Chapter 3.PDF

Chapter 3 Cognitive Development in the Early Years Learning Objectives After reading this chapter, you should be able to: 3.1 Explain Piaget’s constructivist theory of cognitive development and describe the value and limitations of his stages of development. 3.2 Describe Piaget’s...

Chapter 3 Cognitive Development in the Early Years Learning Objectives After reading this chapter, you should be able to: 3.1 Explain Piaget’s constructivist theory of cognitive development and describe the value and limitations of his stages of development. 3.2 Describe Piaget’s sensorimotor stage and current views of cognitive development in infants including development in the areas of object concept, representational thought, and intentional action. 3.3 Describe Piaget’s preoperational stage and current views of cognitive development in preschool children including development in the areas of executive functions, numbers, theory of mind, and language. 3.4 Explain Vygotsky’s sociocultural theory and its contribution to current views of cognitive development and compare his constructivist perspectives to those of Piaget. Sayda is 3 years old. Her maternal grandparents immigrated to the United States from Honduras before her mother was born, and they spoke Spanish with their children. Now Sayda’s mother is a high school English teacher and her father is an attorney. Sayda’s parents value her mother’s fluency in both English and Spanish, and they are raising Sayda to be bilingual. Since birth, Sayda has heard only English from her father and only Spanish from her mother. She also attends a child care program where teachers speak both languages. Her mother’s family is delighted that Sayda is learn- ing Spanish, but her paternal grandparents are not in favor of this bilingual strategy. They worry that Sayda will be confused and fall behind other children in her under- standing of both languages and perhaps even develop learning problems. Recently, while taking care of Sayda over a weekend, her paternal grandparents had a conver- sation with her that alarmed them. On a walk through a city park, Sayda looked at a statue and said, “That’s funny. Statues are not alive, but you can still see them.” Her grandmother said, “What’s funny about that?” and Sayda replied, “My abuelito (her maternal grandfather) is dead, and that’s sad because we’ll never see him again.” Her grandmother tried to explain: “Things like statues and tables and chairs are never alive so they can’t die,” but Sayda was still confused. “Yeah,” she said, “isn’t that funny? Tables and chairs are not alive and we can still see them.” Sayda’s grandparents were alarmed because her apparent understanding of “alive” and “dead” seemed so distorted, and they mistakenly attributed her confu- sion to her bilingual upbringing. Their worst fears seemed to be coming true! But they 77 78 Chapter 3 need not have worried. Sayda’s odd thought process is typical of a 3-year-old. In fact, it is developmentally helpful that she is starting to notice the contradictions in her beliefs about life and death. She will soon make real progress in understanding what it means to be alive. Learning these concepts in two languages is not causing her mis- understanding, and she is likely to reap rich cognitive benefits from her bilingualism over time. (The conversation between Sayda and her grandparents is an adaptation of one between Susan Carey, a developmental scientist, and her own 3-year-old daughter [Carey, Zaitchik, & Bascandziev, 2015].) Is there any value for helping professionals in learning the details of infants’ and preschool children’s cognitive development? The benefits are obvious if you work pri- marily with young children and their parents, but what if the majority of your clients are older children, adolescents, and adults? As you have already seen, developments at these later ages cannot be divorced from earlier events. Skills, abilities, and tenden- cies that develop in the early years of life establish trajectories that influence the prog- ress and direction of later developments. To put it simply, who a person will become is at least partially channeled even before birth. You might wonder why understanding early cognitive processes should be an important part of your concern. After all, helping professionals usually work with their clients on emotional and social issues. The fundamental reason is that cogni- tive, emotional, and social processes are so intimately interconnected that you can have little understanding of any one of these processes without some knowledge of all of them. Cognitive processes affect social functioning, and social experiences have important impacts on cognitive development, as you will readily see in this chap- ter. In fact, realms that seem discrete, like emotion and logic, are typically two dif- ferent aspects of one global process. In the next chapter, where you will learn more about emotional development, you will find that logic without emotion turns out to be rather illogical! In this chapter, we focus on the intellectual growth of infants and young children, looking first at how Jean Piaget described the many changes that occur in these early years. You will see that findings from modern research have led to revisions of many of his views. Especially influential in these re-interpretations are ideas from information processing theories. Finally, we take a look at another classic theory of cognitive develop- ment, that of Lev S. Vygotsky, a contemporary of Piaget’s whose ideas and findings were compatible with his in many ways but who added a special emphasis on the importance of culture and social experience to the story of intellectual change in childhood. Piaget’s Constructivist Theory 3.1 Explain Piaget’s constructivist theory of cognitive development and describe the value and limitations of his stages of development. Debbie, age 10, and Mark, age 4, are overheard discussing their mother’s pregnancy. Their parents have read them children’s books about how babies are conceived and born, and the topic has been discussed openly in the family. The children have the fol- lowing conversation: Debbie: Do you know how the baby got there? Mark: Sure. Mommy got a duck. Debbie: A duck? Mark: Yeah, they just get a duck or rabbit and it grows a little more and it turns into a baby. Debbie: A duck will turn into a baby? Mark: Sure. They give them some food, people food, and they grow into a baby. Debbie: Where did you get that idea? Mark: I saw it in a book and Mommy and Daddy told me. Debbie: They told you that ducks turn into babies? Mark: Yeah! (Based on Cowan, P. A. (1978). Piaget with feeling: Cognitive, social and emotional dimensions. New York: Holt, Rinehart & Winston; and Bernstein, A. C. & Cowan, P. A. (1975). Children’s concepts of how people get babies. Child Development, 46, 77–91.)  Cognitive Development in the Early Years 79 This anecdote illustrates a fundamental feature of Bill Anderson/Photo Researchers, Inc/Science Source learning, knowing, and understanding according to Piag- et’s theory: that the human mind constructs its knowledge. When infants and children are presented with new stimuli or pieces of information, what is learned or stored is not just a “true” reflection of what comes from the environ- ment. That is, new information is not simply written on a blank slate, as John Locke and other empiricists assumed. Rather, children learn by a process of adaptation. You saw in Chapter 2 that adaptation is adjustment to change. Piaget used the term specifically to describe how children’s knowledge adjusts to new stimulation from the environ- ment. First, children interpret new stimulation in ways that fit with what they already know, sometimes distorting it as a result. This aspect of adaptation is called assimilation. Piaget was one of the first theorists to propose that children actively As the new information is assimilated, the child’s existing construct their knowledge. knowledge may be modified somewhat, providing a better match or fit to what is new. The latter process is called accommodation. Assimilation and accommodation are complementary activities involved in every interaction with the environment. To accommodate (learn), children must be able to assimilate. In other words, they cannot learn something that they cannot make some sense out of already. Assimilation often means that new information is distorted or changed so that sense can be made of it. A child’s understandings are gradually changed as a result of inter- actions with the environment, although what a child will learn in any single step is always shaped by what the child already knows, and the new “understanding” may not be a completely accurate reflection of reality. In Mark’s case, his parents’ expla- nations, which apparently included comparing human reproduction to ducks lay- MyLab Education ing eggs, far outstripped Mark’s knowledge structures, and Mark’s assimilation and Video Example 3.1 accommodation of his parents’ elaborate explanations produced a charmingly naive These children are observing linear progression: Ducks turn into people. tadpoles and learning something Piaget spent a lifetime doing intensive research on the development of knowl- new about growth. They can edge; he wrote dozens of books on his findings and hundreds of articles (see Box 3.1). assimilate the idea that the tadpole His own ideas evolved and changed as new work was completed, discussed, and grows legs, but they need to challenged by scientists around the world. Since his death, developmental research- accommodate their concept of growth to understand why the ers have followed up on his pioneering work, and, naturally, the field has moved on. tadpole’s tail gets smaller. Not all of his ideas have been corroborated, but in a remarkable number of areas, his research has been the starting point for more expanded, clarifying work, and his theo- retical explanations have informed newer theories. The idea that knowledge is constructed by the developing child (and adult) is a Piagetian view that has become an underlying assumption of much of the current research on cognitive development and educational practice (e.g., American Psycho- logical Association, Coalition for Psychology in Schools and Education, 2015). This constructivist stance takes the child to be an active participant in the learning pro- cess, constantly seeking out and trying to make sense of new