Cliff or step? Posture-specific learning at the edge of a drop-off.

Infants require locomotor experience to behave adaptively at a drop-off. However, different experimental paradigms (visual cliff and actual gaps and slopes) have generated conflicting findings regarding what infants learn and the specificity of their learning. An actual, adjustable drop-off apparatus was used to investigate whether learning to distinguish a step from a cliff transfers from crawling to walking. Experienced 12-month-old crawlers (n = 16) refused to crawl over risky drop-offs but novice 12-month-old walkers (n = 17) stepped repeatedly over the edge. Experienced 18-month-old walkers (n = 18) refused to walk over risky drop-offs but descended using alternative methods. These findings suggest that infants do not acquire generalized responses like fear or wariness of heights. Rather, infants learn to perceive affordances for the experienced action.