Thursday, September 15, 2011

Beyond Physical Milestones, Part II: Maturation

(Please note, this is an updated version of a previously published post...)
The first major proposed solution to Bernstein’s problem is known as maturation theory or the theory of neural networks.  Here, psychologists and others propose that an infant’s physical milestones occurred in a set sequence that is determined by innate forces (like genes).  Most also believe that these developments are closely linked with the development of the central nervous system. 
In the late 1920s, the German professor and pediatrician Albrecht Peiper conducted a series of neurological observations on newborns. He was not overly interested in the age of the babies- simply the development of neurological activity.  As a result of his research, however, he was able to see patterns in the ages and brain activities of the babies.  Furthermore, he observed that reflexes disappear as brain activity increases.  More specifically, he observed the slow diminishing of the reflexes until they completely disappear.  For example, the Moro or startle reflex morphs into what Peiper referred to as the “parachute reflex” before vanishing.
Child psychologist Arnold Gesell, who was known as the “baby doctor” until the rise of Dr. Spock and is one of the leaders in maturation theory research, believed that human growth should be studied through growth patterns, which followed the increased ability to coordinate different parts of the child’s growing body, largely as a result of the development of the nervous system.  Gesell believed that all children go through a process of maturation in similar, sequenced stages; in fact, many of the milestones commonly mentioned in baby books (lifts head, rolls over, etc.) are based upon the work of Gesell and other researchers with similar theories. 
It should be noted that, given their focus on biological aspects of development, Peiper’s and Gesell’s research supports the “nature” fans in the nature vs. nurture debates.  As such, some challenge that his growth patterns do not recognize the full potential of children who are in learning-rich environments and that children can progress much faster than Gesell’s observed patterns.  Peiper would counter this argument; however, as he believed that motor development was essentially completely dependent upon brain development.  One of his studies mentioned a 6-month old girl who suffered a hip injury and was placed in a full cast until she was 18 months old.  At that time, the full cast was replaced with a half cast.   One day later, she was walking!  Rather fascinating.  Other research (from 1940) that supports the idea that nurture (i.e. the environment) plays little role in the development of motor skills focuses on Hopi Indian babies.  For the first months of life, the Hopi babies were carried on a cradleboard and swaddled so tightly that their movements were largely restricted. Still, they began walking at about the normal time.  For full disclosure, given the very nature of this blog, I believe that the environment in which a child is raised plays an important role in development.
Gesell’s research emphasized the development of the nervous system as children progress through each stage.  For example, infants cannot control the movement of their eyes at birth.  They circle around without focus.  Soon, however, they are able to focus at specific objects, likely human faces.  This shows the development of nerve impulses from the brain to the eye.  Later, infants are able to follow toys that their parents hold in front of them with their eyes and even turn their heads, demonstrating further development of the nervous system to exert control on gross muscle movement.  Next, babies are able to focus on objects they are holding in their own hands- coordinating the nerve impulses to the eyes, head, and hands.  Eventually, babies will be able to pick up items with their fingers (the pincer grasp- using the index finger and thumb is typically not mastered until about 10 months). 
Beyond his study of development in coordination with the development of the nervous system, one specific pattern that Gesell first observed is known as reciprocal interweaving.  The pattern focuses on the theory that opposing forces (either muscles or hands or even personality traits) alternate dominance until the baby masters a movement or achieves a preferred movement.  During the development of walking, reciprocal interweaving takes place between extending the leg muscle and bending the leg muscle.  This pattern is also seen in the development of handedness.  Babies sometimes use their left hand, sometimes their right, and sometimes both.  Eventually, they will develop a preference for one hand, typically at around 2 years.  Gesell even believed that a baby’s personality goes through a process of reciprocal interweaving.  Until about age 5, the child may alternate between introversion and extroversion.  Some shifts may continue between the two until about age 16.  
In relation to child rearing, perhaps Gesell’s most important contribution is the fact that he strongly believed that each child is an individual and should be treated as such.  While, as previously stated, he believed that all humans go through sequenced maturation that is biologically dictated by genes, he believed that the timing of this growth and development varies from child to child, perhaps as a result from differences in a child’s temperament.  Gesell believed that a culture should adapt to meet the needs of each child’s temperament, despite whether the child was ahead of or behind on Gesell’s observed milestones. 
In order to do this, parents should take their cues from their children.  Gesell was a strong supporter of feeding on demand, stating,

The infant is fed when he is hungry; he is allowed to sleep when he is sleepy; he is not roused to be fed; he is changed if he fusses on being wet; he is granted some social play when he craves it. He is not made to live by the clock on the wall, but rather by the internal clock of his fluctuating needs.

Crain, W. (2011). Theories of development: Concepts and applications. New Jersey:      Prentice Hall.
Eliot, L. (1999). What’s going on in there? New York: Bantam Books.
Parmelee, A. (1962). European Neurological Studies of the Newborn. Child Development, 33(1). 169-180.
 Salkind, N. (2004). An introduction to the theories of human development. California: Sage Publications.
 Sporns, O. & Edelman, G.. (1993). Solving Bernstein's problem: A proposal for the development of coordinated movement by selection. Child Development. 64(4). 960-981.

1 comment:

  1. Gesell's theory of reciprocal interweaving seems fairly intiuitive. I wonder if it has any application to adults learning new movements? I would say that whenever I try to do yoga, I experience "opposing forces (either muscles or hands or even personality traits) alternat[ing] dominance until [I] master a movement or achieve a preferred movement." :)


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