information. In other words, children are intrinsically motivated to learn—another idea that is now widely accepted by developmental scientists. Piaget also considered a child’s active explo- ration to be organized and organizing. When children assimilate new information to what they already know, they are fitting the new information into an organized way of thinking—some sort of knowledge structure. When they accommodate their knowledge structures to fit what is new in the environment, the organization is chang- ing. (We will have more to say about knowledge structures in later chapters.) The ideas that mental activity is organized and that the organization evolves in response to the environment are further Piagetian notions that seem to be taken for granted by modern researchers. Thus, many widely accepted assumptions about cognitive development are derived from Piaget. But some of his fundamental ideas are particularly controversial. Among these is the idea that cognitive development can be characterized by stages (see Chapter 1). Although Piaget believed cognitive change was the result of small, 80 Chapter 3 Box 3.1: Biographical Sketch: Jean Piaget Jean Piaget (1896–1980) was remarkably precocious as a child, and design provocative, ingenious research tasks. Given the publishing his first scholarly paper at the age of 10. At 14, after breadth, depth, and complexity of Piaget’s work, it is not surpris- producing a series of scientific reports, he was offered a posi- ing that others often oversimplify it in their effort to understand. tion as curator of a museum of natural history—an offer promptly For example, Piaget has been described as a nativist by some withdrawn when his age was discovered. Piaget completed a and as an empiricist by others. In fact, Piaget was a true interac- bachelor’s degree by age 18 and a PhD by 22, despite spending tionist. He, like modern systems theorists, viewed development a year away from school when he suffered a “nervous break- as taking place at the proximal interface between the organism down” (which he later attributed to his study of philosophy). His and the environment. Biological and psychological systems affect early education, research, and writing ranged widely from biologi- how the knower acts on the environment, and the environment cal science (his first published article reported his observations “feeds” the knower. What the environment provides is absorbed of an albino sparrow) to mathematics and logic, to experimental and changed by the organism, but the environment also shapes psychology, to psychoanalysis, to psychopathology. He even and changes the organism’s knowledge. wrote a philosophical novel! He found a way to integrate many Educators have been especially affected by Piaget’s work, of his interests when Henri Simon, an early developer of IQ tests, although again, they have sometimes misinterpreted its implica- hired him to standardize an English test with French children. tions. Piaget saw schooling as an opportunity to provide children Piaget soon lost interest in the task he was assigned—asking with food for their naturally occurring “mental digestion.” He children test questions, recording their responses, and specifying warned teachers, however, that children will either memorize new whether they were right or wrong for the purposes of quantifying information by rote or ignore it if it is beyond their current level of intelligence. But he was intrigued by the qualitative features of the understanding. But if information is at least partially comprehensi- children’s answers. Even children’s wrong answers often seemed ble to them or moderately novel, children will actively and eagerly to reveal an underlying structure or pattern of thought. While explore and absorb it. Unfortunately, educators have sometimes studying psychopathology, Piaget had learned to conduct clinical misinterpreted Piaget’s emphasis on children’s active exploration interviews with mentally ill patients. He began to combine clinical as a recommendation that children simply be provided with lots interview techniques with the use of standardized questions in an of interesting and fun “stuff” and then left on their own to learn. effort to reveal the nature of children’s knowledge and reason- Instead, Piaget encouraged educators to plan the presentation ing. After publishing several articles on his findings, Piaget was of learning opportunities carefully, being especially sensitive to invited to become the director of studies in the Institute Jean- children’s current level of functioning in introducing tasks and Jacques Rousseau in Geneva, a center for scientific child study allowing children to actively explore and discover but recognizing and teacher training. At the age of 25, his life’s work had begun. that an orchestrated, if flexible, presentation of tasks aimed at the Until his death at 84, Piaget wrote prolifically on the development child’s level of understanding can promote development of children’s knowledge, reporting an endless stream of studies (e.g., 1970). and constructing a wide-ranging, coherent theory. His empirical Interestingly, although Piaget recognized the advantage of methods combined observations of children’s hands-on problem teachers’ carefully crafting a program of learning opportunities solving with the probing, clinical interview technique that he pio- to optimize a child’s progress, he was somewhat exasperated neered in Simon’s laboratory. He originated a remarkable array of by what he referred to as “the American question”: “How can problem tasks that are easy for adults to solve, but not easy for we speed up children’s development?” He once remarked that children, revealing what appeared to be astonishing age changes kittens have been found to go through some developments in 3 in our reasoning about the world. As Piaget put it, “Just as the months that take human babies 9 to 12 months to achieve. But tadpole already breathes, though with different organs from “the kitten is not going to go much further. The child has taken those of the frog, so the child acts like the adult, but employing longer, but he is capable of going further so it seems to me a mentality whose structure varies according to the stages of its that the nine months were not for nothing” (as quoted in Elkind, development” (Piaget, 1970, p. 153). 1968). His respect for and appreciation of children’s cognitive It is rare today to find any subject in cognitive development, pace as well as his enormous empathy may be what made from perception to mathematical reasoning to memory to social Piaget so successful in uncovering the mysteries of cognitive perspective taking, for which Piaget did not pose key questions development in general. gradual reorganizations of knowledge structures, he described periods of time in which all of a child’s mental structures can be expected to have some organizational properties in common. For example, the infancy and preschool periods covered in this chapter were divided by Piaget into two stages, the sensorimotor stage (from birth to about age 2) and the preoperational stage (between ages 2 and 7). Each of these stages was further divided into substages. The notion of stages implies that children’s  Cognitive Development in the Early Years 81 understandings within a stage (or a substage) about many different things will have some general similarities. So, for example, in the early preoperational stage, whether we are examining a child’s understanding of number or causality, we should be able to detect some similarities in the ways in which children organize their thinking about these concepts. Although Piaget did find many such similarities, more recent research, using different kinds of tasks, finds less support for the notion of overarching stages. In particular, infants and preschoolers sometimes show signs of understandings that Piaget believed to be possible only for much older children. And children’s prog- ress in understanding concepts from different domains of knowledge is not always organized or structured in the same ways at the same time. Rather, progress is often domain specific — development can proceed at different rates in different domains. Domains that have been studied in detail include number concepts, morality, bio- logical versus physical realities, and so on. For example, if we want to learn about children’s understanding of causality, we may need to look at it within particular domains of knowledge. Children’s understanding of physical causality, such as how objects move, may progress differently from their understanding of human or animal agency, such as how animate organisms move. We should note that Piaget, in his later years, continued to revise his theory. Translations of his later work show that he put less emphasis on stages and more on the dynamic quality of repeated assimilation and accommodation in the context of feedback from the environment (e.g., Piaget, 1975/1985). Nonetheless, most developmental scientists, clinicians, and educators still find Piaget’s stage divisions to be useful for many purposes. On the whole, for example, infants’ understandings of many different concepts are more similar to one another’s than they are to those of a 5-year-old. For this reason, in this chapter and in other dis- cussions of cognitive development in this book, we use Piaget’s stage divisions as an aid in describing children’s cognitive progress. MyLab Education Self-Check 3.1 Infant Cognition: The ­Sensorimotor Stage 3.2 Describe Piaget’s sensorimotor stage and current views of cognitive development in infants including development in the areas of object concept, representational thought, and intentional action. Infants’ cognitive functioning seems more mysterious than that of older children and adults because infants do not talk. We cannot ask them to describe what they can see or how many objects are in front of them or to tell us their solutions to a problem. Most efforts to probe cognition at all other age levels depend on giving verbal instructions, and they usually require at least some verbal responses from study participants. How then can we understand what a baby knows, thinks, or even feels? Piaget’s research with infants, done primarily with his own three children, focused on detailed analyses of babies’ motor interactions with the environment. A newborn’s reflexive responses to sensory stimuli—like looking and following when a visual stimulus moves across the visual field, head turning in the direction of a sound, grasping at a touch to the palm, and sucking at a touch to the lips—were examined under many different stimulus conditions. Piaget carefully noted how these sensorimotor patterns functioned and, especially, how they changed with time and experience. From such observations, Piaget inferred what babies might actually understand or be capable of learning. 