Tuesday, May 10, 2011

Learning to Walk

For the inaugural learnalittle post, let’s start at the beginning: learning to walk.

After learning to crawl, sit-up, scoot, and cruise, most babies begin to walk anywhere between 9 and 18 months. This basic but vital skill emerges as infant muscle strengthens and motor cortex function refines. But what explains the big age range in which a child might take their first steps?

When a child first walks is likely determined by a mix of environment, genetics, individual temperament, and actual movement practice. As this last factor is easiest to control, many developmentally obsessed parents take special precautions to ensure their baby doesn’t fall behind, some going to extreme measures.

But to what extent does practice trump physical and neurological development? A famous 1940 study considers the Hopi cradleboard custom. At the time, most Hopi babies spent the majority of their first months snuggly strapped to their mother’s back, which would – presumably – preclude any walking practice. However, when compared to their non-cradleboarded cousins, there was no difference in when they began walking on their own.

This contrasts with a 1987 study of the Ache people, a nomadic tribe in the rain forests of Paraguay. Until they hit three years, Ache children spent 80 to 100% of their time in direct contact with their mothers. Further, when these hunter-gatherers make camp, they tend to clear just enough ground to sit and sleep – not an ideal training site for the aspiring toddler. As a result, Ache children tend to take their first steps at an average 23 months, about year after their US counterparts. On the flip side, once Ache children begin moving around on their own, they climb tall trees daily and walk effortlessly along branches before they hit double digits. Even though these children are given little room to practice, it seems they have no problem getting around in the long run. While there might be something to the practice theory, it seems a little less vital than some people would like you to believe.

On a parting note, I’d like to address a popular myth (at least one I’ve heard a few times): babies can’t walk because they’re born without kneecaps. The newborn body actually far outstrips the 206 bones of the adult skeleton, with a mix of over 300 bone and cartilage elements.  It’s true that babies’ kneecaps won’t show on an x-ray, but that’s because for the first 3-5 years, kneecaps are cartilage instead of bone. Not only can babies walk on these proto-kneecaps, their spongy composition is far more suited for this trial and error process than the breakable bones they will become.

So here’s a fitting moral to mark the first steps of this blog: regardless of how we learn to walk on our own – or how long it takes us to get there – it’s OK to fall down in the process.

Sources: 123