Psychology Chapter 9 Notes PDF

THINK BACK TO YOUR CHILDHOOD, or look at an old photo of yourself. Are you the same person now as you were at age 5 or 13? Will you be the same person when you are 50 or 80 or even older? Almost certainly, the answer to both questions is no. As virtually all people do, you have changed in many ways...

THINK BACK TO YOUR CHILDHOOD, or look at an old photo of yourself. Are you the same person now as you were at age 5 or 13? Will you be the same person when you are 50 or 80 or even older? Almost certainly, the answer to both questions is no. As virtually all people do, you have changed in many ways over the years and will continue to do so as you age. By changing, you are continually developing into a new version of yourself. Throughout the history of psychology, theorists and scientists have vigorously debated the contributions of nature and nurture to human development. Nearly all psychologists now agree that nature and nurture are equally important, and current research focuses on how, exactly, genes and experiences interact to make us who we are. As discussed in Chapter 3, environment determines how specific genes are expressed. Some portion of who we are is hardwired in our genes, and some portion is the result of experience. This chapter examines the ways biological and social forces combine to shape the path of human development. For psychologists in this area, the big questions are: What factors shape infancy? How do children learn about the world? What changes during adolescence? And what brings meaning in adulthood? 337 Learning Objectives Describe how the prenatal environment can affect development. Explain how dynamic systems theory illuminates the ways biology and environment work together to shape development. Summarize key research findings on infant learning and infant memory. Describe the different types of attachment infants have to their caregivers. (a) {b) FIGURE 9.1 Development in the Womb (a) The union of egg and sperm forms a zygote. (b) The zygote develops into an embryo. (c) The embryo becomes a fetus. What Factors Shape Infancy? This chapter is concerned with changes, over the human life span, in physiology, cognition, emotion, and social behavior. In exploring these changes, the chapter presents the findings of developmental psychology. This subfield examines how genes interact with early experiences to make each of us different. Researchers in developmental psychology seek to understand how, while remaining individuals, people become members of society. In other words, each person grows and adapts within a particular culture or particular cultures. For the most part, human physical development follows a predictable progression. Physically, each human matures at about the same periods in the life span: the prenatal period, which begins with conception and ends with birth; infancy, which begins at birth and lasts 18 to 24 months; childhood, which begins at the end of infancy and lasts until somewhere between ages 11 and 14; adolescence, which begins at the end of childhood and lasts until somewhere between 18 and 21 years; and adulthood, which begins at the end of adolescence and lasts until old age and death. The consistency of this pattern suggests that genes set the order and timing of development. The following sections focus on development within the first two periods: prenatal and infancy. From conception through birth approximately nine months later, remarkable developments occur (FIGURE 9.1). The process begins at the moment of conception, when the sperm from the male unites with the egg from the female to create the zygote, the first cell of a new life. At about 2 weeks after conception, the zygote is firmly implanted in the uterine wall, and the next stage of development begins. From about 2 weeks to 2 months, the developing human is known as an embryo. During this stage, the organs (such as the heart, lungs, liver, kidneys, and sex organs) and internal systems (such as the nervous system) begin to form. During this period, the embryo is especially vulnerable. Exposure to harm- such as toxins, drugs, extreme stress, or poor nutritioncan have lasting effects on developing organ systems. After 2 months of prenatal development, all the organs are formed, the heart begins to beat, and the growing human is called afetus. The body continues to grow into its infant form. The fetus grows larger, stronger, and fatter, as the body organs mature to a point where survival is possible outside the womb. With current medical technology helping out, many fetuses can now survive outside the womb after as little as 22 weeks of prenatal development (FIGURE 9.2). Most healthy full-term pregnancies, however, end with the birth of the baby at between 38 and 42 weeks. One important way that brain circuits mature is through myelination. This process begins on the spinal cord during the first trimester of pregnancy and on the neurons during the second trimester. As discussed in Chapter 3, myelination is the brain's way of insulating its "wires." Nerve fibers are wrapped with a fatty sheath, much like the plastic coating around electrical wire (see Figure 3.3). This wrapping incre;:ises the speed with which the fibers are able to transmit signals. The myelinated axons form synapses with other neurons. As you will learn, brain development continues into early adulthood. Though most neurons are already formed at birth, the brain's physical development continues through the growth of neurons and the new connections they make. By age 4, the human brain has grown to about 80 percent of the adult size. This size increase is due to myelination and to new synaptic connections among neurons, particularly in the frontal lobes (Parades et al., 2016). Far more of these connections develop than the infant brain will ever use. Genetic instruction leads the brain to grow, but the organ is also highly "plastic." That is, the brain organizes itself in response to its environmental experiences, preserving connections it needs in order to function in a given context and pruning out others. In other words, "use it or lose it." When connections are used, they are preserved. When connections are not used, they decay and disappear. This process of synaptic pruning allows every brain to adapt well to any environment in which it may find itself. The brain continues to develop and mature through adolescence and beyond (Matsui et al., 2016). Nutrition affects aspects of brain development, such as myelination, beginning in the womb and extending through childhood. Malnourished children might also lack the energy to interact with objects and people. This lack of stimulation would further undermine brain development. When a child's environment does not_ stimulate her brain, very few synaptic connections will be made. The brain will be less sophisticated and less able to process complex information, solve problems, or allow the child to develop advanced language skills (Perry, 2002; FIGURE 9.3). As discussed in Chapter 3, animals raised in enriched environments show increased generation of new neurons in the hippocampus, which may facilitate learning in complex environments ( Garthe, Roeder, & Kempermann, 2016). FIGURE 9.3 developmental psychology The study of changes, over the life span, in physiology, cognition, emotion, and social behavior. synaptic pruning The synaptic connections in the brain that are used are preserved, whereas those that are not used decay and disappear. One factor that can diminish an environment is poverty. The living conditions that tend to come with poverty (e.g., stress, poor nutrition, exposure to toxins and violence) are bad for the development of human brains. These negative effects begin at a young age-probably before birth-and continue through life (Farah et al., 2008; Lawson, Duda, Avants, Wu, & Farah, 2013). One large study of nearly 400 children followed over two years found that living below the U.S. federal poverty level was associated with reductions in several brain areas linked to school readiness skills (Hair, Hanson, Wolfe, & Pollak, 2015). These children living in poverty went on to have lower scores on achievement tests. Other research shows that poor brain functioning associated with poverty at age 3 predicts several negative life outcomes 40 years later, including health problems, addiction, and greater criminal activity (Caspi et al., 2016). On a more positive front, a program designed to enhance parental support for those living in poverty reduced the effects of poverty on brain development (Brody et al., 2017). Thus, although genes provide instructions for the maturing brain, how the brain changes during infancy and early childhood is also very much affected by environment. EXPOSURE TO TERATOGENS DURING PRENATAL DEVELOPMENT Teratogens are agents that harm the embryo or fetus. (The word teratogens comes from the Greek for "monster makers.") Specifically, these agents can impair development in the womb, sometimes with terrible consequences. Teratogens include drugs, alcohol, bacteria, viruses, and chemicals. In 2015, significant concerns were raised that the Zika virus was causing birth defects throughout the Americas. Zika, spread mainly by infected mosquitoes, can also be transmitted via sexual activity. A pregnant woman may pass the virus on to her fetus, which can produce serious birth defects such as brain abnormalities and microcephaly, an abnormally small head (Rasmussen, Jamieson, Honein, & Petersen, 2016). Such defects are usually quite rare, but 6 percent of infants exposed to Zika have virus-related defects, particularly if exposed during the first trimester (Honein et al., 2017; FIGURE 9.4). The physical effects of exposure to certain teratogens may be obvious at birth, but disorders involving language, reasoning, social behavior, or emotional behavior may not become apparent until the child is older. The extent to which a teratogen causes damage depends on when the embryo or fetus is exposed to it, as well as the length and amount of exposure. The most common teratogen is alcohol. Drinking alcohol during pregnancy can lead to fetal alcohol syndrome (FAS). The symptoms of this disorder are low birth weight; face and head abnormalities; deficient brain growth; and evidence of impairment, as indicated by behavioral or cognitive problems or low IQ (Hoyme et al., 2016; FIGURE 9.5). FAS is most likely to occur among infants of women who drink heavily during pregnancy, especially if they binge drink. However, no minimal amount of alcohol has been determined to be safe for pregnant women and their developing babies. For this reason, many health workers recommend that women abstain from drinking alcohol when they are pregnant or trying to become pregnant (Mukherjee, Hollins, Abou-Saleh, & Turk, 2005). In the United States, the prevalence of FAS is estimated to be between 0.2 and 2.0 cases per 1,000 live births (Centers for Disease Control and Prevention, 2004), though recent studies have found higher numbers, with an estimated rate closer to 8 out of 1,000 children (May et al., 2014). The use of recreational drugs-such as opiates, cocaine, or cannabisduring pregnancy can also affect a child's development. Premature birth and other complications have been associated with the use of all these drugs during pregnancy (Cain, Bornick, & Whiteman, 2013; Hayatbakhsh et al., 2011; Minnes, Lang, & Singer, 2011). Infants of women taking opiates, particularly methadone, have five to ten times greater risk for unexplained sudden death in infancy (Ali, Ahmed, & Greenough, 2012). Among infants exposed to opiates in the womb, 40-80 percent show symptoms of newborn withdrawal (Yazdy, Desai, & Brogly, 2015). These symptoms include irritability, highpitched crying, tremors, vomiting, diarrhea, and rapid breathing. The recent opioid epidemic, discussed in Chapter 4, is associated with a nearly threefold increase in infants born with this condition (Volkow, 2016). most common features are small eye openings, Historically, far less research has been done on the effects of paternal health and lifestyles on prenatal development. There is growing evidence, however, that paternal lifestyle factors, including diet, toxin exposure, and amount of stress experienced, can affect a child's health through epigenetic processes (Schagdarsurengin & Steger, 2016; Siklenka et al., 2015). Recall from Chapter 3 that epigenetic effects occur when parents' environments alter