Learning to crawl

The effects of infants' age, body dimensions, and experience on the d evelopment of crawling was examined by observing 28 infants longitudi nally, from children's first attempts at crawling until they began wa lking. Although most infants displayed multiple crawling postures en route to walking, development did not adhere to a strict progression of obligatory, discrete stages. In particular, 15 infants crawled o n their bellies prior to crawling on hands and knees, but the other 1 3 infants skipped the belly crawling period and proceeded directly to crawling on hands and knees. Duration of experience with earlier fo rms of crawling predicted the speed and efficiency of later, quite di fferent forms of crawling. Most important, infants who had formerly belly crawled were more proficient crawling on hands and knees than i nfants who had skipped the belly-crawling period. Transfer could not be explained by differences in infants' age or body dimensions alone . Rather, experience using earlier crawling patterns may have exerte d beneficial effects on hands-and-knees crawling by shoring up underl ying constituents common to all forms of crawling postures.