82 Chapter 3 Careful observation of infants’ reactions to environmental events is still at the heart of infant research, but today we have strategies that take advantage of technol- ogy to make these observations more precise. Among these strategies, for example, is the habituation paradigm, which takes advantage of a baby’s tendency to orient to new stimulation and to habituate to repeated or old stimulation. Suppose, for exam- ple, that a baby is propped up in an infant seat in a darkened room in front of a large, blank video screen. Suddenly, a picture of a green circle flashes on the screen. The baby is likely to produce an orienting response to this new stimulus. She will look longer at the picture than she had at the blank screen. She will suck more vigorously on the pacifier in her mouth, and her blood pressure and her heart rate are likely to decrease from their previous base rate. If we repeatedly present the green circle, after a time the baby will seem to grow bored with the stimulus. Perhaps it now seems familiar, even “old.” We call this response habituation, and it is indicated by shorter looking times, less vigorous sucking, and a return to base rate for heartbeat and blood pressure. With the help of video cameras and computers, all of these subtle response changes can be closely monitored. Now, suppose we flash a new picture on the screen, a picture of a yellow circle. We are looking for a dishabituation response, that is, a renewed orienting response, which we will take to mean that the baby has noticed the differ- ence between the first circle and the second, and her interest is renewed. If the baby is a newborn, we will be disappointed. Newborns show no sign of being able to tell the difference between green and yellow: They do not dishabituate to yellow after becom- ing habituated to green. But if the baby is 3 months old, she probably will dishabitu- ate to the yellow stimulus, indicating to us that she can discriminate between the two colors. Using this research strategy, we have learned that newborns cannot perceive differences between most colors, but that babies differentiate major color groups by 3 months old, and their color vision approximates that of an adult by 4 to 5 months old (Kellman & Arterberry, 2006). It is notable, however, that physiological measures such as electroencephalography show that color discrimination is not fully adult-like until the teen years (Boon & Dain, 2015). Another strategy for studying infants’ abilities is to determine what they prefer to look at or listen to or taste, and so on, using what are called preferential response paradigms, in which multiple stimuli are presented to the infant and we record which ones the baby seems to respond to most. In the preferential looking paradigm, for instance, we might present a baby with two visual stimuli, side by side, on a screen. Suppose one is a circle with black and white stripes, and the other is an entirely gray circle of the same size. Using video cameras focused on the baby’s eyes, a computer can track the baby’s looks to each circle. Babies tend to look more at patterns than at solid stimuli, and so our baby is likely to look more at the striped circle than the solid gray circle. Now we can use this preference to measure the baby’s visual acuity, that is, to find the level of detail the baby can see. We can vary the stripe width for the striped circle, using finer and finer (narrower and narrower) stripes, until the baby shows no preference for the striped pattern. Because babies consistently prefer pat- terns, “no preference” suggests that the baby can no longer see the difference between the striped circle and the solid color circle. We have learned from such studies that newborns have substantially less visual acuity than adults (their vision is blurrier) but that by 8 months, babies’ visual acuity is nearly adult-like (Cavallini, Fazzi, & Viviani, 2002; Huurneman & Boonstra, 2016). See Table 3.1 for more detailed information about infants’ visual and auditory capacities and the kinds of motor abilities that correspond to these sensory developments. Research using habituation and preferential response paradigms has provided us with much of what we know about infants’ perceptual abilities, especially what they can see and hear. But researchers also use these methods to make inferences about what babies can understand and how they think, as you will see. Modern researchers do not always agree about what inferences to draw from such data, but their work has certainly stimulated a great deal of interest in looking more closely at infant develop- ment, and it has led to several challenges of Piaget’s ideas. Let’s consider now three interesting and important cognitive developments in infancy, combining data from both older and newer approaches.  Cognitive Development in the Early Years 83 TABLE 3.1 Major Milestones in Typically Developing Motor, Visual, and Auditory Processes MOTOR DEVELOPMENT AGE GROSS MOTOR FINE MOTOR VISUAL DEVELOPMENT AUDITORY DEVELOPMENT 1 Month Holds head up without wobbling Holds things placed in hands Visual acuity: 20/600; scans Alert to sounds; prefers when held upright edges of figures and visual human speech to nonspeech objects sounds, and prefers sound of mother’s voice to other voices; distinguishes most speech sounds 2 Months Rolls from side to back Visual acuity: 20/300; shows preference for faces over objects; discriminates basic colors 3 Months On stomach, Faces (especially mother’s face) Locates where sounds come lifts chest with arms perceived as attractive; scans from interiors of faces and objects 4 Months Sits with support; rolls over from Visually guided reaching Visual acuity: 20/160; smooth front to back tracking of slowly moving objects; development of ­stereopsis, or ability to perceive depth based upon information from both left and right eyes 5 Months Rolls over from back to front 6 Months Sits without support Transfers objects from hand to Distinguishes faces, both human Coordination of vision and hear- hand and animal ing; turns eyes to nearby sounds smoothly 7 Months Stands with help Plays with simple toys Begins to show perceptual narrowing, e.g., sounds of native language more discriminable than sounds of other languages 8 Months Pulls self to stand Visual acuity: 20/20 9 Months Crawls Pincer grasp (with thumb and Interprets others’ facial forefinger) expressions; shows perceptual narrowing, e.g., human faces easier to distinguish than animal faces 10 Months Stands holding on; drops and throws things 11 Months Stands alone 12 Months Walks holding on Scribbles with crayon 12–18 Walks alone; begins to walk up Months stairs 18–23 Jumps in place Draws lines; constructs simple Months tower; drinks from cup using one hand 2–3 Years Runs, jumps, climbs; balance Pours milk; improves dressing Oldest age at which surgical improves; kicks ball forward; and feeding skills; builds towers correction of crossed eyes stands on one foot briefly of 6 blocks; turns pages in book for depth perception can be successful 3–4 Years Walks up (and later down) Completes simple puzzles; uses Continued integration of visual- stairs alternating feet; walks art materials, scissors; is more motor systems on tiptoes; hops on one foot; careful in execution of art and improves throwing skills; buttons drawing projects clothing; eats with spoon and fork 4–5 Years Ties knots; dresses and More skillful with scissors undresses easily 84 Chapter 3 Understanding Objects You and I would understand very little about the physical or social world if we did not have a fundamental understanding that there are objects (including human objects) with substance and constancy, occupying locations in a spatial field. To become attached to a parent and to begin the process of healthy emotional development, a baby must have some conception of the parent as a permanent, substantive object in her world. What must infants understand to “know” about objects—that is, to have an object concept? First, they need to know that objects have properties that can stimulate all of their senses: vision, hearing, taste, smell, and touch. What they feel in their mouths as they suck a pacifier is the same as what they see when Mom or Dad holds the pacifier up in front of them. When can they make such connections? It appears that they have some capacity to do so as early as the first month of life. In a classic study, Meltzoff and Borton (1979) gave 1-month-olds an opportunity to suck on either a smooth pacifier or a bumpy one, without letting the infants see the pacifiers. Then, the researchers used the preferential looking paradigm to explore whether the babies had learned anything about the visual characteristics of the pacifiers that they had sucked on but had never seen. The babies looked at a split video screen. On one side was a picture of the smooth pacifier, on the other side a picture of the bumpy pacifier. A camera recorded the infants’ eye movements. The babies spent more time looking at whichever pacifier they had previously sucked—suggesting that they were capable of identifying the appearance of the pacifier from their tactile experience of it. Findings like this one indicate that when young babies perceive an object in one way, they can construct some notion of the object’s other perceptual characteristics. This quality of intersensory integration (also referred to as cross-modal matching or intermodal perception) is not surprising given what we now know about prenatal brain development. The development of one sensory system is influenced by the development of other systems (e.g., Murray et al., 2016; see the discussion of the brain in Chapter 2). Piaget (1954), without the benefit of today’s research methods, assumed that intersensory integration appeared later in infancy, after babies have learned to coordinate their reflexive responses to stimulation. For example, not until about 6 weeks do babies reach up to grasp an object that they are sucking; and not