chpt 5 body and mind

That is how nature makes young children: full of energy and action, with difficulty grasping viewpoints that are not theirs. Developmentalists call that

egocentrism.

Growth is biologically driven and socially guided,

experience-expectant and experience-dependent.

Acquiring Grammar

grammar includes structures, techniques, and rules that communicate meaning. Knowledge of grammar is essential for learning to speak, read, and write. A large vocabulary is useless unless a person knows how to put words together. Each language has its own grammar rules; that's one reason children speak in one-word sentences first. Children apply rules of grammar as soon as they figure them out, using their own theories about how language works and their experience regarding when and how various rules apply (Meltzoff & Gopnik, 2013). Careful research on language development during childhood reveals impressive mastery of grammar long before formal instruction. For example, English-speaking children quickly learn to add an s to form the plural: Toddlers follow that rule when they ask for two cookies or more blocks. Soon they add an s to make the plural of words they have never heard before, even nonsense words. If preschoolers are shown a drawing of an abstract shape, told it is called a wug, and are then shown two of these shapes, they say there are two wugs (Berko, 1958). Young children learn the conventions of grammar almost as soon as they start talking (Pinker, 1999). By age 3, children realize that verbs reflect singular or plural. This is difficult for people learning English, but it is grasped by most 3-year-old native speakers. They not only know that he jumps while they jump (difficult because the s is singular here) but also the difference between are and is. For example, careful monitoring of eye gaze reveals that as soon as they hear the word are when asked "Are there three cookies on the plate?" they look at the plate of cookies rather than a plate with one piece of cake (Deevy et al., 2017). Sometimes children apply the rules of grammar when they should not. This error is called overregularization. By age 4, many children overregularize that final s, talking about foots, tooths, and mouses. This signifies knowledge, not lack of it. Many children first say words correctly (feet, teeth, mice), repeating what they have heard. Later, they are smart enough to apply the rules of grammar, and they assume that all constructions follow the rules (Ramscar & Dye, 2011). The child who says, "I goed to the store" needs to hear, "Oh, you went to the store?" not criticism. overregularization The application of rules of grammar even when exceptions occur, making the language seem more "regular" than it actually is. More difficult to learn is an aspect of language called pragmatics—knowing which words, tones, and grammatical forms to use with whom (Siegal & Surian, 2012). In some languages, it is essential to know which set of words to use when a person is older, or when someone is not a close friend, or when grandparents are on the mother's side or the father's. pragmatics The practical use of language that includes the ability to adjust language communication according to audience and context. English does not make those distinctions, but pragmatics is important for early-childhood learning nonetheless. Children learn variations in vocabulary and tone depending on the context, and once theory of mind is established, on the audience. Knowledge of pragmatics is evident when a 4-year-old pretends to be a doctor, a teacher, or a parent. Each role requires different speech. On the other hand, children often blurt out questions or statements that embarrass their parents ("Why is that lady so fat?" or "I don't want to kiss Grandpa because his breath smells."): The pragmatics of polite speech requires more social understanding than many young children possess.

IMPULSIVENESS AND PERSEVERATION

Neurons have only two kinds of impulses: on-off or, in neuroscience terms, activate-inhibit. Each is signaled by a threshold of biochemical messages from dendrites to axons to neurons. Activation and inhibition keep adults from leaping too quickly or hesitating too long, neither lashing out in anger nor freezing in fear. If an elder becomes too impulsive or too cautious, that is a sign of cognitive loss. However, it is normal for young children to be neurologically unbalanced, with poor impulse control. They might flit from one activity to another, unable to stay quietly on one task. That is apparent even in "circle time" in preschool, when teachers tell children to sit in place, not talking or touching anyone. Some instruct them, literally, to sit on their hands. impulse control The ability to postpone or deny the immediate response to an idea or behavior. At the other extreme, children may be captivated by one task, finding it hard to notice anything else or stop whatever they are doing. That is perseveration: They may play with one toy, hold one fantasy for hours, repeat a phrase or question again and again. Giggles or tears may be uncontrollable because the child is stuck in whatever triggered it. perseveration The tendency to persevere in, or stick to, one thought or action for a long time. No young child is perfect at regulating attention, because immaturity of the prefrontal cortex makes it impossible to moderate the limbic system. Impulsiveness and perseveration follow. Because the amygdala is not well connected to the more reflective parts of the brain, many children become suddenly terrified—even of something that exists only in imagination. Gradually, preschoolers become less likely to perseverate, especially if they are taught how to stop one task to begin another (Zelazo, 2015). A study of children from ages 3 to 6 found increased ability to attend to what adults requested. Attention correlated with academic learning and behavioral control (fewer outbursts or tears) (Metcalfe et al., 2013). Brain maturation (innate) and emotional regulation (learned) eventually allow most children to focus and switch as needed within their culture (Posner & Rothbart, 2017). By adolescence, most North American high school students can successfully change thoughts—from Chinese history to string theory, for instance—at the sound of the bell.

STEM LEARNING

A practical use of Vygotsky's theory concerns STEM (science, technology, engineering, math) education. Many adults wish that more college students would choose a STEM career. How to encourage that? Developmentalists find that interest in STEM vocations begins when young children learn about numbers and science (counting, shapes, fractions, molecular structure, the laws of motion). Spatial understanding—how one object fits with another—is an accomplishment of early childhood that enhances later math skills (Verdine et al., 2017). During the preschool years, the understanding of math and physics develops month by month. To be specific, by age 3 or 4, children's brains are mature enough to comprehend numbers, store memories, and recognize routines. Whether or not children actually demonstrate such understanding depends on what they hear and what they do within their families, schools, and cultures. "Scaffolding and elaboration from parents and teachers provide crucial input to spatial development," which itself leads to the math understanding that underpins STEM expertise (Verdine et al., 2017, p. 25). Some 2-year-olds hear numbers such as "One, two, three, takeoff," "Here are two cookies," or "Dinner in five minutes" several times a day. They are encouraged to touch an interesting bit of moss, or to notice the phases of the moon outside their window, or to play with toys that fit shapes, or to make the connection between their labored breathing and the steepness of a hill they are climbing. Other children never have such experiences—and they have a harder time with math in first grade, with science in third grade, and with physics in high school. If Vygotsky is right that words mediate between brain potential and comprehension, STEM education begins long before first grade.

LANGUAGE AS A TOOL

Although all of the objects of a culture guide children, Vygotsky considered language pivotal. First, talking to oneself, called private speech, is evident when young children talk aloud to review, decide, and explain events to themselves (and, incidentally, to anyone else within earshot) (Al-Namlah et al., 2012). Many adults use private speech as they talk to themselves when alone or as they write down ideas. private speech The internal dialogue that occurs when people talk to themselves (either silently or out loud). Second, language advances thinking by facilitating social interaction, which is vital to learning (Vygotsky, 2012). This social mediation function of speech occurs as mentors guide mentees in their zone of proximal development, learning numbers, recalling memories, and following routines. social mediation Human interaction that expands and advances understanding, often through words that one person uses to explain something to another.

