Abstract
Momentary fluctuations in children’s cognitive performance offer a rich source of signal. To understand this variation, we turn to the field of ADHD research. Children with ADHD exhibit high variability in reaction times. This phenomenon is accompanied by multiple theory-driven predictions about its candidate causes. However, suboptimal methods and datasets have obstructed empirical insights. To address this, we identify and address three sources of heterogeneity. We isolate a theoretically motivated estimate of reaction-time variability using dynamic structural equation modeling and examine its association with developmental problems. Our findings reveal a specific association between symptom-severity in the inattention domain and reaction-time variability in a population-based cohort of 1032 children aged 5.5-to-13.5 in the Netherlands. Moreover, by combining a unique task-design with latent difference-score models we provide support for the mechanistic hypothesis that attentiveness drives reaction-time variability. We conclude with three hypotheses for researchers interested in examining children's development through its momentary dynamics.
