Biological basis of temperament: Respiratory sinus arrhythmia and inhibitory control across childhood.

Temperamental inhibitory control is a foundational capacity for children's social, emotional, and behavioral development. Even though temperament is suggested to have a biological basis, the physiological indicators of inhibitory control remain unclear amid mixed empirical results. In this study, we leveraged a multicohort longitudinal design to examine resting respiratory sinus arrhythmia (RSA) as a physiological correlate of inhibitory control across the early and middle childhood years. Data were collected annually across four time points from cohorts of 4- (n = 150, M_age = 4.53; SD = 0.30; 49.7% female) and 8- (n = 150; M_age = 8.53; SD = 0.29; 49.7% female) year-old children and their caregivers. There were weak, albeit significant, associations between resting RSA and caregiver-reported inhibitory control in middle childhood but not in early childhood. A stronger association was found for older children when latent trait assessments of RSA and inhibitory control were derived from commonalities across the four annual assessments. We conclude that using repeated measures to extract latent trait scores increases power to detect potential physiological indicators of temperament. (PsycInfo Database Record (c) 2024 APA, all rights reserved).