the way that genes are expressed in their offspring. The take-home message here is that life experiences and environmental circumstances can be passed along in sperm as epigenetic information (Chen, Yan, & Duan, 2016). These effects may then be passed along to subsequent generations. An important point to remember is that some heavy substance users and many people exposed to toxins or stress have normal infants. Conversely, some people with only moderate exposure to teratogens have infants with serious developmental effects. Thus, we cannot say with certainty that any given baby born to a drug user or to a person who works around chemicals will be impaired. Likewise, we cannot be assured that light drinking or minimal teratogen exposure will allow for normal development. All potential parents face the responsibility of caring for their own mental and physical health to increase the odds of being able to parent a healthy and robust newborn. Although newborn infants cannot survive on their own, they are not completely helpless. Newborns have various motor reflexes that aid survival. Perhaps you have observed the grasping reflex when a baby held your finger (FIGURE 9.6A). This reflex is a survival mechanism that has persisted from our primate ancestors. Young apes grasp their mothers, and this reflex is adaptive because the offspring need to be carried from place to place. Also appearing at birth is the rooting reflex, the turning and sucking that infants automatically engage in when a nipple or similar object touches anareaneartheirmouths (FIGURE 9.6B). If they find an object, theywill show the sucking reflex (FIGURE 9.6C). These reflexes pave the way for learning more-complicated behavior patterns, such as feeding oneself or walking. Thus, at birth the brain is sufficiently developed to support basic reflexes, but further brain development is necessary for other development to occur. No newborn talks immediately, nor does any baby walk before it can sit up. But most humans make eye contact quickly after they are born, display a first social smile at around 6 weeks, and learn to roll over, to sit up, to crawl, to stand, to walk, and to talk, in that order. Occasionally, a child skips one of these steps or reverses a couple of them, but generally each child follows these steps within a predictable range of ages (FIGURE 9.7). Meanwhile, each person's environment influences what happens throughout that individual's development. For example, infants often achieve developmental milestones at different paces, depending on the cultures in which they are raised. Consider that healthy Baganda infants in Uganda were found to walk, on average, between 9 and 11 months of age, which was one month earlier than African American infants and about three months earlier than European American infants (Kilbride, Robbins, & Kilbride, 1970). Such differences are due in part to different patterns of infant care across cultures. For example, Western infants spend a lot more time in cribs and playpens than African infants do. African infants are often strapped to their mothers' backs all day, practicing holding their heads up virtually from birth. Kipsigi mothers living in the Kohwet village culture in western Kenya were found to put their babies in shallow holes in the ground so the babies could practice sitting upright (Super, 1976). The mothers then marched their babies around while placing their own arms under the babies' underarms, so the children could practice walking. These infants walked about one to two months earlier than American and European infants. When middle-class Kipsigi families who had moved to a larger city were assessed in their Westernized homes, they still deliberately taught their infants motor skills. However, they also let their infants sleep in cribs and lie in playpens like their European counterparts. These urban infants walked two weeks later than the rural infants in Kohwet but one week earlier than infants in Boston, Massachusetts. These findings illustrate the importance of socialization experiences and parental goals in the development of infant motor skills. The aim of these early studies was to find out whether the development of walking was genetically or environmentally determined. Contemporary research has moved beyond such questions because we now know that every new development is the result of complex and consistent interplays between biology and environment. Developmental psychologists now consider new forms of development (such as when an infant is able to walk two weeks after not being able to walk) to be part of a dynamic system. Dynamic systems theory views development as a self-organizing process, in which new forms of behavior emerge through consistent interactions between a biological being and cultural and environmental contexts (Smith & Thelen, 2003; FIGURE 9.8). From this perspective, developmental advances in any domain (physiological, cognitive, emotional, or social) occur through both the person's active exploration of an environment and the constant feedback that environment provides. For example, an infant placed on a play mat may grow bored with the toys dangling above her on a mobile. She suddenly spies an attractive stuffed unicorn about 10 feet away, far from the play mat where her mother placed her. Her physical body is strong enough to get herself off the mat, but because she cannot crawl, she uses her own active strategizing in combination with feedback from the environment to figure out how to reach the toy. She rocks her body from side to side with her arm outstretched toward the toy. The environmental feedback tells her that after one more heavy roll, she will be on her stomach and possibly closer to the toy. She tries for over 10 minutes, and suddenly she rolls over. She continues to heave herself over and over until she has rolled 10 feet and can now grasp the unicorn. Her mother may walk into the room and think, "Wow, she just suddenly learned to roll around the room!" What her mother does not realize is that every new behavioral skill to emerge is the result of a complex and dynamic system of influences, including the child's motivation and personality, that respond to environmental cues. Step into the nursery for newborns, bend over a bassinet, peer at the newborn inside, and stick your tongue out. The baby, less than one hour old, sticks her tongue out at you (FIGURE 9.9). Think about the remarkable activity going on in the baby's young brain. After seeing a face with a tongue sticking out, the baby somehow seems to know that she too has a face with a tongue. The brain finds the tongue in its long list of body parts, sends it a command to get a move on, and out it goes. How does the baby know FIGURE 9.9 Infant Learning Newborns have the ability to imitate adults' sticking out their tongues and other facial expressions (Meltzoff & Moore, 1977). FIGURE 9.10 Infant Vision Improves over Time Newborns have poor visual acuity and poor ability to see colors. These capacities improve rapidly over the first 6 months of life. By 1 year of age, children can see as well as adults. CHAPTER 9 HUMAN DEVELOPMENT a tongue is a tongue? How does the baby's brain know what neural system is in charge of the tongue? How does the baby know how to move the tongue? Why does the baby move her tongue? Obviously, this behavior was not learned by looking in a mirror, nor had it been taught. The ability to imitate must be innate. Imitation is the baby's first social interaction, but babies are discerning. They will imitate the actions of other humans but not of objects. Babies are born categorizing, and newborns already understand they are in the people category, not the object category. The baby brain already has specific neural circuits for identifying biological motion and inanimate object motion, along with specific circuits to identify faces and facial movement (Lloyd-Fox, Blasi, Everdell, Elwell, & Johnson, 2011). What links him to you and you to him in the social world are his imitative actions. You purse your lips, and he purses his lips. He does not lie there like a lump of clay but responds in a way that you can relate to. PERCEPTION Newborns normally come into the world with fairly well-developed perceptual skills: smelling, hearing, tasting, and responding to touch. Although some of these skills are not fully developed at birth, the newborn is able to process a considerable range of sensory stimuli. For instance, 2-hour-old infants prefer sweet tastes to all other tastes (Mennella, Bobowski, & Reed, 2016). Young infants also have a reasonably acute sense of smell, at least for smells associated with feeding. In a number of studies, infants turned their heads toward a pad containing their own mother's milk but not toward pads containing milk from other breast-feeding mothers (e.g., Marin, Rapisardi, & Tani, 2015; Winberg & Porter, 1998). The sense of hearing is also quite good shortly after birth: Infants are startled by loud sounds and often will turn their bodies toward the source of the sounds. When newborns are exposed to the crying of another infant, a distress response is induced, and the newborns will join in the crying. When they hear their own recorded cry played to them, or other random noises, a distress response is not induced, and they do not cry (Dondi, Simion, & Caltran, 1999). These responses suggest that newborns are able to distinguish between their own cry and other infants' cries and have some innate understanding of the difference between themselves and others (Martin & Clark, 1982). Infants' abilities to recognize sounds and locate those sounds in space improve continuously as the infants gain experience with objects and people and as the auditory cortex develops. By the age of 6 months, babies have a nearly adult level of auditory function (DeCasper & Spence, 1986). The sense of vision develops more slowly than hearing. The ability to distinguish differences among shapes, patterns, and colors is known as visual acuity. Newborns' visual acuity for distant objects is poor, but it increases rapidly over the first six months (Teller, Morse, Borton, & Regal, 1974). Infants do not reach adult levels of acuity until they are about a year old (FIGURE 9.10). The increase in visual acuity is probably due to a combination of practice in looking at things in the world, the development of the visual cortex, and the development of the cones in the retina (as noted in Chapter 5, the cones are important for perceiving detail). Infants respond more to objects with high-contrast patterns than to other stimuli. In the early 1960s, Robert Fantz (1963) and other developmental psychologists observed infants' reactions to patterns of black-and-white stripes as well as patches of gray (FIGURE 9.11). In these studies, the mother or another caregiver was asked to hold the infant in front of a display of the two images. The experimenter, not knowing which image was on which side, would observe through a peephole to see where the infant preferred to look. This research revealed that infants look at stripes with high contrast more readily than at gray images. The smaller the stripes are-that is, the less contrast between the images-the more difficult it becomes for infants to distinguish them from the gray patches. This type of research makes use of the preferentiallooking technique (FIGURE 9.12). In using this technique, the researchers show an infant two things. If the infant looks longer at one of the things, the researchers know the infant can distinguish between the two and finds one more interesting. MEMORY The development of memory helps children learn about the world around them. That is, children are able to use new information to build on what they already know. But how do researchers study memory in infants who cannot speak? In a clever experiment (Rovee-Collier, 1999), a mobile hanging over a crib was attached to an infant's ankle with a ribbon (FIGURE 9.13). The infant learned that he could move the mobile by kicking his foot. When the infant was tested later, the ribbon was attached to the ankle but not to the mobile, so the kicks no longer moved the mobile. The rate at which the infant kicked when nothing was attached served as the baseline. If the baby recognized the mobile, presumably it would kick faster than the baseline rate to try to make the mobile move. Infants ranging in age from 2 months to 18 months were trained for two days on the mobile task and