Early pioneers described the development of an infant’s motor skills in great detail. In the 1930s and ‘40s, Arnold Gesell identified 22 stages in the development of crawling, beginning with the lifting of the head from a prone position and ending with an even, balanced crawl on hands and feet. Myrtle McGraw similarly identified seven primary stages in the development of walking, from a newborn’s stepping movements to the baby’s ability to walk independently by the end of its first year. For these pioneers, motor development was a consequence of neuromuscular maturation, that is mainly independent changes in an infant’s brain, its muscles and last but not least its growing skeleton.
This theory of neuromuscular maturation became the popularly accepted explanation for motor development for the next forty years or so. It was not until the 1980s that new research methods and technologies allowed researchers to analyse and measure the development of infants’ motor skills in a different way. One such way is the Dynamic Systems Approach, which was developed by the psychologist Esther Thelen, building on the work of a Russian physiologist Nicholai Bernstein. In this account, new motor skills are believed to emerge from the coming together of a variety of interacting factors. For example, in order for a child to walk independently a number of these factors must be in place: the child’s muscles must be powerful enough to counteract the effects of gravity. As mentioned earlier, the stepping instinct is common in newborn babies, but they lack the bodily strength to maintain an upright position. However, when they are placed in water, thus making them lighter, they begin to make stepping motions. When they are removed from the water, the action ceases. The stepping reflex normally disappears after a few months. By the way, as I’m sure many of you will know newborn babies can swim; however this ability is lost with age and has to be relearnt. In order to walk a child should also have lost the top-heavy body proportions typical of infants. The resulting lowering of its center of gravity gives it better balance and means that it does not have to hold on to things in order to remain upright. They also need a reason to walk. If the baby has no need to go anywhere, why should it? Very young babies cannot see that well, but as its vision and brain matures, it can identify objects from a distance and so its interest is aroused. At the same time this improvement in perception makes it more aware of its environment. In other words it can identify the nature of its surroundings and the type of terrain it needs to traverse, making progress possible.
Perception plays a more important role in another approach to motor skills development—the Perception-Action approach, which was inspired by the work of Jane and Eleanor Gibson. For them, there is a strong correlation between our perception of the world around us and our ability to perform movement within it. In other words, our ability to move is not just down to the physical development of our bodies, but also our perceptual ability. For an action to be planned and executed successfully, we need to have perceptual information about certain properties of the environment, our bodies and the relationship between the two. At the same time, we usually acquire sensory information through the use of movement. For example, we may use exploratory movement of body parts such as the hands, feet, eyes and head to generate perceptual information. In a similar way, actions generate more information for perceptual systems. Furthermore, motor development does not stop after infancy. After mastering basic postural, manipulative and locomotor skills, children acquire many more abilities: writing, playing an instrument, etc. While movement is stiff, wasteful and uncoordinated at first, with practice it becomes progressively more rhythmical, smooth, and efficient.