Motor Development

Over the first years of life, humans exhibit an increasing ability to coordinate movements of the body. The initial emergence of these motor capacities and their subsequent refinement is often referred to as motor development. The physical development of muscle strength is required for this, but visual perception and skills such as postural control and balance are critical as well. The dynamic systems approach to development has been extremely influential in this area, as it has emphasized the need to consider interactions between physical, perceptual, cognitive, social, and motor development in order to understand any of the individual domains.

In adulthood, motor performance peaks and then gradually declines; motor development thus occurs across the life span. The vast majority of research on motor development, however, has focused on the early increases in motor capacity rather than its later deterioration. This entry does so as well.

Over the past several decades, an increasing amount of research has been devoted to characterizing and understanding human motor development. A good description of the ages at which different motor capacities emerge has been compiled, at least within the context of North American and Western European [Page 697]culture. Within this cultural context, the order and approximate ages at which different behaviors first emerge is quite consistent (see Table 1). This consistency has led to claims that motor development is largely mediated by genetically specified maturation, but cross-cultural and experience enrichment studies have both demonstrated the important roles that cultural convention and environmental support play in motor development.

For instance, in the United States, it is very common for infants to begin crawling between 5 and 7 months of age. In an infant population sampled in urban China, however, the onset of self-produced locomotion was found to occur approximately 3 months later. This is almost certainly not due to genetic differences between American and Chinese infants, but rather to an urban Chinese cultural tendency to set infants down only on thickly cushioned surfaces, on which crawling is more difficult. In other cultures, for instance the Kipsigis of Kenya, babies hold their heads up and walk earlier than North American children. Kipsigi parents deliberately teach these skills to their infants, for instance seating them in holes dug in the ground and surrounding them with blankets to hold them upright. By frequently bouncing children on their feet, Kipsigi parents also promote earlier walking behaviors. As with many other aspects of development, it seems that the course of motor development is influenced by interactions between genetic and environmental influences (i.e., nature and nurture). Researchers now believe that motor development is the outcome of a complex interplay between central nervous system processes, physical and physiological variables, and relevant environmental circumstances.

The progression of motor development has often been described as consisting of four phases. (1) Infant development progresses from reflexes to rudimentary movements such as sitting, crawling, creeping, standing, and walking. (2) Fundamental skills such as running, climbing, jumping, balancing, catching, and throwing are next to develop. (3) During late childhood, more specific movement skills will appear, and the general fundamental skills become more refined and appear more fluid and automatic. (4) In adolescence, the specific movements develop further and become more specialized. Specialization depends on talent, motivation, and the amount of practice with a specific skill.

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