FOOD ALLERGIES

An estimated 3 to 8 percent of children are allergic to a specific food, almost always a common, healthy one: Cow's milk, eggs, peanuts, tree nuts (such as almonds and walnuts), soy, wheat, fish, and shellfish are the usual culprits. Diagnostic standards for allergies vary (which explains the range of estimates), and treatment varies even more (Chafen et al., 2010). For some foods the allergic reaction is a rash or an upset stomach when too much is consumed, but for others—especially peanuts or shellfish—the reaction is sudden shock and shortness of breath that could be fatal (Dyer et al., 2015). When a child has a severe allergic reaction, someone should immediately inject epinephrine to stop the reaction. In 2012, all Chicago schools had EpiPens, which were used in dozens of emergencies (DeSantiago-Cardenas et al., 2015). Some experts advocate total avoidance of the offending food—there are peanut-free schools, where no one is allowed to bring a peanut-butter sandwich for lunch lest an allergic child take a bite. However, feeding children who are allergic to peanuts a tiny bit of peanut powder (under medical supervision) is usually a safe and effective way to decrease that allergic reaction (Vickery et al., 2017). Fortunately, many food allergies are outgrown. Other food-related problems increase with age. During middle childhood, children who eat many snacks and fast foods (with high levels of saturated fatty acids, trans fatty acids, sodium, carbohydrates, and sugar) are likely to have asthma, stuffy noses, watery eyes, and itchy skin (Ellwood et al., 2013).

LISTENING, TALKING, AND READING

Because understanding the printed word is crucial, a meta-analysis of about 300 studies analyzed which activities in early childhood aided reading later on. Both vocabulary and phonics (precise awareness of spoken sounds) predicted literacy (Shanahan & Lonigan, 2010). Five specific strategies and experiences were particularly effective for children of all income levels, languages, and ethnicities. Code-focused teaching. Before reading, children must "break the code" from spoken to written words. That means connecting letters and sounds (e.g., "A, alligators all around" or "B is for baby"). Book-reading. Vocabulary and print-awareness develop when adults read to children. Parent education. Educated parents tend to be verbal parents who read books to their children and use a rich vocabulary that expands the child's vocabulary. Language enhancement. Children who ask what a word means need someone to scaffold the explanation. That requires mentors who understand each child's zone of proximal development. Preschool programs. Children learn from teachers, songs, excursions, and other children. (Early education advances language, as discussed next.)

A Sensitive Time

Brain maturation, myelination, scaffolding, and social interaction make early childhood ideal for learning language. As you remember from Chapter 1, scientists once thought that early childhood was a critical period for language learning—the only time when a first language could be mastered and the best time to learn a second or third one. It is easy to understand why they thought so. Young children have powerful motivation and ability to sort words and sounds into meaning (theory-theory). That makes them impressive language learners. However, the critical-period hypothesis is false: A new language can be learned after age 6. Still, while new language learning in adulthood is possible, it is not easy. Early childhood is a sensitive period for rapidly mastering vocabulary, grammar, and pronunciation. Young children are language sponges; they soak up every verbal drop they encounter. One of the valuable (and sometimes frustrating) traits of young children is that they talk about many things to adults, to each other, to themselves, to their toys—unfazed by misuse, mispronunciation, ignorance, stuttering, and so on (Marazita & Merriman, 2010). Language comes easily partly because preoperational children are not self-critical about what they say. Egocentrism has advantages; this is one of them.

Brain Development

By age 2, most neurons have connected to other neurons and substantial pruning has occurred, as explained in Chapter 3. The 2-year-old's brain already weighs 75 percent of what it will weigh in adulthood; the 6-year-old's brain is 90 percent of adult weight. Since most of the brain is already present and functioning by age 2, what remains to develop during early childhood? Connections!

FAST-MAPPING

Children develop interconnected categories for words, a kind of grid or mental map that makes speedy vocabulary acquisition possible. Learning a word after one exposure is called fast-mapping (Woodward & Markman, 1998) because, rather than figuring out the exact definition after hearing a word used in several contexts, children hear a word once and quickly stick it into a category in their mental language grid. For 2-year-olds, mother can mean any caregiving woman, for instance. fast-mapping The speedy and sometimes imprecise way in which children learn new words by tentatively placing them in mental categories according to their perceived meaning. Picture books offer many opportunities to advance vocabulary through scaffolding and fast-mapping. A mentor might encourage the next steps in the child's zone of proximal development, such as that tigers have stripes and leopards spots, or, for an older child, that calico cats are almost always female and that lions with manes are always male. This process explains children's learning of colors. Generally, 2-year-olds fast-map color names (K. Wagner et al., 2013). For instance, blue is used for some greens or grays. The reason is not that children cannot see the hues. Instead, they apply words they know to broad categories and have not yet learned the boundaries that adults use, or specifics such as chartreuse, turquoise, olive, navy. As one team of scientists explains, adults' color words are the result of slow-mapping (K. Wagner et al., 2013), which is not what young children do.

WORDS AND THE LIMITS OF LOGIC

Closely related to fast-mapping is a phenomenon called logical extension: After learning a word, children use it to describe other objects in the same category. One child told her father she had seen some "Dalmatian cows" on a school trip to a farm. Instead of criticizing her foolishness, he remembered that she petted a Dalmatian dog the previous weekend. He realized that she saw Holstein, not Jersey, cows. Bilingual children who don't know a word in the language they are speaking often insert a word from the other language, code-switching in the middle of a sentence. That mid-sentence switch may be considered wrong, but actually it arises from the child's drive to communicate. By age 5, children realize who understands which language, and they avoid substitutions when speaking to a monolingual person. That illustrates theory of mind. Some words are particularly difficult for every child, such as, in English, who/whom, have been/had been, here/there, yesterday/tomorrow. More than one child has awakened on Christmas morning and asked, "Is it tomorrow yet?" A child told to "stay there" or "come here" may not follow instructions because the terms are confusing. It might be better to say, "Stay there on that bench" or "Come here to hold my hand." Every language has difficult concepts that are expressed in words; children everywhere learn them eventually. Abstractions are particularly difficult; actions are easier to understand. A hole is to dig; love is hugging; hearts beat.

Growth Patterns

Compare the body of an unsteady 24-month-old with that of a cartwheeling 6-year-old. Physical differences are obvious. Height and weight increase. However, size is not the most radical change; shape is. Proportions shift: Children slim down as the lower body lengthens and fat gives way to muscle. The average body mass index (BMI, a ratio of weight to height) is lower at ages 5 and 6 than at any other time of life. Gone are the infant's protruding belly, round face, short limbs, and large head. The center of gravity moves from the breast to the belly, enabling cartwheels, somersaults, rhythmic dancing, and pumping legs on a swing: Changing proportions enable new achievements. During each year of early childhood, well-nourished children grow about 3 inches (about 7½ centimeters) and gain almost 4½ pounds (2 kilograms). By age 6, the average child in a developed nation: is at least 3½ feet tall (more than 110 centimeters). weighs between 40 and 50 pounds (between 18 and 23 kilograms). looks lean, not chubby. has adultlike body proportions (with legs constituting about half the total height). Young children enjoy developing their motor skills as brain maturation allows advances. Adults need to provide space and guided practice; children do the rest. Most North American 6-year-olds can climb a tree and jump over a puddle, as well as throw, catch, and kick a ball. Many can ride a bicycle, swim in a pool, and print their names. Some, on other continents, can embroider clothes, swim in oceans, and climb cliffs.

