Past research indicates there is a link between physiological responses and adaptive social responses to another individual's distress. Scholars have theorized that humans may be predisposed, both physiologically and behaviorally to responding to others, especially those who are in distress. Maternal depression has been associated with dysregulated emotional development and may possibly affect the physiological and behavioral responses of a neonate. The present research examined the relationship between neonates' physiological and behavioral responses to naturally generated (compared to artificial) stimuli of other neonates, as well as the role of maternal depression in the responses. Specifically, heart rate, heart period, and heart period variability were measured to assess the newborns' reaction to cries generated by both other newborns and digitally modulated sources. This study found that newborns of depressed mothers had higher heart period variability and showed less behavioral distress when hearing the cry of another infant. / by Joseph Cotler. / Thesis (M.A.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.