The #1 reason why the human species has yet to become extinct

Baby laughter. It's addictive -- especially when it's your own baby who's laughing. Most people will do almost anything for it. They'll drop serious craploads of money, make embarrassing faces, even dance and sing ridiculous songs in a high, off-key falsetto for it.

Yep. Baby laughter. It's the most intoxicating drug ever.

Think about it. What are you willing to do or pay for your highs? For example, would you sing and dance in public for a bottle of wine or a 24 of beer? I'm talking in front of total strangers here -- teenagers, intellectuals, old Italian men, restaurant servers, people in dark business suits, you name it. Or would you prefer to spend the $10-$20 and spare yourself the embarrassment?

Well, when it comes to hearing your baby laugh, you don't even notice those people watching as you gape, snort, chuckle and hop like a crazy person in order to score another hit. And if you did notice, you wouldn't even care.

This is how they suck you in -- and by "they," I mean, all our successive descendants. This how the human race has managed to regenerate itself. Compared to other species, we produce young that are pathetically ill-equipped to survive on their own. Baby chimps are able to hold on to their mother's fur from the moment they're born. Baby tigers start hunting on their own when they're under a year and a half old. And baby gazelles are practically born running.

But what can we do? We can't run. We can't fight. We can't even walk until we're almost a year old. Forget about learning how to feed ourselves -- most of us don't figure that out until we're in our twenties. And by then, most other species have spawned several more generations of themselves.

Not us. The only thing we humans have going for us, biologically speaking, is our enormous brains -- and even they're a liability when we're infants, because thanks to our huge noggins our skull bones aren't even fused when we're born. And those huge noggins are so top-heavy, they'd wobble right off our frail little newborn necks, if our parents didn't do everything in their power to prevent it.

In short, our parents have to do everything for us during the first few years of our life. They have to feed us, clean us, keep us warm, safe, and healthy, and carry us everywhere they go, thus sacrificing the use of at least one of their limbs for many hours on end. They basically have to give up the better part of their lives to ensure we survive.

And why are we as humans willing to do this for our young?

Baby laughter. It's the stuff that drives our evolution.