Babies and ledges--they are two things that seem like they should be diametrically opposed to each other. Yet researchers in child development love to put babies in all sorts of precarious situations to find out what happens, and hopefully learn more about the way children think in the process. The latest shenanigans tested how infants and toddlers of different ages deal with height perception, and suggests that there is a period shortly after they begin crawling/walking in which they may not recognize their own physical limitations.
A 2010 study by New York University developmental psychologist Karen Adolph suggests that young children need to learn (and re-learn) a fear of heights that properly corresponds to their motor skills as they enter a new phase of mobility. Unlike mountain goats, which are born knowing where they should and shouldn't climb, human infants learn their limitations partly through trial and error.
To test this, Karen placed 12- and 18-month-old infants at the top of a wooden "cliff" that could adjust to various heights. They were then beckoned over the edge by their mothers. (Researchers were on hand to safely catch any who actually took the tumble.) It was found that babies who had been crawling for several months generally did not go over drop-offs that were too big for them, even when coached, nor did toddlers who had been walking for a while. But those in the transition phase--the ones who had just started walking or crawling--readily marched right over drop-offs that were beyond their capabilities, including the highest, most hazardous 3-foot plunge. Like teenagers who think they're indestructible, the study suggests that as kids master a new skill, their perception of physical limitations may not keep up with their own ambition.
This doesn't necessarily mean young children are completely without a fear of heights; other research demonstrates that babies do indeed possess a certain amount of innate fear for large drops. (This wasn't the first study to place babies on some sort of ledge and see what happens.) One in particular devised a long, elevated platform for babies to crawl across, while their mothers stood at the other end. In the middle of the platform, the visible "bottom" dropped out, leaving only a glass surface as the floor. When babies encountered this "visual cliff" as an obstacle, they innately sensed danger and looked to their mothers for cues about what to do. Babies whose mothers gave a reassuring look continued right on their merry way. Babies whose mothers were instructed to look worried, however, were able to sense this emotion. They stopped dead in their tracks, sat, and started to cry.
So although young children may possess some innate fears of heights (and may also be coached into disregarding these inclinations if mom says so), the newest study suggest there is a definite learning period, during which tots may lack the proper judgment about what types of terrain are within the capabilities of their new-found mobility. Much like the eyes may want more than the stomach can handle, a baby's brain may envision larger feats than the body is capable of accomplishing.
So as your little one enters one of these windows of recalibration, it's a good time to be extra vigilant. You don't need to protect them from every little spill, but you don't want them taking a 12-foot tumble down the stairs, either. The ledges on stages, landscaping dividers, and playground steps are other potential problem areas. Watch the fall hazards as your tot is learning just what amazing feats their developing mobility can accomplish.
You will find interesting child safety information, teaching materials, books and more on our website at www.keepyourchildsafe.org.