Fathers’ active caring of infants changes their brains to be more like mothers’

Photo: Ste Elmore. Creative Commons.

When fathers engage in active day-to-day care of children, they show greater activation in the "emotional network" of their brains, like mothers do.

When fathers engage in active day-to-day care of children – particularly when fathers assume the traditional maternal primary carer role and raise their babies with no maternal involvement –they become as attuned and sensitive to the baby’s cues as mothers do. They show greater activation in the “emotional network” of their brains like mothers do, something that does not happen unless they are continually involved.

Throughout history and across cultures, women have typically assumed the primary-caregiving responsibilities. While maternal care has remained relatively uniform across time and cultures, paternal care has shown great variability throughout human evolution. In the last few decades, the ‘traditional’ family constellation has undergone profound and rapid changes, and nowadays fathers are becoming more and more involved in childrearing in many different contexts. A growing number of children are raised in two-father families with no maternal involvement since birth. This provides a new and unique opportunity to study the neurobiology of fathers in different caring situations.

In a “traditional family” where the mother is the primary caregiver and the father is the secondary caregiver, mothers are typically more attuned to infant’s needs and more coordinated with infant’s social cues, and differences can be seen in brain activity between mothers and fathers. In mother’s brain the “emotional” network is more active, whereas in father’s brain the “socio-cognitive” network is more dominant.

These two brain networks that support parenting in humans are:

  1. The “emotional” brain network. This is an evolutionary ancient subcortical system, including the amygdala and other limbic regions. It is linked to instant emotional processing and responses, vigilance, motivation and immediate response to infant’s distress, and operates via “fight or flight” responses, danger and motivational signals.
  1. The “socio-cognitive” brain network. This is a later developing circuit, including cortical and frontal brain areas, such as the superior temporal sulcus (STS). It is associated with mentalizing, cognitive empathy, and social understanding. In relation to caring for an infant, it enables a parent to infer infant’s mental state from behavior, to predict infant needs and plan future caregiving activities.

However, when fathers engage in active day-by-day caregiving of the young, particularly if they are the primary carer, they not only become as attuned and sensitive to the infant’s cues as mothers do, but they show greater activation in the “emotional network”, like mothers do, and at the same time, higher activation in the “socio-cognitive network”, like fathers do. Interestingly, both networks integrate (possibly the “socio-cognitive” network recruits the “emotional” one) to form a new “social perception network”. This can be seen because the amygdala and STS, in the two different parts of the brain, are activated together. The more fathers spend in direct childcare, the more these two networks act together.

Our study looked at 89 parents in three groups: primary caregiving heterosexual mothers, secondary caregiving heterosexual fathers and primary caregiving homosexual fathers. We visited the families’ homes. We videotaped parent-infant interactions, examined “synchrony” – the mutual social reciprocity between a parent and an infant, and how the parent responded to his/her infant signals, and measured oxytocin levels in both parents. A few days later, during MRI scans, parents watched those videos to test parental brain response to infant-related stimuli.

Our findings provide the first support of the brain malleability with caregiving experience in human fathers, and have led us to conclude that evolution has created alternative forms of adaptation to the parental role in humans, other than the ancient pathway that is linked to pregnancy, birth and lactation in women only. The changes come about with practice, day-by-day caregiving and experiences in all parents, mother, fathers, biological and non-biological parents.