Differences Between Cross Sectional and Longitudinal Studies Questions
Differences Between Cross Sectional and Longitudinal Studies Questions
The Chapter Analysis Projects (TCAP) are information processing exercises to foster learning skill development as well as mastery of the chapter contents. The Chapter 5 TCAP is structured to guide your learning within each Focus Area of the chapter. You will be given four questions for each of the six areas of the Chapter- a total of 24 questions. The page numbers of the text where the answers to the questions will be explained are provided to help guide your learning. To complete this assignment each student is responsible for preparing thorough and complete answers to the questions. Each answer should be written as a paragraph. A paragraph is at least five to six sentences, although more sentences may be needed to provide a complete and thorough answer to some of the questions. The paragraph should include definitions and explanations of terms/concepts found in the question. Using examples can be very helpful when explaining an idea or concept. The textbook provides examples of constructs which you should include in your answers to the questions. The text also describes research studies that pertain to the question you will be answering. These also should be included in your answers. Other sources can be used for information gathering, although your textbook should be your primary source. The paragraph must be written in your own words, and not copied from the textbook or any other source. Quoting should never be used. DO NOT QUOTE what the author says. The answers/explanations must be written in your words. Focus Area 1: Research Designs; Fetus and the Newborn Pages 145 – 148 1. What are the different types of research designs? What are the differences between cross sectional and longitudinal studies both in design and purpose? 2. What are the advantages and disadvantages of Longitudinal and Cross Sectional designs? 3. What is the Cohort Effect, and what design reduces the cohort effect and makes other improvements on both the longitudinal and cross sectional designs? 4. Describe and detail the steps in Prenatal Development, and explain the behaviors and events that can cause unsuccessful development and why. Focus Area 2: Infancy; and Piaget’ View of Cognitive Development 152 Pages 148 – 1. Describe how infants see and recognize faces, and the relationship between infants’ vision and motor abilities. 2. How do researchers measure hearing in infants and how do they detect whether infants know the difference between two sounds? 3. Describe the methods used to study infants’ ability to learn and remember information. 4. How does ‘Schema’ serve as the foundation for the learning process of children? Describe the learning process, according to Piaget. Focus Area 3: Piaget’s Sensorimotor Stage; and Preoperational Stage Pages 152 – 158 1. What is the Sensorimotor Stage and what is the age of onset? 2. Do infants and young children have a sense of self, and how has that been measured? 3. Identify the three principle characteristics of the Piaget’s Preoperational stage? 4. How do preoperational children behave relative to egocentrism, theory of mind, differentiating appearance from reality, and conservation? Focus Area 4: Piaget’s Stages of Concrete Operations &Formal Operations; and Erickson’s Description of Human Development, Infancy and Childhood Pages 159 – 164 1. What ages are the onset of Concrete vs Formal Operations, and what are the distinctions in behaviors and abilities between them? 2. How do Piaget’s views on child development differ from Vygotsky’s? 3. What is Erikson’s theory of Social and Cultural development and what is accomplished at each of the eight stages psychosocial development? 4. What are the categories of attachment, how have they been studied, and how does attachment during early-childhood correlate with a person’s relationships later on in life? Focus Area 5: Social Development in Childhood, Adolescence, Adulthood and Old Age, and the Psychology of Facing Death Pages 165 – 169 1. What occurs within teenagers during adolescence? 2. What are the types of identity formation that occur during adolescence? 3. What are the stages of adulthood, and how can we live our lives to avoid feelings of despair during older age? 4. How do people cope with thoughts of death? Focus Area 6: Gender, Cultural, Ethnic and Family Influences on Development Pages 171-179 1. What are some of the differences and explanations for gender roles? 2. How can culture influence behaviors, and explain the differences between acculturation and biculturalism? 3. Describe parenting styles and the associated behaviors and personality of children. 4. What impact do non-traditional families, divorce and parental conflict have on children. Development Arthur Tilley/Photodisc/Getty Images MODULE 5.1 Cognitive Development in Infancy and Childhood Research Designs for Studying Development Infancy Jean Piaget’s View of Cognitive Development Piaget’s Sensorimotor Stage Piaget’s Preoperational Stage Piaget’s Stages of Concrete Operations and Formal Operations How Grown Up Are We? MODULE 5.2 Social and Emotional Development MODULE 5.3 Diversity: Gender, Culture, and Family Erikson’s Description of Human Development Infancy and Childhood Social Development in Childhood and Adolescence Adulthood Old Age The Psychology of Facing Death Gender Influences Cultural and Ethnic Influences The Family In Closing: Many Ways of Life In Closing: Social and Emotional Issues through the Life Span In Closing: Understanding Children Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. module . Cognitive Development in Infancy and Childhood After studying this module, you should be able to: ● Contrast cross-sectional designs and longitudinal designs. ● Give examples of cohort effects. ● Explain how psychologists infer the cognitive abilities of infants. ● List and describe Piaget’s stages of cognitive development. ● Discuss two methods of inferring the concept of object permanence. ● Give examples to show that infants develop cognitive abilities gradually. Research Designs for Studying Development Studying psychological development poses a special problem. Should a researcher study younger and older people at the same time, or study one group of people repeatedly as they advance from one age to another? Each method has strengths and limitations. Myrleen Ferguson Cate/PhotoEdit © Robin Kalat ▲ Young children’s artwork is amazingly inventive and revealing. One toddler, ½ years old, proudly showed off a drawing that consisted only of dots. Adults were puzzled. It is a rabbit, the child explained, while making more dots: “Look: hop, hop, hop . . . ” (Winner, ). When my daughter, Robin, was years old, she drew a picture of a boy and a girl wearing Halloween costumes and drawing pictures (see Figure .). For the little girl’s drawing, Robin pasted on some wildlife photos that, she insisted, were the little girl’s drawings. The little boy’s drawing was just a scribble. When I asked why the little girl’s drawing was so much better than the little boy’s, Robin replied, “Don’t make fun of him, Daddy. He’s doing the best he can.” Often, as in this case, a drawing expresses the child’s worldview. As children grow older, ▲ Figure . A drawing of two children drawing pictures, courtesy of 6-year-old Robin Kalat. their art becomes more skillful, but often less expressive. As we grow older, we gain many new abilities and skills, but we lose something, too. Studying the abilities of young children is challenging. They misunderstand our questions and we misunderstand their answers. Our estimate of children has progressed enormously as developmental psychologists have developed clever new ways to test children. One theme you will encounter repeatedly in this module is that we reach different conclusions about children depending on how we measure some ability. As we grow older, we mature, but we revert to childlike behaviors when such behavior is acceptable. M O D U L E 5 . 1 COGNITIVE DEVELOPMENT IN INFANCY AND CHILDHOOD / Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Table . Cross-Sectional and Longitudinal Studies Description Advantages Disadvantages Example . Quick . No risk of confusing age effects with effects of changes in society . Risk of sampling error by getting different kinds of people at different ages . Risk of cohort effects Compare memory abilities of -, -, and -year-olds . No risk of sampling differences . Can study effects of one experience on later development . Can study consistency within individuals over time . Takes a long time . Some participants quit . Sometimes hard to separate effects of age from changes in society Study memory abilities of -year-olds, and of the same children again and years later Jan 2012 Jan 2012 Jan 2012 Cross-sectional Several groups of subjects of various ages studied at one time Jan 2012 Jan 2014 Longitudinal Jan 2016 One group of subjects studied repeatedly as the members grow older Cross-Sectional and Longitudinal Designs A cross-sectional study compares groups of individuals of different ages at the same time. For example, we could compare drawings by -year-olds, -year-olds, and -year-olds. Cross-sectional studies are acceptable for many purposes, but not always. For example, if you compared a random sample of -yearolds with a random sample of -year-olds, you would find that the -year-olds have less interest in sports. You would also find that, on average, -yearolds are shorter and have smaller heads. Why? One explanation is that, on average, women live longer than men. Women tend to be smaller, have smaller heads, and show less interest in sports. The sample of -year-olds you studied was not comparable to the -year-olds. A longitudinal study follows a single group of individuals as they develop. For example, we could study a group of children from, say, age to age . ■ Table . contrasts the two kinds of studies. A longitudinal study necessarily takes years to complete. Also, not everyone who participates the first time is willing and available later. Selective attrition is the tendency for certain kinds of people to drop out of a study for many reasons, including health, moving far away, or loss of interest. The kind of people who stay in the study may differ in many ways from those who quit. Psychologists can compensate for selective attrition by discarding the earlier data for people who left the study. Certain questions logically require a longitudinal study. For example, to study the effects of divorce on children, researchers compare how each child reacts at first with how that same child reacts later. To study whether happy children become happy adults, researchers follow a single group over time. A sequential (or cross-sequential) design combines cross-sectional