until 4 to 6 months do they smoothly coordinate grasping and looking, allowing easy exploration of objects through visually guided reaching. Surely, these motor coordinations enrich a baby’s understanding of objects as “packages” of perceptual characteristics, but such understanding is facilitated by the brain’s overlapping sensory processing earlier than Piaget realized. What else must infants know to have an understanding of objects? Adults realize that objects have a separate existence from the perceiver. Think for a moment about something that is out of sight, like the sink in your bathroom. Despite your inability to see the sink at this moment, you realize that it still exists. Your perceptual processes or actions on the object are not necessary to its continuation. This quality is called object permanence: Objects exist apart from the perceiver. To understand object permanence, a child must have at least a rudimentary capacity to keep an object in mind when it is not present. To put it another way, the child must have a mental representation of the object, like your mental image of the bathroom sink. The capacity to think about things or events that are not currently stimulating our senses is called representational thought. Thus, if we could find out when a baby understands object permanence, we would not only know something about her object MyLab Education concept, but we would also know that she was capable of representational thought. Video Example 3.2 Piaget invented the hidden object test to assess object permanence. An interesting Infants across cultures develop an object, like a small toy, is placed in front of a baby, within her reach. As the baby watches, understanding of object perma- we cover the object with a cloth, so that it is out of sight. What we want to know is, will nence at approximately the same the baby search for the object under the cloth, or does the baby act as if the object’s age, beginning around the end of disappearance means that the object no longer exists? Studies using the hidden object the first year of life. test have consistently found that infants younger than 8 to 12 months fail to search for the object, even though they have the motor skills they need to succeed much earlier (e.g., they engage in visually guided reaching by about 4 months, and they can sit  Cognitive Development in the Early Years 85 without support by about 6 months). Piaget (1954) concluded that understanding object permanence has its rudimentary beginnings late in the first year of life and gradually improves thereafter. He also inferred that representational thought—the ability to form mental representations, such as images—is a skill that begins to develop only in the late months of the first year. Piaget’s work demonstrated that representational ability improves through the second year of life, until, by the end of the sensorimotor period (18 to 24 months), children not only think about objects but can mentally plan their actions, solve simple problems “all in their heads,” remember past experiences, and so on. In other words, they have developed a broad capacity for thinking. Today, we know from studies using procedures such as the habituation para- MyLab Education digm that babies may have some understanding of object permanence, and therefore, Video Example 3.3 perhaps, some representational thinking skills, much earlier in infancy. For example, The toddler in this video Aguiar and Baillargeon (1999, 2002) showed infants a display with a doll standing to understands object permanence the left of one screen (see Figure 3.1). To the right of the screen was a space and then as he searches under the pillow another screen. Babies watched as the doll moved toward the first screen and disap- for the toy. What is the connection peared behind it. Even 2 1/2-month-olds acted surprised if the doll reappeared to the between object permanence and right of the second screen, without ever being visible in the space between the screens. representational thought? You and I would be surprised as well, expecting the doll to follow a normal trajec- tory, emerging from behind the first screen, continuing to move to the right before disappearing again behind the second screen, and then emerging at the far right. If 2 1/2-month-olds expect hidden objects to follow that trajectory as well, perhaps young babies have some sense that objects continue to exist when they cannot be seen. Studies by Baillargeon and her colleagues (see Baillargeon, 2008), as well as other infancy researchers, have created lively controversy about just when representational thinking begins, what the nature of early representations might be, and what aspects of objects young babies are likely to represent (see discussions by Allen & Bickhard, 2013; Bjorklund, 2015; Bremner, Slater, & Johnson, 2015; Carey, 2009; Haith, 2013; Schöner & Thelen, 2006). For Piaget, mental activity in early infancy is sensorimotor: It depends on sensory input and ends in motor output. Eventually these early orga- nizational patterns are transformed into mental images and other products that sup- port “true” representational thought. Many contemporary theorists have described somewhat similar ideas (e.g., Allen & Bickhard, 2013), but others argue that there is “something more” to infants’ earliest mental activity. One view assumes there are innate, primitive concepts, say of objects, that infants can think about, perhaps very briefly, even when sensory input from objects is not there (e.g., Baillargeon, 2008). Nonetheless, there is general agreement that thinking and conceptual developments, such as object permanence that require thinking, gradually improve through the first and second years of life and beyond. In the next section, we will see that studies of infant memory and of babies’ abilities to plan their actions indicate the same kind of gradual development. FIGURE 3.1 Stimuli for a test of object permanence by Aguiar and Baillargeon. Doll disappears Doll emerges from behind first screen. behind second screen. SOURCE: Based on Aguiar, A., & Baillargeon, R. (1999). 2.5-month-old infants’ reasoning about when objects should and should not be occluded. Cognitive Psychology, 39, 116–157. 86 Chapter 3 Remembering Developmental scientists use methods such as the habituation and preferential response paradigms as well as imaging techniques such as fMRI (see Chapter 2) to tap the mysteries of infant memory. Memory is a special interest of researchers who favor information processing theories of cognitive development (see Chapter 1). Learning and storage of information, duration of storage, retrieval of stored information—these are the centerpieces of cognitive functioning from the point of view of scientists who think about the human cognitive system as akin in some ways to a computer proces- sor. What follows is only a sampling of what we are discovering about infant memory. Remembering requires learning, storing, and then retrieving information. With preverbal babies, we look for behavioral signs of retrieval in order to understand what they are learning. Recognition and recall are two different types of retrieval. Suppose you see a person across the room, and you realize that you have seen that person before. The face is present—you are experiencing it—and you have a feeling that it is familiar, that this experience is not new. That feeling of familiarity is recognition. Piaget (1952) guessed from the way babies use their reflexes that they are learning about the stimuli they experience right from the start, because they show early signs of recognition. Ordinarily, babies suck anything that touches their lips, but if they are hungry, they continue to suck only objects that have been associated with nourish- ment in the past, like nipples. Their preferential sucking demonstrates that babies have learned which stimuli are nutritive. Today’s researchers often use the habituation paradigm to assess infant recogni- tion. When babies habituate to a stimulus that is repeatedly presented, they are show- ing us that the stimulus is becoming familiar. Because even newborns habituate to at least some repeatedly presented stimuli, we are now confident that newborns learn from some experiences and are capable of recognition. Operant conditioning has also demonstrated that recognition skills are present from birth. In a classic study, DeCasper and Fifer (1980) found that a 3-day-old infant will learn to suck harder for the reward of hearing its own mother’s voice (rather than a stranger’s voice), indicating that the baby recognizes the mother’s voice. A host of additional studies have corroborated this finding, even with babies as young as 2 hours old (see Lee & Kisilevsky, 2012). A newborn’s recognition of the mother’s voice seems to be a result of many repeated opportunities to hear her voice before birth. Starting at about the 26th week of gesta- tion, when the auditory system begins to function, every time a mother speaks she is likely to be stimulating the fetus’s hearing. Sound pressure into the amniotic fluid causes fetal skull vibrations, leading to cochlear fluid vibrations. A newborn’s famil- iarity with her mother’s voice demonstrates that the capacity for recognition is already in place before birth, but many repetitions of the stimulus seem to be necessary. The fetus can also hear other sounds in the later weeks of pregnancy, such as the father’s voice, but those sounds do not occur with the same frequency as the mother’s voice, and newborns do not show recognition of them (Picciolini et al., 2014). Recognition improves throughout infancy, demonstrating that infants become more efficient at learning and retrieving information. In the newborn period, signs of recognition usually fade after a few minutes or even seconds, but the duration of recognition increases with age, and the speed with which babies habituate increases as well. Younger babies need more exposures to a stimulus than older babies before they show signs of recognition. But there are also individual differences among babies of the same age. Interestingly, how quickly babies habituate to a new stimulus is one of the few measures of infant functioning that has been found to correlate with later intelligence and academic test performance. Recognition speed by 4 months old is an indicator of the efficiency with which a child may later process information (Bornstein, Hahn, & Wolke, 2013). Recognition is a feeling of familiarity when an experience is repeated. Remember- ing an experience from the past when it is not being repeated is called recall. When you bring to mind the face of a friend who is not present, you are engaging in recall. To recall your friend’s face, you must be able to form a mental representation, such as a mental image, that “stands for” the real face. In other words, thinking that involves the ability to form mental representations such as mental images is necessary for recall.  