Fundamental Biobehavioral Mechanisms Underlying the Integrated Development of Emotion, Attachment, and Nutritive Intake in the Mother-Infant Dyad - PROJECT SUMMARY The rate of weight gain in the first year of life is a robust risk factor for future obesity. The use of food to soothe has been linked to greater weight gain and has been theorized to contribute to future reward-driven or emotional overeating. However, avoiding the use of food to soothe is challenging for mothers, particularly for children who are less easily soothed by other strategies. Conceptual models to date have viewed infant distress due to hunger as distinct from infant distress due to other causes. These models encourage a separation of food as nutrition from food as soothing. However, diverse literatures converge to suggest that emotion, mother-infant attachment, maternal feeding, and infant eating behavior are appropriately intertwined and co-develop in adaptive ways. This proposal seeks to test an entirely novel comprehensive model of bidirectional biobehavioral mechanisms underlying the development of an integrated system of emotion, attachment, and nutritive intake in the mother-infant dyad across birth, 3 months, and 6 months. Further, we propose to test the association of this system with maternal feeding behavior, child eating behavior, dietary intake, and adiposity to age 3 years. Using novel experimental methods in a cohort of 120 children, we will address the following aims: Aim 1: To test the cross-lagged associations of maternal-infant dyadic stress physiology and maternal-infant dyadic oxytocin physiology with feeding to soothe and infant adiposity. H1a: Greater maternal and infant cortisol response and heart rate elevation in response to an infant stressor predicts more use of feeding to soothe and greater infant adiposity. H1b: Lower maternal and infant oxytocin response to caregiving predicts greater use of feeding to soothe, and greater infant adiposity. Aim 2: To test the cross-lagged associations of sucrose effects on infant opioid physiology with feeding to soothe and infant adiposity. H2: Behavioral response to sucrose characterized by greater relief of pain, greater relief of distress, and greater hedonic response predicts greater use of feeding to soothe and greater infant adiposity. Aim 3: To test the cross-lagged associations of the potency of maternal social interaction effects on infant eating with feeding to soothe and infant adiposity. H3: Greater effect of social interaction on increasing infant willingness to work for food, reducing capacity for caloric compensation, and relieving distress following a feeding delay predicts greater use of feeding to soothe and greater infant adiposity. Aim 4: To test the association of the ‘emotion-attachment- nutritive intake-system’ in infancy with maternal feeding behavior, child eating behavior, child dietary intake, and child adiposity at age 3 years. H4: Greater maternal-infant dyadic stress physiology, lower maternal-infant dyadic oxytocin physiology, greater sucrose effects on infant opioid physiology, and greater potency of maternal social interaction effects on eating in infancy predicts greater indulgent feeding, eating in the absence of hunger, overeating following caloric preload, reinforcing value of food, affective response to food delay, dietary intake of sweets, and adiposity at age 3 years.