and longitudinal designs. In a sequential design, a researcher starts with people of different ages and studies them again at later times. For example, one might study -year-olds and -year-olds and then examine the same children years later: First study years later Group A, age years Group A, now years old Group B, age years Group B, now years old ✓ concecpkt che . At Santa Enigma College, the average first-year student has a C-minus average, and the average senior has a B-plus average. An observer concludes that, as students progress through college, they improve their study habits. Based on the idea of selective attrition, propose another possible explanation. / CHAPTER DEVELOPMENT Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. remained thrifty and cautious (Rogler, ). In contrast, young people of today have had much more leisure time and more opportunity for recreation (Larson, ). Today’s youth tend to be more selfsatisfied than young people of the past (Twenge & Campbell, ). In the United States long ago, as in many countries today, it was customary for most people to spend their lives in or near the neighborhood where they were born. Today many people move great distances, perhaps repeatedly, in search of a better job. The results include less identification with their community, few lasting friendships, and less feeling of obligation to help their neighbors (Oishi, ). According to Jean Twenge (), cohort effects are similar to cultural differences. Much of today’s technology is so unfamiliar to many older people that they feel like immigrants to this culture. Answer . The first-year students with the lowest grades (who lower the grade average for first-year students) do not stay in school long enough to become seniors. Cohort Effects If you had been born in , your childhood and adolescence would have been very different from today: no Internet, computers, iPods, cell phones, air conditioners, automatic dishwashers, or appliances for washing and drying clothes. You would have listened to radio instead of watching television. Telephone calls to someone outside your hometown were an expensive luxury. Few women or minorities went to college, and they had limited job opportunities afterward. If you had lived then, how would you have been different? People of different generations differ in many ways, called cohort effects (see ▼ Figure .). A cohort is a group of people born at a particular time or a group of people who enter an organization at a particular time. (We could talk about the cohort of students entering a college in a given year, or the cohort of workers a corporation hires in a given year.) The era in which you grew up is a powerful influence on your psychological development. For example, Americans whose youth spanned the Great Depression and World War II learned to save money and to sacrifice for the needs of the country. Even after the war was over and prosperity reigned, most ✓ concecpkt che . Suppose you want to study the effect of age on choice of clothing. Would cohort effects have greater influence on a longitudinal study or a cross-sectional study? Answer Bettmann/Corbis Ron Chapple/Corbis . A cross-sectional study would show cohort effects. If older people dress differently from younger people, it may be that the older generation has always had different standards or tastes. ▲ Figure . People born at different times grow up with different experiences. In an earlier era, bathing suit inspectors prohibited “overly revealing” outfits that would seem modest today. M O D U L E 5 . 1 COGNITIVE DEVELOPMENT IN INFANCY AND CHILDHOOD / Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. drinking is particularly dangerous, and prolonged drinking is worse The Fetus and the Newborn Binge than brief drinking, but researchers cannot identify any level as “safe” (May et al., ). The reason for the nervous system damage is now understood: Developing neurons require persistent excitation to survive. Without it, they activate a selfdestruct program, which is a way of weeding out the less useful neurons. Alcohol interferes with the brain’s main excitatory neurotransmitter (glutamate) and facilitates the main inhibitory neurotransmitter (GABA). It therefore decreases neurons’ arousal and makes many of them self-destruct (Ikonomidou et al., ). Other drugs that interfere with excitatory transmission may be dangerous also, possibly including repeated exposure to anesthetic drugs (Gleich, Nemergut, & Flick, ). Still, it is remarkable that an occasional “high-risk” child—small at birth, exposed to alcohol or other drugs before birth, from a disadvantaged family, a victim of prejudice, and so forth—overcomes all obstacles to become healthy and successful. Resilience (the ability to overcome obstacles) is poorly understood, but it relates partly to genetic influences, education, and supportive relatives and friends (Bonanno & Mancini, ). ✓ concecpkt che . By what mechanism does alcohol harm the brain of a fetus? Answer . Alcohol impairs excitatory transmission in neurons. Neurons that do not get enough excitation during early development execute a self-destruct program. Let’s begin at the beginning. During prenatal development, everyone starts as a fertilized egg cell, or zygote, that develops through its first few stages until it becomes a fetus about weeks after conception. As soon as weeks after conception, the nervous system is mature enough to produce a few movements. The first movements are spontaneous—that is, not elicited by any stimulus. Contrary to what we might have guessed, the muscles and the nerves controlling these movements mature before the sense organs. Those spontaneous movements are essential, and without them the spinal cord does not develop properly. Later, but still before birth, the sense organs appear, the head and eyes begin to turn toward sounds, and the brain alternates between waking and sleeping (Joseph, ). The fetus does a good bit of yawning and hiccupping. Presumably these behaviors serve some function, although that function remains unclear (Provine, ). A serious risk arises if a fetus is exposed to alcohol. Any drugs that a mother takes reach the fetus’s vulnerable developing brain (Hubbs-Tait, Nation, Krebs, & Bellinger, ). If the mother drinks alcohol during pregnancy, the infant may develop fetal alcohol syndrome, a condition marked by malformations of the face, heart, and ears; and nervous system damage, including seizures, hyperactivity, and impairments of learning, memory, problem solving, attention, and motor coordination (Mattson, Crocker, & Nguyen, ). The severity varies from severe to barely noticeable, depending on the amount and timing of the mother’s drinking (see ▼ Figure .). Infancy Research progress depends on good measurement. How can we measure psychological processes in infants who cannot talk and can barely control a few muscles? A researcher monitors the few actions available to infants, drawing inferences about their growing understanding of the world. 3 Anomalies of head and face 2 Anomalies of heart and other organs 1 0 1 2 3 David H. Wells/CORBIS Mean number of anomalies per child 4 more than 3 Ounces of alcohol drunk per day a b ▲ Figure . (a) The more alcohol a woman drinks during pregnancy, the more likely her baby is to have anomalies of the head, face, and organs. (Based on data of Ernhart et al., 1987) (b) A child with fetal alcohol syndrome: Note the wide separation between the eyes, a common feature of this syndrome. / CHAPTER DEVELOPMENT Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Percent of fixation time 36 32 28 24 20 16 12 8 4 0 Face Circles Newsprint White Yellow Red ▲ Figure . Infants pay more attention to faces than to other patterns. These results suggest that infants are born with certain visual preferences. (Based on Fantz, 1963) Infants’ Vision William James, the founder of American psychology, said that as far as an infant can tell, the world is a “buzzing confusion,” full of meaningless sights and sounds. Since James’s time, psychologists have substantially increased their estimates of infants’ vision. We can start by recording an infant’s eye movements. Even -day-old infants spend more time looking at drawings of human faces than at other patterns with similar areas of light and dark (Fantz, ; see ▲ Figure .). However, infants do not have the same concept of “face” that adults do. As shown in ▼ Figure ., newborns gaze equally at distorted and normal faces. However, they gaze longer at right-side-up faces than upside-down faces regardless of distortion. Evidently, the newborn’s concept of face is just an oval with most of its content toward the top (Cassia, Turati, & Simion, ). Total fixation time (s) Normal Distorted Normal upright The ability to recognize faces continues developing for years. Parents in one study repeatedly read a storybook with photographs of two children’s faces from many angles and with many expressions. After weeks, -year-old children easily recognized pictures of the two children. However, when they had to choose between a normal picture and one with altered spacing among the features, they guessed randomly (Mondloch, Leis, & Maurer, ). By age , a child easily sees the difference between the photos in ▼ Figure ., but -year-olds evidently do not. The gradual improvement of face recognition depends on experience, and infants, like all Normal upside-down Distorted upright 160 160 160 120 120 120 80 80 80 40 40 40 0 0 0 Distorted upside-down ▲ Figure . Infants gaze about equally at normal and distorted faces, but they stare longer at upright than upside-down faces. (Source: Cassia, Turati, & Simion, 2004) M O D U L E 5 . 