Humans Are Smart. Why Are Babies So Unsmart?
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Humans Are Smart. Why Are Babies So Unsmart?


Subject A dash 34, neonatal intelligence battery. Trial 17, hour 4, let’s just get on with this. Ok, solve for… solve for X. Looking for more… numbers. We’ll just, I’m gonna, we’ll get back to that
one later. Ok, I’m just going to start my watch. [bang bang bang]
Unorthodox. [banging and baby noises]
It is challenging. [banging]
We’re at 47 minutes. Oh, well if that’s how you’re gonna play then
fine. What is the relationship between these two
objects? [baby noises]
I think he’s gonna get this one! And he’s eating it. You can’t cheat. Marks off for that. Ok this… ahhhhh. Can you spell… Can you spell pituit-
Can you spell P? That is incorrect. Hey Smart People, Joe here. The first thing a baby giraffe experiences
after being born is a 2 meter fall straight down to the ground. But within an hour, it’s standing, walking,
and nursing on its own. And a blue whale calf, after nearly a year
growing inside mom, can swim to the surface moments after being born. Human babies on the other hand? We’re born unable to move or eat on our
own, we can’t communicate or fully sense our world, and we leak. Everywhere. If humans are so smart, why are our babies
so… un-smart? Human babies begin life so undeveloped, that
many people refer to a baby’s first few months of life as the fourth trimester. Compared to other animals, we lie on the “altricial”
end of the spectrum. Compare that with, say, a baby cow, a precocial
animal, whose brain and body is developed enough that they can stand and run just moments
after being born. Tiny humans require a ton of parental care
before we’re ready to be on our own. Our parents not only grow us for 9 months
or so, they carry us, they feed us, they keep us from dying, and teach us how to provide
for ourselves for 15, 18 years… heck these days even over 30 isn’t unheard of. It’s actually totally normal.Ma! I’m shooting a video down here! Gah! Have to start over, edit this. That’s because, well, our brains come out
half-cooked at best. When we’re born our brain is around 30%
the size of our adult brain. That’s the smallest of all of our primate
relatives. Why does our smart species have such small-brained
babies? For a long time, scientists’ best answer
to that question was the obstetric dilemma. Basically, our brains come out as big as they
physically can be. The obstetric dilemma goes like this: if our
brains were any bigger at birth, they wouldn’t fit out the birth canal. And if female pelvises were any wider, they
would make walking and running less efficient… which might not affect your life that much,
but would’ve made it easier for our ancestors to become dinner… which means no babies,
which means no you or me. So here, natural selection found a compromise:
mom’s pelvis stays narrow enough to walk and run, and babies are born earlier so their
noggins don’t get stuck. It’s a pretty logical idea. But it doesn’t hold water. Male and female bodies do have significant
anatomical differences, but research has found that wider or roomier pelvises don’t make
walking and running, AKA “locomotion” less efficient. And, some women already have pelvic openings
wide enough to fit bigger heads and brains. Not every woman does, but if there was strong
pressure from natural selection for roomier pelvises, they’d have become more common. So pelvis size isn’t why our babies come
out half-baked. The real answer might have more to do with
metabolism. The bigger a developing baby gets, the more
it demands from mom. I mean, women grow a completely new organ,
the placenta, not to mention a complete human being, inside their bodies, and that takes
energy! It might be that mom’s ability to provide
enough energy for growing baby determines when baby is born. Humans and all other animals have what’s
called a basal metabolic rate. It’s how much energy we burn when we’re
not doing anything else. A Tour de France cyclist at peak human performance
can hit maybe four or five times their base metabolism. But most of us normal humans? We max out at around two times our basal rate. We just can’t run our biological engines
any higher for very long. Like overclocking a CPU, there’s just a
physical limit to how much extra energy we can create. For the last third of pregnancy, and even
into nursing, a mother is at the limit, burning twice as much energy as before baby. Nine months happens to be right about the
time a growing baby starts to demand more energy than mom can provide, so it’s born. It’s called the EGG hypothesis, or “Energetics
of Gestation and Fetal Growth”. But I like egg. But even energy and metabolism might not be
the full answer. It could be that how helpless our babies are
when they are born has had a big influence on what happens after they are born. How self-sufficient an animal’s young are
at birth can be determined by a lot of things. If they have to run from predators, if their
parents are quickly on the move, or if their egg had enough nutrients to hatch big. But having helpless babies, and helping them
get smarter, might’ve forced ancient human parents to get smarter too. It’s a pretty cool theory. It works like this: When we look at human ancestors, it’s clear
that natural selection favored humans with larger brains, because they tended to be smarter. But human babies’ brains are already born
as big as they can be because of the whole energy thing, so the only way to make a bigger
brain is for the brain to spend more time growing after you’re born. That requires longer parental care, which
requires more intelligent parents, which over time selects for parents with bigger brains. It’s a feedback loop. The more intelligent the parents, the better
and longer they can care for a helpless baby, and the bigger the baby’s brain can eventually
grow. Research tells us that modern human brains
don’t finish developing until about age 25, which means I have been past my peak for
a while, but it supports this idea that intelligent parents caring for their children for longer
have helped extend the amount of time our brains get to grow before they’re done. More intelligence probably made early human
ancestors more social too, which made raising helpless young even easier, which would start
a whole other feedback loop making us more and more social over time. These aren’t the kinds of things that you’d
notice in a generation or two. They’d evolve across hundreds of generations. There are definitely other reasons that our
ancestors’ brains grew. Making tools and hunting animals? That helped a lot. Harnessing fire and cooking food to get more
calories and nutrients helped too. But ask any parent: It is not easy to raise
a helpless baby, especially for a decade or two like humans do. It takes our unique intelligence, and our
unique social abilities to do it. I mean, you give a human baby to a group of
chimpanzees, it’s not gonna end well. In the end, like all interesting and complex
human traits, our extreme intelligence and our babies’ relative lack thereof can’t
be explained by just one reason. It’s a mix of many reasons. Having a baby is not an easy thing to do. But the very fact that humans are so good
at having more humans, and caring for them and each other as deeply and for as long as
we do, is proof enough that we are a very special species indeed. Stay curious. Thanks for watching this video guys, I hope
you enjoyed it. It made me think. You know what else takes a lot of nurturing
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[baby crying]

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