The claim

「Early walkers are smarter」

Q: Early walkers are smarter

Myth — The WHO motor development study puts walking alone between 8.2 and 17.6 months (1st to 99th percentile) — a window of nearly nine months, all of it normal. Timing has no bearing on intelligence. What matters is not any single milestone but whether development keeps moving forward across the board. The WHO Motor Development Study assessed 816 children in Ghana, India, Norway, Oman and the USA and produced "windows of achievement" (1st to 99th percentile) for six gross motor milestones: sitting without support 3.8–9.2 months, standing with assistance 4.8–11.4 months, hands-and-knees crawling 5.2–13.5 months, walking with assistance 5.9–13.7 months, standing alone 6.9–16.9 months and walking alone 8.2–17.6 months. The study concludes that these windows represent normal variation among healthy children. It also found that 4.3% of children never crawled on hands and knees at all.

Verdict

Myth

The WHO motor development study puts walking alone between 8.2 and 17.6 months (1st to 99th percentile) — a window of nearly nine months, all of it normal. Timing has no bearing on intelligence. What matters is not any single milestone but whether development keeps moving forward across the board.

Where the claim comes from

Walking is the most visible milestone — relatives notice at once whose baby stepped first — so walking early gets read as proof of being "advanced" or bright. But gross motor skill is only one strand of development.

What the evidence says

The WHO Motor Development Study assessed 816 children in Ghana, India, Norway, Oman and the USA and produced "windows of achievement" (1st to 99th percentile) for six gross motor milestones: sitting without support 3.8–9.2 months, standing with assistance 4.8–11.4 months, hands-and-knees crawling 5.2–13.5 months, walking with assistance 5.9–13.7 months, standing alone 6.9–16.9 months and walking alone 8.2–17.6 months. The study concludes that these windows represent normal variation among healthy children. It also found that 4.3% of children never crawled on hands and knees at all.

What to do instead

Look at the whole picture rather than one item: the study itself stresses overall development.
There is no need to compare months with other children — inside the window, a few months earlier or later is normal variation.
Give your child plenty of time on the floor to practise at their own pace.

When to see a doctor

Not walking independently after 18 months — that is beyond the upper end of the window (17.6 months). In the study's terms, appearing late is a signal for appropriate screening, so see your paediatrician.
Not just walking: sitting, standing or crawling also falling clearly outside their windows.

Sources

WHO · World Health Organization
World Health Organization. (2006). WHO Motor Development Study: Windows of achievement for six gross motor development milestones. Acta Paediatrica Supplement, 450, 86–95. https://doi.org/10.1111/j.1651-2227.2006.tb02379.x
Direct source · Peer-reviewed paper · checked 2026-10-13

Checked against sources on 2026-10-13