Breastfeeding Predicts Vagal Regulation During a Social Stressor

Open Access
Quigley, Kelsey Michaela
Graduate Program:
Master of Science
Document Type:
Master Thesis
Date of Defense:
October 28, 2014
Committee Members:
  • Ginger A Moore, Thesis Advisor
  • regulatory development
  • physiological co-regulation
  • breastfeeding
  • vagal system
Breastfeeding, an early nurturing behavior common to mammals, serves to soothe infants and relax mothers. However, little is known about how breastfeeding gets under the skin—whether mechanisms are behavioral or physiological, or whether apparent breastfeeding effects are due to environmental factors often confounded with feeding method. The gustatory-vagal hypothesis proposes that early nutritive sucking facilitates regulation of physiological state and contributes to infants’ ability to co-regulate socially. Therefore, due to the unique neuromusculature involved in breastfeeding, regulatory effects may be due in part to infant-mother mutual vagal stimulation, which may serve as an early physiological co-regulatory process. The current study investigated relations between breastfeeding and mothers’ and 6-month-old infants’ vagal regulation during a social stressor (the Face-to-Face Still-Face Paradigm), controlling for potential confounds associated with breastfeeding (maternal sensitivity and demographic variables). Breastfed infants experienced greater vagal withdrawal during the reunion episode of the FFSFP relative to non-breastfed infants, suggesting more effective regulation. Breastfeeding mothers showed greater augmentation of vagal tone than non-breastfeeding mothers during the normal play and experienced lower physiological arousal throughout the task. Effects were independent of maternal sensitivity and of demographic variables. Together, findings suggested that mutual vagal stimulation during breastfeeding may be a physiological co-regulatory process that promotes infants’ and mothers’ self-regulation and that effects are not due to self-selection factors related to feeding method.