The Daddy Brain

The Daddy Brain

Cave Dads Set the Standard

Fatherhood has been evolving since the beginning of time. In pre-historic days, high death rates made children necessary for the survival of our species. Naturally, baby humans required more care than other mammals, so two heads and four hands were needed: Mom and Dad. 

A bundle of children meant Dad hunted extra-large Woolly Mammoths to feed them all, and when he returned, his little Neanderthals flashed their bright smiles and turned him to dad-mush. He roughhoused and played with them, and Cave Mom probably warned him not to get the kids worked up before bed. And Cave Dad was a responsible guy: He taught his children the ways of life and prepared them for adulthood. It’s also likely he did all he could to impress Cave Mom with his paternal skills and score points with her.  

Dads Still Have That Prehistoric Biological Push

“The nurse showed him how to change a diaper in the hospital, and it was his first time ever. He had never held a newborn, never changed a diaper, but from the moment he became a dad, he just naturally did it—swaddling, everything.”       — New Mom

So why did this tough, survival of the fittest champ settle down and make huge sacrifices for his family? Brain research has given us answers: Turns out, Cave Dad was fine-tuning his biology to further support fatherhood. He then passed on to his sons, and all descendent dads thereafter, something very special: the paternal drive to protect and care for their family and the instincts to do it well.

Even before his baby’s arrival, Dad’s body starts producing “fatherhood” chemicals that trigger vital changes, including a sharpened awareness of danger, especially in the last month of pregnancy. His brain has more to do once the baby is born, so it installs a “performance chip” for a massive boost. It also cues Dad and Baby brains to link up and grow in a pattern that continually strengthens their relationship: bonding at its finest! 

READ! Dad’s Secret Superpowers

"I'm a heavy sleeper, and my wife used to say you could drive a bus through our bedroom and I wouldn't wake up, but when our daughter was born it was like—snap—you’re up. It's some sort of genetic programming."

— New Dad

Riding Those Chemical Waves 

When your baby is born, Dad gets a biological boost from skin-to-skin baby contact that fires him up and equips him to protect, love and provide for his baby. 

Major chemicals impacting Dad’s brain:


The smiles Dad gets from his baby send bursts of feel-good ("bonding hormone") oxytocin through his body, shifting him into daddy mode. Aside from snuggles and feedings, Dad gets oxytocin from playing, helping him crawl, walk, talk, stack Legos and build forts. Every physical interaction between them triggers oxytocin, which deepens their bond.


Vasopressin helps Dad bond with his baby, strengthens his relationship with you, and reinforces protective instincts: he’s looking at life through a dad lens now.



Driving to the doctor, you may spot some aggressiveness from Dad if another car inches too close to yours. Or he might start pondering which off-road vehicle is best if the zombie apocalypse starts. Cortisol keeps Dad alert and tuned-in to his baby’s cries and ensures he’s on the job.


Prolactin sparks Dad’s instinctual drive to care for his child. It launches during pregnancy and strengthens after childbirth through hands-on baby care. Prolactin is considered a stress hormone since it's released in response to threats. 


At birth, testosterone drops down for about six weeks, which helps Dad ease up and develop paternal patience. Testosterone also supercharges Dad’s reflex to protect his child and surges when he hears a screaming baby: Daddy to the Rescue! 

READ! Dad Bods & Dad Brains

Biological Fusion of Dads & Babies 

Baby’s impact on Dad’s brain only describes the early phase in fatherhood, and it can sound like an automatic love affair. The truth is, hormones trigger instincts deeply embedded in DNA, but what happens with those hormones depends on Dad. Science has proven ongoing physical contact between a father and child is essential for the development of his daddy instincts. In short: Dads absolutely need one-on-one time with their baby to build a lasting physical and emotional bond.

So rest assured: Dad is definitely built for fatherhood. He's primed to be protective and resourceful and will develop an intense drive to care for his baby. 

READ! Science Proves Fatherhood Influences Success

“With dads, the more interaction they get with the baby the stronger their bond becomes."

- New Mom

"Honestly, do as much as you can to help. It's the best thing in the world because the bond I have with him now is incredible. Absolutely incredible."

- New Dad

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