The Psychobiology of Paternal Behavior (2009)

Undergraduate: Patty Kuo

Faculty Advisor: Karen Grewen
Department: Psychology & Neuroscience

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Studies show father involvement enhances child development, but little is known about the biological underpinnings of paternal behavior and attachment. This study examined the relationships among paternal hormones, father-mother relationship quality, and paternal investment/attachment in their infants. Subjects were 15 fathers (21-38 yrs) and their infants. All men were living with their infant's mother (12 married, 3 unmarried). Fathers-infant dyads attended an experimental lab at 4-18 weeks postpartum. An intravenous catheter was placed for assessment of paternal blood testosterone and prolactin samples, obtained after baseline, infant interaction, and speech stress. Fathers completed questionnaires assessing demographic and relationship characteristics with baby's mother and baby. Fathers were significantly more invested in male than female infants (male: 9.8, female: 5.7; p=0.02) and more attached to their infants as the infants got older (r= +0.61; p=0.02). Higher baseline testosterone was linked to higher dyadic consensus with mother (r= +0.55; p=0.04), as well as attachment to baby (r= +0.56; p=0.03). Baseline prolactin was negatively correlated with baby's age (r= -0.62; p=0.03). Dyadic cohesion between parents was marginally correlated with paternal affection (r= +0.48; p=0.07). These results implicate higher testosterone levels amongst fathers in quality family relationships and that attachment is a growing process in the father-infant dyad.