Training the Brain to Form New Maps and Networks
A few decades ago, the prevailing scientific view held that the brain operated within a fixed scope of ability once the “critical period” had passed. But in the 1990s, through a series of experiments, Dr. Michael Merzenich, co-founder of Scientific Learning Corp., discovered that our brains can change well past the critical period—and throughout our lives.
However, learning that takes place after the early developmental period is no longer as easy. Children and adults must work hard to pay attention to the new information they wish to absorb and master.
The maxim commonly used to describe neural learning and reorganization is “neurons that fire together wire together.” It is this “wiring together” that results in the corresponding structural changes in the brain. Timing is key to the process, with neurons that fire simultaneously wiring together to create the neural communication networks.
The space allocated to a neural map evolves over a number of stages. When learning is taking place, a relatively large space may be allocated to the map.
Once a skill is established, the mapped regions become so efficient that fewer neurons are needed, allowing some of the map space to be pruned and reallocated for new learning. This practical “use-it-or-lose-it” process allows us to continue picking up new skills without bumping into space limits in the brain.
As we develop mastery of a skill, our neurons not only become more efficient, but they begin to process information faster. With that faster processing interconnected neurons tend to fire together more readily, creating more efficient, clearer signal transmission. The clarity of those signals has a great deal to do with how easily the brain learns and remembers what the neurons have processed. The clearer the signal, the easier the information can be processed and remembered.
But what if there are gaps or inefficiencies in the maps that have been established?
Poverty and the Brain
Decades of research show that poverty has a significant impact on the brain and its ability to learn. Back in 1995, Betty Hart and Todd Risley published their groundbreaking research that showed that, by age 4, children born into low socioeconomic families are exposed to 30 million fewer words than children from high socioeconomic families.
This means that the brain of a child in poverty has had 30 million fewer opportunities to wire itself for language. It also means that the child is not receiving the auditory neural stimulation required to establish distinct phoneme representations, build vocabulary, and develop age-appropriate oral language skills.
Language is not the only function in the brain that is affected by poverty; many other cognitive skills are, too. More recently, studies by researchers such as Kimberly G. Noble have demonstrated how poverty is tied to structural differences in the brain, with the largest influence observed among children from the poorest households.
For example, neuroscientists have identified differences in the frontal lobe, which affects cognitive skills like organization and self-control—and can impact a child’s ability to pay attention, listen, and learn on demand. They have found differences in the occipital lobe, which is important for spatial skills. In addition, research findings have shown differences in working memory, which is critical for learning at any age and in any subject.
Working memory allows us to hold on to information for a period of time—long enough to do something new with the information, like take notes or solve a problem. For children, working memory is essential for learning language. Unlike vision, where we can often study an image as long as we need to, everything we hear occurs in time.
A speech signal moves very quickly: an average sentence is about 14 seconds long, an average single syllable word lasts only a quarter of a second, and the average consonant sound may last only 1/12 of a second.
Poverty is also associated with chronic stress, which can have a toxic effect on the brain. Neural pathways responding to stress such as fear and anxiety may overdevelop, while other pathways for things such as reasoning, planning, and learning develop more slowly based on the child’s experiences.
Children from poverty—who now comprise 51 percent of all students in U.S. public schools—bring all of these differences with them to the classroom.
(Next page: 5 ways teachers can help train the plastic brain)
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