then tested after different lengths of time. The findings indicated that compared to younger infants, older infants could retain their memories regarding the connection between the ankle kicking and the mobile movement for longer periods of time. By 18 months, the infants could remember the event even if they were tested several weeks after they had learned the initial associations. What is your earliest explicit memory? Most adults remember few events that occurred before they were 3 or 4 years old. Freud referred to this inability to remember events from early childhood as infantile amnesia. Researchers have offered various explanations for this phenomenon, including immature memory systems in the brain (Madsen & Kim, 2016). Some psychologists believe that children begin to retain explicit memories after developing the ability to create autobiographical memory based on personal experience. Other psychologists suggest that childhood memory develops with language acquisition because the ability to use words and concepts aids in memory retention. Still other psychologists theorize that children younger than 3 or 4 do not perceive contexts well enough to store memories accurately. They argue that improvements in children's abilities to encode new information, retain it for longer periods, and deliberately retrieve it underlie the decrease in infantile amnesia after the first 5 years oflife (Hayne, 2004). There are cultural differences in earliest memory, with the native Maori of New Zealand recalling memories, on average, a few months before their third birthdays. Although Maori mothers do not elaborate events in greater detail, it appears they talk about events in a way that enables their children to understand the relative time when events happened (Hayne, Imuta, & Scarf, 2015) One fundamental need infants have is to bond emotionally with those who care for them. An attachment is a strong, intimate, emotional connection between people that persists over time and across circumstances. Such emotional bonds are the building blocks of a successful social life later on. The attachment process draws on humans' innate tendency to form bonds with others. This tendency to bond is, in ·siueJU! 01 pa11dde s11nsaJ a41 Ja41a4M MOU~ Ol AeM OU seM aJa41 OS 's1uapn1s afia110J aJaM siuedpqJed a41 pue :uoqenJ!S a41 JO saq11enb fiu1Jue4ua.poow a41 Aq paJuanl)U! uaaq aAe4 l4D!W s11nsaJ 1sa1 a41 :11!~S JOJow e 01 uoqe1aJ U! pa1sa1 seM.. aJuafi!11a1u!.. 'ApnJs 1eu!fi!JO a41 u1 ·suoseaJ MaJ e aJe aJa41 :ij3MSN'lf attachment A strong, intimate, emotional connection between people that persists over time and across circumstances. WHA T FACTORS SHAPE INFANCY? FIGURE 9.15 Infant Attachment Behaviors Newborns behave in ways, such as smil ing, that make their caregivers want to nurture them. fact, an adaptive trait. Forming bonds with others provides protection for individuals, increases their chances of survival, and thus increases their chances of passing along their genes to future generations (Bowlby, 1982). Like all young primates, human infants need nurturance and care from adults to survive. Unlike horses and deer, which can walk and find food within hours after birth, humans are born profoundly immature. At that early point, human infants cannot even hold up their own heads or roll over. But they are far from passive. Just minutes after birth, infants' cries cause psychological, physiological, and behavioral reactions in caregivers that compel the offering of food and comfort to the newborns. As discussed earlier, even a newborn can have a social life. Young infants quickly build highly interactive social relationships. For example, within 10 weeks after birth, infants are profoundly affected by their caregivers' facial expressions and may become very upset when their primary caregivers fail to display emotional reactions (Cohn & Tronick, 1983). Caregivers shape much of an infant's early experience, from what the child eats to where the child sleeps to what social connections the child makes. These early interactions with people begin to shape the developing human. They are the first stages in which a person learns how to communicate with others, how to behave appropriately in various situations, and how to establish and maintain relationships. Ultimately, socialization also affects complex human characteristics such as gender roles, a sense of personal identity, and moral reasoning, each of which will be explored in this chapter. Between 4 and 6 weeks of age, most infants display a first social smile. This expression of pleasure typically induces powerful feelings oflove in caregivers. According to John Bowlby (1982), the architect of attachment theory, infants have innate attachment behaviors that motivate adult attention. For instance, they prefer to remain close to caregivers, act distressed when caregivers leave and rejoice when they return, and put out their arms to be lifted. Likewise, adults generally seem predisposed to respond to infants, as in 'picking up and rocking a crying child. They also tend to respond to infants in ways that infants can understand, as in making exaggerated facial expressions and speaking in a higher-pitched voice ( FIGURE 9.15). The next time you observe an adult talking to a baby, notice how even the gruffest men with deep voices change their voices to a higher pitch. Babies attend to high-pitched voices. In virtually every culture studied, men, women, and even children intuitively raise the pitch of their voices when talking to babies, and babies respond by maintaining eye contact (Fernald, 1989; Vallabha, McClelland, Pons, Werker, & Amano, 2007). Bowlby argued that these behaviors motivate infants and caregivers to stay in proximity. Because it heightens feelings of security, attachment is adaptive: It is a dynamic relationship that facilitates survival for the infant and parental investment for the caregivers. ATTACHMENT IN OTHER SPECIES Attachment is important for survival in many other species as well. For instance, infant birds communicate hunger through crying chirps. In doing so, they prompt caregivers to find food for them. Some bird species seem to have a sensitive period in which fledgling chicks become strongly attached to a nearby adult, even one from another species. This pattern occurs for birds such as chickens, geese, and ducks. Because these birds can walk immediately after hatching, they are at risk of straying from their mothers. Therefore, within about 18 hours after hatching, the birds will attach themselves to an adult (usually to their mothers) and then follow the object of their attachment. The ethologist CHAPTER 9 HUMAN DEVELOPMENT Konrad Lorenz (1935) called such behavior imprinting. He noted that goslings that became imprinted on him did not go back to their biological mothers when later given access to them (FIGURE 9.16). Such birds preferentially imprint on a female of their species if one is available, however. During the late 1950s, the psychologist Harry Harlow began conducting research that later allowed him to discover one of the most striking examples ofnonhuman attachment. At that time, psychologists generally believed an infant needed its mother primarily as a food source. For example, Freud viewed the attachment bond as being primarily motivated by the goal of drive reduction. He felt that infants attached to their mothers through having their oral needs met through breast-feeding. Thus, the hunger drive was reduced. But Harlow saw explanations of attachment that were based on food as inadequate for explaining what he observed in infant monkeys. He recognized that the infants needed comfort and security in addition to food. In a now-famous series of experiments, Harlow placed infant rhesus monkeys in a cage with two different "mothers" (Harlow & Harlow, 1966). One surrogate mother was made of bare wire and could give milk through an attached bottle. The second surrogate mother was made of soft terry cloth and could not give milk. Which of these two substitute mothers do you think the infant monkeys preferred-the wire one that provided milk or the soft and cuddly one that could not feed them? The monkeys' responses were unmistakable: They clung to the cloth mother most of the day. They went to it for comfort in times ofthreat. The monkeys approached the wire mother only when they were hungry. Harlow tested the monkeys' attachment to these mothers in various ways. For example, he introduced a strange object, such as a menacing metal robot with flashing eyes and large teeth, into the cage. The infants always ran to the mother that provided comfort, never to the mother that fed them. Harlow repeatedly found that the infants were calmer, braver, and overall better adjusted when near the cloth mother. Once they clung to her, they would calm down and actually confront the feared object! Hence, the mother-as-food theory of mother/child attachment was debunked. Harlow's findings established the importance of contact comfort-the importance of physical touch and reassurance-in aiding social development (see "The Methods of Psychology: Harlow's Monkeys and Their 'Mothers,"' on p. 350). ATTACHMENT STYLE If Bowlby and Harlow were correct in hypothesizing that attachment encourages proximity between infant and caregiver, then we might expect attachment responses to increase when children start moving away from caregivers. And indeed, just when infants begin to understand the difference between their attachment figures and strangers, and at the same time start to move away from strangers by crawling-at around 8-12 months-they typically display separation anxiety. That is, when the infants cannot see or are separated from their attachment figures or are left with babysitters, they may become very distressed. This pattern occurs in all human cultures. To study attachment behaviors in humans, the developmental psychologist Mary D. Salter Ainsworth created the strange-situation test. The researchers observe the test through a one-way mirror in the laboratory. On the other side of the mirror is a playroom. There, the child, the caregiver, and a friendly but unfamiliar adult engage in a series of eight semi-structured episodes. The crux of the procedure is a standard sequence of separations and reunions between the child and each adult. Over the course of the eight episodes, the child experiences increasing distress and a greater need for caregiver proximity. The extent to which the child copes with distress and the strategies he uses to do so indicate the quality of the child's attachment to the caregiver. The researchers record the child's activity level and actions such as crying, playing, and paying attention to the mother and the stranger. Using the strangesituation test, Ainsworth identified infant/caregiver pairs that appeared secure as well as those that appeared insecure, or anxious (Ainsworth, Blehar, Waters, & Wall, 1978; FIGURE 9.17). Secure attachment applies to approximately 60-65 percent of children. A secure child is happy to play alone and is friendly to the stranger as long as the attachment figure is present. When the attachment figure leaves the playroom, the child is distressed, whines or cries, and shows signs of looking for the attachment figure. When the attachment figure returns, the child usually reaches his arms up to be picked up and then is happy and quickly comforted by the caregiver. Then the child feels secure enough to return to playing. The key behavior to notice here, similar to what Harlow found with his monkeys, is the use of the caregiver as a source of security in times of distress. Just as a monkey would calm down when in contact with its cuddly cloth "mother," a securely attached human infant will be soothed immediately after a distressing separation when the caregiver picks up the infant. Insecure attachment applies to the remaining 35- 40 percent of children. Insecure attachments (sometimes referred to as anxious attachments) can take many forms, from an infant's completely avoiding contact with the caregiver during the strangesituation test to the infant's actively hitting or exhibiting angry facial expressions toward the caregiver (Ainsworth et al., 1978). Insecure attachments typically are of two types. Children with avoidant attachment do not get upset or cry at all when the caregiver leaves, and they may prefer to play with the stranger rather than the parent during their time in the playroom. Those with an ambivalent attachment style (sometimes called anxious/resistant) may cry a great deal when the caregiver leaves insecure attachment The attachment style for a minority of infants; the infant may exhibit insecure attachment through various behaviors, such as avoiding contact with the caregiver, or by alternating between approach and avoidance behaviors. WHAT FACTORS SHAPE INFA NCY? ·a11p41 pue a11!11Jns ll!M siueJU! a411e41 poo4!1a~!I a41 flu!seaJJU! 