Video: Baby vertigo: Feeling dizzy yet?

I’m not scared (Image: Reuters/Frank Polich)

STEPPING out onto the glass platform of the Willis Tower, 412 metres above the streets of Chicago is enough to make most people dizzy. Not so babies, who are born with no fear of heights. Now it seems that this wariness develops as a result of crawling.

You might think fear of heights would be innate, since falling from high up can result in injury or death. But babies with little experience of crawling are not afraid of heights. “Mothers almost universally report that their babies go through a phase wherein they will go over the edge of a bed or a changing table if a caregiver doesn’t intervene,” says Joseph Campos at the University of California in Berkeley, who supervised the research. Then suddenly, six weeks or so after they learn to crawl, they seemingly become scared.


So what triggers this dramatic shift? To investigate, Audun Dahl, also at Berkeley and his colleagues put babies who couldn’t yet crawl into go-carts that they could control with joysticks. After three weeks of training, the babies were lowered towards a 1.3 metre drop-off. The heart rates of the baby go-carters increased by 5 beats per minute, suggesting they were anxious, while the heart rates of the non-driving babies remained the same.

Babies were also tested in a “moving room” – a room with moving walls and ceiling to create the sensation of being projected forwards. The go-carting babies recoiled backwards when the walls moved, while the other babies moved far less.

This suggests that the act of propelling yourself around in space teaches the brain to become aware of information in the peripheral visual field and use it to correct balance, says Campos. What’s more, the babies that reacted most to the moving room also had the greatest increase in heart rate when they were lowered over the drop-off (Psychological Science, doi.org/m7v).

Crawling teaches the brain to become aware of the peripheral visual field and use it to correct balance

In a separate experiment, babies who could already crawl were tested in the moving room and then positioned near one edge of a large glass table. One side was lined and the other left clear so the babies could see through to the floor. Those who reacted most dramatically to the moving room were most likely to avoid crossing the clear part of the table to reach their mother on the other side.

The finding might also explain why a passenger looking out of a plane window experiences no vertigo, while the same person in a transparent “bubble cockpit” helicopter can be reduced to a gibbering mess. When you look out of a plane window the information in your peripheral vision is relatively fixed, whereas in a bubble cockpit there is far more happening. “The passenger viewing the world through a transparent bubble canopy has to make lots of minute bodily adjustments, and gets a dizzying sensation,” says Campos.

“What is striking about the origins of fear of falling is its intimate connection with self-movement,” agrees Carlos Coelho of the University of Queensland in Australia. He found that people with extreme vertigo become anxious not only when they have to go higher, but also when they have to move laterally at a fixed height (CyberPsychology and Behavior, doi.org/bhgwjm). “Fear of heights also seems to be modulated by movement in adults,” he says.

Look who’s talking now You have to walk the walk to talk the talk – at least if you’re a baby. Learning to walk appears to trigger a spurt in language development, overturning previous assumptions about how babies start to talk. Until now, we assumed that language develops mainly as a function of age. Research also suggests that walking babies spend more time interacting and make more attempts to babble. To investigate further, Walle asked parents of 44 babies who were 10 months old to complete a bi-monthly survey on their baby’s progress towards walking and talking, until their children were 13.5 months old. He noticed a significant spurt in language development when babies started to walk, regardless of how old they were then (Developmental Psychology, doi.org/m8g). Crawling also seems to prompt the development of other skills, such as locating hidden objects and gaining a fear of heights (see main story). “Starting to walk probably expands on those skills because walking takes the child much further,” says Joseph Campos at the University of California in Berkeley. “They get spooked by being separated from their parent,” he adds. “We think this necessitates an improvement in communication to keep track of them.”

This article appeared in print under the headline “No vertigo until you can crawl”