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4.1 T H E O N S E T O F T H I N K I N G :
P I AG E T ’ S AC C O U N T
Basic Principles of Cognitive Development
Sensorimotor Thinking
Preoperational Thinking
Evaluating Piaget’s Theory
Extending Piaget’s Account: Children’s Naive Theories
4.2 I N F O R M AT I O N P R O C E S S I N G
D U R I N G I N FA N C Y A N D E A R LY
C H I L D H O O D
General Principles of Information Processing
Attention
Learning
Memory
❚ CURRENT CONTROVERSIES:
Preschoolers on the Witness Stand
Learning Number Skills
4.3 M I N D A N D C U LT U R E :
V Y G OT S K Y ’ S T H E O RY
The Zone of Proximal Development
Scaffolding
Private Speech
4.4 L A N G UAG E
The Road to Speech
First Words and Many More
Speaking in Sentences: Grammatical Development
❚ SPOTLIGHT ON RESEARCH:
Infants Infer Grammatical Rules From Speech
Communicating With Others
S U M M A RY
K E Y T E R M S
L E A R N M O R E A B O U T I T
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The Emergence of Thought and Language
Cognitive Development in Infancy
and Early Childhood
O n the TV show Family Guy, Stewie is a 1-year-old who can’t stand his mother (Stewie: “Hey, mother, I come bearing a gift. I’ll give you a hint. It’s in my diaper and it’s not a toaster.”) and hopes to
dominate the world. Much of the humor, of course, turns on the idea that babies are capable of so-
phisticated thinking and just can’t express it. But what thoughts do lurk in the mind of an infant who is
not yet speaking? How does cognition develop during infancy and early childhood? What makes these
changes possible?
These questions provide the focus of this chapter. We begin with what has long been considered
the definitive account of cognitive development, Jean Piaget’s theory. In this theory, thinking progresses
through four distinct stages between infancy and adulthood.
The next two sections of the chapter concern alternative accounts of cognitive development.
One account, the information-processing perspective, traces children’s emerging cognitive skills in
many specific domains, including memory skills. The other, Lev Vygotsky’s theory, emphasizes the cul-
tural origins of cognitive development and explains why children sometimes talk to themselves as
they play or work.
Throughout development, children express their thoughts in oral and written language. In the last
section of this chapter, you’ll see how children master the sounds, words, and grammar of their native
language.
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T hree-year-old Jamila loves talking to her grandmother (“Gram”) on the telephone. Some-
times these conversations are not very successful because Gram asks questions and Jamila
replies by nodding her head “yes” or “no.” Jamila’s dad has explained that Gram (and others
on the phone) can’t see her nodding—that she needs to say “yes” or “no.” But Jamila invariably
returns to head-nodding. Her dad can’t see why such a bright and talkative child doesn’t realize
that nodding is meaningless over the phone.
W HY D O ES JAMILA IN SIST O N N O D D IN G H ER H EAD W H EN SH E’S T ALK IN G O N T H E PH O N E? This behavior is quite typical, according to the famous Swiss psychologist Jean Piaget (1896–1980). In Piaget’s theory, children’s thinking progresses through four qualita- tively diff erent stages. In this section, we’ll begin by describing some of the general features of Piaget’s theory, then examine Piaget’s account of thinking during infancy and during the preschool years, and fi nally consider some of the strengths and weak- nesses of the theory.
| Basic Principles of Cognitive Development
Piaget believed that children are naturally curious. They constantly want to make sense of their experience and, in the process, construct their understanding of the world. For Piaget, children at all ages are like scientists in that they create theories about how the world works. Of course, children’s theories are often incomplete. Nev- ertheless, children’s theories are valuable to them because they make the world seem more predictable.
According to Piaget, children understand the world with schemes, psychological structures that organize experience. Schemes are mental categories of related events, objects, and knowledge. During infancy, most schemes are based on actions. That is, infants group objects based on the actions they can perform on them. For example, infants suck and grasp, and they use these actions to create categories of objects that can be sucked and objects that can be grasped.
Schemes are just as important after infancy, but they are now based primarily on functional or conceptual relationships, not action. For example, preschoolers learn that forks, knives, and spoons form a functional category of “things I use to eat.” Or they learn that dogs, cats, and goldfi sh form a conceptual category of “pets.”
Like preschoolers, older children and adolescents have schemes based on func- tional and conceptual schemes. But they also have schemes that are based on increas- ingly abstract properties. For example, an adolescent might put fascism, racism, and sexism in a category of “ideologies I despise.”
Thus, schemes of related objects, events, and ideas are present throughout devel- opment. But as children develop, their rules for creating schemes shift from physical activity to functional, conceptual, and, later, abstract properties of objects, events, and ideas.
