Development of Visually Guided Locomotion: Barrier Crossing by Toddlers

Abstract

The impact of manipulating the physical layout and the perceptual appearance of the environment on motor behavior and perceptual judgments for action was investigated by presenting 12- to 30-month-old toddlers with a visually guided locomotion task involving stepping over a barrier varying in its height. Experiment 1 observed changes in infants' crossing behavior as a function of barrier height, with successful crossing at low heights, failures in crossing as the height increased, and refusals to attempt crossing at the highest barrier heights for younger infants. Experiment 2 manipulated the barrier's perceived transparency and spatial extent, with a finding of increased crossing thresholds at all ages for barriers of greater spatial extent relative to lesser spatial extent, and increased thresholds for opaque relative to transparent barriers at younger ages. Both studies found that crossing thresholds were strongly related to walking experience, suggesting that for infants and toddlers action in the world is experientially scaled.