11.3 Brain Development

Recall that emotional regulation, theory of mind, and left–right coordination emerge in early childhood. The maturing corpus callosum connects the hemispheres of the brain, enabling balance and two-handed coordination, while myelination speeds up thoughts and behavior. Maturation of the prefrontal cortex—the executive part of the brain—allows the child to begin to plan, monitor, and evaluate. All of these neurological developments continue in middle childhood and beyond. We now look at additional advances in middle childhood.

Coordinating Connections

Increasing maturation results “by 7 or 8 years of age, in a massively interconnected brain” (Kagan & Herschkowitz, 2005, p. 220). Such connections are crucial for the complex tasks that children must master, which require “smooth coordination of large numbers of neurons (Stern, 2013, p. 577). One example is learning to read, perhaps the most important intellectual accomplishment of the school-age child. Reading is not instinctual: Our ancestors never did it, and until recent centuries only a few scribes and scholars were expected to make sense of those marks on paper. Consequently, the brain has no areas dedicated to reading, the way it does for talking or gesturing (Gabrieli, 2009).

How do humans read without brain-specific structures? The answer is “a massively interconnected brain.” Reading uses several parts of the brain—one for sounds, another for recognizing letters, another for sequencing, another for comprehension, and so on (Booth, 2007).

Those massive interconnections are needed for many social skills as well—deciding whom to trust, figuring out what is fair, interpreting ambiguous gestures and expressions. Younger children are not proficient at interpreting social cues (that’s why they are told, “Don’t talk to strangers”). During middle childhood, parts of the brain connect to allow better social decisions. (Crone & Westenberg, 2009).

The prefrontal cortex takes decades to mature. For children who want to be rocket scientists, billionaire stock analysts, or brain surgeons, connecting those distant goals with current behavior or social reality is not yet possible. Nonetheless, connections between one part of the brain and another may be crucial because some neuroscientists believe that “social or linguistic disorders could be caused by disruptions in the pathways” of brain connections, not in the neurons themselves (Minogue, 2010, p. 747).

Advance planning and impulse control are aided by faster reaction time, which is how long it takes to respond to a stimulus. Increasing myelination reduces reaction time every year from birth until about age 16.

A simple example is being able to kick a speeding soccer ball toward a teammate; a more complex example is being able to calculate when to utter a witty remark and when to stay quiet. That depends on four quick reactions, not only (1) to realize that a comment could be made and (2) to decide what it could be, but also (3) to think about the other person’s possible response, and in that split second (4) to realize when something should NOT be said.

Pay Attention Some adults think that computers can make children lazy, because they can look up whatever they don’t know. But imagine the facial expressions of these children if they were sitting at their desks with 30 classmates, listening to a lecture.

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Neurological advances allow children not only to process information quickly but also to pay special heed to the most important elements of their environment. Selective attention, the ability to concentrate on some stimuli while ignoring others, improves markedly at about age 7. School-age children not only notice various stimuli (which is one form of attention) but also select appropriate responses when several possibilities conflict (Wendelken et al., 2011).

In the classroom, selective attention allows children to listen, take concise notes, and ignore distractions (all difficult at age 6, easier by age 10). In the din of the cafeteria, children can understand one another’s gestures and expressions and respond. On the baseball diamond, older batters ignore the other team’s attempts to distract them, and fielders start moving into position as soon as the bat hits a ball.

Indeed, selective attention underlies all the abilities that gradually mature during the school years. “Networks of collaborating cortical regions” (M. H. Johnson et al., 2009, p. 151) are required.

One final advance in brain function in middle childhood is automatization, the process by which a sequence of thoughts and actions is repeated until it becomes automatic and routine. At first, almost all behaviors under conscious control require careful thought. After many repetitions, as neurons fire in sequence, actions become automatic and patterned. Less thinking is needed because the firing of one neuron sets off a chain reaction: That is automatization.

Consider again learning to read. At first, eyes (sometimes aided by a guiding finger) focus intensely, painstakingly making out letters and sounding out each one. This leads to the perception of syllables and then words. Eventually, the process becomes so automatic that, for instance, as you read this text, automatization allows you to concentrate on concepts without thinking about the letters, and as you drive down the highway, you read billboards that you do not want to read.

