Cliff or Step? Posture-Specific Learning at the Edge of a Drop-Off


  • This research was supported by National Institute of Health and Human Development Grant R37-HD33486 to Karen E. Adolph. Portions of this work were presented at the 2009 meeting of the International Society for Developmental Psychobiology, Washington, DC, and the 2010 International Conference on Infant Studies, Baltimore, MD. We gratefully acknowledge Lana Karasik and the members of the NYU Infant Action Lab for help in collecting and coding the data. We thank Samira Iravani for her beautiful illustrations.

concerning this article should be addressed to Karen E. Adolph, Department of Psychology, New York University, 4 Washington Place, Room 410, New York, NY 10003. Electronic mail may be sent to


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.