Summary of Babies on the Brink
The video "Babies on the Brink" challenges the long-held belief that infants develop an innate fear of heights through crawling experience. It revisits the classic 1960 Gibson and Walk "visual cliff" experiment, which showed that babies initially crawl over an apparent drop-off but later avoid it, leading to the assumption that crawling teaches fear of heights. However, Dr. Karen Adolph’s research reveals that this interpretation is flawed and circular: babies avoid the drop-off not because they are afraid, but because they are learning to perceive the relationship between their bodies and the environment.
Dr. Adolph’s lab uses real cliffs without safety glass and adjustable slopes to test infants’ responses across multiple trials and locomotion stages (sitting, crawling, cruising, walking). The data show that babies spend time exploring edges with curiosity and neutral or positive expressions rather than fear. Their ability to judge safe versus risky surfaces improves with experience in each new locomotion mode, producing four distinct learning curves rather than a single fear response.
The conclusion is that babies are not learning to fear heights but are learning to assess affordances—what their bodies can safely do in different environments. This perceptual learning happens without fear, aligning with Eleanor Gibson’s later view that animals and humans simply “know not to go” off edges without emotional fear.
Presenters/Contributors:
- Dr. Karen Adolph (Infant Action Lab researcher)
- Luke Grin (Science Friday contributor/narrator)
Notable Quotes
— 02:01 — « Babies avoid going over the drop off because they're afraid of heights. How do we know they're afraid of heights? Because they avoid crawling over the drop off. So as you may have noticed the argument is circular. »
— 02:17 — « Babies don't look particularly scared; it is a perfectly safe surface of support. So after one trial human infants cleverly figure this out and then they will crawl over the drop off. »
— 04:13 — « There seem to be four learning curves in development as babies learn to sit, crawl, cruise, and then finally walk. »
— 04:23 — « If they were afraid of heights, you should just be afraid of heights in the rain and on a train and in a tree. You shouldn't see four separate learning curves. »
— 04:34 — « What babies are learning over weeks of sitting, crawling, cruising, walking is to perceive the relations between their bodies and the environment; they're discovering what's possible and what's just a little too far, and you can learn that without feeling any sort of fear at all. »
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News and Commentary