'Ja410 4Jea Jeau Ae1s 01 sJaA!DaJeJ pue s1ue1u1 sa1e11now 1uaw4Jem1 :~3MSN'tf Learning Objectives List and describe the stages of development proposed by Piaget. Discuss challenges to Piaget's theory. Define theory of mind and explain its significance for prosocial behavior. Compare and contrast theories of moral reasoning and moral emotions. the room but then be inconsolable when the caregiver tries to calm them down upon return. Insecurely attached infants have learned that their caregiver is not available to soothe them when distressed or is only inconsistently available. These children may be emotionally neglected or actively rejected by their attachment figures. Caregivers of insecurely attached infants typically have rejecting or inconsistently responsive parenting styles. Keep in mind, however, that attachment is a complex developmental phenomenon. As in all relationships, both parties contribute to the quality or success of the interactions. For example, if a child has a disability such as autism spectrum disorderwhich may cause the infant to not cling to the caregiver or not make eye contact- the caregiver may have a more difficult time forming a secure emotional bond with the infant (Rutgers, Bakermans-Kranenburg, van Ijzendoorn, & van Berckelaer-Onnes, 2004). Similarly, if a caregiver is incapacitated by mental illness or extreme stress, the caregiver may not be able to exhibit warm or responsive behaviors to meet the baby's needs, thus reducing the likelihood ofa secure attachment ( Cicchetti, Rogosh, & Toth, 1998). In cases of insecure (or anxious) attachment, it is important that early prevention efforts take place. The caregiver will need to build the skills necessary to increase the likelihood of secure attachments forming. As decades of research show, secure attachments are related to better socioemotional functioning in childhood, better peer relations, and successful adjustment at school (e.g., Bohlin, Hagekull, & Rydell, 2000; Granot & Mayseless, 2001). In contrast, insecure attachments have been linked to poor outcomes later in life, such as depression and behavioral problems (e.g., Munson, McMahon, & Spieker, 2001). CHEMISTRY OF ATTACHMENT Researchers have discovered that the hormone oxytocin is related to social behaviors, including infant/caregiver attachment (Carter, 2003; Feldman, Weller, Zagoory-Sharon, & Levine, 2007). Oxytocin plays a role in maternal tendencies, feelings of social acceptance and bonding, and sexual gratification. In the mother and the infant, oxytocin promotes behaviors that ensure the survival of the young. For instance, infant sucking during nursing triggers the release of oxytocin in the mother. This release stimulates biological processes in the mother that move milk into the milk ducts so the infant can nurse. This line ofresearch provides a helpful reminder that phenomena that appear to be completely social in nature, such as the caregiver/child attachment, also have biological influences. To learn, children need to obtain information from the world. They do so principally through their senses. As noted earlier, newborns have all their senses at birth, although some of the senses are not fully developed. The development of sensory capacities enables infants to observe and evaluate the objects and events around them. The infants then use the information gained from perception to try to make sense of how the world works. In other words, children think about things. How does cognition develop in childhood? CHAPTER 9 HUMAN DEVELOPMENT I 9.6 Piaget Emphasized Stages of Cognitive Development Ultimately, how do we account for the differences between children's ways of thinking and adults' ways of thinking? Are children merely inexperienced adults? Do they simply not have the skills and knowledge that adults normally have learned over time? Or do children's minds work in qualitatively different ways from those of adults? Through careful observations of young children, Jean Piaget (1924) devised an influential theory about the development of thinking (FIGURE 9.18). Several of Piaget's ideas have been supported by subsequent research. For instance, Piaget viewed children as qualitatively different from adults, not simply as inexperienced adults. He also viewed children as actively trying to understand the world around them by interacting with objects and by observing the consequences of their actions. As you will see in the next section, however, researchers have challenged several of Piaget's other assertions. One crucial aspect of Piaget's research is that he paid as much attention to how children make errors as to how they succeed on tasks. Children's mistakes, illogical by adult standards, provide insights into how young minds make sense of the world. By systematically analyzing children's thinking, Piaget developed the theory that children go through four stages of development, which reflect different ways of thinking about the world. These stages are called sensorimotor, preoperational, concrete operational, andformal operational (FIGURE 9.19). From Piaget's perspective, it is not that children know less than adults. Rather, children's views of how the world works are based on different sets of assumptions than those held by adults. Contemporary researchers argue that such developmental "immaturity" in early-stage thinking actually serves very important functions for children's mental abilities to grow (Bjorklund, 2007). Piaget proposed that new schemes are formed during each stage of development. Schemes are ways of thinking based on personal experience. Piaget's idea of schemes is somewhat similar to the concept of schemas defined and discussed in Chapter 7. For Piaget, schemes were organized ways of making sense of experience, and they changed as the child learned new information about objects and events in the world. Piaget believed that each stage builds on the previous one through two learning processes: Through assimilation, a new experience is placed into an existing scheme. Through accommodation (not to be confused with the process of accommodation in the visual system, in Chapter 5), a new scheme is created or an existing one is dramatically altered to include new information that otherwise would not fit into the scheme. For example, a 2-year-old sees a Great Dane and asks, "What's that?" The parent answers that it is a dog. But it does not look anything like the family Chihuahua. The toddler needs to assimilate the Great Dane into the existing dog scheme. The same 2-year-old might see a cow for the first time and shout, "Doggie!" After all, a cow has four legs and fur and is about the same size as a Great Dane. Thus, based on a dog scheme the child has developed, the label "doggie" can be considered logical. But the toddler's parent says, "No, honey, that's a cow1 See, it doesn't say 'Arf1' It says 'Moo!' And it is much bigger than a dog." Because the child cannot easily fit this new information into the existing dog scheme using the process of assimilation, the child must now create a new scheme, cow, through the process of accommodation. SENSORIMOTOR STAGE (BIRTH TO 2 YEARS) From birth until about age 2, according to Piaget, children are in the sensorimotor stage. During this period, children are firmly situated in the present and acquire information primarily through their senses and motor exploration. Thus, very young infants' understanding of objects occurs when they reflexively react to the sensory input from those objects. For example, they learn by sucking on a nipple, grasping a finger, or seeing a face- that is, through perception and observation of the results of their actions. They progress from being reflexive to being reflective. In other words, they become capable of mentally representing their world and experiences with increasingly complex schemes. As infants begin to control their motor movements, they develop their first schemes. These conceptual models reflect the kinds of actions that can be performed on certain kinds of objects. For instance, the sucking reflex begins as a reaction to the sensory input from the nipple: Infants simply respond reflexively by sucking. Soon they realize they can suck on other things, such as a bottle, a finger, a toy, or a blanket. Piaget described sucking on other objects as an example of assimilation to the scheme of sucking. But sucking on a toy or a blanket does not result in the same experience as the reflexive sucking of a nipple. The difference between these experiences leads the child to alter the sucking scheme to include new experiences and information. In other words, the child must continually adjust her understandings of sucking. But you cannot suck something like a milk carton-so the child forms a scheme of things that provide liquid but cannot be sucked. The child creates this new scheme through accommodation. According to Piaget, one important cognitive concept that develops in this stage is object permanence. This term refers to the understanding that an object continues to exist even when it is hidden from view. Piaget noted that until 9 months of age, most infants will not search for objects they have seen being hidden under a blanket. At around 9 months, infants will look for the hidden object by picking up the blanket. Still, their search skills have limits. For instance, suppose during several trials an 8-month-old child watches an experimenter hide a toy under a blanket and the child then finds the toy. If the experimenter then hides the toy under a different blanket, in full view of the child, the child will still look for the toy in the first hiding place. Full comprehension of object permanence was, for Piaget, one key accomplishment of the sensorimotor period. PREOPERATIONAL STAGE (2 TO 7 YEARS) In the preoperational stage, according to Piaget, children can begin to think about objects not in their immediate view. Having formed conceptual models of how the world works, children begin to think symbolically. For example, they can pretend that a stick is a sword or a wand. Piaget believed that what children cannot do at this stage is think "operationally." That is, they cannot imagine the logical outcomes of performing certain actions on certain objects. They do not base their reasoning on logic. Instead, they perform intuitive reasoning based on superficial appearances. For instance, children at this stage have no understanding of the law of conservation of quantity. This law states that even if a substance's appearance changes, its quantity may remain unchanged. If you pour a short, fat glass of water into a tall, thin glass, you know the amount of water has not changed. However, if you ask children in the preoperational stage which glass contains more, they will pick the tall, thin glass because the water is at a higher level. The children will make this error even when they have seen someone pour the same amount of water into each glass or when they pour the liquid themselves. They are fooled by the appearance of a higher water line. They cannot think about how the thinner diameter of the taller glass compensates for the higher-appearing water level (FIGURE 9.20). Piaget thought that another cognitive limitation characteristic of the preoperational period is egocentrism. This term refers to the tendency for preoperational thinkers to view the world through their own experiences. They can understand how others feel, and they have the capacity to care about others. They tend, however, to engage in thought processes that revolve around their own perspectives. For example, a 3-year-old may play hide-and-seek by crouching next to a large tree and facing it with her eyes closed (FIGURE 9.21). The child believes that if she cannot see other people, other people cannot see her. Instead of viewing this egocentric thinking as a limitation, modern scholars agree with Piaget that such "immature" skills prepare children to take special note of their immediate surroundings and learn as much as they can about how their own minds and bodies interact with the world. A clear egocentric focus prevents them from trying to expand their schemas too much before they understand all the complex information inside their own experience (Bjorklund, 2007). CONCRETE OPERATIONAL STAGE (7 TO 12 YEARS) At about 7 years of age, according to Piaget, children enter the concrete operational stage. They remain in this stage until adolescence. Piaget believed that humans do not develop logic until they begin to perform mental operations. The first stage is performing mental operations on concrete objects in the world. That is, a preoperational child lacks logical thought, but a concrete operational child is able to think logically about actual objects. A classic operation is an action that can be undone, such as turning a light on and off. According to Piaget, the ability to understand that an action is reversible enables children to begin to understand concepts such as conservation of quantity. Children in this period are not fooled by superficial transformations in the liquid's appearance in conservation tasks. They can reason logically about the problem. And they begin to understand with much more depth how other people view the world and feel about things. Although this development is the beginning of logical thinking, Piaget believed that children at this stage reason only about concrete things. They do not yet have the ability to reason abstractly, or hypothetically, about what might be possible. 