L E A R N I N G O B J E C T I V E S
According to Piaget, how do schemes, assimilation, and ac- ❚ commodation provide the foundation for cognitive develop-
ment throughout the life span?
How does thinking become more advanced as infants prog- ❚ ress through the sensorimotor stage?
What are the distinguishing characteristics of thinking during ❚ the preoperational stage?
What are the strengths and weaknesses of Piaget’s theory? ❚
How have contemporary researchers extended Piaget’s ❚ theory?
4.1 THE ONSET OF THINKING: PIAGET’S ACCOUNT
scheme
according to Piaget, a mental structure
that organizes information and regulates
behavior
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Assimilation and Accommodation Schemes change constantly, adapting to children’s experiences. In fact, intellectual adaptation involves two processes working together: assimilation and accommoda- tion. Assimilation occurs when new experiences are readily incorporated into existing schemes. Imagine a baby who has the familiar grasping scheme. She will soon discover that the grasping scheme also works well on blocks, toy cars, and other small ob- jects. Extending the existing grasping scheme to new objects illustrates assimilation. Accommodation occurs when schemes are modifi ed based on experience. Soon the infant learns that some objects can only be lifted with two hands and that some can’t be lifted at all. Changing the scheme so that it works for new objects (e.g., using two hands to grasp heavy objects) illustrates accommodation.
Assimilation and accommodation are often easier to understand when you re- member Piaget’s belief that infants, children, and adolescents create theories to try to understand events and objects around them. The infant whose theory is that objects can be lifted with one hand fi nds that her theory is confi rmed when she tries to pick up small objects, but she’s in for a surprise when she tries to pick up a heavy book. The unexpected result forces the infant, like a good scientist, to revise her theory to include this new fi nding.
Equilibration and Stages of Cognitive Development Assimilation and accommodation are usually in balance, or equilibrium. Children fi nd that many experiences are readily assimilated into their existing schemes but that they sometimes need to accommodate their schemes to adjust to new experi- ences. This balance between assimilation and accommodation was illustrated by our infant with a theory about lifting objects. Periodically, however, this balance is upset, and a state of dis- equilibrium results. That is, children discover that their current schemes are not adequate because they are spending too much time accommodating and much less time assimilating. When disequilibrium occurs, children reorganize their schemes to re- turn to a state of equilibrium, a process that Piaget called equili- bration. To restore the balance, current but outmoded ways of thinking are replaced by a qualitatively diff erent, more advanced set of schemes.
One way to understand equilibration is to return to the metaphor of the child as a scientist. As we discussed in Chapter 1, good scientifi c theories readily explain some phenomena but usually must be revised to explain others. Children’s theories allow them to understand many experiences by predicting, for example, what will happen (“It’s morning, so it’s time for breakfast”) or who will do what (“Mom’s gone to work, so Dad will take me to school”), but the theories must be modifi ed when predictions go awry (“Dad thinks I’m old enough to walk to school, so he won’t take me”).
Sometimes scientists fi nd that their theories contain critical fl aws that can’t be fi xed simply by revising; instead, they must create a new theory that draws upon the older theory but is fundamentally diff erent. For example, when the astronomer Coper- nicus realized that the earth-centered theory of the solar system was fundamentally wrong, his new theory built on the assumption that the sun is the center of the solar system. In much the same way, periodically children reach states in which their cur- rent theories seem to be wrong much of the time, so they abandon these theories in favor of more advanced ways of thinking about their physical and social worlds.
According to Piaget, these revolutionary changes in thought occur three times over the life span, at approximately 2, 7, and 11 years of age. This divides cognitive develop- ment into the following four stages:
Period of Development Age Range
Sensorimotor period Infancy (0–2 years)
Preoperational period Preschool and early elementary school years (2–7 years)
assimilation
according to Piaget, taking in information
that is compatible with what one already
knows
accommodation
according to Piaget, changing existing
knowledge based on new knowledge
equilibration
according to Piaget, a process by which
children reorganize their schemes to
return to a state of equilibrium when
disequilibrium occurs
This baby will learn that many objects can be
grasped easily with one hand—illustrating
assimilation—but will also discover that bigger,
heavier objects can be grasped only with two
hands—illustrating accommodation.
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Concrete operational period Middle and late elementary school years (7–11 years)
Formal operational period Adolescence and adulthood (11 years and up)
The ages listed are only approximate. Some youngsters move through the periods more rapidly than others, depending on their ability and their experience. However, the only route to formal operations—the most sophisticated type of thought—is through the fi rst three periods, in sequence. Sensorimotor thinking always gives rise to preoperational thinking; a child cannot “skip” preoperational thinking and move directly from the sensorimotor to the concrete operational period.
