In young infants, activation or inhibition of body movements on perception of environmental events is important to enable them to act on the world or understand the world. To reveal the development of this ability, we observed movement patterns in all four limbs under the two experimental conditions. Infants assigned to the interaction condition…

Two experiments tested the effects of crawling-onset age, amount of crawling experience, and testing age on avoidance of the deep side of a visual cliff apparatus by human infants. Crawling-onset age disciminated between infants because crawling during the tactile phase interferes with later visual control of locomotion. (Author/RD)