Wednesday, July 1, 2009

How Early Experiences Effect Brain Development!

In most regions of the brain, no new neurons are formed after birth. Instead, brain development consists of an ongoing process of wiring and re-wiring the connections among neurons. New synapses between cells are constantly being formed, while others are broken or pruned away. This happens throughout life. However, in early childhood the brain is genetically programmed to produce more synapses than it will ultimately use. Indeed, by 8 months of age a baby may have an astounding 1,000 trillion synapses in his brain! This blooming of synapses happens at different times in different areas of the brain. Development then proceeds by keeping the synapses that are used and pruning away those that aren’t. The pruning of synapses happens over the childhood years as the different areas of the brain develop(Huttenlocher & Dabholkar, 1997).

Our brains shape and reshape themselves in ways that depend on what we use them for throughout our lives. Learning language is a nice example of how experiences contribute to each person’s unique pattern of brain development. The ability to speak and to understand other’s speech requires only the minimal opportunity to communicate that almost all children experience. However, which language a child learns to speak depends on the language he experiences, and his brain will adapt to this specific language. When an infant is 3 months old, his brain can distinguish several hundred different spoken sounds, many more than are present in his native language. Over the next several months, however, his brain will organize itself more efficiently so that it only recognizes those spoken sounds that are part of the language that he regularly hears. For example, a one-year-old baby will not recognize that "la" is different from "ra," because the former sound is never used in his language. During early childhood, the brain retains the ability to re-learn sounds it has discarded, so young children typically learn new languages easily and without an accent. After about age 10, however, plasticity for this function is greatly diminished; therefore, most people find it difficult to learn to speak a foreign language as well as a native speaker if they only begin to learn it in adolescence or adulthood. More importantly, early experiences can determine how proficient a child becomes in his or her native language. Researchers found that when mothers frequently spoke to their infants, their children learned almost 300 more words by age 2 than did their peers whose mothers rarely spoke to them (Huttenlocher et al., 1991; Hart & Risley, 1995). Furthermore, studies have suggested that mere exposure to language such as listening to the television or to adults talking amongst themselves provides little benefit. Rather infants need to interact directly with other human beings, to hear people talking about what they are seeing and experiencing, in order for them to develop optimal language skills. Unfortunately, many parents are under the mistaken impression that talking to babies is not very important because they are too young to understand what is being said.

Children who receive sensitive, responsive care from their parents and other caregivers in the first years of life enjoy an important head start toward success in their lives. The secure relationships they develop with the important adults in their lives lay the foundation for emotional development and help protect them from the many stresses they may face as they grow. Researchers who have examined the life histories of children who have succeeded despite many challenges in their lives consistently found that these people have had at least one stable, supportive relationship with an adult (usually a parent, relative, or teacher) beginning early in life (Werner & Smith, 1992).

Negative early experiences can also profoundly affect the development of the brain. Unfortunately, child abuse and neglect are pervasive social problems. Maltreatment increases a child’s risk of developing depression, self-destructive behavior, eating disorders, attention deficit disorders, drug and alcohol problems, sexual promiscuity, and delinquency. Many researchers believe that these effects can be partly explained by understanding how chaotic, stressful, and traumatic experiences affect brain development.


Huttenlocher, J., Haight, W., Bryk, A., Seltzer, M., & Lyons, T. (1991). Early vocabulary growth:
Relation to language input and gender. Developmental Psychology, 27, 236-248.

Huttenlocher, P. R., & Dabholkar, A. S. (1997). Regional differences in synaptogenesis in the
human cerebral cortex. Journal of Comparative Neurology, 387, 167-178.

Werner, E. E., & Smith, R. S. (1992). Overcoming the odds: High risk children from birth to
adulthood. Ithaca, NY: Cornell University Press.

Dr Mahani

No comments:

Post a Comment