Summary: A controlled study from Emory University found that intranasal oxytocin increases activity in brain regions linked to reward, empathy, and attention when fathers view photos of their toddlers.
Source: Emory Health Sciences
Study looks at neural mechanisms of paternal caregiving
A new Emory University study reports that giving fathers a dose of the hormone oxytocin enhances neural activity in brain regions associated with reward and empathy when they view images of their young children. The findings point to biological mechanisms that may help explain why some men become more emotionally engaged and motivated to care for their offspring.
Lead author James K. Rilling, an anthropologist and director of Emory’s Laboratory for Darwinian Neuroscience, said the results broaden understanding of the hormonal changes that accompany fatherhood. “Our findings add to the evidence that fathers, and not just mothers, undergo hormonal changes that are likely to facilitate increased empathy and motivation to care for their children,” he said. The study also suggests oxytocin could one day be investigated as a way to address reduced paternal motivation observed in some conditions, such as paternal post-partum depression.
The study, published in the journal Hormones and Behavior, is the first to examine how both oxytocin and vasopressin—another neuropeptide implicated in social bonding—affect brain responses in human fathers.
Research has long shown that active paternal involvement improves child health, social, psychological, and educational outcomes. Yet fathers vary widely in the degree and quality of their caregiving. To better understand the neurobiology behind this variation, the research team used functional magnetic resonance imaging (fMRI) to measure brain activity in fathers after administering intranasal oxytocin, intranasal vasopressin, or placebo.
Participants were healthy fathers of toddlers aged one to two. In a double-blind, placebo-controlled, within-subject design, half of the men received 24 IU of intranasal oxytocin before one scan and placebo before another scan; the other half received 20 IU of intranasal vasopressin before one scan and placebo before the other. During fMRI scanning, each father viewed photographs of his own child, an unfamiliar child, and an unfamiliar adult, and in a separate task listened to recordings of unknown infant cries.
When fathers viewed photos of their own children after receiving oxytocin, fMRI revealed significantly increased activation in several brain areas tied to reward and empathy, including the caudate nucleus and the dorsal anterior cingulate cortex, along with enhanced responses in visual cortex. These patterns suggest that oxytocin may amplify feelings of reward, boost empathetic processing, and increase attention toward one’s child—factors that support caregiving motivation and responsiveness.
By contrast, vasopressin did not produce a measurable increase in neural responses to the toddlers in this human sample, a result that differs from some animal studies. For example, research in monogamous prairie voles links vasopressin to both pair bonding and paternal care. The authors note that evolutionary and species differences might lead to different neuroendocrine strategies for promoting paternal behavior across mammals.
The study also found that the order in which oxytocin and placebo were administered influenced the magnitude of oxytocin’s effects: when oxytocin was given before placebo, it produced stronger activation in several reward-related structures (including substantia nigra, ventral tegmental area, and putamen) than when given after placebo. Neither oxytocin nor vasopressin produced robust, consistent effects on neural responses to infant cries in this experiment.
These results contribute to a growing view that hormonal shifts during the transition to parenthood support increased approach motivation and empathy for children in fathers as well as mothers. The authors call for further research to explore whether oxytocin could help normalize deficits in paternal motivation in clinical populations and to better define how individual differences in neurobiology map onto caregiving behavior.
Co-authors of the study include Ting Li (Emory Anthropology), Xu Chen (Emory Anthropology and Emory School of Medicine, Department of Psychiatry and Behavioral Sciences), Jennifer Mascaro (Emory School of Medicine, Department of Family and Preventive Medicine), and Ebrahim Haroon (Department of Psychiatry and Behavioral Sciences).
Funding: The study was supported by the National Institutes of Health through the National Institute of Child Health and Human Development and the National Center for Advancing Translational Sciences.
The study used a double-blind, placebo-controlled pharmaco-fMRI design with 30 fathers of 1–2 year old children to test effects of intranasal oxytocin (OT) and vasopressin (AVP) on neural responses to images of own children, unknown children, and unknown adults, and to infant cry sounds. Intranasal OT, but not AVP, significantly increased BOLD responses when fathers viewed photos of their own children in regions implicated in reward (caudate), empathy (dorsal anterior cingulate), and visual attention. Order of administration modulated OT effects in several reward-related regions. Neither peptide produced consistent main effects on neural responses to cries. The findings suggest hormonal changes associated with fatherhood may enhance approach motivation and empathy toward children and warrant future research on OT’s potential to address deficits in paternal motivation.