Infant biological sensitivity to father engagement in low-income Mexican American families

Paternal depressive symptoms and infant respiratory sinus arrhythmia predict empathy-related behaviors

Children with specific psychophysiological profiles may be more strongly affected by adverse environmental experiences. Guided by a biopsychosocial perspective, we examined whether infant respiratory sinus arrhythmia (RSA), an index of parasympathetic functioning, moderates the associations between paternal postpartum depression (PPD) symptoms and infants' observed empathy-related responses. Participants were 142 families with infants (51% female) assessed at two time points. At T1 (3 months of age), fathers reported their depressive symptoms. Infants' cardiac activity was recorded during rest and estimates of RSA were calculated. In addition, infants' empathy-related responses during a maternal distress simulation were observed and rated at T2 (12 months of age). Higher paternal PPD at T1 predicted higher infant affective (i.e., affective concern) and cognitive (i.e., inquiring behaviors) responses to maternal distress at T2. Infant RSA moderated this relationship for cognitive responses, with a significant positive association only for children with high or average RSA. These findings contribute to the understanding of the psychophysiological mechanisms that support empathy development.

Cortisol response marks biological sensitivity to kindergartners' social hierarchies for emerging school engagement

This longitudinal study investigated how kindergartners' position in the classroom social hierarchy and cortisol response relate to their change in school engagement across the first year of kindergarten (N = 332, M = 5.3 years, 51% boys, 41% White, 18% Black). We used naturalistic classroom observations of social hierarchy positions, laboratory-based challenges to elicit salivary cortisol response, and teacher, parent, and child reports of emotional engagement with school. Robust, clustered regression models revealed that in the fall, lower cortisol response (but not social hierarchy position) was associated with greater school engagement. However, by spring, significant interactions emerged. Highly reactive, subordinate children showed increases in school engagement from fall to spring of the kindergarten year, whereas highly reactive, dominant children showed decreases in school engagement. This is some of the first evidence that higher cortisol response marks biological sensitivity to early peer-based social contexts.