1 COGNITIVE DEVELOPMENT IN INFANCY AND CHILDHOOD / Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. ; see also ▼ Figure .). Evidently, for any kind of locomotion, young children gradually learn what they can and cannot do. Sura Nualpradid/Shutterstock.com Infants’ Hearing ▲ Figure . These faces differ only in the positions of the eyes, nose, and mouth. Four-year-olds do not recognize which face is familiar. (Source: Mondloch, Leis, & Maurer, 2006) of us, become best at recognizing the kinds of faces they frequently see. At age months, infants are about as good at recognizing monkey faces as human faces. (The test is to show one monkey or human face for seconds, and then that face and another one. If the infant looks more at the new face, we infer that it recognized the old face.) Over the next months, infants’ ability to recognize monkey faces declines, unless they have had special training to pay attention to monkey faces (Scott & Monesson, ). By age months, infants have had much visual experience but almost no experience at crawling or reaching. Over the next several months, as they increase their control of arm and leg movements, they learn to pick up toys, crawl around objects, and in other ways coordinate what they see with what they do. At first, they crawl indiscriminately, and parents need to supervise constantly to prevent the infants from crawling off a bed or tumbling down the stairs. After a couple weeks of practice, they learn to avoid crawling off unsafe edges (Adolph, ). They learn that avoidance regardless of whether or not they have had any experience of falling; the act of crawling gives them a sense of distance and depth (Anderson et al., ). They more quickly learn to avoid crawling off ledges if they had the experience of moving around in a powered “baby go-cart” before they were old enough to crawl (Dahl et al., ). Have they learned fear of heights? Well, yes and no. It depends on how we test them. Infants who have learned not to crawl over an unsafe ledge show increased heart rate when held over what would be an unsafe drop (Dahl et al., ). However, when the same infants start to walk a few months later, they again step indiscriminately, and parents need to supervise them until they learn what is and is not a safe step-off distance (Kretsch & Adolph, Infants don’t do much, but one thing they do is suck. Researchers use that response to measure hearing, because infants suck more vigorously when certain kinds of sounds arouse them. In one study, the experimenters played a brief sound and noted how it affected infants’ sucking rate (see ▼ Figure .). On the first few occasions, the sound increased the sucking rate. A repeated sound produced less and less effect. We say that the infant became habituated to the sound. Habituation is decreased response to a repeated stimulus. When the experimenters substituted a new sound, the sucking rate increased. Evidently, the infant was aroused by the unfamiliar sound. When a change in a stimulus increases a previously habituated response, we say that the stimulus produced dishabituation. Monitoring dishabituation tells us whether infants detect a difference between two sounds. For example, infants who have become habituated to the sound ba will increase their sucking rate when they hear the sound pa (Eimas, Siqueland, Jusczyk, & Vigorito, ). Apparently, even month-old infants notice the difference between ba and pa, an important distinction for later language comprehension. Infants, in fact, appear to distinguish among all sounds that occur in any language. Within a few months, however, they begin to distinguish more ▲ Figure . Infants who are starting to crawl learn not to go over deep edges. A few months later when they are starting to walk, they have to learn again what is safe and what is unsafe. / CHAPTER DEVELOPMENT Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. In a follow-up study, pregnant women read a nursery rhyme three times in a row, twice a day. By age weeks postconception (shortly before birth), fetuses showed a heart rate response to the familiar rhyme, and not to a different rhyme (Krueger & Garvan, ). In another study, researchers played a simple piano melody for fetuses to hear twice daily for the last three weeks before birth. Six weeks later, those infants (and not other infants) showed a larger heart rate response to the familiar melody than to a different melody (Granier-Deferre, Bassereau, Ribeiro, Jacquet, & deCasper, ). This study shows memory of prenatal experiences lasting at least six weeks. Normal sucking rate Sucks produce the sound ba Sucks still produce the sound ba 5 minutes later (habituation) Sucks now produce the sound pa 10 20 30 40 50 ✓ concecpkt che Sucks per minute . Suppose a newborn sucks to turn on a tape recording of its father’s voice. Eventually, the baby habituates and the sucking frequency decreases. Now the experimenters substitute the recording of a different man’s voice. What would you conclude if the sucking frequency increased? What if it remained the same? What if it decreased? ▲ Figure . After repeatedly hearing a ba sound, the infant’s sucking habituates. When a new sound, pa, follows, the sucking rate increases. (Based on results of Eimas, Siqueland, Jusczyk, & Vigorito, 1971) accurately among the sounds that are important in the language they are about to learn. For example, the Japanese language does not distinguish between the sounds l and r. At first, Japanese infants respond differentially to the two sounds, but within a few months they stop. Similarly, in German the difference between u and ü alters the meaning of a word, but in English it doesn’t. In some of the languages of India, the difference between k and a harder version of k makes a difference, but in English, it doesn’t. In English, the accent on one syllable or the other changes the meaning (consider decade vs. decayed and weakened vs. weekend), but in French, accent doesn’t matter. At first, infants distinguish among all these sound differences, but within a few months, they get better at distinguishing among sounds important in their language, and worse at distinguishing sound differences meaningless in their language (Byers-Heinlein & Fennell, ; Kuhl, Williams, Lacerda, Stevens, & Lindblom, ; Tsuji & Cristia, ). All this takes place long before they understand what any of those words mean. Carolyn Rovee-Collier (, ) demonstrated that infants can learn a response and remember it. She attached a ribbon to an ankle so that an infant could activate a mobile by kicking with one leg (see ▼ Figure .). Two-month-old infants quickly . Suppose an infant habituates to the sound ba, but when we substitute the sound bla, the infant fails to increase the sucking rate. What interpretation would be likely? . Evidently, the infant does not hear a difference between ba and bla. (This is a hypothetical result; the study has not been done.) Answer . If the frequency increased, we would conclude that the infant recognizes the difference between the father’s voice and the other voice. If the frequency remained the same, we would conclude that the infant did not notice a difference. If the sucking frequency decreased, we would conclude that the infant recognizes a difference, and we would assume that the infant preferred the sound of the father’s voice. ✓ concecpkt che Answer How could we measure learning and memory in infants who cannot speak? Many studies have used the fact that infants learn to suck harder on a nipple if their sucking turns on a sound. Investigators then determined whether infants suck harder for some sounds than for others. In one study, babies younger than days old could turn on a tape recording of a woman’s voice by sucking on a nipple. The results: They sucked more frequently to turn on recordings of their own mother’s voice than another woman’s voice (DeCasper & Fifer, ). Apparently, they preferred their own mother’s voice. Because they showed this preference as early as the day of birth, psychologists believe that the infants learned the sound of the mother’s voice before birth. Carolyn Rovee-Collier Infants’ Learning and Memory ▲ Figure . Two-month-old infants rapidly learn to kick to activate a mobile attached to their ankles with a ribbon. They remember how to activate the mobile when tested days later. (From Hildreth, Sweeney, & Rovee-Collier, 2003) M O D U L E 5 . 1 COGNITIVE DEVELOPMENT IN INFANCY AND CHILDHOOD / Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. learned this response and generally kept the mobile going nonstop for a full -minute session. (Infants have little control over their leg muscles, but they don’t need much control to keep the mobile going.) They remembered what to do when the ribbon was reattached several days later, to the infants’ evident delight. Six-month-old infants remembered the response for weeks. Even after they forgot it, they quickly relearned it (Hildreth, Sweeney, & RoveeCollier, ). Jean Piaget’s View of Cognitive Development Somewhat older children are much easier to test, and one quickly discovers that their thinking differs from that of adults. The theorist who made this point most influentially was Jean Piaget (pee-ah-ZHAY; –). Early in his career, while administering IQ tests to French-speaking children in Switzerland, Piaget was fascinated that so many children of a given age gave the same incorrect answer to certain questions. He concluded that children have qualitatively different thought processes from adults. According to Piaget, as children develop intellectually, they do more than accumulate facts. They construct new mental processes. In Piaget’s terminology, behavior is based on schemata (the plural of schema). A schema is an organized way of interacting with objects. For instance, infants have a grasping schema and a sucking schema. Older infants gradually add new schemata and adapt their old ones through the processes of assimilation and accommodation. Assimilation means applying an old schema to new objects or problems. For example, when a child sees animals move and then sees the sun and moon move, the child may assume that the sun and moon are alive, like animals. Accommodation means modifying an old schema to fit a new object or problem. A child may learn that “only living things move on their own” is a rule with exceptions and that the sun and moon are not alive. Infants shift back and forth between assimilation and accommodation. Equilibration is the establishment of harmony or balance between the two. A discrepancy occurs between the child’s current understanding and some evidence to the contrary. The child accommodates to that discrepancy and achieves an equilibration at a higher level. Similar processes occur in adults. When you see a new mathematical problem, you try several familiar methods until you find one that works. That is, you assimilate the new problem to an old schema. However, if the new problem is sufficiently different, you modify (accommodate) your schema to find a solution. In this way, said Piaget, intellectual growth occurs. Piaget contended that children progress through four major stages of intellectual development: . The sensorimotor stage (from birth to almost years) . The preoperational stage (from just before to years) . The concrete operations stage (from about to years) . The formal operations stage (from about years onward) The ages are variable, and not everyone reaches the formal operations stage. However, all people progress through the stages in the same order. Let’s consider each of Piaget’s stages. Piaget’s Sensorimotor Stage Piaget called the first stage of intellectual development the sensorimotor stage because at this early age (the first ½ to years) behavior is mostly simple motor responses to sensory stimuli—for example, the grasp reflex and the sucking reflex. According to Piaget, infants respond only to what they see and hear at the moment. In particular, he believed that children during this period fail to respond to objects they remember seeing even a few seconds ago. What