MATURATION OF THE PREFRONTAL CORTEX

Connections between the prefrontal cortex and the rest of the brain are virtually absent at age 1, limited at age 2, and develop gradually at least until age 25. Gradual maturation is especially evident for actions that respond to other people (Eggebrecht et al., 2017) and for modulation of the limbic system. Nonetheless, some early brain maturation is evident by age 6: Sleep becomes more regular. Emotions become more nuanced and responsive. Temper tantrums subside. Uncontrollable laughter and tears are less common. One specific example of the maturing brain is in the game Simon Says. Players are supposed to follow the leader only when orders are preceded by the words "Simon says." Thus, if leaders touch their noses and say, "Simon says touch your nose," players are supposed to touch their noses, but when leaders touch their noses and say, "Touch your nose," no one should follow the example. Young children lose at this game because they cannot connect what they have been told with what they see and hear.

Early-Childhood Education

Decades of research have led almost all developmentalists to agree that education of 3- to 6-year-olds aids learning in primary school. Benefits continue for decades.

LONGITUDINAL STUDIES

Evidence for the value of early education comes from three classic programs, each of which educated children for years—sometimes beginning with home visits in infancy, sometimes continuing in after-school programs through first grade. One program, called Perry (or High/Scope), was spearheaded in Michigan (Schweinhart & Weikart, 1997); another, called Abecedarian, got its start in North Carolina (Campbell et al., 2001); a third, called Child-Parent Centers, began in Chicago (Reynolds, 2000). All of these programs focused on children from low-SES families; all provided intense education from well-trained teachers. These three programs compared experimental groups of children with matched control groups and followed up on them for decades. The solid conclusion: Early education, when done well, results in benefits that become most apparent when children are in the third grade or later. By age 10, children who had been enrolled in any one of these three programs scored higher on math and reading achievement tests than did other children from the same backgrounds, schools, and neighborhoods. They were less likely to be placed in classes for children with special needs or to repeat a year of school. Benefits were particularly likely if the early-childhood education was followed by learning within an effective elementary school (Reynolds et al., 2015). As adolescents, the children who had undergone intensive preschool education had higher aspirations, possessed a greater sense of achievement, and were less likely to quit before graduation or become a teenage parent. As young adults, more of them attended college and fewer went to jail. As middle-aged adults, more were healthy, employed taxpayers (Reynolds & Ou, 2011;

Vygotsky: Social Learning

For decades, the magical, illogical, and self-centered aspects of cognition dominated our conception of early-childhood thought. Scientists were understandably awed by Piaget, who demonstrated many aspects of egocentric thought in children. Vygotsky emphasized another side of early cognition—that each person's thinking is shaped by other people. His focus on the sociocultural context contrasts with Piaget's emphasis on the individual (Vygotsky, 1987). As the term sociocultural suggests, Vygotsky was acutely aware of the social and cultural differences in his native Russia. In the early twentieth century, Russia was the only nation that spanned two continents (Europe and Asia), with citizens speaking a dozen languages, practicing many religions, and earning their living in hundreds of ways.

THEORY-THEORY

Humans of all ages seek explanations. As a play on words, when naming their theory about how children think, psychologists explained that their theory is that children construct a theory. Theory-theory refers to the idea that children naturally construct theories to explain whatever they see and hear. theory-theory The idea that children attempt to explain everything they see and hear by constructing theories. According to theory-theory, humans both young and old seek reasons, causes, and underlying principles to make sense of their experience, connecting knowledge and observations. Especially in childhood, theories change as new evidence accumulates (Meltzoff & Gopnik, 2013; Bridgers et al., 2016; Gopnik, 2016). Children follow the same processes that scientists do: asking questions, developing hypotheses, gathering data, and drawing conclusions. As a result, "preschoolers have intuitive theories of the physical, biological, psychological, and social world" (Gopnik, 2012, p. 1623). Of course, the cognitive methods of children lack the rigor of scientific experiments, but children "not only detect statistical patterns, they use those patterns to test hypotheses about people and things" (Gopnik, 2012, p. 1625). Like all good scientists, they will revise theories based on new data, although, like all humans, children sometimes stick to their old theories despite conflicting evidence. One common theory-theory is that everyone intends to do things correctly. For that reason, when asked to repeat something ungrammatical that an adult says, children often correct the grammar. They theorize that the adult intended to speak grammatically but failed to do so (Over & Gattis, 2010).

MENTORS

It was obvious to Vygotsky that cognitive development is embedded in the social context—such as whether a child grew up in the affluent neighborhoods of Moscow or the frozen steppes of Siberia. Children in those disparate contexts are guided to learn different things. Everywhere, parents are the first to engage children in guided participation, although children are guided by many others, especially in an interactive pre-kindergarten (Broström, 2017). Vygotsky stressed that children are curious and observant. They ask questions— about how machines work, why weather changes, where the sky ends—and seek answers from parents, teachers, older siblings, or strangers. The answers they get are affected by the mentors' perceptions and assumptions—that is, their culture—which shapes their thought. According to Vygotsky, children learn because their mentors do the following: Present challenges. Offer assistance (without taking over). Add crucial information. Encourage motivation.

LANGUAGE LOSS AND GAINS

Language-minority parents have a legitimate fear: Their children might make a language shift, becoming fluent in the majority language and losing their home language. Language shift occurs whenever theory-theory leads children to conclude that their parents' language is inferior (Bhatia & Ritchie, 2013). Some language-minority children in Mexico shift to Spanish; some children of Canada's First Nations shift to French; some U.S. children in non-English-speaking homes shift to English. In China, all speak some form of Chinese, but some shift from Wu, Hakka, or another dialect to Mandarin, a shift that troubles their parents. Remember that young children are preoperational: They center on the immediate status of their language (not on future usefulness or past glory), on appearance more than substance. No wonder many shift. Since language is integral to culture, if a child is to become fluently bilingual, everyone who speaks with the child should respect both cultures, in song, books, and conversation. Children learn from listening and talking, so a child needs to hear and speak twice as much to become fluent in two languages (Hoff et al., 2012). If immigrant parents speak only their home language, they should talk often to the child in that language, because fluency in one language makes it easier to learn another (Hoff et al., 2014). Since early childhood is a sensitive time for language, such parents also need to find a social context (school, church, other relatives) where the child will learn the second language. The language shift is less likely if the child already speaks two languages before kindergarten. The same practices make a child fluently trilingual, as some 5-year-olds are. Young children who are immersed in three languages may speak all three with no accent—except the accent of their mother, father, and friends.