Cognitive Development in the Early Years 87 In contrast to the early and rapid development of recognition skills, the ability to recall seems to emerge later in infancy. One indicator of recall is deferred imita- tion: Children observe the actions of another person on one occasion, and then imitate those actions at a later time. To do that, children must be able to mentally represent the actions they previously observed. We should note that babies may imitate some immediate actions early in the first year. For example, if you stick out your tongue at a newborn, you may see the baby’s tongue protrude as well (Meltzoff & Moore, 1977), although whether this response is really imitation has been vigorously debated (e.g., Oostenbroek et al., 2016). But babies do soon imitate some actions by others. If you clap your hands at a 4-month-old, she may clap her hands as well (Piaget, 1951). It seems that babies slowly work out the correspondences between their own and other people’s body parts, and as they do, they extend their range of imitation. But immedi- ate imitation does not indicate recall. Only if there is a time delay between the observed action and the baby’s imitation of it can we say that the ability to form mental repre- sentations of previously experienced events was necessary for the imitation. Based on observations of his own children’s behavior, Piaget believed that deferred imitation begins rather late in the infancy period, around the middle of the baby’s sec- ond year. At 16 months, for example, his daughter Jacqueline watched a visiting boy have a temper tantrum, screaming and stamping his feet in a playpen. The next day, Jacqueline did the same, only she was smiling and her foot stamping was gentle. She was not actually having a temper tantrum, but was imitating her little friend’s fasci- nating performance (Piaget, 1962). More precise testing methods show that infants from about 9 months of age will recall actions that they witnessed at a previous time. In another classic study, Melt- zoff (1988) showed babies an interesting box, and then demonstrated that pushing a button on the box would produce a beep. The next day, the babies played with the box themselves for the first time. Nine-month-old babies who had watched the button pushing the previous day were much more likely to push the button than were babies who had not previously observed the action. As you might guess, there is some con- troversy about when recall begins, related to disagreements among researchers about when mental representation begins (e.g., Rovee-Collier & Cuevas, 2009), but on the whole, deferred imitation appears to begin in the last several months of the first year, consistent with Meltzoff’s findings. It improves dramatically over the second year, both in duration and in the complexity of what can be recalled. For example, 11-month-old babies will imitate a simple action as long as 3 months later, but 20-month-olds can imi- tate more elaborate sequences as long as 12 months later (see Lukowski & Bauer, 2014). Deferred imitation is, of course, what makes observational learning, or modeling, possible. Once children can mentally represent and thus recall the actions of others, they have gained a cognitive skill that is critical for social learning. A toddler who has watched his big sister painting pictures might on his own open a jar of paint, dip a paintbrush into it, and then sweep the paintbrush across some available surface. His proficiency at each of these actions will be limited, but the sequence will be executed more or less correctly because he recalls his big sister’s past actions. The capacity to recall and repeat another’s behavior helps infants learn actions from others, and it also supports language learning (Sundqvist, Nordqvist, Koch, & Heimann, 2016). You have seen that babies usually begin searching for hidden objects at about 8 months of age, and that this is strong evidence that they believe objects are permanent. It also indicates that infants can recall hidden objects. A particularly important sign of such recall is the beginning of separation anxiety. When parents leave a young baby with another caregiver, the baby typically does not seem to miss the absent parents or to mourn their loss while they are gone. When they are out of sight, they seem to be out of mind. But in the second half of the first year, at about 8 months for most babies, leaving a child with another caregiver may be more difficult. The baby may continue for some time to watch for the missing parents, to cry or fuss, and to generally act distressed. Bouts of separation anxiety are usually of fairly short duration at first, but tend to increase in length, suggesting that the child’s ability to recall the parents is increasing in duration. An 18- to 24-month-old left with a babysitter might show signs of anxiety repeatedly throughout the parents’ absence. Of course, many factors contribute to separation anxiety: the familiarity of the alternate caregiver and of the 88 Chapter 3 surroundings, the quality of the infant’s relationship to the parents, the infant’s tem- perament (see Chapter 4), and so on. But the consistency with which babies around the world begin showing separation distress at about 8 months is attributable to advances in basic cognitive skills such as recall and object permanence (e.g., Super, Guldan, Ahmed, & Zeitlin, 2012). Such related cognitive and social developments in the second half of the infant’s first year also correspond to important brain developments. Rapid myelination of axons increases the efficiency of several brain areas, especially in the frontal lobes, which sup- port thought processes like planning; in the corpus callosum, which enhances coordina- tion of functions between the right and left sides of the brain; in the hippocampus, which is important for memory; and in the cerebellum, which helps control movement and bal- ance (e.g., Deoni et al., 2016; Lee et al., 2017; O’Muircheartaigh, 2014). As a result, while representational processes like recall improve, so do motor skills, advancing the infant’s capacity to explore the environment and to enrich her understanding of objects. Thus, biological, cognitive, motor, and social developments are intricately interdependent. Having and Inferring Intentions If we intentionally act, choosing to pick up a fork rather than a spoon, searching through a closet for just the right outfit to wear, or planning a presentation at work, we are think- ing about what we do before we do it. Very little conscious effort may be involved in some intentional acts, but at least some thought is required. Like the other cognitive skills we have examined, the ability to intend to do something has important conse- quences not just for intellectual performance but for social interactions as well. A child who can choose whether to cry to call for attention, for example, is likely to be treated differently than one who can only reflexively cry in response to discomfort. Obviously, the development of intentional action is related to the development of self-control and decision making, which we will discuss at greater length later in this and other chapters. HAVING INTENTIONS When does intentional action begin? Piaget (1952) assumed that infants’ earliest behav- iors are entirely unintentional and are typically based on reflexive responses to incom- ing stimulation and on the need to act, that is, to repetitively exercise one’s reflexes. By 4 to 8 months, infants’ behaviors have expanded as a result of constant differentiation and integration of the original reflexes, according to Piaget, and now a baby has a large repertoire of behavioral responses to stimuli. If one of these behaviors accidentally produces an interesting event, a child is likely to notice the effect and repeat the action, as if she were hoping to repeat the effect. Piaget called this making interesting sights last. He did not consider it to be intentional behavior, but rather a precursor to inten- tional behavior. In fact, it appears to be simple operant conditioning. After a behavior occurs, there is a reinforcing event, and the behavior is likely to be repeated. But there is a twist. Piaget described infants as appearing somewhat reflective, as if they had noticed the connection between their action and the outcome, and they were trying to make it happen again. Modern researchers have observed similar sequences in infants as young as 3 months old (Rovee-Collier & Barr, 2001). When a mobile hanging over a baby’s crib is tied to a baby’s foot, the child will soon learn to shake her foot to make the mobile move. At some point, the baby appears to notice the connection, as if she were having an insight, and then she shakes her foot more vigorously afterward. From these first inklings of intentional behavior, infants move to more clearly intentional action in that magical time, the last several months of the first year. By 8 to 12 months, Piaget reported that babies will engage in means–end behavior: They will divert their attention from a goal, such as grasping a toy, to produce another action that will help achieve the goal. For example, a baby might try to grasp a rattle that is behind a clear Plexiglas screen. When her hand touches the screen, the baby redirects her attention to the screen, perhaps pushing it aside, before focusing again on the rattle. Younger babies simply keep reaching for the rattle and failing. Their behavior seems more controlled by the stimulus of the rattle than by their own plans. Thus, again, it appears that a behavior that requires mental representation, planning, begins in the 8- to 12-month period. At this point, infants may do some fairly complex sizing up of  Cognitive Development in the Early Years 89 such situations (e.g., Paulus & Sodian, 2015; Willatts, 1989). For example, 9-month-olds will put aside a barrier and then pull on a cloth to get an out-of-reach toy resting on the