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 DO NOT QUOTE what the author says.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 t