Learning Two Languages

Language-minority people (those who speak a language that is not their nation's dominant one) suffer if they do not also speak the majority language (Rosselli et al., 2016). In the United States, those who lack fluency in English often have lower school achievement, diminished self-esteem, and inadequate employment. Some of their problem comes from prejudice from native-English speakers, but some is directly connected to their English. Early childhood is the best time to learn languages. Neuroscience finds that if adults mastered two languages before age 6, both languages are located in the same areas of the brain with no detriment to the cortex structure (Klein et al., 2014). Being bilingual seems to benefit the brain lifelong, further evidence for plasticity (Bialystok, 2017). Indeed, the bilingual brain may provide some resistance to neurocognitive disorder due to Alzheimer's disease in old age (Costa & Sebastián-Gallés, 2014). When adults learn a new language, their pronunciation, idioms, and exceptions to the rules lag behind basic grammar and vocabulary. Thus, many immigrants speak the majority language with an accent and are confused by common metaphors, but they are proficient in comprehension (difference is not deficit). From infancy on, listening is more acute than speaking. Almost all young children mispronounce whatever language they speak, blithely unaware of their mistakes. They comprehend more than they say, and they learn rapidly as long as many people use new words and phrases within their zone of proximal development. As the authors of a study of bilingual children summarized, "linguistic richness of a child's early learning experience is critical for language acquisition and cognitive growth, whether that child is learning one language or two" (Marchman et al., 2017). For children to develop two languages, they must speak as well as hear two languages (Ribot et al., 2017). Thus, adults need to scaffold speaking (asking leading questions, listening attentively) instead of ignoring children or saying "Be quiet; listen to me."

Language Learning

Learning language is often considered the premier cognitive accomplishment of early childhood. Two-year-olds use short, telegraphic sentences ("Want cookie," "Where Daddy go?"), omitting adjectives, adverbs, and articles. By contrast, 5-year-olds seem to be able to say almost anything (see At About This Time) using every part of speech. Some kindergartners understand and speak two or three languages, an accomplishment that many adults struggle for years to achieve.

THEORY OF MIND

Mental processes—thoughts, emotions, beliefs, motives, and intentions—are among the most complicated and puzzling phenomena that humans encounter every day. Adults wonder why people fall in love with the particular persons they do, why they vote for the odd political candidates they do, or why they make foolish choices—from signing for a huge mortgage to buying an overripe cucumber. Children are likewise puzzled about a playmate's unexpected anger, a sibling's generosity, or an aunt's too-wet kiss. To know what goes on in another person's mind, people develop a folk psychology, which includes ideas about other people's thinking, called theory of mind. Theory of mind is "essential in communities that rely heavily on the exchange of information, ideas, and points of view" (Lillard & Kavanaugh, 2014, p. 1535). Longitudinal research finds that 2-year-olds do not know that other people think differently than they do, but 6-year-olds know this very well (Wellman et al., 2011). theory of mind A person's theory of what other people might be thinking. In order to have a theory of mind, children must realize that other people are not necessarily thinking the same thoughts that they themselves are. That realization seldom occurs before age 4. Part of theory of mind is realizing that someone else might have a mistaken belief. In a classic experiment, children watch a puppet named Max put a toy dog into a red box. Then Max leaves and the child sees the dog taken out of the red box and put in a blue box. When Max returns, the child is asked, "Where will Max look for the dog?" Without a theory of mind, most 3-year-olds confidently say, "In the blue box"; most 6-year-olds correctly say, "In the red box." The development of theory of mind is evident when young children try to escape punishment by lying. Their faces often betray them: worried or shifting eyes, pursed lips, and so on. Parents might say, "I know when you are lying," and, to the consternation of most 3-year-olds, parents are usually right. In one experiment, 247 children, ages 3 to 5, were left alone at a table that had an upside-down cup covering dozens of candies (Evans et al., 2011). The children were told not to peek, and the experimenter left the room. For 142 children (57 percent), curiosity overcame obedience. They peeked, spilling so many candies onto the table that they could not put them back under the cup. The examiner returned, asking how the candies got on the table. Only one-fourth of the participants (more often the younger ones) told the truth. The rest lied, and their skill at lying increased with their age. The 3-year-olds typically told hopeless lies (e.g., "The candies got out by themselves"); the 4-year-olds told unlikely lies (e.g., "Other children came in and knocked over the cup"). Some of the 5-year-olds, however, told plausible lies (e.g., "My elbow knocked over the cup accidentally"). A study of prosocial lies (saying that a disappointing gift was appreciated) found that children who were advanced in theory of mind and in executive function were also better liars, able to stick to the lie that they liked the gift (S. Williams et al., 2016). This study was of 6- to 12-year-olds, not preschoolers, but the underlying abilities are first evident at about age 4. Many studies have found that a child's ability to develop theories correlates with neurological maturation, which also correlates with advances in executive processing—the reflective, anticipatory capacity of the mind (Mar, 2011; Baron-Cohen et al., 2013). Detailed studies find that theory of mind activates several brain regions (Koster-Hale & Saxe, 2013). This makes sense: Theory of mind is a complex ability that humans develop in social contexts, so it is not likely to reside in just one neurological region. Evidence for crucial brain maturation comes from the other research on the same 3- to 5-year-olds whose lying was studied. The children were asked to say "day" when they saw a picture of the moon and "night" when they saw a picture of the sun. They needed to inhibit their automatic reaction. Their success indicated advanced executive function, which correlated with maturation of the prefrontal cortex. The crucial role of brain maturation was evident: Those who failed the day-night tests typically told impossible lies. Their age-mates who were higher in executive function (measured by the day-night tests) told better lies (Evans et al., 2011). Does the prerequisite of neurological maturation make culture and context irrelevant for theory of mind? Not at all: Nurture is always important. Formal education traditionally began at about age 6 because by then the prefrontal cortex is naturally sufficiently mature to allow sustained attention. But, passive waiting for maturation may be foolish. Experiences before age 6 advance brain development and prepare children for first grade (Blair & Raver, 2015). Many educators and parents focus on young children's intelligence and vocabulary. They are right to do so, because cognition and language development respond to encouragement. However, for brain development and later success in kindergarten and beyond, executive function seems even more crucial than scores on intelligence tests (Friedman & Miyake, 2017). Some helpful experiences before age 6 occur for almost every child: Children develop theory of mind in talking with adults and in playing with other children. Games that require turn-taking encourage memory and inhibitory control, two crucial components of executive control. As brothers and sisters argue, agree, compete, and cooperate, and as older siblings fool younger ones, it dawns on 3-year-olds that not everyone thinks as they do, a thought that advances theory of mind. Thus, siblings advance thinking. By age 5, children have learned how to persuade their younger brothers and sisters to give them a toy. Meanwhile, younger siblings figure out how to gain sympathy by complaining that their older brothers and sisters have victimized them. Parents, beware: Asking, "Who started it?" may be irrelevant: Better is to help the siblings understand each other's perspective.

ORAL HEALTH

Not surprisingly, tooth decay correlates with obesity; both result from too much sugar and too little fiber (Hayden et al., 2013). Sweetened beverages are usually the problem. "Baby" teeth are replaced naturally from ages 6 to 10. The schedule is genetic, with girls a few months ahead of boys. However, tooth brushing and dentist visits should become habitual years before adult teeth erupt. Poor oral health in early childhood harms those permanent teeth (forming below the first teeth) and can cause jaw malformation, chewing difficulties, and speech problems. Teeth are affected by diet and illness, so a young child's teeth can alert a professional to other health problems. The process works in reverse as well: Infected teeth can affect the rest of the child's body. In pregnant adults, tooth infections can cause preterm births (Puertas et al., 2018).

