Hypothalamus volume in men: Investigating associations with paternal status, self-reported caregiving beliefs and adult attachment style

Most studies on mammalian caregiving and attachment have focused on the mother-child relationship, particularly in humans. Yet, changing societal roles of male caregivers have highlighted the necessity for research with fathers. In this study, we examined the volume of the hypothalamus, an important subcortical brain area for caregiving and attachment, in a sample of N=50 fathering (child age 5-6 years) and N=45 non-fathering men using a novel technique to identify the human hypothalamus in 3T MRI. Furthermore, we employed three self-report measures to assess interindividual differences in adult attachment style across all men and caregiving beliefs in fathers. While we did not observe any significant difference in hypothalamus volume between fathers and non-fathers or associations between hypothalamus volume and self-reported adult attachment style across all men, self-reported caregiving beliefs were positively related to total hypothalamus volume in fathers. A follow-up analysis showed that fathers’ self-reported belief that a father’s role is important to child development was specifically related to tuberal hypothalamus volume, while self-reported enjoyment of spending time with the child was not associated with volume in hypothalamus sub-regions. Together, these findings suggest that interindividual variability in self-reported caregiving beliefs in fathers is related to brain structure, warranting further research.