Automatization aids every skill. Learning to speak a second language, to recite the multiplication tables, and to write one’s name are all slow at first but gradually become automatic. Habits and routines learned in childhood are useful lifelong—and when they are not, they are hard to break. That’s automatization.

Measuring the Mind

In ancient times, if adults were strong and fertile, that was usually enough. A few wise men were admired, but most people were not expected to think quickly and profoundly. By the twentieth century, however, a stupid person, even if strong and fertile, was less admired. Because intelligence became increasingly significant, many ways to measure it were developed. As you will see, no method is considered completely accurate.

In theory, aptitude is the potential to master a specific skill or to learn a certain body of knowledge. The brain functions just described—reaction time, selective attention, and automatization—may be the foundation of aptitude, but traditionally intellectual aptitude is measured not by brain scans but by IQ tests. The underlying assumption is that there is one general thing called intelligence (often referred to as g, for general intelligence) and that IQ tests measure that general aptitude.

Originally, an IQ score was literally an Intelligence Quotient: Mental age (the average chronological age of children who attained a particular score on an IQ tests) was divided by a particular child’s chronological age, and the result of that division (the quotient) was multiplied by 100. Obviously, if a child’s mental age was the same as that child’s chronological age, the quotient would be 1. In that case, the child’s IQ would be 100, exactly average for children of that age.

Thus, the IQ of a 6-year-old with a mind typical for 6-year-olds would be 6/6 × 100 = 100. If a 6-year-old answered the questions as well as a typical 8-year-old, the score would be × 100, or 133. The current method of calculating IQ is more complex, but an IQ within one standard deviation of 100 (between 85 and 115) is still considered average (see Figure 11.4).

In Theory, Most People Are Average Almost 70 percent of IQ scores fall within the normal range. Note, however, that this is a norm-referenced test. In fact, actual IQ scores have risen in many nations; 100 is no longer exactly the midpoint. Furthermore, in practice, scores below 50 are slightly more frequent than indicated by the normal curve shown here because severe disability is the result not of normal distribution, but of genetic and prenatal factors.

In theory, achievement is what has actually been learned, not potential (aptitude). Achievement tests in school compare scores to norms established for each grade. For example, third-grade students whose reading is typical of third-grade students everywhere (achievement tests typically have national norms) would be at the third-grade level in reading achievement. [Lifespan Link: Achievement tests are discussed in Chapter 12.]

Note, however, that children who read at the third-grade level could be of any age. If they are, in fact, in the third grade, their reading achievement is exactly on grade level, whether they are 7, 8, or 9 years old. IQ tests take age into account, but achievement tests do not.

The words in theory precede the definitions of aptitude and achievement tests because, although potential and accomplishment are supposed to be distinct, the data find substantial overlap. IQ and achievement scores are strongly correlated for individuals, for groups of children, and for nations (Lynn & Mikk, 2007).

It was once assumed that aptitude was a fixed characteristic, present at birth. Longitudinal data show that this is not the case. Young children with a low IQ can become above average or even gifted adults, like my nephew David (discussed in Chapter 1). Indeed, the average IQ scores of entire nations have risen substantially every decade for the past century—a phenomenon called the Flynn effect, named after the researcher who first described it (Flynn, 1999, 2012).

Most psychologists now agree that the brain is like a muscle, affected by mental exercise—which often is encouraged or discouraged by the social setting. Brain scans show that the neurological structures within each person’s brain grow or shrink depending on past learning in language and music, and probably in other areas as well (Zatorre, 2013).

The idea that intelligence changes over the years is now accepted by almost every expert, whether or not they believe there is such a thing as g, general intelligence. During middle childhood, speed of thought is particularly crucial for high IQ, with working memory also a foundation for intelligence (Demetriou et al., 2013). Both speed and memory are affected by experience.

The reality that scores change over time makes IQ tests much less definitive than they were once thought to be. A more fundamental question is whether any single test can measure the complexities of the human brain. This criticism has been targeted particularly at IQ tests, because those tests assume that there is g, one general aptitude. According to some experts, children instead inherit many abilities, some high and some low, rather than any g (e.g., Q. Zhu et al., 2010).