OBESITY AMONG YOUNG CHILDREN

Older adults often encourage children to eat, protecting them against famine that was common a century ago. Unfortunately, that encouragement may be destructive. As family income decreases, obesity increases—a sign of poor nutrition, likely to reduce immunity and increase later disease (Rook et al., 2014). There are many explanations for the connection between obesity and low SES. Families with little money or education are more likely to have family habits—less exercise, more television, fewer vegetables, more sweetened drinks, frequent fast food—that correlate with overweight (Cespedes et al., 2013). In addition, low-SES children more often live with grandmothers who encourage eating patterns that, in other times and places, protected against starvation. Problems endure lifelong. Children who grow up in food-insecure households learn to eat whenever food is available, becoming less attuned to hunger and satiety signals in their bodies. Consequently, as adults, they overeat when they are not hungry, risking obesity, diabetes, and strokes (Hill et al., 2016). For all children, appetite decreases between ages 2 and 6. Parents need to know this, not enticing children to eat, nor feeding them candy or cake that will fill them up. If a young child develops poor eating habits, nutritional problems appear. In 2012, 8 percent of 2- to 5-year-olds, 18 percent of 6- to 11-year-olds, and 21 percent of 12- to 19-year-olds in the United States were obese (Ogden et al., 2014). Some of those teenagers who were not obese had other eating problems, including anorexia and bulimia. One reason parents urge children to eat is that they underestimate their children's weight. A review of 69 studies found that half the parents of overweight children believe their children are thinner than they actually are. This problem was particularly likely for children ages 2 to 5 (Lundahl et al., 2014), perhaps because parents do not know that 5-year-olds are naturally low in BMI. Immigrant elders do not realize that traditional diets in low-income nations are healthier than foods advertised in developed nations (de Hoog et al., 2014). Sadly, many other nations are adopting Western diets. As a result, "childhood obesity is one of the most serious public health challenges of the 21st century. The problem is global and is steadily affecting many low- and middle-income countries, particularly in urban settings" (Sahoo et al., 2015, p. 187-188). There is some good news in the United States, however. Young children (ages 2 to 5) are eating more fruit, and obesity rates fell accordingly, from 12.1 percent in 2010 to 8.4 percent in 2012 (Ogden et al., 2014). Public education and parents both deserve credit. And many day-care centers have increased exercise and improved snacks: carrot sticks and apple slices, not cookies and chocolate milk (Sisson et al., 2016). This proves that weight gain is not inevitable. However, rates rose again in 2016, to 13.9 percent (Hales et al., 2017). That is bad news—with one hopeful twist: Since weight gain in early childhood is so fluid, parents and communities can make a difference if they choose to.

myelin The fatty substance coating axons that speeds the transmission of nerve impulses from neuron to neuron.

One crucial aspect of brain development is how well and rapidly the parts of the brain connect to each other. Essential for that is myelin, sometimes called the white matter of the brain. Myelin is a coating on the axons that protects and speeds signals between neurons. As you read, most neurons (the gray matter of the brain) are formed prenatally, and dendrites are pruned in late infancy. Despite those losses, the brain becomes heavier. One reason—more myelin. Myelin helps every part of the brain, especially the connections between neurons that are far from each other. This provides more than insulation around the axons: "Myelin organizes the very structure of network connectivity . . . and regulates the timing of information flow through individual circuits" (Fields, 2014, p. 266). Myelin aids coordination of the left and the right halves of the brain, via the corpus callosum, as Inside the Brain explains.

EXECUTIVE FUNCTION

One manifestation of children's impressive learning ability is in the development of executive function, the ability to use the mind to plan, remember, inhibit some impulses, and execute others. Executive function (also called executive control and closely related to emotional regulation, explained in Chapter 6) develops throughout life, allowing students of all ages to learn from experience. It is first evident and measured during early childhood (Eisenberg & Zhou, 2016; Espy et al., 2016; Sasser et al., 2017). executive function The cognitive ability to organize and prioritize the many thoughts that arise from the various parts of the brain, allowing the person to anticipate, strategize, and plan behavior. Usually, three components comprise executive function: working memory, cognitive flexibility, and inhibitory control—which is the ability to focus on a task and ignore distractions. Executive function is a better predictor of later learning in kindergarten than a child's age or language ability (Pellicano et al., 2017).

CONSERVATION AND LOGIC

Piaget discovered many examples of preoperational children disregarding logic. A famous set of experiments involved conservation, the notion that the amount of something remains the same (is conserved) despite changes in its appearance. conservation The principle that the amount of a substance remains the same (i.e., is conserved) even when its appearance changes. Suppose two identical glasses contain the same amount of pink lemonade, and the liquid from one of these glasses is poured into a taller, narrower glass. When young children are asked whether one glass contains more or, alternatively, if both glasses contain the same amount, those younger than 6 answer that the narrower glass (with the higher level) has more. (See Figure 5.1 for other examples.) All four characteristics of preoperational thought are evident in this mistake. Young children fail to understand conservation because they focus (center) on what they see (appearance), noticing only the immediate (static) condition. It does not occur to them that they could pour the lemonade back into the wider glass and recreate the level of a moment earlier (irreversibility). Piaget's original tests of conservation required children to respond verbally to an adult's questions. Contemporary researchers have made tests simple and playful, and then young children sometimes succeed. Moreover, before age 6, children indicate via eye movements or gestures that they understand some logic before they can put their understanding into words (Goldin-Meadow & Alibali, 2013). Instead of sudden insight, many logical ideas are grasped bit by bit, via active, guided experience. Glimmers of understanding may be apparent at age 4 (Sophian, 2013). Thus, as with sensorimotor intelligence in infancy, Piaget underestimated preoperational children. Piaget was right about his basic idea, however: Young children are not very logical (Lane & Harris, 2014). Their cognitive limits make smart 3-year-olds sometimes foolish, as Caleb was (see A Case to Study on page 168).

OBSTACLES TO LOGIC

Piaget noted four limitations that make logic difficult during preoperational thought: centration, focus on appearance, static reasoning, and irreversibility. Centration is the tendency to focus on one aspect of a situation to the exclusion of all others. Young children may, for example, insist that Daddy is a father, not a brother, because they center on the role that he fills for them. This illustrates a type of centration that Piaget called egocentrism—literally, "self-centeredness." Egocentric children contemplate the world exclusively from their personal perspective. centration A characteristic of preoperational thought in which a young child focuses (centers) on one idea, excluding all others. egocentrism Piaget's term for children's tendency to think about the world entirely from their own personal perspective. A second characteristic of preoperational thought is a focus on appearance to the exclusion of other attributes. For instance, a girl given a short haircut might worry that she has turned into a boy. In preoperational thought, a thing is whatever it appears to be—evident in the joy young children have in wearing the hats or shoes of a grown-up, clomping noisily and unsteadily around the house. focus on appearance A characteristic of preoperational thought in which a young child ignores all attributes that are not apparent. Third, preoperational children use static reasoning. They believe that the world is stable, unchanging, always in the state in which they currently encounter it. Many children cannot imagine that their own parents were ever children. If they are told that Grandma is their mother's mother, they still do not understand how people change with maturation. One preschooler asked his grandmother to tell his mother not to spank him because "she has to do what her mother says." static reasoning A characteristic of preoperational thought in which a young child thinks that nothing changes. Whatever is now has always been and always will be. The fourth characteristic of preoperational thought is irreversibility. Preoperational thinkers fail to recognize that reversing a process might restore whatever existed before. A young girl might cry because her mother put lettuce on her sandwich. She might reject the food even after the lettuce is removed because she believes that what is done cannot be undone. irreversibility A characteristic of preoperational thought in which a young child thinks that nothing can be undone. A thing cannot be restored to the way it was before a change occurred.