cloth. But when the toy is not on the cloth, they simply play with the barrier, as though they realize there is no point in pulling on the cloth. More sophisticated intentional control of behavior emerges in the second year. Whereas a 10-month-old typically will use only previously practiced actions as means to an end, 12- to 18-month-olds begin to actively invent new variations on their actions to fit the situation, trying out one variation after another. By 24 months, toddlers’ con- trol of their mental representations is advanced enough that they will mentally invent new means to an end. Rather than trying this and trying that, sometimes they solve a problem by quietly studying the situation first, and producing a useful means to an end on the first try. The beginning of intentional behavior by the end of the first year is evident in babies’ communicative behaviors. When a younger baby repeats an action that has attracted attention in the past, such as patting Mommy’s cheek, the child may be doing no more than “making interesting sights last.” But by 8 to 12 months, most babies are using some of their behaviors, including some vocalizations, not just to attract attention but as a communicative means to an end. For example, a typical 12-month-old might make a wailing sound while intently looking at her father. When he looks in her direction, she extends her hand in an urgent reach in the direction of a particular toy, apparently indi- cating that she would like her father to retrieve it. These complex behavior sequences certainly look like intentional communication. Intentionally controlling our own behav- ior and thought—setting goals, determining what we will pay attention to, and choosing to make one response rather than another—are among a set of cognitive processes that researchers today refer to as executive functions (EFs). These functions heavily engage areas of the prefrontal cortex, which, as we noted earlier, shows maturational gains late in the first year. You will learn more about executive functions later in this chapter. INFERRING OTHERS’ INTENTIONS As babies are developing intentions of their own, what do they understand about the intentions of others? Researchers make a distinction between a child’s understanding of human agency and of human intention. Agency refers to the ability to act without an external trigger (self-propulsion). People and animals have agency because they can act without being pushed or “launched” by some other force, whereas objects require launching. Intention is an internal mental state, such as a plan or a desire that is the source of an action. Infants begin to understand agency by the end of the first year. Just trying to get other people to do things for her, like the baby described in the last paragraph, suggests that the baby has some sense that others are agents. It is also likely that trying to maneuver her father into retrieving an object for her shows that she sees him as able to engage in goal-directed action, like herself. So, by the end of the first year, babies appear to view people both as agents and as intentional actors (see Baillargeon, Scott, & Bian, 2016). Knowing that others can act intentionally is just the start of understanding what other people’s intentions, desires, feelings, beliefs, and knowledge might be. As you will see in the discussion of the preoperational stage, understanding intentions is part of developing a theory of mind (ToM), and it is a complex and long-term process (e.g., Birch et al., 2017). Yet, as with other cognitive skills, there appear to be preliminary developments in the understanding of intentions even early in the first year. Using a habituation task, Woodward (1998) found some apparent awareness of the goal-directedness (intention- ality) of human action even in babies as young as 6 months. In her study, babies saw an actor’s arm reach for one of two toys that were side by side on a platform. Say, for example, that the arm reached for the toy on the left. The sequence was repeated until the babies habituated. Then, the position of the toys was switched, so that the toy that had been on the left was now on the right. The babies now witnessed one of two events. In the first event, the actor reached for the same toy as before, but the actor’s arm had to reach in a different direction (to the right in our example) because the toys had been switched. In other words, the actor’s goal remained the same—to pick up the same toy. In the second event, the actor reached for a new toy that was now in the original location (on the left in our example). Babies dishabituated more to the second event, as 90 Chapter 3 though they were surprised by the change in goal. The change in the direction of move- ment in the first event did not seem to be experienced as particularly new or important. Rather, it was the change in goal that the babies noticed. The same study done with an inanimate rod “reaching” toward the toys did not produce the same results. The babies seemed to expect goal-directedness from humans, but they did not expect it from an inanimate rod. The results of Woodward’s study suggest that although full understand- ing of human intentions may take a long time, babies appear to have a rudimentary sense that there are significant differences between humans and other objects as early as 6 months. What helps a baby progress in understanding other people’s intentions? There are many contributing factors. One is likely to be that as 1- to 2-year-olds more clearly experience their own actions, such as reaching for an object, as intentionally driven, seeing a similar action by another person helps them to view the other as “like me”— driven by similar intentions (Meltzoff, 2007). Interacting directly with other people seems to aid the process. Moll and Tomasello (2007) argued that “When the infant is truly jointly engaged with another, he or she has formed with that partner some kind of joint goal and joint plans of actions... In these interactions infants register... important aspects of what the partner is experiencing... ”(p. 316). Joint attention and interaction may not be necessary for a baby to begin to access others’ intentions—there are many cultures in which adults rarely interact in playful, “shared goal” kinds of interactions and yet children develop an understanding of others’ intentions. But shared social experiences do seem to facilitate the process (Schneidman & Woodward, 2016). MyLab Education Self-Check 3.2 Preschoolers’ Cognition: The ­Preoperational Stage 3.3 Describe Piaget’s preoperational stage and current views of cognitive development in preschool children including development in the areas of executive functions, numbers, theory of mind, and language. By the age of 2, children have moved beyond the limits of sensorimotor activity to become thinkers. They may begin life, as Piaget believed, responding to the world primarily by connecting sensation to action, constantly exercising and adapting reflex- ive patterns of behavior. But by age 2, children can engage the world on the plane of thought. They understand that objects exist apart from their own perceptions and actions. They can call to mind previously experienced events. They can plan and exe- cute complex behaviors, even behaviors they have not tried before, and they know that humans, unlike objects, are agents of action whose behavior is goal directed. Whereas there are precursors to most or all of these skills even in early infancy, and scientists argue about when the earliest representations actually occur, the flowering of thinking in the second year of life is indisputable. Among the abilities that toddlers’ thinking permits is the use of symbols (Piaget, 1962). Symbols are stand-ins for other things. Words are symbols; so are the props used MyLab Education in pretend play when they stand for something else, the way a broom stands for a Video Example 3.4 horse when a child gallops around “riding” the broom. To use and understand such When young children begin to understand that symbols such symbols, children must be able to mentally represent the things being symbolized. As as words and pictures represent babies’ representational skills grow, especially over the second year, language skill and objects, their development of pretend play begin to blossom. In this section, we will highlight some of the typical language and other cognitive cognitive achievements of the preschool years. You will find that Piaget celebrated processes expands. the growth of thinking skills in this period, but he also argued that young children are  Cognitive Development in the Early Years 91 “preoperational” or prelogical. He theorized that children’s early thought tends to be slow and centered on one salient feature of an experience or event at a time, a tendency he called centration. They have trouble understanding the principles that govern events, the “underlying realities” (Flavell, Miller, & Miller, 1993). As children inter- act with the world and practice representing the events they observe, their thinking speeds up and becomes more efficient. Eventually they can “decenter.” They consider multiple pieces of information simultaneously, a process referred to as decentration. As a result, important relationships among their observations can be discovered and represented, and their thinking becomes more logical and sensible from an adult’s point of view. Consider Sayda’s confusion about what is alive and what is not at the beginning of this chapter. She conflates being “visible” with being “alive.” Part of her confusion is that she has distorted the facts: Dead things are usually hidden away and eventually decay, but that does not mean they are invisible. In addition, Piaget would probably attribute Sayda’s confusion to her inability to sufficiently decenter. She cannot reflect on all of the facts she has learned about life, death, and non-living things at one time in order to organize the information correctly; she is unable to sort out characteristics of the biological and physical world in order to construct more well-grounded concepts. She cannot yet identify the organizing principles that are “beneath the surface” of her observations. Piaget’s research on preschool children identified some of the limits of their logical thinking, as you will see. More recent data suggest that preschoolers possess greater skill than Piaget realized, and some of these findings