Developmental Direction
The principle of developmental direction was first formulated by Arnold Gesell (1954) as a means explaining increased coordination and motor control as being a function of the maturing nervous system Through observation, Gesell noted an orderly, predictable sequence of physical development that proceeds from the head to the feet (cephalocaudal) and from the center of the body to its periphery (proximodistal). The principle of developmental direction has, however, come into some criticism during the last few years, and should not be viewed as operational at all levels of development nor in all individuals. The observation of tendencies toward distinct developmental directions may not be an exclusive function of the maturing nervous system as originally hypothesized, but it may be due, in part, to the demands of the specific task itself. For example, the task demands of independent walking are considerably greater than those for crawling or creeping There is less margin for error in independent walking than there is in creeping and, in turn, crawling. In other words, it is mechanically easier to crawl than it is to creep, and to creep than it is to walk. Therefore, the apparent cephalocaudal progression in development may not be simply due to maturation of the nervous system, but also to the specific performance demands of the task itself.