AP PSYCH UNIT 3: DEVELOPMENT

odule 3.1 Themes and Methods in Developmental Psychology Learning Targets 3.1-1 Explain three themes that have engaged developmental psychologists and two methods they typically use to study human development over time. My [DM’s] story, and yours, began when a man and a woman together contributed 20,000+ genes to an egg that became a unique person. Those genes coded the protein building blocks that, with astonishing precision, form our body and predispose our traits. My grandmother handed down to my mother a rare hearing-loss pattern, which she, in turn, gave to me (the least of her gifts). My father was an amiable extravert, and sometimes I forget to stop talking (although as a child, my talking was impeded by embarrassing stuttering, for which Seattle Public Schools provided speech therapy). Along with my parents’ nature, I also received their nurture. Like you, I was born into a particular family and culture, with its own way of viewing the world. My values have been shaped by a family culture filled with talking and laughter, by a religious culture that speaks of love and justice, and by an academic culture that encourages critical thinking (asking, What do you mean? How do you know?). We are formed by our genes and by our contexts, so our stories all differ. But in many ways we are each like nearly everyone else on Earth. Being human, you and I have a need to belong. My mental video library, which began after age 4, is filled with scenes of social attachment. Over time, my attachments to parents loosened as peer friendships grew. After lacking confidence to date in high school, I fell in love with a college classmate and married at age 20. Natural selection predisposes us to survive and perpetuate our genes. Sure enough, two years later a child entered our lives, and I experienced a new form of love that surprised me with its intensity. But life is marked by change. That child and his brother now live 2000 miles away, and their sister has found her calling in South Africa. The tight rubber bands linking parent and child have loosened, as yours likely have as well. Change also marks most vocational lives, which for me transitioned from a teen working in the family insurance agency, to a premed chemistry major and hospital aide, to (after discarding my half-completed medical school applications) a psychology professor and author. I predict that in 10 years you, too, will be doing things you do not currently anticipate. Stability also marks our development: Our life situations change, but we experience a continuous self. When I look in the mirror, I do not see the person I once was, but I feel like the person I have always been. I am the same person who, as a late teen, played basketball and discovered love. Sixty years later, I still enjoy basketball and still love (with less passion but more security) the life partner with whom I have shared life’s griefs and joys. We experience a continuous self, but that self morphs through stages — for me, growing up, raising children, enjoying a career, and, eventually, life’s final stage, which will demand my presence. As I wend my way through this cycle of life and death, I am mindful that life’s journey is a continuing process of development, seeded by nature and shaped by nurture, animated by love and focused by work, begun with wide-eyed curiosity and completed, for those blessed to live to a good old age, with peace and never-ending hope. Across the lifespan, we grow from newborn to toddler, from toddler to teenager, and from teenager to mature adult. At each stage of life there are physical, cognitive, and social-emotional milestones. Developmental Psychology’s Major Themes 3.1-1 What three themes have engaged developmental psychologists, and what are two methods they typically use to study human development over time? Researchers find human development interesting for the same reasons most of us do — they want to understand more about how we’ve become our current selves, and how we may change in the years ahead. Developmental psychology examines our physical, cognitive, and social-emotional development across the lifespan. Developmental psychologists study both the chronological order of this development and its key themes. They often do cross-sectional studies (comparing people of different ages) and longitudinal studies (following people across time) to explore three major themes: Nature and nurture: How does our genetic inheritance (our nature) interact with our experiences (our nurture) to influence our development? How have your nature and your nurture influenced your life story? Continuity and stages: Which parts of development are gradual and continuous, like riding an escalator? Which parts change abruptly in separate stages, like climbing rungs on a ladder? Stability and change: Which of our traits persist through life? How do we change as we age? AP® Science Practice Research Developmental psychology often features longitudinal and cross-sectional studies — because these research design methods help us learn about development across the lifespan (changes over time). AP® Exam Tip All three of these themes are important for development. Nature and nurture, of course, weave their way through almost every module. Look for the nature/nurture idea throughout this text (and on the AP® exam). Nature and Nurture The unique gene combination created when our mother’s egg engulfed our father’s sperm helped form us as individuals. Genes predispose both our shared humanity and our individual differences. But our experiences also shape us, in the womb and in the world. Our families and peer relationships teach us how to think and act. Even differences initiated by our nature may be amplified by our nurture. We are not formed by either nature or nurture, but by the interaction between them. Biological, psychological, and social-cultural forces interact. Mindful of how others differ from us, however, we often fail to notice the similarities stemming from our shared biology. Regardless of our culture, we humans share the same life cycle. We speak to our infants in similar ways and respond similarly to their coos and cries (Bornstein et al., 1992a,b). Although ethnic groups have differed in some ways, including average school achievement, these differences are “no more than skin deep.” To the extent that family structure, peer influences, and parental education predict behavior in one of these ethnic groups, they do so for the others. Compared with the person-to-person differences within groups, between-group differences are small. Continuity and Stages Do adults differ from infants as a giant redwood differs from its seedling — a difference created by gradual, cumulative growth? Or do they differ as a butterfly differs from a caterpillar — a difference of distinct stages? Stages of the life cycle Researchers who emphasize experience and learning typically see development as a slow, continuous shaping process. Those who emphasize biological maturation tend to see development as a sequence of genetically predisposed stages or steps: Although progress through the various stages may be quick or slow, everyone passes through the stages in the same order. Are there clear-cut stages of psychological development, as there are physical stages such as walking before running? The stage theories we will consider — Jean Piaget’s theory of cognitive development, and Erik Erikson’s theory of psychosocial development — propose developmental stages (summarized in Figure 3.1-1). But as we will also see, some research casts doubt on the idea that life proceeds through neatly defined age-linked stages. Figure 3.1-1 Comparing the stage theories 1 Although many modern developmental psychologists do not identify as stage theorists, the stage concept remains useful. The human brain does experience growth spurts during childhood and puberty that correspond roughly to Piaget’s stages (Thatcher et al., 1987). And stage theories contribute a developmental perspective on the whole lifespan by suggesting how people of one age think and act differently when they arrive at a later age. Stability and Change As we follow lives through time, do we find more evidence for stability or change? If reunited with a long-lost childhood friend, do we instantly realize that “it’s the same old Jordan”? Or do long-ago friends now seem like strangers? (At least one acquaintance of mine [DM’s] would choose the second option. At his 40-year college reunion, he failed to recognize a former classmate. The understandably appalled classmate was his first wife!)