have helped specify step-by-step changes in the abilities that Piaget first described. You will also see that many significant changes in cognitive functioning through the preschool years are conceptualized by today’s scientists as grounded in the devel- opment of executive functions (EFs). The notion of executive functions emerged from information processing theories, which you will learn more about in Chapter 6. For now, let’s consider what these EFs are, and how they develop in the preschool years. Taking Control: The Mind in Charge Suppose you see this word: Green. And suppose I ask you to tell me what the word says. Your response would be immediate: You would automatically read the word. Now suppose that I ask you to tell me the color of the ink the word is printed in. Your response on this “Stroop task” would probably be a little slower and would require more effort. Most people feel that they have to inhibit the automatic tendency to read the color named by the word in order to name the color of the ink. This kind of volun- tary inhibition of a dominant response is an example of executive functions at work. Executive functions are a set of general abilities needed to purposefully complete a task or reach a goal, especially in new situations. They have been called “the cogni- tive toolkit of success” (Hendry, Jones, & Charman, 2016, p. 2). The three fundamental tools in the toolkit are working memory, self-regulation (or inhibitory control), and cognitive flexibility. Together they allow us to control and regulate our attention and behavior, and they make it possible for us to do tasks that require conscious mental effort, such as planning and problem solving (e.g., Diamond, 2016; Zelazo, 2015). Working memory holds information that we are thinking about at the moment. You might think of it as a “short-term memory” that also actively processes the informa- tion being “stored” (Cowan, 2014). Consider Piaget’s claim that a preschooler’s think- ing is initially centered, tending to focus on one thought at a time. A modern version of this idea re-interprets centering as a working memory limitation (e.g., Case, 1985). A preschooler’s working memory has a very small capacity compared to that of older children or adults. A simple way to test working memory capacity is to use a digit span test: Present a series of digits and ask a child to say the digits back in the correct order. Two-year-olds cannot always perform on this test, but typically they seem to be able to hold in mind only about 1 digit. Four-year-olds can generally recall 2 to 3 digits correctly, 12-year-olds about 6 digits, and average adults about 7 digits (e.g., Cowan, 2016). If we test working memory size with visual stimuli, children’s capacity seems a 92 Chapter 3 bit greater, but on the whole young children are somewhat handicapped by the limita- tions of their working memories. Self–regulation, or inhibitory control, is the ability to stay focused on what you want by suppressing your attention to other things. It also includes the ability to stop yourself from responding automatically and to make yourself perform a response that is not the dominant or automatic one (e.g., Diamond, 2016). Self-regulation is involved in much of what we consider to be “mature” behavior, such as ignoring distractions, waiting your turn, resisting temptations, sticking with a boring task until it’s finished, and so on. The Stroop task presented at the beginning of this section is designed to test self-regulation. A child-friendly version (the Silly Sounds Stroop; Willoughby & Blair, 2016) asks children to bark like a dog when they see a picture of a cat and to meow like a cat when the picture shows a dog. Children’s performance on this task gradually improves from 3 to 5 years. When you purposefully shift your goals or attention back and forth as circum- stances require you are showing cognitive flexibility. Imagine a set of cards with colored shapes on them. If we ask 3-year-olds to sort the cards by shape (squares in one pile, triangles in another, etc.), they will probably do that easily. But if we then ask them to take the same cards and sort them by color instead, they usually perseverate on the initial instruction and keep sorting by shape, even though they would have no trouble sorting the cards by color if we had started out with that request! Four- and 5-year-olds are much more likely to be able to make the switch, demonstrating cognitive flexibility (Zelazo et al., 2013). The three aspects of executive functioning are difficult to separate. Taking charge of your own behavior in a goal-directed way seems to require all three at once. As a result, tasks that researchers use to test any one of these skills in children typically involve the others as well. For example, do you remember the game “Simon Says”? To play, one person acts as a guide, and everyone else is supposed to do what the guide says (e.g., “touch your elbow”), but ONLY if the instruction is preceded by “Simon says.” More complex versions of this game are often used to assess self-regulation, but they also tap working memory and cognitive flexibility. In one version, “Head, Toes, Knees, Shoulders,” children follow the directions of the guide as in Simon Says, but the rules require that children do the opposite of what the guide says. When the guide says “Touch your head,” the rule is to touch your toes and vice versa. When the guide says “Touch your shoulders,” the rule is to touch your knees and vice versa. For chil- dren to be successful at this game, their working memories must keep the rules avail- able; children must inhibit their dominant responses (which is to do what the guide is saying to do) in order to follow the rules; and they must be cognitively flexible, shifting attention between the instruction and the rule (McClelland & Cameron, 2012). Today’s developmental scientists usually assume that advancing executive func- tions are necessary (if not sufficient) for children to reason carefully and to construct adequate understandings of the facts they learn. Self-regulation helps children main- tain attention to a difficult mental task; working memory allows multiple facts to be kept in mind simultaneously; and cognitive flexibility helps children shift attention among possible interpretations of contradictory information. Three-year-old Sayda, who was beginning to keep in mind contradictory facts as she pondered life and death, would probably need more expanded working memory space and cognitive flexibility to begin to construct alternative explanations and assess their adequacy. “As Piaget insisted, (mental) construction is an active process, and the EFs are a seat of conceptual activity” (Carey et al., 2015, p. 51). Infants and toddlers are clearly beginning to develop executive functions (Hendry, Jones, & Charman, 2016). Think of the 12-month-old who can shift her attention from the object she desires to her father in order to communicate her desire to him. Execu- tive functions improve substantially from ages 2 to 5, and studies in several countries, including the United States, Taiwan, China, and South Korea, find that preschoolers’ performance on tests of executive functioning predicts their later academic progress (e.g., Nelson et al., 2017). Even in preschool, children who score higher on EF tests are likely to become more engaged in learning activities, and they are less likely to be dis- ruptive (Nesbitt, Fahran, & Fuhs, 2015).  Cognitive Development in the Early Years 93 Improvement of executive functions is a result of many factors, from the maturing prefrontal cortex to environmental variables, such as parents’ caregiving and disciplinary strategies (see Chapters 4 and 5). And just as EFs support the development of many of the skills described in this chapter, such as theory of mind and language skills, these other skills also help improve executive functioning. For example, as children acquire language, their self-regulation skills also advance. As you will see, Vygotsky and o ­ thers have argued that language in the form of private speech is especially important for the development of self-control (Alderson-Day & Fernyhough, 2015; Vygotsky & Luria, 1930). Remember that influences on development are often bidirectional. Inter- relationships among causal processes make development very complex, but they can also provide a special benefit to helping professionals. It is often possible to make improvements in multiple skill areas by focusing on one or two areas that are intimately tied to all of the rest. For example, in the Applications section of this chapter, you will read about an intervention called “Tools of the Mind” that uses teacher-guided role play (focusing on theory of mind skills and language practice) to improve children’s executive functions. This intervention helps children make gains in self-regulation, cognitive flexibility, and problem solving in general. Understanding Numbers Knowledge of numbers is central to cognitive development. Piaget (1952) launched the systematic study of children’s number skills by inventing the number conservation task. A set of discrete items, let’s say 5 candies, is laid out in a neatly spaced line. Below the first set is a second set, laid out the same way, with the candies in each row matched one to one. A child is asked if the two rows have the same number or whether one or the other has more candies. Typically, 3- and 4-year-olds recognize that the two rows have the same number of candies. But when the researcher then changes the appearance of the second row by spreading out the candies, preschoolers usually think that the number has changed along with the appearance of the row. Most frequently, they say that the longer row now has more candy. Even if they count the candies and report that each has 5, they believe that the longer row has more. Do they really believe that? They seem to. If you ask them which row they would rather have to eat, they will choose the longer row! Much debate has swirled around the meaning of preschoolers’ failure on this number conservation task. Piaget felt that children were revealing centered t­hinking, focusing on just one thing at a time. When they look at the rows of candies, preschool- ers notice the differences in length, but they ignore the differences in density. If they thought about both, especially the transformations that occurred in both as the second row was reconfigured, they