A new study has revealed dads' brains shrink slightly when their baby is born - allowing them to become more empathetic. The brain physically changes in the areas which are linked to empathy and visual processing.
This process contribute to neuroplasticity, the brain's ability to create and form new synaptic connections to adapt to new experiences. Professor Darby Saxbe, of the University of Southern California and senior author of the study, said: "Becoming a parent entails changes to your lifestyle and your biology.
"And it requires new skills like being able to empathise with a nonverbal infant, so it makes sense but has not been proven that the brain would be particularly plastic during the transition to parenthood as well." The study, published in the journal Cerebral Cortex, examined brain scans from 40 expectant fathers – 20 in the US and 20 in Spain.
For comparison, the researchers also studied a group of 17 childless fathers who had been scanned in Spain. For the Spanish fathers (mean age of 35), researchers scanned their brains before their partners became pregnant and then again two to three months after their partners gave birth.
The childless men also underwent scans at similar intervals. For the men in the US, researchers scanned their brains when their partners were in their third trimester (around 30 weeks along).
They scanned the fathers' brains again seven to nine months after the birth. The scientists found that the most significant changes, both in the Spanish and American men, occurred in the cortex — the brain's outer layer which is involved with attention, planning and executive functioning.
Comparisons of the fathers' scans before the babies were born and afterward showed changes in portions of the cortex that affect processing visual information. There were also changes in areas that are part of the brain's default mode network – the part of the brain associated with passive tasks like daydreaming, memory recall or thinking about the future – whereas the childless men had no such changes.
Scientists believe the regions of this network are involved with empathy – thinking about other people's thoughts and feelings. Previous studies of mothers have shown changes in cortical areas which are key for the default mode network.
The women also had changes in their subcortical areas (below the surface of the cortex) that are linked with emotion, threat and reward processing in mothers. This is the key difference between the mothers versus the fathers, the researchers said.
Prof Saxbe said: "It's too soon to speculate with such a small sample but it might suggest that more, higher-order cognitive processing is involved in fatherhood specifically, whereas mothers are also showing change at the more basic mammalian level. In any case, the fact that we have found changes in the cortex both for fathers and mothers suggests that there is some remodelling of the social brain taking place."