'FORMAL OPERATIONAL STAGE (12 YEARS TO ADULTHOOD) Piagetbelieved that after about age 12, individuals can reason in sophisticated, abstract ways. Thus, the formal operational stage is Piaget's final stage of cognitive development. Formal operations involve critical thinking. This kind of thinking is characterized by the ability to form a hypothesis about something and test the hypothesis through deductive logic. It also involves using information to systematically find answers to problems. Piaget devised a way to study this ability. He gave teenagers and younger children four flasks of colorless liquid and one flask of colored liquid. He then explained that the colored liquid could be obtained by combining two of the colorless liquids. Adolescents, he found, can systematically try different combinations to obtain the correct result. Younger children just randomly combine liquids. Adolescents can form hypotheses and systematically test them. They are able to consider abstract notions and think about many viewpoints at once. Piaget revolutionized the understanding of cognitive development and was right about several things. For example, infants do learn about the world through sensorimotor exploration. Also, people do move from intuitive, illogical thinking to a more logical understanding of the world. Piaget also believed, however, that as children progress through each stage, they all use the same kind oflogic to solve problems. His framework thus leaves little room for differing cognitive strategies or skills among individuals- or among cultures. Work by Piaget's contemporary Lev Vygotsky emphasized social relations over objects in thinking about cognitive development. Vygotsky focused on the role of social and cultural context in the development of both cognition and language. According to Vygotsky, humans are unique because they use symbols and psychological tools-such as speech, writing, maps, art, and so on-through which they create culture. Culture, in turn, dictates what people need to learn and the sorts of skills they need to develop (FIGURE 9.22). For example, some cultures value science and rational thinking. Other cultures emphasize supernatural and mystical forces. These cultural values shape how people think about and relate to the world around them. Vygotsky distinguished between elementary mental functions (such as innate sensory experiences) and higher mental functions (such as language, perception, abstraction, and memory). As children develop, their elementary capacities are gradually transformed. Culture exerts the primary influence on these capacities (Vygotsky, 1978). Central to Vygotsky's theories is the idea that social and cultural context influences language development. In turn, language development influences cognitive development. Children start by directing their speech toward specific communications with others, such as asking for food or for toys. As children develop, they begin directing speech toward themselves, as when they give themselves directions or talk to themselves while playing. Eventually, children internalize their words into inner speech: verbal thoughts that direct both behavior and cognition. From this perspective, your thoughts are based on the language you have acquired through your society and through your culture, and this ongoing inner speech reflects higher-order cognitive processes. In challenging Piaget's framework of universal developmental milestones, Vygotsky proposed the important interaction between self and environment. Another challenge to Piaget's view is that many children move back and forth between stages if they are working on tasks that require varying skill levels. They may think in concrete operational ways on some tasks but revert to preoperational logic when faced with a novel task. Theorists believe that different areas in the brain are responsible for different skills and that development does not necessarily follow strict and uniform stages (Bidell & Fischer, 1995; Case, 1992; Fischer, 1980; FIGURE 9.23). In addition, Piaget thought that all adults were formal operational thinkers. Morerecent work has shown that without specific training or education in this type of thinking, many adults continue to reason in concrete operational ways, instead of using critical and analytical thinking skills. These adults may think abstractly regarding topics with which they are familiar but not on new and unfamiliar tasks (De Lisi & Staudt, 1980). A good example of this kind of thinking is the candle-and-tack problem illustrated in Figure 8.22a-b. Moreover, Piaget underestimated the age at which certain skills develop. For example, contemporary researchers have found that object permanence develops in the first few months oflife, instead of at 8 or 9 months of age, as Piaget thought. With new scientific methods that do not require infants to physically search for hidden objects, researchers have found object permanence abilities in infants as early as 3.5 months of age (Baillargeon, 1987). Consider the apple/carrot test devised by the developmental psychologist Renee Baillargeon (1995). The researcher shows an apple to an infant who is sitting on his parent's lap. The researcher lowers a screen in front of the apple, then raises the screen to show the apple. Then the researcher performs the same actions, but this time raises the screen to show a carrot-a surprising, impossible event. If the infant looks longer at the carrot than he had looked at the apple, the researcher can assume that the infant expected to see the apple. By responding differently to such an impossible event than to possible ones, infants demonstrate some understanding that an object continues to exist when it is out of sight. Thus, in his various testing protocols, Piaget may have confused infants' physical capabilities with their cognitive abilities. UNDERSTANDING THE LAWS Of" NATURE: PHYSICS The tasks used by Piaget implied that infants and young children have a relatively poor understanding of physical forces, such as conservation of quantity. Numerous studies conducted by the developmental psychologist Elizabeth Spelke and colleagues have indicated that infants even have a primitive understanding of some of the basic laws of physics (Spelke, 2016). These researchers created cognitive tasks that do not rely on language or physical capabilities. For example, humans are born with the ability to perceive movement. A newborn will follow a moving stimulus with her eyes and head, and a newborn will also prefer to look at a moving stimulus than to look at a stationary one. As infants get older, they use movement information to determine if an object is continuous-that is, if it is all one object, even if the infant cannot see the entire thing because it is partially hidden (Kellman, Spelke, & Short, 1986). In one experiment, the researchers showed 4-month-old infants a rod moving back and forth behind a block. Once the infants had viewed the scene many times, they quit responding to it. That is, they had habituated to the stimulus (recall from Chapter 6 that habituation is decreased responding to an unchanging stimulus). The infants were then shown two scenes: In one scene, the block was removed and there was a single rod. In the other scene, the block was removed and there were two small rods. The infants looked longer at the two small rods (FIGURE 9.24). This response indicated that they expected the rod moving behind the block to be one continuous object rather than two small ones. Studies such as these rely on the orienting reflex. This term refers to humans' tendency to pay more attention to new stimuli than to stimuli to which they have become habituated (Fantz, 1966). Even from birth, an infant will look away more quickly from something familiar than from something unfamiliar or puzzling. Understanding the relation between the movement and the physical properties of the rod requires various cognitive skills. It requires the ability to see the rod as an object separate from the block and to surmise that since the two ends are moving together, they must be part of the same whole rod, even though part of the rod is hidden. If the experiment is conducted with a stationary rod, however, the infants do not look longer at the two small rods. Therefore, infants appear to use movement to infer that objects moving together are continuous, whereas for infants two stationary objects may or may not be continuous. UNDERSTANDING THE LAWS OF NATURE: MATHEMATICS How much do you think infants and toddlers know about counting and other mathematical operations? Piaget believed that young children do not understand numbers and therefore must learn counting and other number-related skills through memorization. For some of his experiments in this area, he showed two rows of marbles to children 4-5 years old. Both rows had the same number of marbles, but in one row the marbles were spread out. The children usually said the longer row had more marbles (FIGURE 9.25). Piaget concluded that children understand quantity-the concepts more than and less than-in terms oflength. He felt that children do not understand quantity in terms of number. Challenging Piaget's view, Jacques Mehler and Tom Bever (1967) argued that children younger than 3 years of age can understand more than and less than. To demonstrate their point, they cleverly repeated Piaget's experiment using M&M's candy. They showed the children two rows of four M&M's each and asked if the rows were the same. When the children said yes, the researchers then transformed the rows. For instance, they would add two candies to the second row, but compress that row so it was shorter than the row with fewer candies. Then they would tell the children to pick the row they wanted to eat. More than 80 percent picked the row with more M&M's, even though it was the visually shorter row (FIGURE 9.26). This research indicated that when children are properly motivated, they understand and can demonstrate their knowledge of more than and less than. Despite Piaget's enormous contributions to the understanding of cognitive development, the growing evidence that infants have innate knowledge challenges his theory of distinct stages of cognitive development. Moreover, the available evidence According to current thinking among developmental psychologists, early social interactions between infant and caregiver are essential for understanding other people and communicating with them through language. In turn, these skills enable individuals to live in society. To interact with other people successfully, individuals need to be aware of others' intentions, behave in ways that generally conform to others' expectations, develop moral codes that guide their actions, learn and follow rules, and so on. Consider a routine activity such as driving a car. To drive safely, a person needs to predict and respond to the actions of others: car drivers, truck drivers, motorcyclists, bicyclists, and pedestrians. Any of those