evidence could he have for this view? what’s the evidence? Bill Anderson/Science Source The Infant’s Concept of Object Permanence Jean Piaget (on the left) demonstrated that children with different levels of maturity react differently to the same experience. Piaget argued that infants in the first few months of life lack the concept of object permanence, the idea that objects continue to exist even when we do not see or hear them. That is, for an infant, “Out of sight, out of existence.” How would he know that? Piaget drew his inferences from observations like this: Place a toy in front of a -month-old infant, who reaches out for it. Later, place a toy in the same place, but before the infant has a chance to grab it, cover it with a clear glass. The infant removes the glass and takes the toy. Now repeat that procedure but use an opaque (nonclear) glass. The infant, who watched you place the glass over the toy, makes no effort to remove the glass and obtain the toy. Next, place a thin barrier / CHAPTER DEVELOPMENT Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Hypothesis An infant who sees an event that would be impossible (if objects are permanent) will be surprised and therefore will stare longer than will an infant who sees a similar but possible event. Method Infants aged or months watched a series of events. The infant watched the Doug Goodman/Science Source ▲ between the infant and the toy. An infant who cannot see the toy does not reach for it (Piaget, /) (see Figure .). According to Piaget, the infant does not know that the hidden toy continues to exist. However, the results vary depending on circumstances. For example, if you show a toy and then turn out the lights, a -month-old infant reaches out toward the unseen toy if it was a familiar toy but not if it was unfamiliar (Shinskey & Munakata, ). A study by Renee Baillargeon () also suggests that infants show signs of understanding object permanence when they are tested differently. Doug Goodman/Science Source experimenter raise a screen to show the track and then watched a toy car go down a slope and emerge on the other side of the screen, as shown here. This was called a “possible” event. ▲ Figure . (a) A 6- to 9-month-old child reaches for a visible toy but not one that is hidden behind a barrier (b) even if the child sees someone hide the toy. According to Piaget, this observation indicates that the child hasn’t yet grasped the concept of object permanence. Possible event. The box is behind the track, and the car passes by the box. The researchers measured how long the child stared after the car passed by. They repeated the procedure until the child’s staring time decreased for three trials in a row (showing habituation). Then the experimenters presented a series of “possible” events, as just described, and “impossible” events like this: In an impossible event, the raised screen showed a box on the track where the car would pass. After the screen lowered, the car went down the slope and emerged on the other side. (The experimenters pulled the box off the track after lowering the screen.) The experimenters measured each child’s staring times after both kinds of events. They repeated both events two more times, randomizing the order of events. Results As shown in ▼ Figure ., infants stared longer after seeing an impossible event. They also stared longer after the first pair of events than after the second and third pairs (Baillargeon, ). Interpretation Why did the infants stare longer at the Impossible event. The raised screen shows a box on the track where the car would pass. After the screen lowers, the car goes down the slope and emerges on the other side. impossible event? The inference—admittedly only an inference—is that the infants found the impossible event surprising. To be surprised, infants had to expect that the box would continue to exist. If so, even -month-old infants have some understanding of object permanence, as well as elementary physics. A later study with a slightly different method demonstrated object permanence in infants as young as ½ months (Baillargeon, ). Still, remember that -month-olds failed Piaget’s object permanence task of reaching out to pick up a M O D U L E 5 . 1 COGNITIVE DEVELOPMENT IN INFANCY AND CHILDHOOD / Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Second, concepts develop gradually. An infant may show a concept in one situation and not another. 70 Sense of Self Impossible event 50 40 30 Possible event 20 10 0 0 1 2 3 Test pair ▲ Figure . Infants stared longer after watching impossible events than after watching possible events. (From Baillargeon, 1986) hidden object. Do infants understand object permanence or not? Evidently, it is not a good question. Infants use a concept in some situations and not others. The same is true for all of us. Did you ever learn a grammatical rule in English class and then violate it in your own speech? Did you ever learn a math formula and then fail to apply it to a new situation? Other psychologists modified this procedure to test many other infant concepts. Researchers put five objects behind a screen, added five more, and removed the screen. Nine-month-olds stared longer when they saw just five objects than when they saw ten, suggesting some understanding of addition (McCrink & Wynn, ). Researchers buried a ball in the sand and then retrieved apparently the same ball from the same or a different location. Infants stared longer when the ball emerged from the new location (Newcombe, Sluzenski, & Huttenlocher, ). When infants watched an animated display in which a larger figure and a smaller figure crossed paths, -month-olds stared longer if the larger one bowed and stepped aside to let the smaller one pass (Thomsen, Frankenhuis, Ingold-Smith, & Carey, ). If we assume that staring means surprise, then infants apparently understand something about social dominance. Related studies suggest that -month-olds understand that liquids can pass through a barrier, but solids cannot (Hespos, Ferry, & Rips, ). However, infants as old as months show no surprise if you place a toy into a container and then pull out a toy of different shape or color (Baillargeon, Li, Ng, & Yuan, ). Evidently, infants imagine that objects can magically change shape or color. Here are two conclusions: First, we should be cautious about inferring what infants or anyone else can or cannot do, because the results vary with the procedures. Do young children have a concept of “self”? How would we know? Here is the evidence: Someone puts a spot of unscented rouge on an infant’s nose and then puts the infant in front of a mirror. Infants younger than ½ years old either ignore the red spot on the baby in the mirror or reach out to touch the mirror. At some point after age ½ years, infants instead touch themselves on the nose, indicating that they recognize themselves in the mirror (see ▼ Figure .). Infants show this sign of selfrecognition at varying ages; the age when they first show self-recognition is about the same as when they begin to act embarrassed (M. Lewis, Sullivan, Stanger, & Weiss, ). They show a sense of self in both situations or in neither. Before this time, do infants fail to distinguish between self and other? Perhaps, but we cannot be sure. Before age ½, we see no evidence for a sense of self, but absence of evidence is not evidence of absence. Perhaps younger infants would show a sense of self in some other test that we have not yet devised. Thierry Berrod, Mona Lisa Production/Science Source Looking time (sec) 60 ▲ Figure . If someone places a bit of unscented rouge on a child’s nose, a 2-year-old looking at a mirror shows self-recognition by touching his or her own nose. / CHAPTER DEVELOPMENT Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Piaget’s Preoperational Stage By age ½ to , children begin speaking. A child who asks for a toy obviously understands object permanence. Nevertheless, young children still misunderstand much. They do not understand how a mother can be someone else’s daughter. A boy with one brother will assert that his brother has no brother. Piaget refers to this period as the preoperational stage because the child lacks operations, which are reversible mental processes. For a boy to understand that his brother has a brother, he must be able to reverse the concept of “having a brother.” According to Piaget, three typical aspects of preoperational thought are egocentrism, difficulty distinguishing appearance from reality, and lack of the concept of conservation. Egocentrism: Failing to Understand Other People’s Perspective ▲ According to Piaget, young children’s thought is egocentric. Piaget did not mean selfish. Instead, he meant that a child sees the world as centered around himself or herself and cannot easily take another person’s perspective. If you sit opposite a preschooler, the child can describe how the blocks on the table look from the child’s side but not how they would look from your side. Another example: Young children hear a story about Lucy, who wants her old pair of red shoes. Lucy’s brother Linus enters the room, and she asks him to bring her red shoes. He goes and brings back her new red shoes, and she is angry because she wanted the old red shoes. Young children hearing the story are surprised that he brought the wrong shoes because they knew which shoes she wanted (Keysar, Barr, & Horton, ). However, young children do sometimes understand another person’s perspective. In one study, - and -year-old children had to tell an adult to pick up a particular glass. If a child saw that the adult could see two glasses, the child usually said to pick up the “big” or “little” glass to identify the right one. If the child saw that the adult could see only one glass, the child often said just “the glass” (Nadig & Sedivy, ; Figure .). ✓ concept check . Which of the following is the clearest example of egocentric thinking? a. A writer who uses someone else’s words without giving credit b. A politician who blames others for everything that goes wrong c. A professor who gives the same complicated lecture to a freshman class as to a convention of professionals . c is a case of egocentric thought, a failure to recognize another person’s point of view. Answers Theory of Mind: Understanding that Different People Know Different Things To say that a child is egocentric implies that he or she does not understand what other people know or don’t know. Psychologists say that a young child lacks, but gradually develops theory of mind, which is an understanding that other people have a mind, too, and that each person knows some things that other people don’t know. How can we know whether a child has this understanding? Here is an example of a research effort. ▲ Figure . Sometimes, a child saw that the adult could see two glasses. At other times, it was clear that the adult could see only one. If two glasses were visible, the child usually told the adult which glass to pick up, instead of saying, “pick up the glass.” (From Nadig & Sedivy, 2002) what’s the evidence? Children’s Understanding of Other People’s Knowledge and Beliefs How and when do children first understand that other people have minds and knowledge? Researchers have devised clever experiments to explore this question. Hypothesis A child who understands that other people have minds knows that someone could have a false belief. Method A child watches and listens as an adult acts out this story: Maxi sees his mother put chocolate into the blue cupboard. He plans to return later and get some. However, while he is absent, his mother moves the chocolate to the green cupboard. The questions are: Where will Maxi look for the chocolate? If his grandfather is available to help, where will Maxi tell him to look? If an older brother wants to take the chocolate, and Maxi wants to prevent the brother from finding the chocolate, where will he point? (See ▼ Figure ..) Results Older children answer correctly: Maxi looks in the blue cupboard and tells his grandfather to get chocolate from the blue cupboard, but tells his brother to look in the green cupboard. Younger children answer incorrectly, as if they thought Maxi had all the correct M O D U L E 5 . 