CHILD-CENTERED PROGRAMS

Programs that are child-centered, or developmental, stress each child's development and growth. Teachers in such programs believe children need to follow their own interests. For example, they agree that "children should be allowed to select many of their own activities from a variety of learning areas that the teacher has prepared" (Lara-Cinisomo et al., 2011). The physical space and the materials (such as dress-up clothes, art supplies, puzzles, blocks, and other toys) are arranged to allow exploration. Child-centered programs are often influenced by Piaget, who emphasized that each child will discover new ideas if given a chance, or by Vygotsky, who thought that children learn from playing, especially with other children, with adult guidance. Most child-centered programs encourage artistic expression, including music and drama (Bassok et al., 2016). Some educators argue that young children are gifted in seeing the world more imaginatively than older people do. According to advocates of child-centered programs, creative vision should be encouraged; children need to tell stories, draw pictures, dance, and make music for their own delight. One type of child-centered school began in the slums of Rome in 1907, when Maria Montessori opened a nursery school (Standing, 1998). She believed that children needed structured, individualized projects to give them a sense of accomplishment. Her students completed puzzles, used sponges and water to clean tables, traced shapes, and so on. Contemporary Montessori schools still emphasize individual pride and achievement, presenting many literacy-related tasks (e.g., outlining letters and looking at books) to young children. Specific materials differ from those that Montessori developed, but the underlying philosophy is the same. Children seek out learning tasks; they do not sit quietly in groups while a teacher instructs them. That makes Montessori programs child-centered (Lillard, 2013). Montessori schools Schools that offer early-childhood education based on the philosophy of Maria Montessori, which emphasizes careful work and tasks that each young child can do. Another child-centered form of early-childhood education is Reggio Emilia, named after the town in Italy where it began. In Reggio Emilia, children are encouraged to master skills that are not usually taught in North American schools until age 7 or so, such as writing and using tools. Although many educators worldwide admire the Reggio philosophy and practice, it is expensive to duplicate in other nations—there are few dedicated Reggio Emilia schools in the United States. Reggio Emilia A program of early-childhood education that originated in the town of Reggio Emilia, Italy, and that encourages each child's creativity in a carefully designed setting. Reggio schools do not provide large-group instruction, with lessons in, say, forming letters or cutting paper. Instead, hands-on activities are chosen by each child, perhaps drawing, cooking, or gardening. Measurement of achievement, such as standardized testing to see whether children recognize the 26 letters of the alphabet, is antithetical to the conviction that every child should explore and learn in his or her own pace and manner. Each child's learning is documented via scrapbooks, photos, and daily notes—not to measure progress but to make the child and parent proud (Caruso, 2013). Appreciation of the arts is evident. Originally, every Reggio Emilia school had a studio, an artist, and space to encourage creativity (Forbes, 2012). Children's art is displayed on white walls and hung from high ceilings, and floor-to-ceiling windows open to a spacious, plant-filled playground. Big mirrors are part of the schools' décor—again, with the idea of fostering individuality and self-expression. Cooperation is also valued. Group projects are encouraged, especially those that engage the young scientists to explore their natural world. A third type of child-centered school is called Waldorf, first developed by Rudolf Steiner in Germany in 1919. The emphasis again is on creativity and individuality—with no homework, no tests, and no worksheets. As much as possible, children play outdoors—appreciation of nature is basic to Waldorf schools. Children of various ages learn together because older children serve as mentors for younger ones, and the curriculum follows the interests of the child, not the age of the child. Waldorf An early-childhood education program than emphasizes creativity, social understanding, and emotional growth. It originated in Germany with Rudolf Steiner, and now is used in thousands of schools throughout the world. There is a set schedule—usually circle time in the beginning and certain activities on certain days (always baking on Tuesdays, for instance)—but children are not expected to master specific knowledge at certain ages. All child-centered schools emphasize creativity; in Waldorf schools, imagination is particularly prized (Kirkham & Kidd, 2017).

Quality of Early Education

Since price does not indicate quality, what does matter? Consider how many adults there are and what they do. Ideally caregivers talk, listen, laugh, guide, and play with the children; if they sit, watch, and command ("Stop hitting," "Sit here," "Share the toy"), that suggests low quality. Another question is whether the goals of the program are to encourage each child's creative individuality (child-centered) or to prepare children for formal education (teacher-directed). Both approaches may succeed, but the teachers need to know the goals and work to accomplish them, not simply babysit. (See Visualizing Development, page 186.)

OVERIMITATION

Sometimes scaffolding is inadvertent, as when children copy something that adults would rather the child not do. Young children curse, kick, and worse because someone else showed them how. More benignly, children imitate meaningless habits and customs in overimitation. Children eagerly learn from mentors, allowing "rapid, high-fidelity intergenerational transmission of tool-use skills and for the perpetuation and generation of cultural forms" (Nielsen & Tomaselli, 2010, p. 735). Overimitation is universal: Young children follow what others do. Adults worldwide teach children, using words, gestures, eye contact, and facial expressions (Heyes, 2016). Young children are "socially motivated," which enables them to learn when someone structures and guides that learning. They also are eager to explore, deciding which actions to perform, whom to imitate, what to try (Gopnik, 2016).

TEACHER-DIRECTED PROGRAMS

Teacher-directed preschools stress academics, often taught by one adult to the entire group. The curriculum includes learning the names of letters, numbers, shapes, and colors. Orderly, scheduled activities teach routines: Every child naps, snacks, and goes to the bathroom at certain times. Children learn to sit quietly and listen to the teacher. Praise and other reinforcements are given for good behavior, and time-outs (brief separation from activities) are imposed to punish misbehavior. The goal of teacher-directed programs is to make all children "ready to learn" when they enter elementary school. For that reason, basic skills are stressed, including precursors to reading, writing, and arithmetic, perhaps via teachers asking questions that children answer together in unison. Behavior is also taught, as children learn to respect adults, to follow schedules, to hold hands when they go on outings, and so on. Children practice forming letters, sounding out words, counting objects, and writing their names. If a 4-year-old learns to read, that is success. (In a child-centered program, that might arouse suspicion that there was too little time to play or socialize.) Many teacher-directed programs were inspired by behaviorism, which emphasizes step-by-step learning and repetition, with reinforcement (praise, gold stars, prizes) for accomplishment. Another inspiration for teacher-directed programs comes from information-processing research indicating that children who have not learned basic vocabulary and listening skills by kindergarten often fall behind in primary school. Many state legislatures mandate that preschoolers master specific concepts, an outcome best achieved by teacher-directed learning (Bracken & Crawford, 2010). A program that now seems more teacher-directed than child-centered is Head Start. In the early 1960s, millions of young children in the United States were thought to need a "head start" on their formal education to foster better health and cognition before first grade. Consequently, since 1965, the federal government has funded preschool education for 4-year-olds from low-SES families or with disabilities. Head Start A federally funded early-childhood intervention program for low-income children of preschool age. The goals for Head Start have changed over the decades, from lifting families out of poverty to promoting literacy, from providing dental care and immunizations to teaching Standard English, from focusing on 4- and 5-year-olds to including younger children. In 2015, more than 8 billion dollars in federal funds were allocated to Head Start, which enrolled almost a million children. In 2016, new requirements for Head Start included at least 6 hours a day and 180 days a year (initially, most programs were half-day), with priorities for children who are homeless, or have special needs, or are learning English. Those children were targeted partly because federal research found that Head Start benefits are strongest for them (U.S. Department of Health and Human Services, 2010). Moreover, they are least likely to be enrolled in private preschools (Crosnoe et al., 2016). Historical data show that most Head Start children of every background advanced in language and social skills, but non-Head Start children often caught up in elementary school. However, there was one area in which the Head Start children maintained their superiority—vocabulary. This seems especially significant for Spanish-speaking children whose teachers instruct in English at least half of the time (Garcia, 2018). Since there are about 8 million 3- and 4-year-olds in the United States, only about 12 percent of U.S. children that age are in Head Start. Many others are in private programs (about 83 percent of 4-year-olds from the wealthiest families are enrolled in private preschools) or state-sponsored programs, which range in quality from excellent to woefully inadequate (Barnett et al., 2016).