Module 3.2a Physical Development Across the Lifespan: Prenatal Development, Infancy, and Childhood Learning Targets 3.2-1 Describe the course of prenatal development, and explain how teratogens affect that development. 3.2-2 Explain some abilities of the newborn, and explain how researchers are able to explore infants’ mental abilities. 3.2-3 Explain key developmental changes in the brain and in motor skills during infancy and childhood. 3.2-4 Explain how an infant’s brain begins processing memories. Developmental psychologists study physical development, including the developing brain (and blossoming mind), from inside the womb to out in the room, and throughout childhood. Prenatal Development and the Newborn 3.2-1 What is the course of prenatal development, and how do teratogens affect that development? Your life story began when two lives — and their ancestral genetic histories — merged, and your wonder-filled development began. Conception Nothing is more natural than a species reproducing itself. And nothing is more wondrous. For you, the process started inside your grandmother — as an egg formed inside a developing female inside of her. (Your biological mother was born with all the immature eggs she would ever have.) Your biological father, in contrast, began producing sperm cells nonstop at puberty — in the beginning at a rate of more than 1000 sperm during the second it takes to read this phrase. Some time after puberty, your mother’s ovary released a mature egg — a cell roughly the size of the period that ends this sentence. Like space voyagers approaching a huge planet, some 250 million deposited sperm began their frantic race upstream, approaching a cell 85,000 times their own size. The small number reaching the egg released digestive enzymes that ate away the egg’s protective coating (Figure 3.2-1a). As soon as the one winning sperm penetrated that coating and was welcomed in (Figure 3.2-1b), the egg’s surface blocked out the others. Before half a day elapsed, the egg nucleus and the sperm nucleus fused: The two became one. Figure 3.2-1 Life is sexually transmitted (a) Sperm cells surround an egg. (b) One sperm penetrates the egg’s jellylike outer coating, triggering a series of chemical events that will cause sperm and egg to fuse into a single cell. If all goes well, that cell will subdivide again and again to emerge 9 months later as a 37-trillion-cell human being (Bianconi et al., 2013). Consider it your most fortunate of moments. Among some 250 million sperm, the one needed to make you, in combination with that one particular egg, won the race. (As individual humans, we do not reproduce; we recombine.) And so it was for innumerable generations before us. If any one of our ancestors had been conceived with a different sperm or egg, or died before conceiving, or not chanced to meet their partner, or …. The mind boggles at the improbable, unbroken chain of events that produced us. Prenatal Development How many fertilized eggs, called zygotes, survive beyond the first 2 weeks? Fewer than half (Grobstein, 1979; Hall, 2004). But for us, good fortune prevailed. One cell became 2, then 4 — each just like the first — until this cell division had produced some 100 identical cells within the first week. Then the cells began to differentiate — to specialize in structure and function (“I’ll become a brain, you become intestines!”). About 10 days after conception, the germinal stage completes as the zygote attaches to the mother’s uterine wall, beginning approximately 37 weeks of the closest human relationship. Near the beginning of this maternal bodybuilding feat, the tiny clump of cells forms two parts. The inner cells become the embryo (Figure 3.2-2a). Many of the outer cells become the placenta, the life-link that transfers nutrients and oxygen from mother to embryo. Over the next 6 weeks, the embryo’s organs begin to form and function. The heart begins to beat. Figure 3.2-2 Prenatal development (a) The embryo grows and develops rapidly. At 40 days, the spine is visible and the arms and legs are beginning to grow. (b) By the start of the ninth week, when the fetal period begins, facial features, hands, and feet have formed. (c) As the fetus enters the sixteenth week, its 3 ounces could fit in the palm of your hand. By 9 weeks after conception, an embryo looks unmistakably human (Figure 3.2-2b). It is now a fetus (Latin for “offspring” or “young one”). During the sixth month, organs such as the stomach develop enough to give the fetus a good chance of surviving and thriving if born prematurely. At each prenatal stage, genetic and environmental factors affect our development. By the sixth month, the fetus is responsive to sound. Microphone readings taken inside the uterus reveal that the fetus is exposed to the sound of its mother’s muffled voice (Ecklund-Flores, 1992; Hepper, 2005). Immediately after emerging from their underwater world, newborns prefer their mother’s voice to another woman’s, or to their father’s (DeCasper et al., 1986, 1994; Lee & Kisilevsky, 2014). They also prefer hearing their mother’s language. In one study, day-old American and Swedish newborns paused more in their pacifier sucking when listening to familiar vowels from their mother’s language (Moon et al., 2013). After repeatedly hearing a fake word (tatata) in the womb, Finnish newborns’ brain waves displayed recognition when hearing the same word after birth (Partanen et al., 2013). If their mother spoke two languages during pregnancy, newborns displayed interest in both (Byers-Heinlein et al., 2010). And just after birth, the melodic ups and downs of newborns’ cries bear the tuneful signature of their mother’s native tongue (Mampe et al., 2009). Babies born to French-speaking mothers tended to produce cries with the rising intonation of French; babies born to German-speaking mothers produced cries with the falling tones of German (Mampe et al., 2009). Would you have guessed? The learning of language begins in the womb. In the 2 months before birth, fetuses demonstrate learning in other ways, as when they adapt to a vibrating, honking device placed on their mother’s abdomen (Dirix et al., 2009). Like people who adapt to the sound of trains in their neighborhood, fetuses get used to the honking. Moreover, 4 weeks later, they recall the sound (as evidenced by their mild response, compared with the reactions of those fetuses not previously exposed to such honking). Sounds are not the only environmental factors that impact fetal development. In addition to transferring nutrients and oxygen from mother to fetus, the placenta screens out many harmful substances. Even so, some slip by. Teratogens, agents such as viruses and drugs, can damage an embryo or fetus. This is one reason pregnant women are advised not to drink alcoholic beverages or use nicotine or marijuana (Kuehn, 2019; Saint Louis, 2017). A pregnant woman never smokes, vapes, or drinks alone. When alcohol enters her bloodstream and that of her fetus, it reduces activity in both their central nervous systems. Alcohol use during pregnancy may prime the woman’s offspring to like alcohol and put them at risk for heavy drinking and alcohol use disorder during their teen years. In experiments, when pregnant rats drank alcohol, their young offspring later displayed a liking for alcohol’s taste and odor (Youngentob & Glendinning, 2009; Youngentob et al., 2007). AP® Science Practice Research The alcohol experiments described here were conducted on rats. That is because it would be unethical to introduce a teratogen, such as alcohol, into humans. The American Psychological Association has ethical guidelines for animal welfare in research as well (see Module 0.5). Worldwide, 1 in 10 women report consuming alcohol while pregnant (Popova et al., 2019). Even light drinking, occasional binge drinking, or marijuana smoking can affect the fetal brain (CDC, 2018c; Ghazi Sherbaf et al., 2019; Marjonen et al., 2015). Persistent heavy drinking puts the fetus at risk for congenital (present at birth) disabilities, future behavior problems, and lower intelligence. For 1 in about 130 children worldwide and 1 in 30 in the United States, the effects are visible as fetal alcohol spectrum disorder (Lange et al., 2017; May et al., 2018). Its most serious form is fetal alcohol syndrome (FAS), which is marked by lifelong physical and mental abnormalities. The fetal damage may occur because alcohol has an epigenetic effect: It leaves chemical marks on DNA that switch genes abnormally on or off (Liu et al., 2009). Smoking cigarettes or marijuana during pregnancy also leaves epigenetic scars that may increase vulnerability to stress or addiction (Stroud et al., 2014; Szutorisz & Hurd, 2016). If a pregnant woman experiences extreme stress, the stress hormones flooding her body may indicate a survival threat to the fetus and produce an earlier delivery (Glynn & Sandman, 2011). And malnourishment, maternal illness, and genetic mutations can put a child at risk for health problems and psychiatric disorders (Glynn & Sandman, 2011; Hardie & Landale, 2013; Santavirta et al., 2018).

