Why do babies
learn skills in
the same order?
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The full narration of the video.
Around the world, nine in ten babies learn their skills in the same order. Head up, then rolling, sitting, crawling, standing, and walking last of all. The toddler downstairs is already walking. Yours is still crawling, and it's hard not to worry.
Let's follow one baby from lying down to standing up, and see who wrote this timetable. A newborn's head is huge, about a quarter of its whole body length. The neck and back muscles have to hold up that big head first.
The brain's wiring to the body runs roughly from head to toe, switching on one section at a time. First the neck, then the shoulders and waist, and the legs come last. That's why holding the head up always comes first, and walking always comes last.
It's a bit like school: you learn adding before multiplying. If you can't add, multiplying makes no sense. Babies are the same: a steady head lets them sit, steady sitting lets them crawl, and strong hips and legs let them stand.
Every baby is using the same textbook, so the order barely changes. But the brain isn't the only thing holding babies back. Hold a newborn under the arms, and once its feet touch a table, its legs step, one after the other.
At around two months, the stepping disappears. Scientists used to think the brain had switched it off. Then someone noticed the legs fatten up fast in those weeks. Too heavy to lift.
Put the baby's legs in water, let the water hold them up, and the stepping comes right back. A new skill waits on the brain, and on the body growing into the right shape. This head-to-toe order has a textbook name: the cephalocaudal principle.
The milestone chart in your child's health booklet is this textbook's table of contents. Same textbook, very different pace. In World Health Organization data on walking alone, the earliest start just past eight months, the latest near eighteen, and all of it is normal.
Practice speeds things up too: where parents prop babies up to sit every day, plenty can sit alone by five months. And a premature baby fits the chart once you count its age from the due date. If a baby is far outside the range, or loses a skill it had, ask a doctor.
And this textbook skips pages: some babies never crawl at all, and just stand up and walk. Take a guess: out of a hundred babies, how many never crawl?
Nine in ten babies
take the same path
Head up, then rolling, sitting, crawling, standing, and walking last of all.
The World Health Organization followed more than 800 healthy babies in five countries. About nine in ten learned these big movements in the same order.
But “around the same age” is only half true. The order lines up; the timing spreads out a lot. More in part 5.
Head to toe,
one section at a time
A newborn’s head is about a quarter of its whole body length.
The neck and back have to hold up that big head first. The brain’s wiring to the body comes online roughly from head to toe, one section at a time: first the neck, then the shoulders and waist, and the legs last.
That’s why holding the head up always comes first, and walking always comes last. Textbooks call this the cephalocaudal principle, which just means “head to tail”.
For why the head is so big, see Why do babies have a soft spot on their head.
Like the same
textbook
You learn adding before multiplying. If you can’t add, multiplying makes no sense.
Babies are the same: a steady head lets them sit, steady sitting lets them crawl, and strong hips and legs let them stand. Every baby uses the same textbook, so the order barely changes.
Waiting for the brain
isn’t enough
Hold a newborn under the arms, and once its feet touch a table, its legs step, one after the other.
At around two months, the stepping disappears. Scientists used to think the brain had switched it off. Then someone noticed the legs fatten up fast in those weeks: too heavy to lift. Put the legs in water, let the water hold them up, and the stepping comes right back.
A new skill waits on the brain, and on the body growing into the right shape. For all that kicking and waving, see Why do little babies flail their arms and legs.
Same textbook,
very different pace
Just past eight months, or close to eighteen: all of it is normal.
That’s the range for walking alone in the WHO study. Practice speeds things up too: in some places parents prop babies up to sit every day, and plenty of them sit alone by five months.
For a premature baby, count its age from the due date (its “corrected age”) and it fits the chart. The milestone chart in your child’s health booklet is this textbook’s table of contents.
This textbook
skips pages too
Some babies never crawl a single day; they just stand up and walk.
In that study, those babies were healthy too. The order is the general direction; not every page has to be turned.
Half a year apart is still normal.
Quick check
Newborns step when held up, then stop at around two months. What turned out to be a big reason?
With the legs held up in water, the stepping comes right back, so heavy legs are a big part of it.
