Early complexity supports development of motor behaviors in the first months of life

Complexity in motor behavior is a hallmark of healthy systems. The purpose of this study was to investigate postural complexity during development of early motor behaviors and under two conditions. Twenty-two infants participated from 1 to 6 months of age. Linear and nonlinear measures of displacement of the center of pressure at the base of support were used to quantify magnitude and temporal structure of postural control. Behavioral coding was used to quantify the emergence of midline head control and early reaching. Results suggest that infants have complexity in postural control strategies early in development. This complexity decreases as infants learn motor behaviors, even when magnitude of the postural variability does not change. Infants were able to adapt the magnitude of postural control variability under different conditions. We propose that infants proceed through three stages which support the infant's ability to adapt motor behaviors.