DO MOM AND DAD LOVE US DIFFERENTLY?

Yes, thanks to an evolutionary quirk that means homo sapiens dad was roped into childcare much later than mom.

The quirk relates to the massive size of the human brain – it’s six times bigger than it should be for a mammal of our size, which means if a baby went full term, her head wouldn’t fit through the birth canal, mom and baby would die and the species line would come to an abrupt end.

We’ve evolved therefore to birth our babies early, resulting in a baby whose brain isn’t yet fully developed – and hence is incapable of doing anything alone for a significant period of time post-birth.

At the start of human evolution, moms turned to their female kin to help look after their growing horde of babies and toddlers and human fathers were nowhere to be seen. But about 500 000 years ago, evolution caught up with men too and dads finally began to pick up the slack.

We can still see that evolutionary time-lag today. In 2012, Israeli scientists put 15 pairs of parents of six-month-old babies in an fMRI scanner to have their brain activity assessed while they watched videos of their children playing.

Both moms and dads showed activity in the areas of the brain linked to empathy and understanding others’ feelings, equally demonstrating the strong attachment they felt to their child. But in other areas of the brain, there was a distinct difference. In mothers, the evolutionarily ancient limbic system, which reflects the key characteristics of mothering – giving affection and nurturing – was the most active part of the brain.

By contrast, in fathers the relatively young neocortex, which is associated with social cognition, was set alight, seeming to reflect dad’s role in teaching and encouraging his child to strive towards independence. Mothering is as old as time, present in the earliest reptiles, whereas human fatherhood is hardwired into the newest areas of the brain.

Adapted by Alison Roberts from Why We Love by Anna Machin ( Weidenfeld & Nicolson, R335* at Takealot. com). © Anna Machin 2022.

Paternal feelings involves a different part of the brain than maternal ones as men evolved to take part in child-rearing later than women.