Development of the Mind PDF

Development of the Mind: Development of the Mind This chapter so far has described body development, from peak strength and health at about age 25 through gradual decline over the adult years. Now we turn to cognition, which follows another pattern. Some losses occur, but gains are evident, too. VI...

Development of the Mind: Development of the Mind This chapter so far has described body development, from peak strength and health at about age 25 through gradual decline over the adult years. Now we turn to cognition, which follows another pattern. Some losses occur, but gains are evident, too. VIDEO: Brain Development Animation: Middle Adulthood offers an animated look at how the brain changes with age. The Brain with Age Like every other body part, the brain slows down. Neurons fire more slowly, and reaction time lengthens because messages from the axon of one neuron are not picked up as quickly by the dendrites of other neurons. However, research on the brain is quite positive. Remember head-sparing in infancy? That continues. For most adults, cognitive reserve, homeostasis, and allostasis protect the brain, even more than the rest of the body, enabling new learning to occur. Thus, adults may be slower, losing to a teenager at a video game, but their analysis may be more comprehensive, with the postformal thinking described in Chapter 11. This is one reason why decades of adult experience seem a prerequisite for judges, popes, and world leaders. CAUSES OF BRAIN LOSS Evidence-based science requires that we temper this encouraging conclusion. For about 1 percent of all adults, brain loss is significant between ages 25 and 65. There are five main causes. Drug abuse. Psychoactive drugs can harm the brain. Most common is chronic alcohol abuse, which reduces thiamine (a vitamin) and causes Wernicke-Korsakoff syndrome (“wet brain”). Poor circulation. Everything that impairs blood flow — such as hypertension, extreme obesity, and cigarette smoking — impairs brain circulation. That slows down thought (Sweeney et al., 2018). Viruses. Various membranes, called the blood–brain barrier, protect the brain from most viruses, but a few — including HIV and the prion that causes mad cow disease — cross that barrier and destroy neurons. Genes. About 1 person in a thousand inherits a dominant gene for Alzheimer’s disease. That begins to destroy the brain in middle age. A few other inherited diseases, such as Huntington’s chorea, cause severe neurocognitive disorders in midlife (Burlina, 2018). Traumatic brain injury (TBI). A blow to the skull, an extremely loud noise, or a rapid acceleration of the head can damage the brain. This may occur with a concussion in a contact sport (football, hockey, boxing, and so on), a whiplash in a car crash, a punch in an assault, an explosion in a war. None of these always causes damage, but all can, especially if repeated (Capizzi et al., 2020). RECOVERY Brains continue to mature throughout adulthood. Regarding the first and last items above (drug abuse and TBI), the human brain is designed to reestablish broken connections, and to compensate with other brain areas if neurons in one part are destroyed. Time and rest (no more drugs or blows to the head) may allow full recovery. On the other hand, several causes of brain malfunction may cluster together. An adult with alcohol use disorder who is genetically vulnerable and is repeatedly hit on the head may suffer irreversible brain damage. Time aids recovery, but organ reserve may be reduced, and thus neuronal connections weaken as time goes on (Corps et al., 2015). Neurons Growing Even in adulthood, dendrites grow (pale yellow in this picture). Here the cells are in a laboratory and the growth is cancerous, but we now know that healthy neurons develop many new connections in adulthood. Barring these serious problems, age strengthens the connections between various parts of the brain, improving cognition, because better connections enable adults to appreciate how one aspect of life impacts another. This can happen on a global scale — the connection between famine in South Sudan and electricity use in North Dakota — as well as on a more personal level, how a partner’s shouted insult connects to a snowstorm outside. Encouraging evidence comes from stroke victims, whose brains can restructure themselves. Paralysis of one part of the body, or loss of one aspect of language, may not be permanent because the brain can develop other circuits to repair the damage. Plasticity is characteristic of all brains, lifelong (Sampaio-Baptista et al., 2018). One recent example comes from extensive neurological research that confirms that meditation strengthens brain connections (Brandmeyer & Delorme, 2021). Overall, myelination continues and dendrites grow, depending on experience. An adult who performs a particular action, time and time again, becomes better and quicker at it because of changes in their brain. Inside the Brain Brain Growth in Adulthood It has long been known that brains slow down and shrink with age. Neurons form rapidly during prenatal development, but early pruning eliminates most of them. Based on those facts, neuroscientists thought that human brain growth and neurogenesis (the formation of neurons) stopped long before adulthood. But in the past decades, scientists learned that parts of the brain grow during adulthood. Dendrites form, pathways strengthen, and new neurons may arise, especially in the hippocampus, where memories form. That neurogenesis “appears to contribute significantly to hippocampal plasticity across the life span” (Kempermann et al., 2015). The specific area of the hippocampus where new neurons settle is the dentate gyrus, a region active in forming new memories and exploring new places. Exercise, particularly, increases circulation, connections, and myelination. The resulting brain changes may reduce depression and other disorders (J-L. Zhao et al., 2020). Thus, shrinkage of some parts of the brain may be counterbalanced by expansion and reorganization. New