Module 3.2b Physical Development Across the Lifespan: Adolescence and Adulthood Learning Targets 3.2-5 Define adolescence, and explain how the physical changes during this period affect developing teens. 3.2-6 Explain the physical changes that occur during middle and late adulthood. Many psychologists once believed that childhood sets our traits. Today’s developmental psychologists see development as lifelong. As this lifespan perspective emerged, psychologists began to look at how maturation and experience shape us not only in infancy and childhood, but also — after we are no longer handed the children’s menu — in adolescence and adulthood. Physical Development in Adolescence 3.2-5 How is adolescence defined, and how do physical changes affect developing teens? Adolescence — the years spent morphing from child to adult — starts with the physical beginnings of sexual maturity and ends with the social achievement of independent adult status. Thus, in cultures where postpubertal teens are self-supporting, such as among Aboriginal Australians, adolescence hardly exists (Senior et al., 2021). And in Western cultures, where sexual maturation occurs earlier and independence later, adolescence is lengthening (Sawyer et al., 2018; Worthman & Trang, 2018). In industrialized countries, what are the teen years like? In Leo Tolstoy’s Anna Karenina, the teen years were “that blissful time when childhood is just coming to an end, and out of that vast circle, happy and gay, a path takes shape.” But another teenager, Anne Frank, writing in her diary while hiding from the Nazis, described tumultuous teen emotions: My treatment varies so much. One day Anne is so sensible and is allowed to know everything; and the next day I hear that Anne is just a silly little goat who doesn’t know anything at all and imagines that she’s learned a wonderful lot from books…. Oh, so many things bubble up inside me as I lie in bed, having to put up with people I’m fed up with, who always misinterpret my intentions. G. Stanley Hall (1904), one of the first psychologists to describe adolescence, believed that the tension between biological maturity and social dependence creates a period of “storm and stress.” It’s a time of diminishing parental control (Lionetti et al., 2019). It’s also a time when teens crave social acceptance, but often feel socially disconnected. Three in four U.S. friendships started in seventh grade dissolve by the end of eighth grade (Hartl et al., 2015). Such social disconnection hits adolescents hard — increasing their risk for substance abuse and depressive symptoms (Hussong et al., 2019). Indeed, after age 30, many who grow up in independence-fostering Western cultures look back on their teenage years as a time they would not want to relive — a time when their peers’ social approval was imperative, their sense of direction in life was in flux, and their feeling of alienation from their parents was deepest (Arnett, 1999; Macfarlane, 1964). But for others, adolescence is a time of vitality without the cares of adulthood — a time of rewarding friendships, heightened idealism, and a growing sense of life’s exciting possibilities. Cultural Awareness Notice the mentions of industrialized countries and Western culture, as well as Aboriginal Australian culture in the discussion of adolescence. Culture plays an important role in how we experience this stage of life. Can you think of a way culture influences the experience of teens? Viewing the experience of others purely through our own cultural lens can lead to misunderstanding. Adolescence begins with puberty, the time when we mature sexually. Puberty follows a surge of hormones, which may intensify moods and which trigger a series of bodily changes discussed in Module 3.3. The Timing of Puberty Just as in the earlier life stages, the sequence of physical changes in puberty (for example, breast buds and visible pubic hair before menarche — the first menstrual period) is far more predictable than their timing. Some girls start their growth spurt at age 9, some boys as late as age 16. Early maturation can be a challenge. Early maturing adolescents are at increased risk for mental health problems (Hamlat et al., 2019; Lee et al., 2020; Ullsperger & Nikolas, 2017). This vulnerability is greatest for teen girls and boys with emotionally reactive temperaments. Also, if a girl’s physical development outpaces her emotional maturity and her friends’ development, she may associate with older adolescents, suffer teasing or sexual harassment, and ruminate more (Alloy et al., 2016; Weingarden & Renshaw, 2012). The Teenage Brain The adolescent brain is a work in progress. Until puberty, brain cells increase their connections, like trees growing more roots and branches. Then, during adolescence, comes a selective pruning of unused neurons and connections (Blakemore, 2008). What we don’t use, we lose. As teens mature, their prefrontal cortex (in the forward part of the frontal lobes) also continues to develop. The continuing growth of myelin, the fatty tissue that forms around axons and speeds neurotransmission, enables better communication with other brain regions (Whitaker et al., 2016). These developments bring improved judgment, impulse control, and long-term planning. A landmark study following 11,000 youth from late childhood to early adulthood is examining influences on teens’ brain development, such as drugs, screen time, and sleep (NIMH, 2019; Wadman, 2018). Maturation of the prefrontal cortex nevertheless lags behind that of the emotional limbic system. Puberty’s hormonal surge and limbic system development help explain teens’ occasional impulsiveness, risky behaviors, and emotional storms — slamming doors and turning up the music (Smith, 2018; Steinberg & Icenogle, 2019). No wonder younger teens (whose unfinished prefrontal cortex isn’t yet fully equipped for making long-term plans and curbing impulses) may succumb to the lure of risky behaviors. Teens actually don’t underestimate the risks of vaping, fast driving, and unprotected sex. Their brains are just biased toward immediate rewards, which helps explain why teens worldwide struggle with self-control (Hansen et al., 2019; Steinberg et al., 2018). The teenage brain is like a car with a forceful accelerator and underdeveloped brakes (Figure 3.2-6). Figure 3.2-6 Impulse control lags reward seeking Surveys of more than 7000 American 12- to 24-year-olds reveal that sensation-seeking peaks in the mid-teens, with impulse control developing more slowly as their prefrontal cortex matures. (National Longitudinal Study of Youth and Children and Young Adults survey data presented by Steinberg, 2013.) AP® Science Practice Data Interpretation Consider Figure 3.2-6. Identify the variables represented in the graph. Are the data presented in this graph qualitative or quantitative? Explain your choice. Which age group shows the most impulse control? Which age group shows the most sensation-seeking? So, when Junior drives recklessly and struggles academically, should his parents reassure themselves that “he can’t help it; his prefrontal cortex isn’t yet fully developed”? They can take hope: Brain changes underlie teens’ new self-consciousness about what others are thinking as well as their valuing of risky rewards (Barkley-Levenson & Galván, 2014; Somerville et al., 2013). And the brain with which Junior begins his teens differs from the brain with which he will end his teens. Unless he slows his brain development with heavy drinking — leaving him prone to impulsivity and addiction — his prefrontal cortex will continue maturing until about age 25 (Crews et al., 2007; Giedd, 2015). It will also become better connected with the limbic system, enabling better emotion regulation (Cohen et al., 2016; Steinberg, 2012).

