% male; 67% White, 4% Black, 5% Asian, 3% Hispanic, 9% biracial/mixed identity, 12% unknown) performed behavioral interval timing, executive functioning, and processing speed tasks, along with a movement skills assessment. We found that processing speed moderated the relation between movement skills and interval timing such that poorer movement skills most strongly predicted more variable interval timing in children with very slow processing speed. Processing speed also statistically mediated the relation between poorer executive functions (working memory and inhibitory control) and more variable interval timing. This suggests that children with movement difficulties who also have very slow processing speed may be most at risk for dysfunctions in timing-based movement skills and that slow processing speed may interfere with efficient operation of executive functions involved in interval timing skills. We discuss the possible role that processing speed may play in understanding individual variation in children's interval timing skills and how combined difficulties in timing skills, motor ability, and processing speed may represent a particularly at-risk profile for children with neurodevelopmental disorders. (PsycInfo Database Record (c) 2026 APA, all rights reserved).