people's actions can be erratic. THEORY OF MIND Humans have an innate ability to understand that others have minds and that those minds have desires, intentions, beliefs, and mental states. People are also able to form, with some degree of accuracy, theories about what those desires, intentions, beliefs, and mental states are. David Premack and Guy Woodruff (1978) coined the term theory of mind to describe this ability. In dealing with other people, we try to recognize each person's mental state. That is, we infer what the person is feeling or thinking. From that inference, we anticipate the other person's behavior. Predicting another person's behavior based on that person's mental state constitutes theory of mind. Beginning in infancy, young children come to understand that other people perform actions for reasons (Gergely & Csibra, 2003; Sommerville & Woodward, 2005). The recognition that actions can be intentional reflects a capacity for theory of mind, and it allows people to understand, predict, and attempt to influence others' behavior (Baldwin & Baird, 2001). In one study, an adult began handing a toy to an infant. On some trials, the adult became unwilling to hand over the toy ( e.g., teasing the infant with the toy or playing with it himself). On other trials, the adult became unable to hand it over (e.g., "accidentally" dropping it or being distracted by a ringing telephone). Infants older than 9 months showed greater signs of impatience-for example, reaching for the toy-when the adult was unwilling than when the adult was unable (Behne, Carpenter, Call, & Tomasello, 2005). This research shows that very young children understand other peoples' intentions, capabilities, and reasoning behind their actions. By the end of the second year, perhaps even by 13 to 15 months of age, children become very good at reading intentions (Baillargeon, Li, Ng, & Yuan, 2009). In other words, even though preschool-age children tend to behave in egocentric ways and view the world through their own perspectives, mounting evidence suggests that they have the cognitive abilities to understand others' perspectives (Baillargeon, f) Sally goes away. D "Where will Sally look for her marble?" Scott, & Bian, 2016). The understanding of complex mental states, such as that people can have false beliefs, develops later in childhood. A common test offalse belief is shown in FIGURE 9.27. Children's development of theory of mind appears to coincide with the maturation of the brain's frontal lobes. The importance of the frontal lobes for theory of mind is also supported by research with adults. In brain imaging studies, prefrontal brain regions become active when people are asked to think about other people's mental states (Mar, 2011; Schurz, Radua, Aichhorn, Richlan, & Perner, 2014). People with damage to this region have difficulty attributing mental states to characters in stories (Stone, Baron-Cohen, & Knight, 1998). Brain imaging studies of theory of mind conducted in Canada, the United States, England, France, Germany, Japan, and Sweden have found similar patterns of activity in prefrontal regions (Frank & Temple, 2009). These findings support the idea that the ability is universal and biologically based. UNDERSTANDING SOCIAL EMOTIONS Having insight into other minds enables us to predict how other people will feel in a given situation. Children learn to predict CHAPTE R 9 HUMAN DEVELOPMENT when their caregivers, siblings, and friends will be angry, sad, embarrassed, and so on. Research on children's social emotions has focused largely on empathy and sympathy. Empathy involves understanding another's emotional state and relies on theory of mind. Empathy involves feeling with the other person, as in wincing when you see another person injured. Recall the discussion of mirror neurons in Chapter 6. When people observe another person experiencing pain, such as a finger being cut, mirror neurons are active in the observer along with activity in brain regions that process pain (Decety & Howard, 2014; Lamm, Decety, & Singer, 2011). In contrast, sympathy arises from feelings of concern, pity, or sorrow for another (Eisenberg, 2000 ). Sympathy involves feeling for the other person. Sympathy may produce different emotions from those experienced by the other person, such as feeling pity for a person who recently lost his job. Someone with the capacity for theory of mind might seek to comfort a person who is upset. Doing so is an example of prosocial behavior, which is any voluntary action performed with the specific intent of benefiting another person (Eisenberg, VanSchyndel, & Spinrad, 2016). Consider that young infants become distressed when they see other infants crying (Zahn-Waxler & Radke-Yarrow, 1990). Generally, children's early attempts to soothe other children are ineffective. For instance, they tend initially to comfort themselves rather than the other children. Still, this empathic response to other people's suffering suggests that prosocial behavior is hardwired in humans. Starting after 1 year of age, children become willing to help others, such as by picking up objects for someone who has dropped them (Warneken, 2015). A recent meta-analysis found that children with higher scores on theory of mind tests are more likely to behave prosocially (Imuta, Henry, Slaughter, Selcuk, & Ruffman, 2016). Research has shown that parents' behaviors influence their children's level of both social emotions and prosocial behavior. When parents are high in sympathy, promote an understanding of and focus on others, do not express hostility in the home, allow their children to express negative emotions in ways that do not harm others, and help their children cope with negative emotions, they tend to have children who are high in sympathy (Eisenberg, 2002; FIGURE 9.28). Morality plays a central role in human life, influencing both trivial and consequential choices and actions. When is it okay to use or take someone else's possessions? When is it acceptable to perform an action that may harm others or that may break social contracts? The ability to consider questions about morality develops during childhood and continues into adulthood. Theorists typically divide morality into moral reasoning, which depends on cognitive processes, and moral emotions, which are linked to societal interests as a whole (Haidt, 2003). Moral emotions motivate people to do good things and avoid doing bad things. They include shame, guilt, disgust, embarrassment, pride, and gratitude. Piaget suggested that children's developing cognitive skills allowed for increasingly sophisticated moral reasoning. In keeping with this cognitive perspective, psychologists who study moral behavior have focused largely on Lawrence Kohlberg's stage theory. Kohlberg (1984) tested moral-reasoning skills by asking people to respond to hypothetical situations in which a main character was faced with a moral dilemma. For example, the character had to steal a drug to save his dying wife because he could FIGURE 9.28 Parental Behavior Affects Children's Behavior Parents who are high in sympathy, and who allow their children to express negative emotions without shame or hostility, tend to have children who are high in sympathy. "JO!Ae4aq 1epos0Jd WJOJJad 01 A1a~!I c!JOW aJe PU!W JO AJoa41 JOJ A1pedeJ JaJeaJfl l!Q!4xa 04M aso41 =!:13MSN'V HOW DO CHILDREN LEARN ABOUT THE WORLD? preconventional level Earliest level of moral development; at this level, self-interest and event outcomes determine what is moral. conventional level Middle stage of moral development; at this level, strict adherence to societal rules and the approval of others determine what is moral. postconventional level Highest stage of moral development; at this level, decisions about morality depend on abstract principles and the value of all life. social intuitionist model The idea that moral judgments reflect people's initial and automatic emotional responses. (a) (b) FIGURE 9.29 Emotions, Judgments, and Facial Gestures A person makes similar facial gestures, wrinkling the nose and raising the upper lip, when (a) disgusted by recei ving unfair treatment and (b) tasting something unpleasant, such as a bitter taste. not afford the drug. Kohlberg was most concerned with the reasons people provided for their answers, rather than the answers themselves. He devised a theory of moral judgment that involved three main levels of moral reasoning. At the preconventional level, people classify answers in terms of self-interest or pleasurable outcomes. For example, a child at this level might say, "He should steal the drug because then he will have it." At the conventional level, people's responses conform to rules of law and order or focus on others' disapproval. For example, a person at this level might say, "He shouldn't take the drug. You are not supposed to steal, so everyone will think he is a bad person." At the postconventional level, the highest level of moral reasoning, people's responses center around complex reasoning about abstract principles and the value of all life. For example, a person at this level might say, "Sometimes people have to break the law if the law is unjust. In this case, it's wrong to steal, but it's more wrong to charge too much money for a drug that could save a person's life." Thus, Kohlberg considered advanced moral reasoning to include a consideration of the greater good for all people, with less thought given to personal wishes or fear of punishment. There have been criticisms ofKohlberg's theory because the initial research examined only American males (Gilligan, 1977). At issue is whether the same stage theory applies to females or to those raised in different cultures (Snarey, 1985). Moralreasoning theories have also been faulted for emphasizing the cognitive aspects of morality to the detriment of emotional issues that influence moral judgments. Of course, cognition and emotions are intertwined. If people lack adequate cognitive abilities, their moral emotions may not translate into moral behaviors (Tangney, Stuewig, & Mashek, 2007). Similarly, moral reasoning is enhanced by moral emotions (Moll & de Oliveira-Souza, 2007). EMOTION AS THE BASIS OF MORALITY According to Jonathan Haidt's (2001) social intuitionist model, moraljudgments reflect people's initial and automatic emotional responses. When most people are asked to consider sticking a pin in a child's hand or stealing money from a church they have automatic, intuitive negative emotional reactions. Subsequently, they might think about the actions using cognitive skills, but their thoughts are influenced by their emotional reactions. In other words, the emotions come first and thinking follows (Haidt, 2007). Recall the study described in Chapter 4 in which a posthypnotic suggestion to feel disgust to an otherwise neutral word (e.g., the word often) led participants to make more-extreme moral judgments when reading innocuous stories that included the word. According to some researchers (Pizarro, Inbar, & Helion, 2011), emotions such as disgust may not produce moral responses as much as increase those responses. These researchers point out that some actions can be disgusting to think about ( e.g., a person picking his nose in private) but would not be considered immoral. It is clear, however, that emotions bias moral judgments. In one study, people evaluated gay men more negatively when making judgments in a room that smelled disgusting than did those in a room that did not smell (Inbar, Pizarro, & Bloom, 2012). Immorality elicits the same physical disgust reaction as a bad taste. A person disgusted by receiving unfair treatment makes similar facial gestures as when tasting something unpleasant (Chapman, Kim, Susskind, & Anderson, 2009; FIGURE 9.29). Children's developing sense of morality is influenced by their emotional reactions to events. BIOLOGICAL BASIS OF MORALITY Research using brain imaging has identified a number of brain regions involved in moral reasoning and during the experience of moral emotions. Many of the identified regions are similar to those that are active when people perform theory of mind tasks, such as the prefrontal cortex (Decety & Porges, 2011). Researchers studied two people who had experienced prefrontal damage during infancy (Anderson, Bechara, Damasio, Tranel, & Damasio, 1999). This brain region was the one whose damage led to Phineas Gage's dramatic personality change (see Figure 3.27). Both individuals showed