brain cells facilitate learning and memory (Lepousez et al., 2015). All neuroscientists now agree that brain plasticity is evident lifelong. But not everyone agrees that a significant number of new neurons are born in adulthood. One team of 19 scientists reported that the number of new neurons created after age 13 is so low as to be undetectable (Sorrells et al., 2018). That conclusion is contrary to the one found by another team of 12 scientists. They reported that, although the rate of neurogenesis slows down, it does not stop: New neurons form even at age 79 (Boldrini et al., 2018). The number of scientists (19 and 12) in each of these two studies reveals that this is not a controversy between an optimist and a pessimist; it is a dispute between two teams of careful scientists. For neuroscientists, this is an exciting dispute because “the role that adult neurogenesis plays within the context of hippocampal function, neuroplasticity, and brain repair brings up many unsolved questions” (Kuhn et al., 2018, p. 10406). Researchers are attracted to new hypotheses and unsolved questions like moths to a flame. Scientists await more painstaking studies with new techniques to discover exactly how the adult brain develops. Many now believe that neurogenesis can occur (Kempermann et al., 2018; Lucassen et al., 2020). At the moment, they are certain that cognitive reserve, homeostasis, and allostasis protect the brain long after other parts of the body begin to fail. Intelligence in Adulthood Is “intelligence” some kind of physical thing, like a lump in the brain that some people have more of than others and that stays about the same size until old age shrinks it? That is what people once thought. It was assumed that intelligence was born into a person, in the same way as eye color. Genetic instructions were thought to make that inborn intelligence grow until it reached full capacity at about age 18, when the rest of the body was grown. MEASURING INTELLIGENCE As already mentioned in Chapter 7, that lump could be called general intelligence or “g.” Although g cannot be measured directly, Spearman (a leading theorist) thought it could be inferred from various subtests that measured language, memory, math, perception, and knowledge. By testing various abilities, a person’s g could be calculated and presented as an IQ score. That belief in g continues, as “g is one of the most thoroughly studied concepts in the behavioral sciences. Measures of intelligence are predictive of a wide range of educational, occupational, and life outcomes” (Geary, 2018, p. 1028). Since g was thought to be inborn, many researchers searched for the genetic underpinnings of intellectual capacity. One recent effort, contending that “intelligence is highly heritable,” examined the entire genome and found 1,016 genes linked to intelligence (Savage et al., 2018, p. 912). Other researchers looked elsewhere for the origins of g — perhaps prenatal brain development, experiences in infancy, or physical health. One leading scholar suggests that how well the mitochondria function is the crucial factor (Geary, 2018). However, no one has succeeded in finding any particular intelligence gene or in proving that a particular biological entity is g. A counter movement from other researchers suggests that no inborn g exists. Some criticize the psychometric approach as “neglecting the roles of emotion, motivation, stress, intuition, and creativity in cognitive development” (Zelazo, 2018, p. 44). As one scholar wrote: “Intelligent researchers will likely continue to disagree about g” (Gignac, 2016, p. 84). Nonetheless, no current scholar believes, as Spearman did, that IQ is exclusively inborn. Instead, all agree that IQ overall, as well as specifics such as vocabulary or memory, often change in adulthood. From about age 20 to age 70, national values, particular experiences, and years of education all affect the size of that lump of intelligence. For decades scientists have known that reflects genes, early education, and other influences before age 20, but it is now also known that adult experiences can cause a major shift in intelligence (Grønkjær et al., 2019). When a particular person is assessed longitudinally, researchers find “virtually every possible permutation of individual profiles” (Schaie, 2013, p. 497). Cross-sectional research also finds variability from item to item and age to age (Fagot et al., 2018). The data on adult intelligence illustrate the life-span perspective: Intelligence is multi-directional, multi-cultural, multi-contextual, and plastic. NEUROSCIENCE AND G Currently, many believe that g arises from brain functioning. One scholar notes that the size of one part of the adult midbrain (the caudate nuclei) correlates with adult IQ (Grazioplene et al., 2015). Another neuroscientist, on the contrary, says that no particular part of the brain is crucial, but rather that brain “network flexibility and dynamics are crucial for the diverse range of mental abilities underlying general intelligence” (Barbey, 2018, p. 15). In other words, the hubs and interconnections of brain parts may be pivotal. An intelligent person has strong and flexible networks, which allows the brain to combine, say, social perception and statistical logic, or verbal proficiency and visual acuity. Details vary from person to person over the life span, but always g originates from individual differences in the system-wide topology and dynamics of the human brain…. the capacity to flexibly transition between network states provides the foundation for individual differences in g — supporting the rapid exchange of information across networks and capturing individual differences in cognitive processing at a global level. Components of Intelligence: Many and Varied Developmentalists seek patterns of cognitive gain and loss. Individuals vary, as does each aspect of intelligence. What are those aspects? We consider here only two proposals, one that posits two distinct abilities and the other, three. [Life-Span Link: There are many more formulations, notably