Physiological responses to social and physical challenges in children: Quantifying mechanisms supporting social engagement and mobilization behaviors.

Physiological response patterns to laboratory-based social and physical challenges were investigated in 37 typically-developing 3- to 5-year-old children. The study was conducted to determine whether the response profiles during each challenge were similar and whether individual differences in the response profiles to the challenges were correlated. Results demonstrated challenge specific physiological response strategies. In response to the social challenge, respiratory sinus arrhythmia and heart period increased and motor activity decreased. In contrast, in response to the physical challenge, respiratory sinus arrhythmia and heart period decreased and motor activity increased. Neither challenge reliably elicited changes in salivary cortisol. Only heart period responses were correlated between the challenges.