severe deficiencies in moral and social reasoning. When given Kohlberg's moral-dilemma task, both patients scored at the preconventional level. These patients also neglected social and emotional factors in their life decisions. Both failed to express empathy, remorse, or guilt for wrongdoing, and neither had particularly good parenting skills. One engaged in petty thievery, was verbally and physically threatening (once to the point of physical assault), and frequently lied for no apparent reason. There is consistent evidence that the prefrontal cortex supports the capacity for morality, likely by being involved in theory of mind abilities that enable people to consider how their actions affect others (Forbes & Grafman, 2010). In addition to the prefrontal cortex, brain regions associated with emotional responses, including the insula and amygdala, are active during moral judgments (Greene, Sommerville, Nystrom, Darley, & Cohen, 2001; Shenhav & Greene, 2014). These regions are also active during the experience of moral emotions (Moll et al., 2002). The specific types of moral emotions are associated with activation of different brain regions. For example, people considering moral violations that elicit disgust show insula activity (Parkinson et al., 2011), whereas moral violations that cause injury produce amygdala activity (Shenhav & Greene, 2014). In short, the prefrontal cortex likely helps us judge the effects of our behavior on others, whereas the insula and amygdala produce the emotional responses that contribute to morality. As noted above, cognition and emotion interact to produce morality. What Changes During Adolescence? Normal human development turns a child into an adolescent. An adolescent then develops into an adult. During these transitions, the person undergoes various changes. In addition to physical changes during and after puberty, social changes emerge as part of the renegotiation of relationships with caregivers and peers, cognitive changes arise as part of the emergence of critical and analytical thinking, and psychological changes accompany the formation of a gender identity and a cultural identity. Physical, social, cognitive, and psychological forces work together in the creation of a self. J 9.10 Puberty Causes Physical Changes Biologically, adolescence begins with puberty, the onset of sexual maturity and thus the ability to reproduce. Puberty typically begins around age 8 for females and age 10 for males (Ge, Natsuaki, Neiderhiser, & Reiss, 2007). Most girls complete pubertal development by the age of 16, with boys ending by the age of18 (Lee, 1980; FIGURE 9.30). During puberty, hormone levels increase throughout the body. The increased hormones stimulate physical changes. For example, the clear dividing line between childhood and the start of puberty is the adolescent growth spurt, a rapid, hormonally driven increase in height and weight. Puberty also brings the development of the primary sex characteristics: maturation of the male and female sex organs; in females, the beginning of menstruation; in males, the beginning of the capacity for ejaculation. Also developing at this time are the secondary sexual characteristics, including pubic hair, body hair, muscle mass increases for boys, and fat deposits on the hips and breasts for girls. Boys' voices deepen and their jaws become more angular. Girls lose baby fat on their bellies as their waists become more defined (Lee, 1980). BIOLOGY AND ENVIRONMENT Puberty may appear to be a purely biological phenomenon. Like all aspects of human development, however, it is affected by a complex and dynamic interaction between biological systems and environmental experiences. For example, when girls live in homes with nongenetically related adult males (such as the mother's boyfriend or a stepfather), they tend to start puberty months earlier than girls who live in homes with only genetically related males. Also, girls who live in extremely stressful environments or have a history of insecure attachments to caregivers begin menstruating earlier than girls in peaceful or secure environments (Wierson, Long, & Forehand, 1993). These findings suggest that the body responds to cues of threat (in the form of stress or family changes). Evolutionarily speaking, these threat cues increase a female's need to reproduce sooner to increase her chances of continuing her gene pool. Thus, hormonal changes are triggered by environmental forces, which allow the girl to enter puberty (Belsky, Houts, & Fearon, 2010). Because boys do not have an easily identifiable pubertal event like the initiation of menstruation in girls, we know less about environmental impacts on the timing and experience of puberty in boys. Boys and girls experience similar changes in their brain development during adolescence, however, so researchers are able to identify a few key characteristics of the "teenage brain." At the same time teenagers are experiencing pubertal changes, their brains are also in an important phase of reorganization, with synaptic connections being refined and gray matter increasing. The frontal cortex of the brain is not fully myelinated until the mid-20s (Mills, Lalonde, Clasen, Giedd, & Blakemore, 2014). Because a teenager's limbic system- the reward and emotional center of their brain-tends to mature more quickly than his frontal lobes, teenagers are likely to act on their impulses (Blakemore & Choudhury, 2006; Casey, Jones, & Somerville, 2011). The capacity to exert control is overwhelmed by strong temptations, which contribute to adolescent risk taking (Somerville, Hare, & Casey, 2011). The research on such physiological changes points to an important fact about adolescence: It is not necessarily a stressful period of life, full of turmoil. For those kids who already have stressful home lives, experience many family changes, or display attachment difficulties, adolescence may be difficult. But for most kids, pubertal and brain changes can be a bit annoying, but they do not necessarily lead to the high rates of depression or anger that many in the general public associate with teenagers. In fact, if adolescents receive warm, supportive parenting with the proper CHAPTER 9 HUMAN DEVELOPMENT guidance and discipline, and if they are allowed to express themselves openly, adolescence can be a positive time of growth and change, solidifying the youth's sense of identity (Steinberg & Sheffield, 2001). As a child develops and learns more about the world, she begins creating a sense of identity. That is, the child starts to establish who she is. Identity formation is an important part of social development, especially in Western cultures, where individuality is valued. After all, who a person is can enormously affect how that person interacts with others. The psychologist Erik Erikson (1980) proposed a theory of human development that emphasized age-related, culture-neutral psychosocial challenges and their effects on social functioning across the life span. Erikson thought of identity development as composed of eight stages, which ranged from an infant's first year to old age (TABLE 9.1). Erikson further conceptualized each stage as having a major developmental "crisis," or development challenge to be confronted. Each of these crises is present throughout life, but each one takes on special importance at a particular stage. According to this theory, while each crisis provides an opportunity for psychological development, a lack of progress may impair further psychosocial development (Erikson, 1980). The challenge at each stage provides skills and attitudes that the individual will need in order to face the next challenge successfully. Successful resolution of these challenges depends on the supportive nature of the person's environment as well as the person's active search for information about his own competence. According to Erikson's theory, adolescents face perhaps the most fundamental crisis: how to develop an adult identity. Erikson's theory has been influential but is lacking empirical support. There is little evidence that there are eight stages of psychosocial development, that psychosocial development is culture-neutral, and that human identity develops in this exact sequence. Nonetheless, Erickson's stages are helpful for considering the psychosocial challenges that people face at different times in their lives. Given that adolescents are undergoing pubertal changes, brain development and the resultant emotional highs and lows, and myriad social role expectations, it is impressive that so many teenagers are able to negotiate a pathway to a stable identity. Part of this process includes breaking away from childhood beliefs by questioning and challenging parental and societal ideas (Erikson, 1968). Three major changes generally cause adolescents to question who they are: Their physical appearance transforms, leading to shifts in self-image; their cognitive abilities grow more sophisticated, increasing the tendency for introspection; and they receive heightened societal pressure to prepare for the future (in particular, to make career choices), prompting exploration ofreal and hypothetical boundaries. In exploring boundaries, teenagers may investigate alternative belief syste~ s and subcultures. They may wonder what they would be like if they were raised in other cultures, by other caregivers, or in other historical times. They may shift between various peer groups and try out different activities, hobbies, and musical styles. As teenagers move away from spending all their time with caregivers and toward a peer-oriented lifestyle, caregivers continue to shape adolescents' development, but peers also play an important role in identity development. Let's look more closely at some specific aspects of identity development. DEVELOPMENT OF GENDER IDENTITY The terms used to discuss gender identity can be confusing, so we need to get them straight. Most psychologists use the term sex to refer to the biological status of being either male or female. That is, biological sex refers to the genes that differentiate males and females (i.e., XY versus XX chromosomes) and result in different physical characteristics (see Figure 9.30). They reserve the term gender for psychological differences between males and females. Gender identity is one's sense of being male or female. A gender role is a behavior that is typically associated with being male or female. Most people believe that their sex and gender are major components of who they are. How different are females and males (FIGURE 9.31)? Certain physical differences are obvious, but how do females and males differ psychologically? According to evolutionary theory, gender differences ought to reflect different adaptive problems males and females have faced, and this notion is generally supported by research (Buss, 1995). Since males and females have faced similar adaptive problems, however, they are actually similar on most dimensions (Hyde, 2005). The biological factors that influence gender come from many sources, such as brain chemistry. Gender identity begins very early in prenatal development. It results from a complex cascade ofhormones, changes in brain structure and function, and intrauterine environmental forces (Swaab, 2004). Recall from Chapter 3 that the gonads-testes in males and the ovaries in females-influence sexual behavior. They also influence the development of secondary sex characteris- {a) B1olog1cal {b) Biological -~ male -~ female { ) y tics (e.g., breast development in females, growth of facial hair in males). Androgens are more prevalent in males, and estrogens are more prevalent in females. For some people, the issue of being male or female is more complicated (Blackless et al., 2000). For these people, aspects of biological sex are either ambiguous or inconsistent with each other. This phenomenon is known as intersexuality. About 1 or 2 of every 100 people experience some ambiguity in their biological sex (Intersex Society of North America, 2008). The main causes of such ambiguity are abnormalities in the sex chromosomes or in hormones, both of which can affect how the genitals look (American Psychological Association, 2006). Given intersexuality, many people believe it is more accurate to view biological sex as not just male or female, but as including greater or lesser physical aspects of each sex (FIGURE 9.32). For example, in December 2016, New York City issued the first birth certificate