1 COGNITIVE DEVELOPMENT IN INFANCY AND CHILDHOOD / Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Answer . It means that the child has “theory of mind.” The child understands that Maxi, who was absent while the mother moved the chocolate, will have a false belief. We might be tempted to the simple interpretation that young children lack theory of mind, but at some point they suddenly gain it. However, development is seldom a sudden, all-or-nothing process. In the “Maxi” situation, it is likely that many -year-olds don’t fully understand the questions. In a later study, -year-olds watched as a Lego figure representing a girl put bananas (which she liked to eat) in one of two refrigerators. Then the girl moved forward, with her back to the refrigerators, while the experimenter moved the bananas from one refrigerator to the other. When the experimenter invited the child to play with the girl figure and asked, “What is she going to do now?” in most cases the child moved the figure to the refrigerator that previously had the bananas, indicating theory of mind. However, if the experimenter asked where the girl would look for the bananas, the child answered with the wrong refrigerator (Rubio-Fernández & Geurts, ). That is, a nonverbal response showed that the child understood what the girl would know, but answering in words caused confusion. In an even more simplified task, even -month-olds showed an understanding of theory of mind (Senju, Southgate, Snape, Leonard, & Casibra, ). In short, gaining theory of mind—or any other concept—is not a sudden transition. A child can show indications of understanding in some ways or situations and not in others. Distinguishing Appearance from Reality ▲ Figure . Maxi watches his mother place chocolate in one place. While he is absent, she moves it. Where will Maxi look for it? Younger children point to the new location, suggesting they do not understand that Maxi will have an incorrect belief. information that the observers themselves had. The percentage of children answering correctly increases from age to age , and most children beyond about ½ answer correctly (Wellman, Cross, & Watson, ; Wimmer & Penner, ). Interpretation Evidently, children gradually develop in their ability to understand other people’s thoughts, beliefs, and knowledge. ✓ concecpkt che . If the chocolate is now in the green cupboard, what does it mean if a child says Maxi will look in the blue cupboard? During Piaget’s preoperational stage, children apparently do not distinguish clearly between appearance and reality. For example, a child who sees you put a white ball behind a blue filter will say that the ball is blue. When you ask, “Yes, I know the ball looks blue, but what color is it really?” the child replies that it really is blue (Flavell, ). Similarly, a -year-old who encounters a sponge that looks like a rock will say that it really is a rock, but a child who says it is a sponge will also insist that it looks like a sponge. However, the results depend on exactly how we ask the question. Psychologists showed -year-olds a sponge that looked like a rock and let them touch it. When the investigators asked what it looked like and what it was really, most of the children said “rock” both times or “sponge” both times. However, if the investigators asked, “Bring me something so I can wipe up some spilled water,” the children brought the sponge. And when the investigators asked, “Bring me something so I can take a picture of a teddy bear with something that looks like a rock,” they brought the same object. So evidently, the children did understand that something could be a sponge and / CHAPTER DEVELOPMENT Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. a A 21/2-year-old is shown a small room where a stuffed animal is hidden. Child is unable to find the stuffed animal in the larger room. Child is told that the machine expands the room. Child stands out of the way during some noises and then returns. b Child is shown a small room where a stuffed animal is hidden. Child is able to find the stuffed animal in the “blown-up” room. ▲ Figure . If an experimenter hides a small toy in a small room and asks a child to find a larger toy “in the same place” in the larger room, most 2½-year-olds search haphazardly. (a) However, the same children know where to look if the experimenter says this is the same room as before, but a machine has expanded it (b). look like a rock, even if they didn’t say so (Sapp, Lee, & Muir, ). Repeatedly, we are seeing this pattern: A child can show a concept in one way and not another. Also consider this experiment: A psychologist shows a child a playhouse room that is a scale model of a full-size room. The psychologist hides a tiny toy in the small room and explains that a bigger toy just like it is “in the same place” in the bigger room. (For example, if the little toy is behind the sofa in the little room, the big toy is behind the sofa in the big room.) Then the psychologist asks the child to find the big toy in the big room. Most -year-olds go to the correct place at once (DeLoache, ). Most ½-year-old children, however, search haphazardly (see ▲ Figure .a). Again, the results depend on how we ask the question. As before, a psychologist hides a toy in the small room while the child watches. Then the psychologist shows the child a “machine that can make things bigger.” The psychologist aims a beam from the machine at the room and takes the child out of the way. They hear some chunkata-chunkata sounds, and then the psychologist shows the full-size “blown-up” room and asks the child to find the hidden toy. Even ½-year-olds go immediately to the correct location (DeLoache, Miller, & Rosengren, ; see ▲ Figure .b). (Incidentally, the children had no doubt that the machine had expanded the room. Many continued to believe it even after the psychologist explained what happened!) Developing the Concept of Conservation According to Piaget, preoperational children lack the concept of conservation. They fail to understand that objects conserve such properties as number, length, volume, area, and mass after changes in the shape or arrangement of the objects. They cannot perform the mental operations necessary to understand the trans- formations. ■ Table . shows typical conservation tasks. For example, if we show two equal glasses with the same amount of water and then pour the contents of one glass into a third glass that is taller and thinner, preoperational children say that the third glass contains more water (see ▼ Figure .). I once thought perhaps the phrasing of the questions tricks children into saying something they do not believe. If you have the same doubts, find a -year-old child and try it yourself with your own wording. Here’s my experience: Once when I was discussing Piaget in my introductory psychology class, I invited my son Sam, then ½ years old, to take part in a class demonstration. I started with two glasses of water, which he agreed contained equal amounts of water. Then I poured the water from one glass into a wider glass, lowering the water level. When I asked which glass contained more water, Sam confidently pointed to the tall, thin one. After class he complained, “Daddy, why did you ask me such an easy question? Everyone could see that there was more water in that glass! You should have asked me something harder to show how smart I am!” The following year, I brought Sam, now ½ years old, to class for the same demonstration. I poured the water from one of the tall glasses into M O D U L E 5 . 1 COGNITIVE DEVELOPMENT IN INFANCY AND CHILDHOOD / Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Table . Typical Tasks Used to Measure Conservation Conservation of number Preoperational children say that these two rows contain the same number of pennies. Preoperational children say that the second row has more pennies. Conservation of volume Preoperational children say that the two same-size containers have the same amount of water. 250 cc 250 cc Preoperational children say that the taller, thinner container has more water. 