Why Do Babies Laugh?

How does a three month old child know what is funny? Maybe it is in our human DNA.

A couple of weeks ago, I posted on social media a video of our first grandchild, Poppy, belly laughing at a 60's vintage Playskool toy we rehabilitated. My wife found it in the attic of my in-laws' house down in Mississippi a few years ago, and when Poppy was exposed to it at just three months old, she thought it was the funniest thing ever.

How do babies from all over this globe, with so little exposure to the world, know when something is funny?

Beyond that, how do they know a smile signifies happiness or familiarity? Why not some other physical sign or signal? How can such a context for either be constructed in such a short period of time?

These questions have been marinating in my head ever since I first heard Poppy genuinely guffaw. I mean hard, deep laughter. It's really nothing new; our children did it too, but back then, I think I was too busy or too preoccupied with not dropping them on their heads to consider the deeper meaning of laughter at such a young age.

People often say that laughter is just a natural reaction, akin to crying when babies are hungry or uncomfortable. These reactions can be traced to something physical – an empty tummy, too long without a nap, being too hot or too cold – something tangible that we as parents and grandparents eventually learn to interpret, sometimes setting our watches by feeding times.

But I'm not sure laughter is the same. It seems to me that laughter is created by situations that stimulate the brain; it's less sensory and more intellectual, something far more complex.

Charles Darwin observed his own children as they grew, publishing these observations eighteen years after "On the Origin of Species." He theorized that pleasure causes babies to smile and laugh. But how do babies understand pleasure with such immediacy? Is it merely the absence of discomfort or pain?

Is it possible that laughter is encoded in our DNA? I've studied and written about epigenetic memory – I included it in my first attempt at a novel, a “thriller” several years ago. Epigenetics explores heritable characteristics passed through DNA, and I became fascinated by the possibility of ancestral memories being transmitted this way.

In my novel, the son of a father who was captured in Vietnam and transported to China discovers that he has knowledge and skills in areas he had never been trained. He later finds out that the stress and torture his dad experienced in China pierced the barriers of his dad’s DNA to reveal survival mechanisms that allowed him to escape Chinese imprisonment and that after his return to the US, the Army had worked with is dad to create an even stronger connection to those memories.

He finds this out after his own experience of being kidnapped in China and targeted for experiments – because the Chinese scientists had been tracking, he and his father.

The main character is drawn from some of my own experiences, of lucid dreams and awareness of things – times and places, I have no idea how I know. I believe at some point, most of us experience “memories” we cannot explain, but they seem as real as what happened five minutes ago.

Could it be that when we experience déjà vu, we are accessing memories from someone in the distant reaches of our family tree? What about how humans instinctively understand certain aspects of the natural world, or how animals, particularly mammals, know behaviors critical to survival from birth?

Are smiles and laughter the physical remnants of our ancestors' happy memories? If mammals are encoded to understand things from birth, and we are fundamentally mammals, it seems possible we might also inherit some of our forebears' happiness.

I'm no scientist or researcher, but the laughter of innocents suggests there's more to us than just a meat and bone-filled sack of skin. What an amazing thing it would be to understand why babies laugh and then to intentionally access that centuries-deep reservoir of happiness.