might recognize that as the length of the row increased, the density of the row decreased, so that the number of candies stayed the same despite the increased length. Because their thought is centered, Piaget argued, pre- operational children tend to link observations in serial order, rather than discovering and representing the more complex relationships among them. In the number conser- vation task, even when children notice both the change in length and the change in density of the second row, they observe these changes serially, and they cannot detect the reciprocal relationship between them. Piaget found that children’s understand- ing of number conservation moves forward rapidly from ages 5 to 7. He attributed this achievement to decentering. With practice, children’s thinking in situations like this speeds up, eventually allowing them to “see” beyond the superficial changes and realize that without adding or subtracting items the number must remain the same. Consistent with this idea, advances in executive functions, like working memory, are strongly related to preschoolers’ progress in understanding numbers (Schmitt, ­Geldhof, ­Purpura, ­Duncan, & McClelland, 2017). Newer research on number understanding emphasizes how much preschoolers do know, even though they still fail Piaget’s number conservation task. Even newborns appear to discriminate differences between small numbers; they will habituate to dis- plays of two items, but then dishabituate to a display of three items. Five-month-olds 94 Chapter 3 may even have some implicit understanding of simple addition and subtraction. If they see one doll placed behind a screen, and then a second doll placed behind the same screen, babies seem surprised if there is only one doll there when the screen is removed. They are not surprised if there are two dolls (see Siegler & Braithwaite, 2017). In exploring the number skills of preschoolers, Gelman and her colleagues (e.g., Gelman & Gallistel, 1978; see also Gelman, 1982; Gelman & Williams, 1998) found that 2- to 3-year-olds have at least implicit understanding of many fundamental counting principles. For example, they know that counting requires the “one-to-one” principle: one number for one item. Such young children sometimes do mistakenly recount items, but they seem to realize that recounting is not really acceptable. Between 3 and 5 years, children can count the same set of items in versatile order, starting once with the item on the left, another time with the item on the right, and so forth. Gelman calls this the “order-irrelevance principle.” She even found that children as young as 3 can some- times remain focused on number despite changes in the length and density of rows. In a classic series of studies using “magic number games,” Gelman showed children two plates, each with a row of toy mice, two mice on one plate, and three mice on the other. For some children, the rows of mice were of equal length but of unequal density; for other children, the rows of mice were of unequal length but equal density. First, the children were trained to pick the “winner” plate (the one with three mice) by giving them lots of trials and telling them whether they were right or wrong. Once they had learned to pick the correct plate without error, the researcher surreptitiously changed the appearance of the plates. For example, if the rows of mice had been of equal length, they were changed to be of equal density. Children tended to register surprise when the changed plates were revealed, but they still correctly picked the winners. Thus, it was clear that they had learned to select the correct plate on the basis of number, not on the basis of length or density differences. It appears that under the right circumstances, young children can pay attention to “underlying realities,” although their ability to do so is quite fragile and easily disrupted. The same children who succeeded in the magic number games still failed Piaget’s classic number conservation tasks. Gelman’s magic number games are characteristic of many of the tasks that modern researchers have designed to explore the apparent limitations of preschoolers’ think- ing. They are different from Piaget’s tasks in that they provide simple instructions, and they often do not require verbal responses or explanations. They also establish different criteria for granting children some knowledge or skill. Piaget’s criteria were conservative. He wanted children to demonstrate that they had complete mastery of a skill or concept, such as the concept of number, so that it could not be disrupted by counter-suggestions or by superficial transformation, before he granted that the skill was present. He often required that children be able to give sensible explanations of their right answers before he credited them with true understanding. Today’s research- ers tend to make minimal demands on children and to grant them the presence of a skill even when children’s success can be easily disrupted by increased demands. The data are not in dispute, but the interpretation of the data is (e.g., Geary, 2006). One approach to resolving the dispute is to assume that children understand concepts such as number in ever-increasing depth and breadth. Today’s researchers often focus on specifying what those levels of understanding are and determining what kinds of experiences help children to advance from one level to another (Bidell & Fischer, 1997; Blewitt, 1994; Jara-Ettinger, Piantadosi, Spelke, Levy, & Gibson, 2016). Studies by Siegler (e.g., Laski & Siegler, 2014; Siegler & Ramani, 2009) are good examples of research that shows how experience can help preschoolers’ number understanding. They began by noting that at the beginning of first grade, children vary greatly with regard to how much they know about numbers. For example, some children (especially higher SES children) can do a good job on “number line estimation.” That just means that if we draw a line, and mark one end with a “1” and the other end with a “10,” these children can figure out approximately where a 7 should go on the line. To do this right, a child has to have some implicit knowledge of the relative size of different numbers (e.g., 4 is twice as big as 2). It’s an important understanding, one that is foundational for acquiring other math skills. Lower SES  Cognitive Development in the Early Years 95 children are less likely than higher SES children to start school with this skill. Siegler and Ramani hypothesized that the difference is due to how often higher versus lower SES families play counting and number games with their children, including board games that involve numbers. They developed a number board game called The Great Race, somewhat like Chutes and Ladders, where the object of the game is to advance along a series of 10 squares, each marked by a number. If lower SES preschoolers played the number board game repeatedly over a 2-week period, the children’s “number line estimation” skills improved dramatically in comparison to children who played a similar game that did not include numbers. The effectiveness of The Great Race game highlights the value of play for cogni- tive development in early childhood. Toddlers and young preschoolers spontaneously engage in exploratory play. They manipulate objects, check out their properties, sort, and organize them. In so doing, children learn not only about the properties of objects, but also about spatial relations, numerical relations, categorical relations, and so on. For example, Mix, Moore, and Holcomb (2011) quite elegantly demonstrated the direct benefits of children’s exploratory play for learning about number equivalence. First, they tested 3-year-olds for their ability to match one set of items (e.g., 3 turtles) with an equivalent set of other items (e.g., 3 flowers). Only children who failed the original test were included in the remainder of the study. The researchers gave the children sets of toys to take home and play with over the course of 6 weeks, with no instructions regarding what to do with the toys. Parents were asked to make sure the toys were continuously available and to keep a log of what children did with them. One group of children received “objects with slots” that made one-to-one correspondence play easy, such as six balls and a muffin tin—the balls fit just right into the six slots of the muffin tin. Another group of children received “objects with objects,” such as six balls and six toy frogs (see Figure 3.2). Children who were given “objects with slots” engaged in much more one-to-one play as reported in parent logs, and when they were tested after 6 weeks, many of these children showed substantial improvement on the numeri- cal equivalence matching test. Clearly, play is a medium for learning. We have learned a great deal about children’s number understanding since Piaget’s early work, but many of Piaget’s characterizations of the limitations of pre- operational thought remain useful. Preschoolers do seem to make appearance-based conclusions, and they frequently miss the deeper significance of events. Also, their thinking often does seem especially affected by singular, salient dimensions of a situa- tion. However, most researchers recognize that such limitations aptly describe young children’s abilities sometimes, but not always, and that experience, especially the way adults interact with young children, can be an important factor in how early abilities develop. Understanding the Mind Piaget (1926; Piaget & Inhelder, 1956) pioneered the investigation of children’s under- standing of other people’s mental processes by studying perspective-taking skills in preschoolers. In his “three mountains task,” a three- dimensional model of three mountains was shown to FIGURE 3.2 Examples of toys for one-to-one children from several different angles. Children then had ­correspondence play from Mix, Moore, & Holcomb. to select a picture of how the scene looked to them, as well as a picture of how it looked to another observer on a different side of the display. Until about age 7, children tended to select the same picture both times, suggest- ing that they believed that other observers shared their ­perspective. Piaget believed children’s poor perspec- tive-taking skills reflected preoperational egocentrism. Because preschoolers can think about only one thing at a time, they are centered on their own perspective and have no awareness of t