250 cc 250 cc Conservation of mass Preoperational children say that the two same-size balls of clay have the same amount of clay. Preoperational children say that a squashed ball of clay contains a different amount of clay than the same-size round ball of clay. ▲ Figure . Preoperational children don’t understand that the volume of water remains constant despite changes in its appearance. During the transition to concrete operations, a child finds conservation tasks difficult and confusing. / CHAPTER DEVELOPMENT Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Tony Freeman/PhotoEdit of your classes again!” The question that used to be embarrassingly easy had become embarrassingly difficult. The next year, when he was ½, I tried again (at home). This time he answered confidently, “Both glasses have the same amount of water, of course. Why? Is this some sort of trick question?” Tony Freeman/PhotoEdit a wider one and asked him which glass contained more water. He looked and paused. His face turned red. Finally, he whispered, “Daddy, I don’t know!” After class he complained, “Why did you ask me such a hard question? I’m never coming back to any At about age , children enter the stage of concrete operations and begin to understand the conservation of physical properties. The transition is gradual, however. A -year-old may understand that squashing a ball of clay does not change its weight but still think that squashing it changes how much water it displaces when dropped into a glass. According to Piaget, during the stage of concrete operations, children perform mental operations on concrete objects but still have trouble with abstract or hypothetical ideas. For example, ask this question: “How could you move a mountain of whipped cream from one side of the city to the other?” Older children enjoy devising imaginative answers, but children in the concrete operations stage complain that the question is silly. Or ask, “If you could have a third eye anywhere on your body, where would you put it?” Children in this stage generally respond immediately that they would put it right between the other two, on their foreheads. Older children suggest more imaginative ideas such as on the back of their head, in the stomach (so they could watch food digesting), or on the tip of a finger (so they could peek around corners). Finally, in Piaget’s stage of formal operations, adolescents develop logical, deductive reasoning and systematic planning. According to Piaget, children reach the stage of formal operations at about age . Later researchers found that many people reach this stage later or not at all. Thinking with formal operations demonstrates planning. For example, we set up five bottles of clear liquid and explain that it is possible to mix some combination to produce a yellow liquid. The task is to find that combination. Children in the concrete operations stage plunge right in with no plan. They try combining bottles A and B, then C and D, then perhaps A, C, and E. Soon they have forgotten which combinations they’ve already tried. Adolescents in the formal operations stage approach the problem more systematically. They may first try all the two-bottle combinations: AB, AC, AD, AE, BC, and so forth. If those fail, they try three-bottle combinations: ABC, ABD, ABE, ACD, and so on. By trying every possible combination only once, they are sure to succeed. ■ Table . summarizes Piaget’s four stages. ✓ concecpkt che . In which of Piaget’s stages is each of these children? a. Child understands conservation but has trouble with abstract and hypothetical questions. b. Child performs well on tests of object permanence but has trouble with conservation. c. Child has schemata but does not speak in complete sentences and fails tests of object permanence. d. Child performs well on hypothetical questions and other tasks. Answer . a. concrete operations stage; b. preoperational stage; c. sensorimotor stage; d. formal operations stage. Piaget’s Stages of Concrete Operations and Formal Operations Are Piaget’s Stages Distinct? Piaget regarded the four stages of intellectual development as distinct. He believed a transition from one stage to the next required a major reorganization of thinking, like a caterpillar metamorphosing into a chrysalis or a chrysalis metamorphosing into a butterfly. That is, intellectual growth has periods of revolutionary reorganization. Later research casts doubt on this conclusion. If it were true, then a child in a given stage of development—say, the preoperational stage— should perform consistently at that level. In fact, children’s performance fluctuates as a task is made more or less difficult. For example, consider the conservation-of-number task, in which an investigator presents two rows of seven or more objects, spreads out one row, and asks which row has more. Table . Summary of Piaget’s Stages of Cognitive Development Stage and Approximate Age Achievements and Activities Limitations Sensorimotor (birth to ½ years) Reacts to sensory stimuli through reflexes and other responses Little use of language; seems not to understand object permanence in the early part of this stage Preoperational (½ to years) Develops language; can represent objects mentally by words and other symbols; can respond to objects that are remembered but not present Lacks operations (reversible mental processes); lacks concept of conservation; focuses on one property at a time (such as length or width), not on both at once; still has trouble distinguishing appearance from reality Concrete operations ( to years) Understands conservation of mass, number, and volume; can reason logically with regard to concrete objects that can be seen or touched Has trouble reasoning about abstract concepts and hypothetical situations Formal operations ( years onward) Can reason logically about abstract and hypothetical concepts; develops strategies; plans actions in advance None beyond the occasional irrationalities of all human thought M O D U L E 5 . 1 COGNITIVE DEVELOPMENT IN INFANCY AND CHILDHOOD / Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. of conservation, mainly on their own. Teaching a concept means directing children’s attention to the key aspects and letting them discover the concept. In contrast, Russian psychologist Lev Vygotsky () argued that educators should not wait for children to rediscover the principles of physics and mathematics. Indeed, the value of language is that it lets us profit from the experience of previous generations. Vygotsky certainly did not mean that adults should ignore a child’s developmental level. Rather, every child has a zone of proximal development, the distance between what a child can do alone and what is possible with help. Instruction should remain within that zone. For example, one should not try to teach a typical -year-old the concept of conservation of volume. However, a -year-old who does not yet understand the concept might learn it with help and guidance. Similarly, children improve their recall of lists or stories if adults help them understand and organize the information (Larkina, Güler, Kleinknecht, & Bauer, ). Vygotsky compared this help to scaffolding, the temporary supports that builders use during construction: After a building is complete, the scaffolding is removed. Good advice for educators is to be sensitive to a child’s zone of proximal development and pursue how much further they can push a child. a b ▲ Figure . (a) With the standard conservation-ofnumber task, preoperational children answer that the spread-out row has more items. (b) With a simplified task, the same children say that both rows have the same number of items. Preoperational children reply that the spread-out row has more. However, when Rochel Gelman () presented two rows of only three objects each (see ▲ Figure .) and then spread out one of the rows, even - and -year-old children usually answered that the rows had the same number of items. Whereas Piaget believed children made distinct jumps from one stage to another, most psychologists today see development as gradual and continuous (Courage & Howe, ). That is, the difference between older children and younger children is not so much a matter of gaining a new ability. It is a matter of using their abilities in more and more situations. ✓ concecpkt che Differing Views: Piaget and Vygotsky . What would Piaget and Vygotsky think about the feasibility of teaching the concept of conservation? Answer . Piaget recommended waiting for a child to discover the concept by himself or herself. For Vygotsky, the answer depends on the child’s zone of proximal development. An adult can help a child at the right age. One implication of Piaget’s view is that children must discover certain concepts, such as the concept ©Geo Martinez/Shutterstock.com How Grown Up Are We? The zone of proximal development is the gap between what a child does alone and what the child can do with help. Both Piaget and Vygotsky implied that we start with infant cognition and eventually attain adult thinking, which we practice from then on. Are they right, or do we sometimes slip into childish ways of thought? Consider egocentric thinking. Young children seem to assume that whatever they know or understand, other people will know or understand also. Sometimes, adults make the same mistake. Suppose you say, “The daughter of the man and the woman arrived.” Did one person arrive (who is the daughter of the man and the woman) or two people (the man’s daughter and some other woman)? You know what you meant, but you might overestimate how well other people understand you (Keysar & Henly, ). / CHAPTER DEVELOPMENT Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. we suppress our childlike ways of thinking, but we don’t lose them completely. You still have a child’s mind hidden inside you. ✓ concecpkt che Answer . How could you get someone to pour you a larger than average drink? . Ask to have the drink in a short, wide glass. Another example: According to Piaget, after about age , we all understand conservation of number, volume, and so forth. If we show two equally tall, thin containers of water and pour the water from one of them into a wider container, older children and adults confidently say that the two containers have equal amounts of water. However, let’s test in a different way: We give people a tall, thin glass or a short, wide glass and invite them to add as much juice as they want. Adults as well as children usually put more juice into the short, wide glass, while thinking that they are getting less juice than usual. Even professional bartenders generally pour more liquor into a short, wide glass than into a tall, thin one (Wansink & van Ittersum, ). Evidently, even adults don’t fully understand conservation of volume if they are tested in this way. In short, as we grow older, in closing module . Understanding Children Jean Piaget called attention to the ways in which children differ from adults. They are not just slower or less well informed; they process information differently. Everything that we do develops over age. But as you can see, it takes much work to pin down exactly what infants and small children understand, and what they misunderstand. Furthermore, the changes are gradual and incomplete. Even adults revert to childlike thinking at times. Development is not a matter of suddenly gaining cognitive skills. It is a matter of applying skills more consistently and under a wider variety of conditions. Summary ● ● ● ● ● ● Cross-sectional and longitudinal studies. Cross-sectional studies examine people of different ages at the same time. Longitudinal studies monitor people as they grow older. A sequential design combines both methods. (page ) Cohort effects. Many differences between young people and old people are not due to age but to the era in which they grew up. (page ) Prenatal development. The brain begins to mature long before birth. Exposure to drugs such as alcohol decreases brain activity and releases neurons’ self-destruct programs. Some people manage to do well in life despite unpromising circumstances. (page ) Inferring infant capacities. We easily underestimate newborns’ capacities because they have so little control over their muscles. Careful testing demonstrates greater