Module 3.4 Cognitive Development Across the Lifespan Learning Targets 3.4-1 Explain how a child’s mind develops from the perspectives of Piaget and today’s researchers. 3.4-2 Explain how Vygotsky viewed children’s cognitive development. 3.4-3 Explain what it means to develop a theory of mind. 3.4-4 Explain adolescent and cognitive moral development according to Piaget and later researchers. 3.4-5 Explain how memory changes with age. Cognitive Development in Infancy and Childhood 3.4-1 How did Piaget broaden our understanding of the way a child’s mind develops, and how have today’s researchers built on his work? Somewhere on your journey “from egghood to personhood” (Broks, 2007), you became conscious. When was that? And once conscious, how did your mind grow? Developmental psychologist Jean Piaget [pee-ah-ZHAY] spent his life searching for the answers. He studied children’s developing cognition — all the mental activities associated with thinking, knowing, remembering, and communicating. His interest in children’s cognitive development began in 1920, when he was in Paris developing questions for children’s intelligence tests. While administering the tests, Piaget became intrigued by children’s wrong answers, which were often strikingly similar among same-age children. Where others saw childish mistakes, Piaget saw developing intelligence at work. Such accidental discoveries are among the fruits of psychological science. Jean Piaget (1896–1980) “If we examine the intellectual development of the individual or of the whole of humanity, we shall find that the human spirit goes through a certain number of stages, each different from the other” (1930). SPOTLIGHT ON: Jean Piaget A half-century spent with children convinced Piaget that a child’s mind is not a miniature model of an adult’s. Thanks partly to his careful observations, we now understand that children reason differently than adults, in “wildly illogical ways” (Brainerd, 1996). Piaget’s studies led him to believe that a child’s mind develops through a series of stages, in an upward march from the newborn’s simple reflexes to the adult’s abstract reasoning power. Thus, an 8-year-old can comprehend things a toddler cannot, such as the analogy that “getting an idea is like having a light turn on in your head.” As we saw in Module 2.2a, Piaget proposed that children build schemas — concepts that enable us to organize our experiences — and that they actively construct and modify their understanding of the world through the processes of assimilation and accommodation. Seeing an airplane for the first time, a small child trying to assimilate the new information may point and say “Bird!” When his mother says “That’s an airplane,” the child is forced to accommodate, adapting his bird schema and developing a new schema for airplane. Piaget’s Theory and Current Thinking Piaget viewed children’s cognitive development as a process guided by biological maturation (see Module 3.2) and environmental interaction. He believed that children construct their understanding of the world while experiencing it. In Piaget’s view, cognitive development consists of four major stages — sensorimotor, preoperational, concrete operational, and formal operational — each with distinctive characteristics that permit specific kinds of thinking. Sensorimotor Stage In the sensorimotor stage, from birth to nearly age 2, babies take in the world through their senses and actions — through looking, hearing, touching, mouthing, and grasping. As their hands and limbs begin to move, they learn to make things happen. Very young babies seem to live in the present: Out of sight is out of mind. In one test, Piaget showed an infant an appealing toy and then flopped his beret over it. Before the age of 6 months, the infant acted as if the toy ceased to exist. Young infants lack object permanence — the awareness that objects continue to exist when not perceived. By 8 months, infants begin exhibiting memory for things no longer seen. If you hide a toy, the infant will momentarily look for it (Figure 3.4-1). Within another month or two, the infant will look for it even after being restrained for several seconds. Figure 3.4-1 Object permanence Infants younger than 6 months seldom understand that things continue to exist when they are out of sight. But for this older infant, out of sight is definitely not out of mind. So, does object permanence blossom suddenly at 8 months, much as tulips blossom in spring? Today’s researchers believe object permanence unfolds gradually, and they see development as more continuous than Piaget did. Researchers also believe Piaget and his followers underestimated young children’s competence. Young children think like little scientists. They test ideas, make causal inferences, and learn from statistical patterns (Gopnik et al., 2015). Consider these simple experiments: Baby physics: Like adults staring in disbelief at a magic trick (the “Whoa!” look), infants look longer at and explore impossible scenes — a car seeming to pass through a solid object, a ball stopping in midair, or an object violating object permanence by magically disappearing (Shuwairi & Johnson, 2013; Stahl & Feigenson, 2015). Why do infants show this visual bias? Because impossible events violate infants’ expectations (Baillargeon et al., 2016). Baby math: Karen Wynn (1992, 2000, 2008) showed 5-month-olds one or two objects (Figure 3.4-2a). Then she hid the objects behind a screen, and visibly removed or added one (Figure 3.4-2d). When she lifted the screen, the infants sometimes did a double take, staring longer when shown a wrong number of objects (Figure 3.4-2f). But were they just responding to a greater or smaller mass of objects, rather than a change in number (Feigenson et al., 2002)? Later experiments showed that babies’ number sense extends to larger numbers, to ratios, and to such things as drumbeats and motions (Libertus & Brannon, 2009; McCrink & Wynn, 2004; Spelke et al., 2013). If accustomed to a Daffy Duck puppet jumping three times on stage, they showed surprise if it jumped only twice. Figure 3.4-2 Baby math Shown a numerically impossible outcome, 5-month-old infants stare longer (Wynn, 1992). Clearly, infants are smarter than Piaget appreciated. Even as babies, we have a lot on our minds. Preoperational Stage Piaget believed that until about age 6 or 7, children are in a preoperational stage — able to represent things with words and images but too young to perform mental operations (such as imagining an action and mentally reversing it). For a 5-year-old, the milk that seems “too much” in a tall, narrow glass may become just right if poured into a short, wide glass. Focusing only on the height dimension, this child cannot perform the operation of mentally pouring the milk back. Before about age 6, said Piaget, children lack the concept of conservation — the principle that quantity remains the same despite changes in shape (Figure 3.4-3). Figure 3.4-3 Piaget’s test of conservation This visually focused preoperational child does not yet understand the principle of conservation. When the milk is poured into a tall, narrow glass, it suddenly seems like “more” than when it was in the shorter, wider glass. In another year or so, she will understand that the amount stays the same. pretend and parallel play Symbolic thinking and the pretend play it enables appear at an earlier age than Piaget supposed. Judy DeLoache (1987) showed children a model of a room and hid a miniature stuffed dog behind its miniature couch. The 2 1 2 -year-olds easily remembered where to find the miniature toy, but they could not use the model to locate an actual stuffed dog behind a couch in a real room. Three-year-olds — only 6 months older — usually went right to the actual stuffed animal in the real room, showing they could think of the model as a symbol for the room. Similarly, 2 1 2 -year-olds tend to engage in parallel play, in which they play next to other children but do not try to influence others. At a playground, they may play beside a friend, focused on their play and oblivious to their friend’s behaviors. ap® science practice Research The DeLoache study described here is a nice example of a cross-sectional study, one that compares people of different ages at the same point in time to look for developmental differences. egocentrism