The Vocabulary Explosion

The average child knows about 500 words at age 2 and more than 10,000 at age 6 (Herschensohn, 2007). That's more than six new words a day. As with many averages in development, the range is vast: The number of root words (e.g., run is a root word, not running or runner) that 5-year-olds know ranges from 2,000 to 6,000 (Biemiller, 2009). In fact, it is very difficult to determine vocabulary size, although almost everyone agrees that building vocabulary is crucial (Milton & Treffers-Daller, 2013). To understand why vocabulary is difficult to measure, consider the following: Children listened to a story about a raccoon that saw its reflection in the water, and then they were asked what reflection means. Five answers: "It means that your reflection is yourself. It means that there is another person that looks just like you." "Means if you see yourself in stuff and you see your reflection." "Is like when you look in something, like water, you can see yourself." "It mean your face go in the water." "That means if you the same skin as him, you blend in." (Hoffman et al., 2014, pp. 471-472) In another example, a story included "a chill ran down his spine." Children were asked what chill meant. One answer: "When you want to lay down and watch TV—and eat nachos" (Hoffman et al., 2014, p. 473). Which of the five listed responses indicated that the child knew what reflection means? None? All? Some number in between? The last child was given no credit for chill; is that fair?

INSIDE THE BRAIN Connected Hemispheres

The brain is divided into two halves, connected by the corpus callosum, a long, thick band of nerve fibers that grows and myelinates rapidly in early childhood (Ansado et al., 2015). For that reason, young children become much better at coordinating the two sides of their brains and, hence, both sides of their bodies. They can hop, skip, and gallop at age 6, unlike at age 2. corpus callosum A long, thick band of nerve fibers that connects the left and right hemispheres of the brain and allows communication between them. Serious disorders, almost always including intellectual disability, result when the corpus callosum fails to develop (Cavalari & Donovick, 2014). Abnormal growth of the corpus callosum is one symptom of autism spectrum disorder, as well as dozens of other disorders (Al-Hashim et al., 2016; Travers et al., 2015; J. Wolff et al., 2015). To appreciate the corpus callosum, note that each side of the body and brain specializes and is therefore dominant for certain functions. This is lateralization, literally, "sidedness." lateralization Literally, "sidedness," referring to the specialization in certain functions by each side of the brain, with one side dominant for each activity. The left side of the brain controls the right side of the body, and vice versa. The entire human body is lateralized, apparent not only in right- or left-handedness but also in the feet, the eyes, the ears, and the brain itself. People prefer to kick a ball, wink an eye, or listen on the phone with their preferred foot, eye, or ear, respectively. Genes, prenatal hormones, and early experiences all affect which side does what. Astonishing studies of humans whose corpus callosa were severed to relieve severe epilepsy, or who sustained major damage to their left or right brains, reveal how the brain's hemispheres specialize. Typically, the left half controls the body's right side as well as areas dedicated to logic, detailed analysis, and language. The brain's right half controls the body's left side and areas dedicated to emotional and creative impulses, including appreciation of music, art, and poetry. Thus, the left side notices details and the right side grasps the big picture. This left-right distinction has been exaggerated, especially when broadly applied to people (Hugdahl & Westerhausen, 2010). No one is exclusively left-brained or right-brained, except individuals with severe brain injury in childhood, who may use half of their brain to do all of the necessary thinking. For everyone else, every skill usually activates both sides of the brain. That makes the corpus callosum crucial. Logic (left brain) without emotion (right brain) is a severe impairment, as is the opposite (Damasio, 2012). As myelination progresses, signals between the two hemispheres become quicker and clearer, enabling better coordination of body parts, as well as part of the brain. For example, no 2-year-old can hop but most 6-year-olds can—an example of brain balancing. Many songs, dances, and games that are beloved by young children (hokey-pokey, eensy-weensy spider, head/shoulders/knees and toes) involve moving their bodies in some coordinated way—challenging, but fun because of that. The emotions of the young child (right brain) are gradually influenced by awareness of other people (left brain). Bursting into tears is less common at age 6 than at age 2. Left-handed people tend to have thicker corpus callosa than right-handed people do, perhaps because they often need to use their nondominant hand. For example, most left-handed people brush their teeth with their left hand because using that hand is more natural, but they shake hands with their right hand because that is what social convention requires. Left lateralization is an advantage in some professions, especially those involving creativity and split-second actions. A disproportionate number of artists, musicians, and sports stars were/are left-handed, including Pelé, Babe Ruth, Monica Seles, Bill Gates, Oprah Winfrey, Jimi Hendrix, Lady Gaga, and Justin Bieber. Five of the past eight presidents of the United States were lefties: Gerald Ford, Ronald Reagan, George H. W. Bush, Bill Clinton, and Barack Obama. The corpus callosa of those celebrities may have been especially well-developed, enabling coordination of logic and emotion, body and mind. Scoring a goal, singing a song, or winning an election may seem to require only one skill, but to do them extraordinarily well requires the entire brain.

Children's Theories

The contrast between Piaget and Vygotsky is apparent: Piaget highlighted the child's own curiosity and brain maturation, while Vygotsky stressed mentors, especially parents and teachers, in guiding children's learning. But do not let this difference obscure the more important truth: Both men recognized that young children are great learners, striving to understand their world. Children do more than master words and ideas; they develop theories to explain what they observe.