In the next few pages of this chapter, we consider Piaget’s account of sensorimotor and preoperational thinking, the periods from birth to approximately 7 years of age. In Chapter 6, we will return to Piaget’s theory to examine his account of concrete and formal operational thinking in older children and adolescents.
| Sensorimotor Thinking
Piaget (1951, 1952, 1954) believed that the fi rst 2 years of life form a distinct phase in human development. The sensorimotor period, from birth to roughly 2 years of age, is the fi rst of Piaget’s four periods of cognitive development. In the 24 months of this stage, infants’ thinking progresses remarkably along three important fronts.
Adapting to and Exploring the Environment Newborns respond refl exively to many stimuli, but between 1 and 4 months refl exes are fi rst modifi ed by experience. An infant may inadvertently touch his lips with his thumb, thereby initiating sucking and the pleasing sensations associated with sucking. Later, the infant tries to re-create these sensations by guiding his thumb to his mouth. Sucking no longer occurs only refl exively when a mother places a nipple at the infant’s mouth; instead, the infant has found a way to initiate sucking himself.
At about 8 months, infants reach a watershed: the onset of deliberate, intentional behavior. For the fi rst time, the “means” and “end” of activities are distinct. If, for ex- ample, a father places his hand in front of a toy, an infant will move his father’s hand to be able to play with the toy. “The moving the hand” scheme is the means to achieve the goal of “grasping the toy.” Using one action as a means to achieve another end is the fi rst indication of purposeful, goal-directed behavior during infancy.
Beginning at about 12 months, infants become active experimenters. An infant may deliberately shake a number of diff erent objects trying to discover which produce sounds and which do not. Or an infant may decide to drop diff erent objects to see what happens. An infant will discover that stuff ed animals land quietly whereas big- ger toys often make a more satisfying “clunk” when they hit the ground. These actions represent a signifi cant extension of intentional behavior; now babies repeat actions with diff erent objects solely for the purpose of seeing what will happen.
Understanding Objects Objects fi ll the world. Some, including dogs, spiders, and college students, are animate; others, including cheeseburgers, socks, and this textbook, are inanimate. But they all share a fundamental property—they exist independently of our actions and thoughts toward them. Much as we may dislike spiders, they still exist when we close our eyes or wish they would go away. Piaget’s term for this understanding that objects exist independently is object permanence. And Piaget made the astonishing claim that in- fants lacked this understanding for much of the fi rst year. That is, he proposed that an infant’s understanding of objects could be summarized as “out of sight, out of mind.” For infants, objects exist when in sight and no longer exist when out of sight.
Piaget concluded that infants have little understanding of objects. If a tempting object such as an attractive toy is placed in front of a 4- to 8-month-old, the infant will probably reach and grasp the object. If, however, the object is subsequently hidden by a barrier or covered with a cloth, the infant will neither reach nor search. Instead, the
sensorimotor period
fi rst of Piaget’s four stages of cognitive
development, which lasts from birth to
approximately 2 years
object permanence
understanding, acquired in infancy, that
objects exist independently of oneself
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infant seems to lose all interest in the object, as if the now hid- den object no longer exists. Paraphrasing the familiar phrase, “out of sight, out of existence!”
Beginning at about 8 months, infants search for an object that an experimenter has covered with a cloth. In fact, many 8- to 12-month-olds love to play this game: an adult covers the object and the infant sweeps away the cover, laughing and smil- ing all the while! But despite this accomplishment, their under- standing of object permanence remains incomplete, according to Piaget. If 8- to 10-month-olds see an object hidden under one container several times and then see it hidden under a second container, they usually reach for the toy under the fi rst container. Piaget claimed that this behavior shows only a fragmentary un- derstanding of objects because infants do not distinguish the object from the actions they use to locate it, such as reaching for a particular container.
Piaget argued that not until approximately 18 months do infants have full under- standing of object permanence. However, in a few pages, we’ll see that infants know more about objects than Piaget claimed.
Using Symbols By 18 months, most infants have begun to talk and gesture, evidence of their emerging capacity to use symbols. Words and gestures are symbols that stand for something else. When a baby waves, it’s a symbol that’s just as eff ective as saying “good-bye” to bid farewell. Children also begin to engage in pretend play, another use of symbols. A 20-month-old may move her hand back and forth in front of her mouth, pretending to brush her teeth.