Module 3.5 Communication and Language Development Learning Targets 3.5-1 Explain how we acquire language, and explain the concept of universal grammar. 3.5-2 Explain the milestones in language development, and identify the critical period for acquiring language. 3.5-3 Identify the brain areas involved in language processing and speech. 3.5-4 Explain the relationship between thinking and language, and discuss the value of thinking in images. Imagine an alien species that could pass thoughts from one head to another merely by pulsating air molecules in the space between them. Perhaps these weird creatures could inhabit a future science fiction movie? Actually, we are those creatures! When we speak, our brain and voice apparatus transmit air pressure waves that we send banging against another person’s eardrum — enabling us to transfer thoughts from our brain into theirs. As cognitive psychologist Steven Pinker (1998) noted, we sometimes sit for hours “listening to other people make noise as they exhale, because those hisses and squeaks contain information.” Depending on how you vibrate the air, you may get a scowl or a kiss. Language is more than vibrating air — it is our spoken, written, or signed words, and the ways we combine them to communicate meaning. When I [DM] created this paragraph, my fingers on the keyboard generated electronic binary numbers that morphed into the squiggles in front of you. When transmitted by light rays into your retina (or by sound waves into your ear), these squiggles trigger formless nerve impulses that travel to several areas of your brain, which integrate the information, compare it to stored information, and decode meaning. Thanks to language, information is moving from my mind to yours. Many animals know little more than what they sense. Thanks to language, we comprehend much that we’ve never seen and that our distant ancestors never knew. And thanks to technology, we can use language to communicate across vast distances — through spoken, written, and even pictorial “emoticon” words (including the 2015 Oxford English Dictionary “word of the year,” the emoji: ). Language transmits knowledge Whether spoken, written, or signed, language — the original wireless communication — enables mind-to-mind information transfer, and with it the transmission of civilization’s accumulated knowledge across generations. Language Acquisition and Development We humans have an astonishing knack for language. With little effort, we draw from tens of thousands of words in our memory; assemble them, on the fly, using the rules of our language; and spew them out, three words a second (Vigliocco & Hartsuiker, 2002). Given how many ways we can mess up, our language capacity is truly amazing. Language Acquisition: How Do We Learn Language? 3.5-1 How do we acquire language, and what did Chomsky mean by universal grammar? Linguist Noam Chomsky has argued that language is an unlearned human trait, separate from other parts of human cognition. He initially proposed that we are born with a language acquisition device, which allows us to learn any human language. Spoken languages require three building blocks. Phonemes are the smallest distinctive sound units in a language. (To say that, English speakers utter the phonemes th, a, and t.) Morphemes are the smallest language units that carry meaning. (The word readers contains three morphemes: read; er, signaling that we mean “one who reads”; and s, signaling that we mean not one, but multiple readers.) Every word in a language contains one or more morphemes. Grammar is a language’s set of rules that enable people to communicate. Grammatical rules guide us in deriving meaning from sounds (semantics) and in ordering words into sentences (syntax). Cultural Awareness All human languages — over 6000 of them — follow similar grammatical rules. But each language also reflects its speakers’ culture. Gestures and phrases that are quite appropriate in one culture might be extremely inappropriate in another. You will learn more about language and culture later in this module. Chomsky later expanded his thinking and suggested that we are born with a built-in predisposition to learn grammar. This ability, which he called universal grammar (UG), helps explain why preschoolers pick up language so readily and use grammar so well. It happens so naturally—as naturally as birds learn to fly—that training hardly helps. Whether we’re born in Indiana or Indonesia, we intuitively follow similar grammatical rules that transform arbitrary symbols to generate an infinity of ideas (Aryawibawa & Ambridge, 2019). Whatever language we experience as children, whether spoken or signed, we will readily learn its specific grammar and vocabulary (Bavelier et al., 2003). And we always start speaking mostly in nouns (kitty, da-da) rather than in verbs and adjectives (Bornstein et al., 2004). Biology and experience work together. Creating a language Brought together as if on a desert island (actually a school), Nicaragua’s young deaf children over time drew upon sign gestures from home to create their own Nicaraguan Sign Language, complete with words and intricate grammar. Activated by a social context, nature and nurture work creatively together (Osborne, 1999; Sandler et al., 2005; Senghas & Coppola, 2001). SPOTLIGHT ON: Noam Chomsky Language Development: When Do We Learn Language? 3.5-2 What are the milestones in language development, and when is the critical period for acquiring language? Make a quick guess: How many words of your native language will you have learned between your first birthday and your high school graduation? Although you use only 150 words for about half of what you say, you probably will have learned about 60,000 words (Bloom, 2000; McMurray, 2007). That averages (after age 2) to nearly 3500 words each year, or about 10 each day! How you do this — how those 3500 words could so far outnumber the roughly 200 words your schoolteachers consciously taught you each year — is one of the great human wonders. A natural talent Human infants come with a remarkable capacity to soak up language. But the particular language they learn reflects their unique interactions with others. Could you even now state the structural rules — for example, the correct way to string words together to form sentences — for the language(s) you speak fluently? Most of us cannot. Yet before you were able to add 2 + 2, you were creating your own original sentences and applying these rules. As a preschooler, you