HOME VERSUS PRESCHOOL

The longitudinal evidence within the United States and the proliferation of early-education programs in many nations raise another question: Is every child better educated in a preschool of some sort than at home? No! Quality matters (Gambaro et al., 2014). If the home learning environment is poor, a good preschool significantly advances health, cognition, and social skills. If, instead, a family provides excellent early education but the preschool is overcrowded, children may not benefit from attendance, at least according to studies in the United States (Karch, 2013). The problem is that the easiest way for a preschool to reduce expenses is to hire fewer staff members. Many government subsidies are low. As one critic complained: "Parents can find cheap babysitting that's bad for their kids on their own. They don't need government help with that" (Barnett, quoted in Samuels & Klein, 2013, p. 21). A U.S. program that gave mothers of young children a small subsidy for early child care if they had jobs found that many mothers entered the labor force, but their children learned no more than their peers whose mothers stayed home (A. Johnson et al., 2014). The exceptions were children of immigrants, who became better at English-reading skills. But, on most measures, the subsidized children did no better than the home-staying children, who actually learned more math than the children who attended low-quality preschools. Quality is not indicated by name (preschool, nursery school, day-care center, pre-primary, or pre-K) or sponsorship (public or private, religious or secular, corporate or independent). What does matter is the training, warmth, and experience of the teachers. Unfortunately, "because quality is hard for parents to observe, competition seems to be dominated by price" (Gambaro et al., 2014, p. 22), which means fewer, and less trained, adults. However, expensive preschools are not necessarily high in quality, because owners may spend money on attractive space, toys, and equipment, but not on teachers.

STRESS AND THE BRAIN

The relationship between stress and brain activity depends partly on a person's age (childhood is most vulnerable) and partly on the degree of stress. Some stress may be good; too much is destructive. In an experiment, brain scans and hormone measurements were taken of 4- to 6-year-olds immediately after a fire alarm (Teoh & Lamb, 2013). As measured by the hormone cortisol, some children were upset and some were not. Two weeks later, they were questioned, either by a friendly adult or by a stern one. Those with higher cortisol reactions to the alarm remembered more details. That conclusion is found in other research as well—some stress, but not too much, aids cognition (Keller et al., 2012). However, this study and many others found that when adults ask questions in a stern, stressful manner, children's memories are less accurate. There are evolutionary reasons for both outcomes: People need to remember experiences that arouse their emotions so that they can avoid, or adjust to, similar experiences in the future. On the other hand, the brain protects itself from too much stress by shutting down. Studies of maltreated children suggest that excessive stress-hormone levels in early childhood may permanently damage brain pathways, blunting or accelerating emotions lifelong (Evans & Kim, 2013; Wilson et al., 2011). Of course, every child experiences some stress, but especially then they need caregivers to help them manage. Sadly, this topic applies to the Romanian children mentioned in Chapter 4. When adopted Romanian children saw pictures of happy, sad, frightened, or angry faces, their limbic systems were less reactive than were those of Romanian children who were never institutionalized. Their brains were also less lateralized, suggesting less efficient thinking (C. Nelson et al., 2014). Thus, institutional life, without the stress reduction of loving caretakers, impaired their brains. Direct maltreatment may be worse, causing not only shrinkage of various regions of the brain but also decreases in white matter—and thus in the connections between parts of the brain (Puetz et al., 2017). A person who was abused as a child might get stuck—perhaps on fear, or on fantasy, or even on a happy or neutral thought, unable to coordinate and modulate the mixed emotions of most experiences.

INTERNATIONAL EARLY-CHILDHOOD EDUCATION

Those three U.S. programs 50 years ago reached relatively few children, but they inspired thousands of educators who are teaching millions of 2- to 5-year-olds in virtually every nation. Currently, in most developed nations, over 90 percent of 3- to 5-year-olds attend school paid for by the government. In nations where major government funding is scarce, preschools that are privately or religiously funded proliferate (Georgeson & Payler, 2013). In the United States, 54 percent of 3- to 4-year-olds are in some sort of educational program. That is the lowest rate among major developed nations, but it is five times as high as in 1965, according to the National Center for Education Statistics. About half of those young children are in programs funded by federal or local governments, and about half are in privately funded programs. The highest rates are in Norway, where the government heavily subsidizes preschool education for every child from age 1 on (Ellingsaeter, 2014). More than 90 percent of young Norwegian children attend, with advances in language and social skills, and no apparent cognitive or emotional deficits (Zachrisson et al., 2013). In Norway, because of paid parental leave, parents are more likely to stay home with their youngest babies and then most women return to their jobs when their children reach age 1. Most mothers—of all ethnic and economic backgrounds—are now convinced that the best care and ideal education for young children is in an educational program, not at home (Ellingsaeter et al., 2017).

SCAFFOLDING

Vygotsky believed that all individuals learn within their zone of proximal development (ZPD), an intellectual arena in which new ideas and skills can be mastered. Proximal means "near," so the ZPD includes the ideas and skills children are close to mastering but cannot yet demonstrate independently. Learning depends, in part, on the wisdom and willingness of teachers to provide scaffolding, or temporary sensitive support, to help children within their developmental zone (Mermelshtine, 2017). zone of proximal development (ZPD) Vygotsky's term for intellectual arena that is comprised of skills—cognitive as well as physical—that a person can learn with assistance. scaffolding Temporary support that is tailored to a learner's needs and abilities and aimed at helping the learner master the next task in a given learning process. Good mentors offer extensive scaffolding, encouraging children to look both ways before crossing the street (pointing out speeding trucks, cars, and buses while holding the child's hand) or letting them stir the cake batter (perhaps covering the child's hand on the spoon handle, in guided participation). Crucial in every activity is joint engagement, when both learner and mentor are actively involved together in the ZPD (Adamson et al., 2014).

Piaget: Preoperational Thought

You have just learned that every year of early childhood advances motor skills, brain development, and impulse control. That allows impressive learning, described by Piaget, Vygotsky, and others. Early childhood is the time of preoperational intelligence, the second of Piaget's four periods of cognitive development (described in Table 1.6 on p. 27). Piaget called early-childhood thinking preoperational because children do not yet use operations (logical reasoning) (Inhelder & Piaget, 1964/2013a). preoperational intelligence Piaget's term for cognitive development between the ages of about 2 and 6; it includes language and imagination (which involve symbolic thought), but logical, operational thinking is not yet possible at this stage. Preoperational children are beyond sensorimotor intelligence because they can think in symbols, not solely via senses and motor skills. In symbolic thought, an object or word can stand for something else, including something out of sight or imagined. Language is the most apparent example of symbolic thought. Words make it possible to think about things that are not immediately present. symbolic thought A major accomplishment of preoperational intelligence that allows a child to think symbolically, including understanding that words can refer to things not seen and that an item, such as a flag, can symbolize something else (in this case, a country). Symbolic thought helps explain animism, the belief of many young children that natural objects (such as trees or clouds) are alive and that nonhuman animals have the same characteristics as human ones, especially the human each child knows best, him or herself. Many children's stories include animals or objects that talk and listen (Aesop's fables; Winnie-the-Pooh; Good Night, Gorilla; The Day the Crayons Quit). Preoperational thought is symbolic and magical, not logical and realistic. animism The belief that natural objects and phenomena are alive, moving around, with sensations and abilities that are humanlike. Among contemporary children, animism gradually disappears as the mind becomes more mature, by age 10 if not earlier (Kesselring & Müller, 2011). However, scholars contend that animism characterized preindustrial thought—people prayed to sky and trees, for instance—and that human history is best understood by considering Piaget's stages of cognition (e.g., Oesterdiekhoff, 2014).