Gardner’s theory of nine intelligences, described in Chapter 7.] TWO CLUSTERS OF INTELLIGENCE In the 1960s, a leading researcher, Raymond Cattell, teamed up with a promising graduate student, John Horn, to study intelligence tests. They concluded that adult intelligence is best understood by grouping various measures into two categories, which they called fluid and crystallized. As its name implies, fluid intelligence is like water, flowing to its own level no matter where it happens to be. Fluid intelligence is quick and flexible, enabling people to learn anything, even things that are unfamiliar and disconnected to what they already know. Curiosity, learning for the joy of it, solving abstract puzzles, and the thrill of discovery are marks of fluid intelligence. People who are high in fluid abilities draw inferences, grasp relationships between concepts. Working memory is large and flexible. Questions that test fluid intelligence might be: What comes next in each of these two series?1 4 9 1 6 2 5 3 V X Z B D The accumulation of facts, information, and knowledge is called crystallized intelligence. The size of a person’s vocabulary, the knowledge of chemical formulas, and long-term memory for dates in history all indicate crystallized intelligence. Tests designed to measure this intelligence might include questions like these: What is the meaning of the word eleemosynary? Who was Descartes? Explain the difference between a tangent and a triangle. Why does the city of Peking no longer exist? Overall, IQ might be stable over the years of adulthood, but the mix of abilities changes from fluid to crystalized. Other researchers from many nations have found similar trends. IQ scores typically increase, or are at least maintained, in adulthood, because performance on timed items declines but on verbal items increases (Salthouse, 2019). THREE FORMS OF INTELLIGENCE Robert Sternberg (1988, 2015) agrees that a single intelligence score is misleading. He proposed three fundamental forms of intelligence: analytic, creative, and practical (see Table 12.3). Table 12.3 Sternberg’s Three Forms of Intelligence Analytic Intelligence Creative Intelligence Practical Intelligence Mental processes Abstract planning Strategizing Focused attention Verbal skills Logic Imagination Appreciation of the unexpected or unusual Originality Vision Adaptive actions Understanding and assessing daily problems Applied skills and knowledge Valued for Analyzing Learning and understanding Remembering Thinking Intellectual flexibility Originality Future hopes Adaptability Concrete knowledge Real-world experience Indicated by Multiple choice tests Brief essays Recall of information Inventiveness Innovation Resourcefulness Ingenuity Performance in real situations “Street smarts” Information from Sternberg, 1988, 2003, 2011, 2015. Analytic intelligence includes all of the mental processes that foster academic proficiency by making efficient learning, remembering, and thinking possible. Thus, it draws on abstract planning, strategy selection, focused attention, and information processing, as well as on verbal and logical skills. Strengths in those areas are valuable in emerging adulthood, particularly in college and in graduate school. Multiple-choice tests and brief essays that call forth remembered information, with only one right answer, indicate analytic intelligence. Creative intelligence is flexible and innovative, divergent rather than convergent, valuing the unexpected, imaginative, and unusual rather than standard and conventional answers. Sternberg developed tests of creative intelligence that include writing a short story titled “The Octopus’s Sneakers” or planning an advertising campaign for a new doorknob. Those with many novel ideas earn high scores. Practical intelligence is adaptive. This capacity includes an accurate grasp of the expectations and needs of other people and understanding what skills are needed to meet whatever challenges appear. Then people who are high in practical intelligence can use their social insights and skills to accomplish whatever is needed. Practical intelligence is sometimes called tacit intelligence because it is not obvious on tests (Cianciolo & Sternberg, 2018). Instead, it comes from “the school of hard knocks” and is sometimes called “street smarts,” not “book smarts.” Choosing which intelligence to use takes wisdom, which Sternberg considers the fourth ingredient of successful intelligence. He wrote: One needs creativity to generate novel ideas, analytical intelligence to ascertain whether they are good ideas, practical intelligence to implement the ideas and persuade others of their value, and wisdom to ensure that the ideas help reach a common good. [Sternberg, 2012, p. 21] [Life-Span Link: Wisdom is discussed in Chapter 14.] Practical intelligence comes to the fore in adulthood. Few adults need to define obscure words or deduce the next item in a number sequence (analytic intelligence), and few need to compose new music, restructure local government, or invent an innovative gadget (creative intelligence). Intelligence in Action Lin-Manuel Miranda created and starred in Hamilton: An American Musical, that has been one of the hottest tickets on Broadway since it opened in 2015. His creative intelligence is obvious, but his analytic and practical intelligence are also part of his success. Ideally, by adulthood, those few have found people with practical intelligence to implement their analytic or creative ideas. The college professor with their “head in the clouds,” or the celebrity entertainer who relies on their manager, are high in analytic or creative intelligence, but they need someone with practical intelligence to get them through the day with their shirt clean and their appointments met. Practical intelligence helps people maintain a home; advance a career; manage money; sift information (from media, mail, the internet, friends); decide what habits to maintain, stop, or begin; and address the emotional needs of lovers, relatives, neighbors, and colleagues.