comprehended and spoke with a facility that far outpaced even the brightest adult’s ability to learn a new language. Receptive Language Children’s language development moves from simplicity to complexity. Babies come prepared to learn any language, with a slight bent toward the language they heard in the womb. By 4 months of age, babies can recognize differences in speech sounds (Stager & Werker, 1997). They can also read lips: We know this because in studies by Patricia Kuhl and Andrew Meltzoff (1982), babies have preferred looking at a face that matches a sound — an “ah” coming from wide open lips and an “ee” from a mouth with corners pulled back. Recognizing such differences marks the beginning of the development of babies’ receptive language, their ability to understand what is said to and about them. At 7 months and beyond, they grow in their power to do what adults find difficult when listening to an unfamiliar language: to segment spoken sounds into individual words. Productive Language Long after the beginnings of receptive language, babies’ productive language — their ability to produce words — matures. Before nurture molds babies’ speech, nature enables a wide range of possible sounds, such as cooing and babbling. In the babbling stage, beginning around 4 months, babies seem to sample all the sounds they can make, such as ah-goo. Babbling does not imitate the adult speech babies hear — it includes sounds from various languages. From this early babbling, a listener could not identify an infant as being, say, French, Korean, or Ethiopian. By about 10 months, infants’ babbling has changed so that a trained ear can identify the household language (de Boysson-Bardies et al., 1989). Deaf infants who observe their deaf parents using sign language begin to babble more with their hands (Petitto & Marentette, 1991). Without exposure to other languages, babies lose their ability to do what adults cannot — to discriminate and produce sounds and tones outside their native language (Kuhl et al., 2014; Meltzoff et al., 2009). Thus, by adulthood, those who speak only English cannot discriminate certain sounds in Japanese speech. Nor can Japanese adults with no training in English hear the difference between the English r and l. For a Japanese-speaking adult, “la-la-ra-ra” may sound like the same syllable repeated. Around their first birthday, most children enter the one-word stage. They know that sounds carry meanings, and they begin to use sounds — usually only one barely recognizable syllable, such as ma or da — to communicate meaning. But gradually the infant’s language conforms more to the family’s language. Across the world, baby’s first words are often nouns that label objects or people (Tardif et al., 2008). At this one-word stage, “Doggy!” may mean “Look at the dog out there!” At about 18 months, children’s word learning explodes from about a word per week to a word per day. By their second birthday, most have entered the two-word stage (Table 3.5-1). They start uttering two-word sentences in telegraphic speech. Like yesterday’s telegrams that charged by the word (“TERMS ACCEPTED. SEND MONEY”), a 2-year-old’s speech contains mostly nouns and verbs (“Want juice”). They may also overgeneralize grammar rules, such as saying “tooths” rather than “teeth.” Also like telegrams, their speech arranges words in a sensible order. English-speaking children typically place adjectives before nouns — white house rather than house white. Spanish reverses this order, as in casa blanca. table 3.5-1 Summary of Language Development Month (approximate) Stage 4 Babbles many speech sounds (“ah-goo”) 10 Babbling resembles household language (“ma-ma”) 12 One-word speech (“Kitty!”) 24 Two-word speech (“Get ball.”) 241 Rapid development into complete sentences Moving out of the two-word stage, children quickly begin uttering longer phrases (Fromkin & Rodman, 1983). By early elementary school, they understand complex sentences and begin to enjoy the humor conveyed by double meanings: “You never starve in the desert because of all the sand-which-is there.” All the while, babies also communicate without words — with gestures (Zubler et al., 2022). They learn to lift arms to be picked up, to wave goodbye, to clap hands when excited, and to point when asking for something or answering a question. To help them communicate, many care providers now teach babies basic signs, such as for “more” and “all done.”

Module 3.6a Social-Emotional Development Across the Lifespan: Infancy & Childhood Learning Targets 3.6-1 Explain how caregiver-infant attachment bonds form. 3.6-2 Explain how psychologists have studied attachment differences, and synthesize what they have learned. 3.6-3 Explain how experiencing adversity affects children’s social development. 3.6-4 Explain the onset and development of children’s self-concepts. 3.6-5 Explain the differences among the four main parenting styles. As Aristotle recognized long ago, we are, from infancy onward, social animals. Thanks to our ancient ancestors surviving in groups that together hunted, gathered, and shared, nature has given us a need to belong. Whether babies, teens, or retirees, we flourish when supported by close relationships. Psychologist Urie Bronfenbrenner’s (1977) ecological systems theory argued that different environments we encounter affect our cognitive, social, and biological development (see Figure 3.6-1). As Pope Francis has said, “Everyone’s existence is deeply tied to that of others.” Figure 3.6-1 The ecological systems theory Directly and indirectly, our social environments influence our development. Social-Emotional Development in Infancy and Childhood 3.6-1 How do caregiver-infant attachment bonds form? From birth, most babies are social creatures, developing an intense attachment to their caregivers. Infants come to prefer familiar faces and voices, then to coo and gurgle when given a caregiver’s attention. By 4.5 months, infants can distinguish between familiar and unfamiliar languages (Fecher & Johnson, 2019). After about 8 months, soon after object permanence emerges and children become mobile, a curious thing happens: They develop separation anxiety when away from caregivers, and stranger anxiety in the presence of strangers. They may greet strangers by crying and reaching for familiar caregivers, as if to say “No! Don’t leave me!” Children this age have schemas for familiar faces — and may resist being handed to someone unfamiliar (Quinn et al., 2019). Once again, we see an important principle: The brain, mind, and social-emotional behavior develop together. Origins of Attachment One-year-olds typically cling tightly to a caregiver when they are frightened or expect separation. Reunited after being apart, they often shower the caregiver with smiles and hugs. This striking caregiver-infant attachment bond is a powerful survival impulse that keeps infants close to their caregivers. Infants usually become attached to those — typically their parents — who are comfortable and familiar. For many years, psychologists reasoned that infants became attached to those who satisfied their need for nourishment. But an accidental finding overturned this explanation. Body Contact During the 1950s, psychologists Harry Harlow and Margaret Harlow bred monkeys for their learning studies. To equalize experiences and to isolate any disease, they separated the infant monkeys from their mothers