in the United States listing "intersex" instead of "male" or "female" in the sex field. It was issued to 55-year-old Sara Keenan, who was born with male genes, female genitalia, and mixed internal reproductive organs. Many of the differences between males and females have as much to do with socialization as with biology. This distinction is not always easy to make, because the biological and psychosocial aspects of being female or male are usually so entwined that we cannot separate them (Hyde, 2005). Each person is treated in certain ways based on his biological sex, and each person's behaviors reflect both biological components and social expectations. For example, as discussed in Chapter 3, researchers have identified some differences between the brains of men and of women. They have not determined whether these differences are the result of genetics, of the way girls and boys are treated during development, or, more likely, of genetics (nature) combined with treatment (nurture). Nor do we know how or if sex-related brain differences translate into thoughts and actions. However it forms, your gender identity helps shape how you behave. Children as young as 2 years old can indicate whether they are boys or girls. Once children discover that they are boys or girls, they seek out activities that are culturally appropriate for their sex (Bern, 1981). Gender roles are culturally defined norms that differentiate behaviors, and attitudes, according to maleness and femaleness. In North American culture, for example, most parents and teachers discourage girls from playing too roughly and boys from crying. The separation of boys and girls into different play groups is also a powerful socializing force. Most boys and girls strive to fulfill the gender roles expected of them by their cultures. Biology has a strong effect on whether people identify as female, male, or transgender. A transgender person was born as one biological sex but feels that her true gender identity is that of the other sex. One theory of why gender and biological sex differ for those who are transgender has to do with timing of hormonal events during pregnancy. Early in pregnancy, the presence or absence of testosterone leads to the formation of male or female sex organs, respectively. Later in pregnancy, hormones influence the sexual differentiation of the brain (Bao & Swaab, 2011). These developmental processes are independent and may produce different effects for those who aretransgender. In keeping with this idea, various brain imaging studies have shown that brains oftransgender people are more similar to those who share their gender identity than to those who share their biological sex (Nawata et al., 2010). Indeed, there is evidence that brain networks are wired differently for those who are transgender (Hahn et al., 2015). Awareness has been growing about transgender over the last few years. For example, U.S. federal law now prohibits inappropriate treatment of people who are transgender and gender nonconforming. The increase in children reporting being transgender has led some to question whether the children are simply playing or pretending to be a different sex ( FIGURE 9.33). A recent study looked at 32 transgender children 5-12 years old (Olson, Key, & Eaton, 2015). The research methods included selfreports and implicit measures of gender identity. The results indicated that the children thought of themselves in terms of their preferred gender identity, not their birth sex. In addition, the pattern of responses of the transgender children was similar to the pattern of responses from children who accepted their birth sex as their gender identity. In other words, transgender children are not confused or playacting. They are aware of their gender identity, which simply does not match their birth sex. ETHNIC IDENTITY In addition to a gender identity, each adolescent establishes a racial and/or ethnic identity. The process of forming such an identity can be complicated. Because of prejudice and discrimination and the accompanying barriers to economic opportunities, children from underrepresented groups, such as people of color, often face challenges with regard to the development of their ethnic identities. Children entering middle childhood have acquired an awareness of their ethnic identities to the extent that they know the labels and attributes that the dominant culture applies to their ethnic groups. Many researchers believe that during middle childhood and adolescence, children in underrepresented groups often engage in additional processes aimed at ethnic identity formation (Phinney, 1990). The factors that influence these processes vary widely among individuals and groups. Consider a child of Mexican immigrants to the United States. This child may struggle to live successfully in both a traditional Mexican household and an American neighborhood and school. The child may have to serve as a "cultural broker" for her family, perhaps translating materials sent home from school, calling insurance companies to ask about policies for her parents, and handling more adultlike responsibilities than other children the same age. In helping the family adjust to a stressful life as immigrants in a foreign country, the child may feel additional pressures but may also develop important skills in communication, negotiation, and caregiving (Cooper, Denner, & Lopez, 1999). Even for people of color born in the United States, it can be quite challenging to persevere in the face of racism and discrimination while also trying to succeed in the mainstream school system and work environment (Spencer, Fegley, & Harpalani, 2003). When a minority child successfully forms a strong sense of identity related to both his own group and the majority culture, the child has developed a bicultural identity. That is, the child strongly identifies with two cultures and seamlessly combines a sense of identity with both groups (Vargas-Reighley, 2005). A bicultural individual who is able to develop a bicultural identity is likely to be happier, be better adjusted, and have fewer problems in adult social and economic roles than will an individual who identifies strongly with only one culture to the exclusion of recognizing the other aspects of who she is. Caregivers, teachers, and spiritual and community leaders play key roles in teaching young people the values of their specific cultures in order to help them formulate healthy ethnic identities. The impact of parents versus peers on young people has become a controversial topic in developmental psychology. People often describe individuals as "coming from a good home" or as having "fallen in with the wrong crowd." These cliches reflect the importance of both peers and parents in influencing adolescent development. THE IMPORTANCE OF PEERS Developmental psychologists increasingly recognize the importance of peers in shaping identity (FIGURE 9.34). Children, regardless of their cultures, tend to spend much of their time interacting with other children, usually playing in various ways. In developmental terms, attention to peers begins at the end of the first year oflife, when infants begin to imitate other children, smile, and make vocalizations and other social signals to their peers (Brownell & Brown, 1992). Attention to peers may then continue throughout life. For example, people learn how to behave from their friends. When people behave appropriately, their friends provide social rewards. When people behave inappropriately, their friends provide social punishments. In developing their identities, children and adolescents compare their strengths and weaknesses with those of their peers. For example, as part of the search for identity, teenagers form friendships with others whose values and worldviews are similar to their own. Adolescents use peer groups to help them feel a sense of belonging and acceptance. They also draw on peer groups as resources for social support and identity acceptance. Despite wide differences in the experiences of teenagers around the world, adolescent peer groups tend to be described by a fairly small set of stereotypical names: jocks, brains, loners, druggies, nerds, and other not-so-flattering designations. Outside observers tend to quickly place teenagers who dress or act a certain way into groupings, called cliques. Members of cliques are thought to exhibit the same personality traits and be interested in the same activities. Individuals are seen as virtually interchangeable, and community members may respond to all youths from that group in similar ways (Urberg, Degirmencioglue, Tolson, & Halliday-Scher, 1995). The teenagers, however, may not see themselves as part of homogeneous groups of peers. In fact, they may see themselves as completely unique and individual, separate from anyone else, or they may see themselves as connected to a small subset of close friends (FIGURE 9.35). Adolescent identity development is thus shaped by the perceptions of adults, the influences of peers, and the teen's own active exploration of the world. Keep in mind that even though peers become the primary concern for many teenagers, the importance of parental support and guidance does not wane with age. BULLYING Bullying is a complex behavior with many contributing factors. However, experts tend to agree that bullies might not strongly feel the moral emotions of guilt and shame (Hymel, RockeHenderson, & Bonanno, 2005). Bullies also often show increased moral disengagement, such as indifference or pride, when explaining their behavior and more-positive attitudes about using bullying to respond to difficult social situations. This is especially true of bullies with high self-esteem, who tend to rationalize and justify their mistreatment of others (Menon et al., 2007). The advent of social networking sites produced the phenomenon of cyberbullying. Estimates of the prevalence of cyberbullying vary widely, with 3-72 percent of adolescents reporting being victims across separate studies (Selkie, Fales, & Moreno, 2016). Whether in person or via the web, being bullied can have devastating effects. A study of over 1,400 participants found that being bullied during childhood is associated with psychological disorders such as anxiety disorders and depression (Copeland, Wolke, Angold, & Costello, 2013). Consider the case of15-year-old Amanda Todd. In September 2012, Amanda posted a soundless YouTube video displaying a series of handwritten messages that described her years of being bullied (FIGURE 9.36). The bullying began in the seventh grade, when Amanda used video chat to meet people over the Internet. A man convinced Amanda to pose topless and then threatened to blackmail her unless she posted more-explicit sexual images of herself. Amanda informed her parents, who contacted the police. By this point, Amanda's pictures had been widely circulated over the Internet. Her fellow students started verbally abusing her. Amanda went into a tailspin, experiencing feelings of anxiety and depression. About a month after she posted her You Tube video, Amanda committed suicide. This tragic case shows the urgency of preventing bullying and of supporting people who are bullied. THE IMPORTANCE OF PARENTS Much research has confirmed that parents have substantial influence throughout an individual's life. Significantly, researchers have emphasized that neither the peer group nor the family can be assigned the primary role in a child's social development. Instead, the two contexts play complementary roles. B. Bradford Brown and colleagues (1993) have argued that parents' influence can be direct or indirect. Parents contribute to specific individual behaviors, but they also affect social development indirectly by influencing the choices the child makes about what kind of clique to join. In observations of695 young people from childhood through adolescence, Robert Cairns and Beverly Cairns (1994) found that parents and teachers played a major role in realigning social groups so they were consistent with family norms. Important support for the significance of child-parent interaction comes from the New York Longitudinal Study, begun in 1956 by Stella Chess and Alexander Thomas. The study ran for six years, assessing 141 children from 85 middle- to upper-middleclass families. Chess and Thomas (1984) pinpointed the most important factor in determining a child's social development: the fit between the child's biologically based tem