abilities than we might have supposed. (page ) Infant vision and hearing. Newborns stare at some visual patterns longer than others. They habituate to a repeated sound but dishabituate to a slightly different sound, indicating that they hear a difference. (page ) Infant memory. Newborns suck more vigorously to turn on a recording of their own mother’s voice than some other woman’s voice, indicating that they recognize the sound of the mother’s voice. Infants just months old learn to kick and move a mobile, and they remember how to do it several days later. (page ) ● ● ● ● ● ● ● Piaget’s view of children’s thinking. According to Jean Piaget, children’s thought differs qualitatively from adults’ thought. He believed children grow intellectually through accommodation and assimilation. (page ) Piaget’s stages of development. Children in the sensorimotor stage respond to what they see, hear, or feel at the moment. In the preoperational stage, they lack reversible operations. In the concrete operations stage, children reason about concrete problems but not abstractions. Adults and older children are in the formal operations stage, in which they plan strategies and deal with hypothetical or abstract questions. (page ) Egocentric thinking. Young children often fail to understand other people’s point of view. (page ) Theory of mind. Children gradually develop their ability to assess other people’s knowledge and beliefs, including false beliefs. (page ) Appearance and reality. Young children sometimes seem not to distinguish between appearance and reality. However, with a simpler task, they do distinguish. Children may show a concept under some conditions and not others. (page ) Vygotsky. According to Lev Vygotsky, children must learn new abilities from adults or older children, but only within their zone of proximal development. (page ) Adults. Adults revert to childlike reasoning in certain situations. (page ) M O D U L E 5 . 1 COGNITIVE DEVELOPMENT IN INFANCY AND CHILDHOOD / Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Key Terms accommodation (page ) assimilation (page ) cohort (page ) conservation (page ) cross-sectional study (page ) dishabituation (page ) fetal alcohol syndrome (page ) fetus (page ) egocentric (page ) equilibration (page ) habituation (page ) longitudinal study (page ) object permanence (page ) operation (page ) preoperational stage (page ) schema (pl. schemata) (page ) selective attrition (page ) sensorimotor stage (page ) sequential design (page ) stage of concrete operations (page ) stage of formal operations (page ) theory of mind (page ) zone of proximal development (page ) zygote (page ) Review Questions 1. Which of these characterizes a cross-sectional study of development? (a) Researchers compare people from several cultures. (b) Researchers compare one group of people at several times as they grow older. (c) Researchers compare people of different ages, at the same time. (d) Researchers examine many aspects of behavior, for one group of people at one point in time. 2. Suppose a survey reports different political leanings by older adults than younger adults. A possible explanation is that people change their views as they age. Another is that older people have different priorities from younger people. What is still another possibility? (a) Demand characteristics (b) A cohort effect (c) Zone of proximal development (d) Equilibration 3. Theoretically, which of the following drugs should produce effects similar to those of fetal alcohol syndrome, if a mother takes them during pregnancy? (a) Cocaine (which increases activity at dopamine synapses) (b) Anti-anxiety drugs (which increase activity at inhibitory synapses) (c) Nicotine (which stimulates acetylcholine synapses) (d) Caffeine (which increases heart rate) 4. Suppose an infant habituates to the sound ba, but when we substitute the sound boo, the infant fails to increase the sucking rate. What interpretation would be likely? (a) The infant hears a difference between the two sounds. (b) The infant does not hear a difference between the two sounds. (c) The infant prefers the sound ba. (d) The infant prefers the sound boo. 5. Suppose a newborn sucks to turn on a tape recording of its father’s voice. Eventually the infant habituates and the sucking frequency decreases. Now the experimenters substitute the recording of a different man’s voice. Which of the following results would indicate that the infant detects a difference between the two voices? (a) The sucking rate increases. (b) The sucking rate decreases. (c) The sucking rate remains the same. 6. What evidence suggests that even 6- to 8-month-old infants understand object permanence? (a) They reach around an opaque barrier to grasp an unseen toy. (b) They ask for toys that they do not currently see. (c) They stare longer at events that would be impossible if unseen objects continue to exist. (d) After they have repeatedly seen one toy and habituated to it, they dishabituate when they see a new toy. 7. To demonstrate “theory of mind,” what must a child understand? (a) That someone else can have a false belief (b) That human mental abilities are more advanced than those of other species (c) That mental activity is inseparable from brain activity (d) That all mental activity requires sensory input 8. A child watches an experimenter hide a small toy in a small room, and then tries to find a larger version of the same toy hidden “in the same place” in a larger room. At what age can most children first succeed on this task? (a) 4 years old (b) 3 years old (c) It depends on how you ask the question. (d) It depends on the child’s interest in the toy. 9. One year ago, Sarah did not seem to understand conservation of number, volume, or mass. Today she does. According to Piaget, Sarah has progressed from which stage to which other stage? (a) Preoperational stage to concrete operations stage (b) Sensorimotor stage to preoperational stage (c) Concrete operations stage to formal operations stage (d) Formal operations stage to concrete operations stage 10. Which of the following would be evidence in favor of Vygotsky’s “zone of proximal development”? (a) Most 3-year-olds can observe a toy hidden in a small room and use it to locate a larger toy in a larger room, but 2½-year-olds cannot. (b) It is possible to teach conservation of volume to many 6-year-olds but not many 4-year-olds. (c) Children in the stage of concrete operations have trouble with abstract or hypothetical ideas. (d) Intellectual development varies from one culture to another. Answers: 1c, 2b, 3b, 4b, 5a, 6c, 7a, 8c, 9a, 10b. / CHAPTER DEVELOPMENT Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. module . Social and Emotional Development After studying this module, you should be able to: ● Characterize Erikson’s stages of social and emotional development. ● Explain how psychologists measure attachment in young children. ● with basic trust versus mistrust. An infant with a supportive environment forms strong attachments that positively influence future relationships with other people (Erikson, ). An infant who is mistreated fails to form a trusting relationship and has trouble developing close ties with people later. In adolescence, the key issue is identity. Most adolescents in Western societies consider many options of how they will spend the rest of their lives. Discuss the major social and emotional issues people face during adolescence, adulthood, and old age. You are a contestant on a new TV game show, What’s My Worry? Behind the curtain is someone you cannot see, who has an overriding concern. You are to identify that concern by questioning a psychologist who knows this person well, asking only questions that can be answered with a single word or phrase. Here’s the catch: The more questions you ask, the smaller the prize. If you guess correctly after the first question, you win $,. After two questions, you win $, and so on. Your best strategy is to ask as few questions as possible and then make an educated guess. What would your first question be? A good one would be: “How old is this person?” The worries of teenagers differ from those of -year-olds, which differ from those of older adults. Each age has its own concerns, opportunities, and pleasures. Erik Erikson divided the human life span into eight periods that he called ages or stages. At each stage, he said, people have specific tasks to master, and each stage generates its own social and emotional conflicts. ■ Table . summarizes Erikson’s stages. According to Erikson, failure to master the task of any stage leaves unfortunate consequences that carry over to later stages. For example, an infant deals Bettmann/Corbis Erikson’s Description of Human Development Erik Erikson emphasized that each age has special conflicts. Table . Erikson’s Stages of Human Development Stages Main Conflict Typical Question Infant Basic trust versus mistrust Is my social world predictable and supportive? Toddler (ages –) Autonomy versus shame and doubt Can I do things by myself or must I always rely on others? Preschool child (ages –) Initiative versus guilt Am I good or bad? Preadolescent (ages –) Industry versus inferiority Am I successful or worthless? Adolescent (early teens) Identity versus role confusion Who am I? Young adult (late teens and early s) Intimacy versus isolation Shall I share my life with another person or live alone? Middle adult (late s to retirement) Generativity versus stagnation Will I succeed in my life, both as a parent and as a worker? Older adult (after retirement) Ego integrity versus despair Have I lived a full life or have I failed? M O D U L E 5 . 