shortly after birth and raised them in individual cages, each of which included a cheesecloth baby blanket (Harlow et al., 1971). Then came a surprise: When their soft blankets were taken to be washed, the monkeys became distressed. The Harlows recognized that this intense attachment to the blanket contradicted the idea that attachment derives from an association with nourishment. But how could they show this more convincingly? To pit the drawing power of a food source against the contact comfort of the blanket, they created two artificial mothers. One was a bare wire cylinder with a wooden head and an attached feeding bottle; the other was a cylinder with no bottle, but covered with foam rubber and wrapped with terry cloth. When raised with both artificial mothers, the monkeys overwhelmingly preferred the comfy cloth mother (Figure 3.6-2). Like other infants clinging to their live mothers, anxious monkey babies would cling to their cloth mothers, soothed by this contact comfort. When exploring their environment, they used her as a secure base, as if attached to her by an invisible elastic band that stretched only so far before pulling them back. Researchers soon learned that other qualities — rocking, warmth, and feeding — made the cloth mother even more appealing. Figure 3.6-2 The Harlows’ monkey mothers The Harlows’ discovery surprised many psychologists: The infants much preferred contact with the comfortable cloth mother, even while feeding from the nourishing wire mother. SPOTLIGHT ON: Harry Harlow and Margaret Harlow Human infants, too, become attached to parents who are soft and warm and who rock, feed, and pat. Much parent-infant emotional communication occurs via touch, which can be either soothing (snuggles) or arousing (tickles) (Hertenstein et al., 2006). People across the globe agree that the ideal mother “shows affection by touching” (Mesman et al., 2015). Such parental affection not only feels good, but also boosts brain development and later cognitive ability (Davis et al., 2017). Another aspect of human attachment is one person providing another with a secure base from which to explore and a safe haven when distressed. As we mature, our secure base shifts — from parents to peers and partners (Cassidy & Shaver, 1999; Schmidt et al., 2019). But at all ages we are social creatures. We gain strength when someone offers, by words and actions, a safe haven: “I will be here. I am interested in you. Come what may, I will support you” (Crowell & Waters, 1994). Familiarity Contact is one key to attachment. Another is familiarity. In many animals, attachments based on familiarity form during a critical period — an optimal period when certain events must take place to facilitate proper development (Bornstein, 1989). As we saw in Module 3.5, humans seem to have a critical period for language. Goslings, ducklings, and chicks have a critical period for attachment, called imprinting, which falls in the hours shortly after hatching, when the first moving object they see is normally their mother. From then on, the young fowl follow her, and her alone. Daddy duck? While researching imprinting, Konrad Lorenz (1937) wondered: What would ducklings do if he was the first moving creature they observed? What they did was follow him around: Everywhere that Konrad went, the ducks were sure to go. Children — unlike ducklings — do not imprint. However, they do become attached, during a less precisely defined sensitive period, to what they’ve known. Mere exposure to people and things fosters fondness. Children like to reread the same books, rewatch the same movies, and reenact family traditions. They prefer to eat familiar foods, live in the same familiar neighborhood, and attend school with the same old friends. Familiarity is a safety signal. Familiarity breeds content. Attachment Differences: Temperament and Parenting 3.6-2 How have psychologists studied attachment differences, and what have they learned? What accounts for children’s attachment differences? To answer this question, Mary Ainsworth (1979) designed the strange situation. She observed mother-infant pairs at home during their first 6 months. Later she observed the 1-year-old infants in a strange situation (usually a laboratory playroom) with and without their mothers. Such research has shown that about 60 percent of infants and young children display secure attachment (Moulin et al., 2014). In their mother’s presence they play comfortably, happily exploring their new environment. When she leaves, they become distressed; when she returns, they seek contact with her. Other infants show insecure attachment, marked by anxiety or by avoidance of trusting relationships. These infants are less likely to explore their surroundings; they may even cling to their mother. When she leaves, they either cry loudly and remain upset or seem indifferent to her departure and return (Ainsworth, 1973, 1989; Kagan, 1995; van IJzendoorn & Kroonenberg, 1988). Infants who display disorganized attachment show no consistent behavior during these separations and reunions. Ainsworth and others found that sensitive, responsive mothers — those who noticed what their babies were doing and responded appropriately — had infants who exhibited secure attachment (De Wolff & van IJzendoorn, 1997). Insensitive, unresponsive mothers — mothers who attended to their babies when they felt like doing so but ignored them at other times — often had infants who were insecurely attached. The Harlows’ monkey studies, with unresponsive artificial mothers, produced even more striking effects. When put in strange situations without their artificial mothers, the deprived infants were terrified (Figure 3.6-3). Figure 3.6-3 Social deprivation and fear In the Harlows’ experiments, monkeys raised with artificial mothers were overwhelmed when placed in strange situations without those mothers. SPOTLIGHT ON: Mary Ainsworth Many remember Harry Harlow as the researcher who tortured helpless monkeys, and today’s climate of greater respect for animal welfare would likely prevent such primate studies. But Harlow defended his methods: “Remember, for every mistreated monkey there exist a million mistreated children,” he said, expressing the hope that his research would sensitize people to child abuse and neglect. “No one who knows Harry’s work could ever argue that babies do fine without companionship, that a caring mother doesn’t matter,” noted Harlow biographer Deborah Blum (2011, pp. 292, 307). “And since we … didn’t fully believe that before Harry Harlow came along, then perhaps we needed — just once — to be smacked really hard with that truth so that we could never again doubt.” AP® Science Practice Research The Harlows’ monkey studies would likely not be permitted today because the American Psychological Association now has guidelines that protect animal welfare. You can revisit Module 0.5 to review these guidelines. So, caring parents (and other caregivers) matter. But is attachment style the result of parenting? Or are other factors also at work? Temperament and Attachment How does temperament — a person’s characteristic emotional reactivity and intensity — affect attachment style? Studies reveal that heredity affects temperament, and that temperament affects attachment style (Picardi et al., 2011; Raby et al., 2012). ap® exam tip Note that temperament is a contribution from the nature side of the nature–nurture debate.

