Physiological Markers of Early Social Skills in Rural South Africa: The Role of Frontal Alpha Asymmetry and Heart Rate Variability

Early social skills underlie the development of crucial regulatory and behavioral processes across childhood. EEG frontal alpha asymmetry and heart rate variability are two physiological markers that have been extensively studied in relation to social skills in high-income country (HIC) samples. The prevalence of adversities in low- and middle-income countries (LMICs) is linked to pervasive deficits in early social skills, yet little is known about the role of physiology in contributing to these processes. The current study explores two physiological measures across two timepoints in relation to social skills in a rural, low-resourced context. In a sample of 229 young children from Greater Tzaneen, South Africa, we assessed how both frontal alpha asymmetry and change in heart rate variability from 17 to 36 months related to 36-month social skills. Left frontal asymmetry predicted poorer social skills, while greater increase in heart rate variability across timepoints predicted higher social skills, especially in children displaying right-lateralized asymmetry. Findings extend work from HICs to a LMIC context, suggesting potential implications for later mental health challenges, while identifying autonomic maturation as a possible protective factor in low-resource settings for specific neurophysiological profiles.