Two leading developmentalists (Sternberg and Gardner) are among those who believe that humans have multiple intelligences, not just one. [Lifespan Link: Sternberg’s three intelligences are discussed in Chapter 21.] Gardner’s concepts are directly relevant to middle childhood, because these concepts influence the curriculum in many primary schools. For instance, children might be allowed to demonstrate their understanding of a historical event via a poster with drawings, not a paper with a bibliography.

Gardner originally described seven intelligences: linguistic, logical-mathematical, musical, spatial, bodily-kinesthetic (movement), interpersonal (social understanding), and intrapersonal (self-understanding), each associated with a particular brain region (Gardner, 1983). He subsequently added an eighth (naturalistic: understanding nature, as in biology, zoology, or farming) and a ninth (spiritual/existential: thinking about life and death) (Gardner, 1999, 2006; Gardner & Moran, 2006).

Although every normal person has some of all nine intelligences, Gardner believes each individual excels in particular ones. For example, someone might be gifted spatially but not linguistically (a visual artist who cannot describe her work) or might have interpersonal but not naturalistic intelligence (an astute clinical psychologist whose houseplants die).

Gardner finds that cultures and families dampen or encourage particular intelligences. For instance, a child who is gifted musically and grows up in a family of musicians is more likely to develop musical intelligence than a child whose parents are tone deaf.

Another criticism of the IQ test arises from multicultural understanding. Every test reflects the culture of the people who create, administer, and take it. This is obviously true for achievement tests: A child may score low because of the school, the teacher, the family, or the culture, not because of ability. Indeed, one reason IQ tests are still used is that achievement tests do not necessarily reflect aptitude.

However, scores on aptitude tests are also influenced by culture. Some experts have tried to develop tests that are culture-free asking children to identify pictures, draw shapes, repeat stories, hop on one foot, name their classmates, sort objects, and so on.

Even with such tests, culture is relevant. One group reports that Sudanese children averaged 40 points lower when IQ tests required that they use a pencil to write answers. The reason: They had no experience with pencils (Wicherts et al., 2010). By contrast, most American children begin using markers before age 2; by school age, automatization allows them to write without thinking about how to hold and push a writing implement. Even such a crucial aspect of testing as answering questions from a stranger is culturally biased.

One way to indicate aptitude is to measure the brain directly, avoiding the pitfalls of written exams or individual questions. Neurological measures do not necessarily correlate with written IQ tests, which leads some neuroscientists to consider IQ scores inaccurate. Yet interpretation of brain scans is not straightforward either. For example, although it seems logical that less brain activity means less intelligence, such a conclusion is mistaken.

In fact, many areas of a young child’s brain are activated simultaneously, and then, with practice, automatization reduces the need for brain activity, so the smartest children might have less active brains. Some research finds that a thick cortex correlates with higher ability but also that thickness develops more slowly in gifted children (Karama et al., 2009; Miller, 2006). Further, brain patterns in children who are highly creative differ from those who are highly intelligent (Jung & Ryman, 2013). The gifted patterns are puzzling—but so is much brain research.

Neuroscientists agree, however, on three conclusions:

1. Brain development depends on a person’s specific experiences because “brain, body, and environment are…dynamically coupled” (Marshall, 2009, p. 119), and thus any brain scan is accurate only for the moment it is done.
2. Brain development continues throughout life. Middle childhood is crucial, but developments before and after these years are also significant.
3. Children with disorders often have unusual brain patterns, and training their brains may help. However, brain complexity and normal variation mean that neuroscience diagnosis and remediation are far from perfect.

This leads to the final topic of this chapter, children with special needs.

Brain Fitness Aerobic fitness was measured (by VO₂—volume of oxygen expelled after exercise) in 59 children (average age 10, none of whom had ADHD or were pubescent); then the children’s brains were scanned. Overall brain size did not correlate with fitness—genes and early nutrition are more important for that. However, the volume of crucial areas for cognitive control (attention, contextualizing, planning) was significantly greater in the children who were in better shape. This is one more reason to go biking, running, or swimming with your child.

Source: Chaddock et al., 2010.
PUBLISHED IN L. CHADDOCK ET AL., 2010. COPYRIGHT © 2010 KARGER PUBLISHERS.