Module 3.6b Social-Emotional Development Across the Lifespan: Adolescence, Emerging Adulthood, and Adulthood Learning Targets 3.6-6 Explain the social tasks and challenges of adolescence. 3.6-7 Explain the differences between parental and peer influences during adolescence. 3.6-8 Explain the characteristics of emerging adulthood. 3.6-9 Describe the themes and influences that mark our social journey from early adulthood to death. 3.6-10 Explain changes in well-being across the lifespan. 3.6-11 Describe the range of reactions to the death of a loved one. Social-Emotional Development in Adolescence 3.6-6 What are the social tasks and challenges of adolescence? Psychologist Erik Erikson (1963) contended that each stage of life has its own psychosocial task, a crisis that needs resolution. Young children wrestle with issues of trust, then autonomy (independence), then initiative. School-age children strive for competence (also called industry), feeling able and productive. But for people your age, the task is to synthesize past, present, and future possibilities into a clearer sense of self (Table 3.6-2). Adolescents wonder, “Who am I as an individual? What do I want to do with my life? What values should I live by? What do I believe in?” Erikson called this quest the adolescent’s search for identity. table 3.6-2 Erikson’s Stages of Psychosocial Development Stage (approximate age) Issue Description of Task Infancy (to 1 year) Trust and mistrust If needs are dependably met, infants develop a sense of basic trust. Toddlerhood (1–3 years) Autonomy and shame and doubt Toddlers learn to exercise their will and do things for themselves, or they doubt their abilities. Preschool (3–6 years) Initiative and guilt Preschoolers learn to initiate tasks and carry out plans, or they feel guilty about their efforts to be independent. Elementary school (6 years to puberty) Competence (industry) and inferiority Children learn the pleasure of applying themselves to tasks, or they feel inferior. Adolescence (teen years into 20s) Identity and role confusion Teenagers work at refining a sense of self by testing roles and then integrating them to form a single identity, or they become confused about who they are. Young adulthood (20s to early 40s) Intimacy and isolation Young adults learn to form close relationships and gain the capacity for intimate love, or they feel socially isolated. Middle adulthood (40s to 60s) Generativity and stagnation Middle-aged people discover a sense of contributing to the world, usually through family and work, or they may feel a lack of purpose. Late adulthood (late 60s and older) Integrity and despair Reflecting on their lives, older adults may feel a sense of satisfaction or failure. AP® Exam Tip Become familiar with Table 3.6-2, Erikson’s Stages of Psychosocial Development, and be able to identify an individual who may be dealing with the issue in each stage. For example, a teenager may be dealing with the identity and role confusion issue. Forming an Identity To refine their sense of identity, adolescents in individualist cultures usually try out different “selves” in different situations. They may act out one self at home, another with friends, another online, and still another at school. If two situations overlap — as when a teenager brings new friends home — the discomfort can be considerable (Klimstra et al., 2015). The teen often wonders, “Which self should I be? Which is the real me?” The eventual resolution is a self-definition that unifies the various selves into a consistent and comfortable sense of who one is — an identity. For both adolescents and adults, group identities are often formed based on how we differ from those around us — in gender and sexual orientation, in age and relative wealth, in abilities and beliefs. When living in Britain, I [DM] become conscious of my Americanness. When spending time in Hong Kong, I [ND] become conscious of my White race. For international students, for those of a minority ethnic or religious group, for gay and transgender people, or for people with a disability, a social identity often forms around their distinctiveness. (Stay tuned for more on social identity and prejudice in Module 4.1.) Erikson noticed that some adolescents forge their identity early, simply by adopting their parents’ values and expectations (a familial identity). Other adolescents may develop a racial or ethnic identity, gender identity, religious identity, or occupational identity. Traditional, collectivist cultures teach adolescents who they are, rather than encouraging them to decide on their own. Multicultural adolescents form complex identities as they integrate group memberships and their feelings about them (Marks et al., 2011). Teens’ consideration of possible selves — the versions of themselves they imagine becoming in the future — may facilitate their identity formation (see Module 4.6). Researchers have contended that identity formation proceeds through a series of stages, as adolescents explore and gradually commit to who they will become. They begin in the diffusion stage, without a clear commitment to a particular identity and perhaps with little sense of who they are. This is followed by foreclosure: a premature commitment to an identity with little exploration (“I’m a jock”). In the moratorium stage, teens more actively seek a meaningful identity. Finally, they reach identity achievement — a committed sense of self, and a desire to accomplish something personally meaningful that contributes to the world beyond oneself (Fuligni, 2019; Marcia, 1966, 1980). Most young people develop a sense of contentment with their lives. Which statement best describes you: “I would choose my life the way it is right now” or “I wish I were somebody else”? When U.S. teens answered, 81 percent picked the first option, and 19 percent chose the second (Lyons, 2004). Reflecting on their existence, 76 percent of U.S. college and university students say they “discuss religion/spirituality” with friends (Stolzenberg et al., 2019). AP® Science Practice Research Findings such as 81 percent of U.S. teens selecting “I would choose my life the way it is right now” come from survey methods. Recall from Module 0.3 that surveys are vulnerable to the wording effect. Would you answer differently if the option was “There is nothing I would change about my life” instead? Who shall I be today? By varying the way they look, adolescents try out different “selves.” Although we eventually form a consistent and stable sense of identity, the self we present may change with the situation. Interventions that aim to boost adolescents’ health and well-being work best when appealing to their desires for self-esteem, status, and respect (Yeager et al., 2018). (Which of these arguments do you find more convincing: “Eating well is important for your health” or “Buying junk food gives money to rich adults who disrespect you by thinking you don’t know better”?) During the early to mid-teen years, self-esteem typically falls and, for girls, depression scores often increase (Kwong et al., 2019; Salk et al., 2017). Teen depression and suicide rates have increased since the spread of social media and the peer comparisons they enable. (More on this in Module 4.7b.) If your life feels dull compared with all of the fun experiences your online friends are posting, be consoled: Most of your friends feel the same way (Deri et al., 2017). But self-image rebounds during the late teens and twenties, and self-esteem gender differences shrink (Zuckerman et al., 2016). Agreeableness and emotional stability scores also increase in late adolescence (Klimstra et al., 2009). The late teens and twenties are the years when many people in industrialized countries begin exploring new opportunities by attending college or working full time. Many college and university seniors have achieved a clearer identity and a more positive self-concept than they had as first-year students (Waterman, 1988). Those who have achieved a clear sense of identity are less prone to alcohol misuse (Bishop et al., 2005). Cultural Awareness When talking about attending college or working, the authors qualify their statement by specifying industrialized countries. This is because adolescents’ expectations and experiences are culture-bound. Although there are some universal experiences (for example, teens and parents have conflicts), notice how often the findings described in this module are culture-specific. Erikson contended that adolescent identity formation (which continues into adulthood) is followed in young adulthood by a developing capacity for intimacy, the ability to form emotionally close relationships. When Mihaly Csikszentmihalyi [chick-SENT-me-hi] and Jeremy Hunter (2003) used a beeper to sample the daily experiences of U.S. teens, they found them to be unhappiest when alone and happiest when with friends. Romantic relationships, which tend to be emotionally intense during the teenage years, are reported by some two in three North American 17-year-olds, but by fewer in collectivist countries such as China (Collins et al., 2009; Li et al., 2010). Those individuals who enjoy high-quality (intimate, supportive) relationships with family and friends also tend to enjoy similarly high-quality romantic relationships in adolescence, which set the stage for healthy adult relationships. Such relationships are, for most of us, a source of great pleasure. Parent and Peer Relationships 3.6-7 How do parents and peers influence adolescents? This next research finding will not surprise you: As adolescents in Western cultures seek to form their own identities, they begin to pull away from their parents. Adolescence is typically a time of diminishing parental influence and growing peer influence (Blakemore, 2018; Giletta et al., 2021). The preschooler who can’t be close enough to her mother, who loves to touch and cling to her, gradually becomes the 14-year-old who wouldn’t be caught dead holding hands with Mom. As children, we recognize adult faces more readily than other children’s faces; by adolescence, we display superior recognition for our peers’ faces (Picci & Scherf, 2016). Puberty alters attachments and primes perceptions.