2 SOCIAL AND EMOTIONAL DEVELOPMENT / Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. They entertain alternative identities and consider many possible futures. According to Erikson, the key decision of young adulthood is intimacy or isolation—that is, sharing your life with someone else or living alone. The quality of an intimate relationship has enormous impact throughout adult life. If you live a full life span, you will spend about half your life in middle adulthood, where the issue is generativity (producing something important, e.g., children or work) versus stagnation (not producing). If all goes well, you take pride in your success. If not, then your difficulties and disappointments continue into old age, where the issue is integrity versus despair. You might describe the main concerns of certain ages differently from what Erikson said. Nevertheless, two of his general points seem valid: Each stage has its own special difficulties, and an unsatisfactory resolution to the problems of one age produces extra difficulty in later life. Let’s examine in more detail some of the major social and emotional issues of particular ages. Infancy and Childhood An important aspect of human life is attachment— a feeling of closeness toward another person. Attachments begin in infancy. John Bowlby () proposed that infants who develop good attachments have a sense of security and safety, and those without strong attachments have trouble developing close relations later as well. Later research confirms this idea. A longitudinal study found that toddlers who received lower-quality care developed into young adults who had trouble forming strong romantic attachments. They erupted into verbal hostility with their partners significantly more often than most other people do (Oriña et al., ). Most research on attachment has measured it in the Strange Situation (usually capitalized), pioneered by Mary Ainsworth (). In this procedure, a mother and her infant (typically to months old) come into a room with many toys. Then a stranger enters the room. The mother leaves and then returns. A few minutes later, both the stranger and the mother leave. Then the stranger returns, and finally, the mother returns. Through a one-way mirror, a psychologist observes the infant’s reactions to each coming and going. Observers classify infants’ responses in the following categories: ● Securely attached. The infant uses the mother as a base of exploration, cooing at her, showing her toys, and making eye contact with her. The infant shows some distress when the mother leaves but cries only briefly if at all. When she returns, ● ● ● the infant goes to her with apparent delight, cuddles for a while, and then returns to the toys. Anxious (or resistant). Responses toward the mother fluctuate between happy and angry. The infant clings to the mother and cries profusely when she leaves, as if worried that she might not return. When she does return, the infant clings to her again but does not use her as a base to explore the toys. A child with an anxious attachment typically shows many fears, including a strong fear of strangers. Avoidant. While the mother is present, the infant does not stay near her and seldom interacts with her. The infant may or may not cry when she leaves and does not go to her when she returns. Disorganized. The infant seems not even to notice the mother or looks away while approaching her or covers his or her face or lies on the floor. The infant alternates between approach and avoidance and shows more fear than affection. The prevalence of the various attachment styles differs from one country to another, but the secure pattern is usually the most common (Ainsworth, Blehar, Waters, & Wall, ). Of course, many children do not fit neatly into one category or another, and some who are classified as “secure” or “avoidant” are more secure or avoidant than others. Most children remain stable in their classification from one time to another (Moss, Cyr, Bureau, Tarabulsy, & Dubois-Comtois, ). In fact, psychologists can predict later attachment behavior from observations on infants as young as months. In the Still-Face Paradigm, a parent plays with a child and then suddenly shifts to an unresponsive, expressionless face. Infants who continue looking at the parent with little sign of distress are likely to show a strong, secure attachment at a year old and beyond (Braungart-Rieker et al., ). The Strange Situation also can be used to evaluate the relationship between child and father (Belsky, ), child and grandparent, or other relationships. As a rule, the quality of one relationship correlates with the quality of others. For example, most children who have a secure relationship with the mother also have a secure relationship with the father, and chances are the parents are happy with each other as well (Elicker, Englund, & Sroufe, ; Erel & Burman, ). Most infants who have a secure relationship with their parents at age months continue to have a close relationship with them decades later (Waters, Merrick, Treboux, Crowell, & Albersheim, ). Those who show a secure attachment in infancy are more likely than others to form high-quality romantic attachments in adulthood (Roisman, Collins, Sroufe, & Egeland, ). They are quick to resolve conflicts with romantic partners and other people (Salvatore, Kuo, Steele, Simpson, & Collins, ). Why do some children develop more secure attachments than others? One reason is that children differ genetically in their temperament—their tendency to be active or inactive, and to respond vigorously or quietly to new stimuli (Bouchard, Lykken, McGue, Segal, & Tellegen, ; Matheny, ). Temperament is fairly consistent throughout life for most people (Durbin, Hayden, Klein, & Olino, ). Those with a “difficult” temperament are frightened more easily than others from infancy through adulthood (Kagan, Reznick, & Snidman, ; Kagan & Snidman, ; Schwartz, Wright, Shin, Kagan, & Rauch, ). How long an infant fixates on one object at a time at age months correlates with self-control at age years, and impulse control at age years correlates with impulse control in adulthood (Papageorgiou et al., ; Slutske, Moffitt, Poulton, & Caspi, ). Attachment style also relates strongly to how responsive the parents are to the infants’ needs, including holding, touching, facial expressions, and so forth. Gentle touch can be very reassuring (Hertenstein, ). Developing a secure attachment takes time and effort. One study examined children who were reared in an orphanage in Africa, Asia, eastern Europe, or Latin America for one to three years before adoption by a U.S. family. By three months after adoption, about / CHAPTER DEVELOPMENT Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The status of adolescents varies among cultures and eras. If you had been born in the s or early s, or in many parts of the world today, your education probably would have ended in your early teens, if not before, and you would have begun working full-time or taking care of your children. In Western societies today, improved health and nutrition have lowered the average age of puberty (Okasha, McCarron, McEwen, & Smith, ), but the economic situation encourages young people to stay in school and postpone marriage, family, and career. The result is a long period of physical maturity without adult status. Adolescence is often described as a time of “storm and stress.” Most adolescents report occasional ✓ concecpkt che . If a child in the Strange Situation clings tightly to the mother and cries furiously when she leaves, which kind of attachment does the child have? Answer . In the United States, this pattern would indicate an anxious or insecure attachment. In Japan, however, it is an understandable reaction to a surprising experience. Social Development in Childhood and Adolescence ©Syda Productions/Shutterstock.com half of the children showed an attachment to their adopting parents, and by nine months, about two-thirds showed a secure attachment (Carlson, Hostinar, Mliner, & Gunnar, ). Patterns of attachment are similar across cultures, with a few apparent exceptions. However, what appears to be a difference in attachment sometimes reflects difficulties in measurement. In one study, Western psychologists observing Black children in South Africa found low consistency between measurements of attachment in one situation and another. When they enlisted local people as co-investigators, the local observers, who understood the local customs, reported data with much greater consistency (Minde, Minde, & Vogel, ). Another study reported an unusually high prevalence of “anxious attachment” among Japanese infants. However, Japanese mothers customarily stay with their babies almost constantly, including bathing with them and sleeping in the same bed. When the Japanese mothers were persuaded to leave their infants alone with a stranger, it was in many cases a new experience for the infant, who reacted with horror. The same reaction by a U.S. child would have a different meaning (Rothbaum, Weisz, Pott, Miyake, & Morelli, ). Doug Menuez/PhotoDisc./Getty Images Jeremy Horner/Encyclopedia/Corbis Whereas attachment to parents or other caregivers is critical for infants, relationships with age-mates become increasingly important during childhood and adolescence. Around puberty, the onset of sexual maturity, sexual interest begins to enter into peer relationships. Children learn social skills by interacting with brothers, sisters, and friends close to their own age. (a) American teenagers are financially dependent on their parents but have the opportunity to spend much time in whatever way they choose. (b) In many nontechnological societies, teenagers are expected to do adult work and accept adult responsibilities. M O D U L E 5 . 2 SOCIAL AND EMOTIONAL DEVELOPMENT / Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. periods of moodiness and conflict with their parents in early adolescence, though the conflicts decrease in later adolescence (Laursen, Coy, & Collins, ). As a rule, adolescents who receive sympathetic support and understanding experience less conflict with their parents (R. A. Lee, Su, & Yoshida, ). Of course, we need to ask what caused what. Did the sympathetic parents cause the adolescents to feel less conflict, or did calm, well-behaved adolescents bring out the best in their parents? Adolescence is also a time of risk-taking behaviors, not only in humans but in other species, too (Spear, ). Adolescents are certainly aware of the dangers. If asked about the advisability of drunk driving, unprotected sex, and so forth, they describe the dangers as well as adults do. Why, then, don’t they behave like adults? Well, most of the time they do, at least when they take time to consider their decisions. They make impulsive, risky decisions mainly when they decide quickly, especially under peer pressure (Luna, Padmanabhan, & O’Hearn, ). One hypothesis to explain impulsive behavior in adolescents is that the prefrontal cortex, important for inhibiting inappropriate behaviors, is slow to mature, not reaching full maturity until the late teens or early s (Luna, Padmanabhan, & O’Hearn, ). However, this cannot be the full explanation. Take a look at the following items and quickly rate each on a scale from (very bad idea) to (very good idea): Ride a bicycle down a staircase. Eat a salad. Swim with alligators. Watch the stars on a clear night. Take unknown pills at a party. People between ages and responded to items like these. If making cautious decisions depended on brain maturation, we should expect ratings on the risky items to be highest in the youngest participants, and gradually decreasing for older ones. In fact, as ▼ Figure . shows, acceptance of risky Risk favorability 20 15 10 5 0 10–14 18–25 15–17 26–30 Age ▲ Figure . On average, people around age 20 gave higher acceptability ratings to risky activities than did those who were either younger or older. (Based on data from Shulman 2014) activities increased up to …
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