Three Ways that Every Brain is Unique
School systems tend to assume that children’s brains are pretty similar, that most kids can learn specific content at a specific age. All humans are intelligent, but there are many different kinds of intelligence, different ways for a child to be intelligent, different kinds of problems each child can solve. Books have been written about differences and challenges in learning, but there is one undeniable way that children learn differently. Simply, every child’s brain is unique; it is different from every other child’s brain. There are three guaranteed ways that each brain is different: genetics, development, and experience.
Genetic Uniqueness
With the exception of identical twins, every child is genetically unique with half of the child’s DNA coming from mother’s genes and half from father. DNA forms the fundamental architecture of each person that, by itself, guarantees each child has a unique brain. Some personal traits like eye and hair color are clearly defined by certain genes, but genes associated with learning ability are harder to identify for two reasons. First is that learning ability is much harder to categorize than eye and hair color. Second is that learning ability results from the interactions of billions of neurons in the brain in ways that are extraordinarily hard to measure.
An Athletic Analogy for the Learning Brain. It’s estimated that 20 to 80 percent of athletic performance is genetic. Can there be similar differences in mental performance? Since physical performance is much easier to measure than mental performance, the genetic association is instructive even though is a totally unproven analogy to mental performance. Here’s how top athletic performance is associated with the possession of certain gene variants:
- A specific HFE gene mutation improves oxygen transport: this gene variant is 12 times more frequent among international champions compared to general population. (Hermine et al., 2015)
- The ACTN3 (R/R) gene is associated with athletic power (muscular performance). (Yang et al., 2003, 2009; Papadimitriou et al., 2008; Eynon et al., 2009)
- The ACE (I/I) and COL5A1 genes are associated with athletic endurance (sustained effort). (Montgomery et al., 1998; Brown et al., 2011; Ma et al., 2013)
(optional) To learn more about genes related to athletics, read: Genetic influence on athletic performance, (Guth, L.M. & Roth, S.M., 2013). Describes the influence of genes, specifically ACE I/I (endurance) and ACTN3 R/R (power) on top atheletic performance: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3993978/
Developmental Uniqueness
Every brain is unique due to developmental differences. The genetic associations above do not determine athletic ability; they influence it along with many other factors. Similarly, genetic differences alone do not determine learning ability, but they have a strong influence. For this discussion, we’ll define two kinds of brain development: how the brain develops through the period from before birth through age 3, and how the brain prunes (or deletes) neuronal connections (synapses) from about ages 3 to 8.
The Developing Brain. Neurons begin forming in the second trimester. While genes tell the new neurons roughly where they should go as the brain expands, a neuron’s journey and role is affected by the mother’s health, by competing neurons, and by the emerging connectivity of the growing brain. This is called neuronal migration and happens most actively 10-to-20 weeks after conception. Consider that a growing plant’s leaves follow a genetic pattern, but the exact placement, size, and shape are emergent properties that guarantee that each leaf is unique. Similarly, just through neuronal growth, each child’s brain is different as it grows from the second trimester through age 3. During this time is massive growth in neuronal synapses, the trillions of connections among neurons. Synapses grow and are strengthened with use as when the speech that a baby hears strengthens the auditory language synapses. Synapses that are not used, such as those which could produce sounds in languages the baby doesn’t hear, are eliminated or pruned.
Pruning: Half of the Synapses are Eliminated. By age three, an infant has twice the number of synapses as an adult. Roughly half of the synapses, those connections where learning occurs, are pruned between the ages of 3 and 8. When synapses such as those for vision or learning discrimination are not used, they are eliminated forever. If a baby’s eyes are not exposed to light for the beginning of its life, those neurons are pruned, and the baby will never be able to learn to see normally. During pre-school and early elementary years, the child’s environment and experiences shape the learning brain by eliminating connections not used, permanently damaging or eliminating certain kinds of learning.
Environmental, Experiential Uniqueness
Every Experience Changes the Brain. A child growing up in Switzerland automatically learns French, German, Italian, and a bit of English. Growing up in Singapore, she would effortlessly learn to understand and speak Mandarin, Malay, and English, all like a native speaker with no accent. A child growing up in a mono-lingual environment not only doesn’t learn other languages in childhood, but he loses the capability of learning them without a great deal of effort. A child growing up on a farm knows how cow and horse babies are made and born before entering school. Growing up in a family of readers with a wide variety of books and magazines, a child who is read to and who hears others reading has a mental framework for reading that children in an illiterate family doesn’t have. You can imagine many experiential differences that affect a child’s ability to learn certain material at certain ages. Artists, musicians, mathematicians and others have actually changed their brains, and that change begins when their interest and practice begins in childhood. Your environment and experiences also affect the expression of your genes, when a gene activates or deactivates.
Each child is ready to learn ideas and skills that connect to what she already knows or can do. Without those experiences, children have to somehow “build” new connections. Imagine you are 40 years old and must learn a language very different from the only one you know. Imagine an English speaker trying to learn Arabic or a Japanese speaker trying to learn English. That’s what it is like for a child trying to learn something for which he is not developmentally or experientially ready. Brain differences may be especially pronounced due to a child’s culture in a minority or majority community, a low-income or high-income neighborhood, or an extended or broken family.
EVERY Brain is Unique. There is no one-size-fits-all curriculum or teaching formula that can be successful. This is one of the greatest challenges of education. Several approaches to this challenge have been at least partly successful, and one hold hope for the future. Montessori and Finnish schools have strong experiential approaches that help develop common foundational brain frameworks that support future learning. The Differentiated Learning movement from the 1990’s attempted to address this issue, and emerging Personalized Learning ideas could help future schools and children.
For more information on brain development, visit “Baby’s Brain Begins Now: Conception through Age 3,” http://www.urbanchildinstitute.org/why-0-3/baby-and-brain