Once infants can use symbols, they can begin to anticipate the consequences of actions mentally instead of having to perform them. Imagine that an infant and parent construct a tower of blocks next to an open door. Leaving the room, a 12- to 18-month-old might close the door, knocking over the tower because he cannot foresee this outcome of closing the door. But an 18- to 24-month-old can anticipate the consequence of closing the door and move the tower beforehand.
In just 2 years, the infant progresses from refl exive responding to actively exploring the world, understanding objects, and using symbols. These achieve- ments are remarkable and set the stage for preoperational thinking, which we’ll examine next.
| Preoperational Thinking
Once they have crossed into preoperational thinking, the magical power of symbols is available to young children. Of course, mastering this power is a lifelong process; the preschool child’s eff orts are tentative and sometimes incorrect (DeLoache, 1995). Piaget identifi ed a number of characteristic shortcomings in preschoolers’ fl edgling symbolic skills. Let’s look at three.
Egocentrism Preoperational children typically believe that others see the world—both literally and fi guratively—exactly as they do. Egocentrism is diffi culty in seeing the world from another’s outlook. When youngsters stubbornly cling to their own way, they are not simply being contrary. Preoperational children simply do not comprehend that other people diff er in their ideas, convictions, and emotions.
One of Piaget’s famous experiments, the three-mountains problem, demonstrates preoperational children’s egocentrism (Piaget & Inhelder, 1956, chap. 8). Youngsters were seated at a table like the one shown in ❚ Figure 4.1. When preoperational children were asked to choose the photograph that corresponded to another person’s view of
When interesting toys are covered so that they
can’t be seen, young babies lose interest, as if
“out of sight” means “out of existence.”
Ja n
M ue
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Toddlers frequently gesture, a sign of their grow-
ing competence at using symbols.
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egocentrism
diffi culty in seeing the world from an-
other’s point of view; typical of children in
the preoperational period
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the-mountains, they usually picked the photograph that showed their own view of the mountains, not the other person’s. Preoperational youngsters evidently suppose that the mountains are seen the same way by all; they presume that theirs is the only view, not one of many conceivable views. According to Piaget, only concrete operational children fully understand that all people do not experience an event in exactly the same way.
Recall that, in the vignette, 3-year-old Jamila nods her head during phone conver- sations with her grandmother. This, too, refl ects preoperational egocentrism. Jamila assumes that, because she is aware that her head is moving up and down (or side- to-side), her grandmother must be aware of it, too. Because of this egocentrism, pre- operational youngsters often attribute their own thoughts and feelings to others. They may even credit inanimate objects with life and lifelike properties, a phenomenon known as animism (Piaget, 1929). A preschool child may think that the sun is unhappy on a cloudy day or that a car hurts when it’s in an accident. Caught up in their ego- centrism, preoperational youngsters believe that inanimate objects have feelings just as they do.
Centration A second characteristic of preoperational thinking is that children seem to have the psychological equivalent of tunnel vision: They often concentrate on one aspect of a problem but totally ignore other, equally relevant aspects. Centration is Piaget’s term for this narrowly focused thought that characterizes preoperational youngsters.
Piaget demonstrated centration in his experiments involving conservation. In the conservation experiments, Piaget wanted to determine when children realize that im- portant characteristics of objects (or sets of objects) stay the same despite changes in their physical appearance. Some tasks that Piaget used to study conservation are shown in ❚ Figure 4.2. Each begins with identical objects (or sets of objects). Then one of the objects (or sets) is transformed, and children are asked if the objects are the same in terms of some important feature.
Figure 4.1 ❚ Egocentrism: When asked to select the
photograph that shows the mountains as the
adult sees them, preschool children often
select the photograph that shows how the
mountain looks to them.
animism
crediting inanimate objects with life and
lifelike properties such as feelings
centration
according to Piaget, narrowly focused type
of thought characteristic of preoperational
children
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A typical conservation problem involves conservation of liquid quantity. Children are shown identical beakers fi lled with the same amount of juice. After children agree that the two beakers have the same amount of juice, the juice is poured from one bea- ker into a taller, thinner beaker. The juice looks diff erent in the tall, thin beaker—it rises higher—but of course the amount is unchanged. Nevertheless, preoperational children claim that the tall, thin beaker has more juice than the original beaker. (And, if the juice is poured into a wider beaker, they believe it has less.)
What is happening here? According to Piaget, preoperational children center on the level of the juice in the beaker. If the juice is higher after it is poured, preoperational
Liquid quantity
Pour water from one glass into a shorter, wider glass.
Is there the same amount of water in each glass?
Are there the same number of pennies in each row?
Are these sticks the same length?
Does each ball have the same amount of clay?
Now does each piece have the same amount of clay, or does one have more?
Does each cow have the same amount of grass to eat?
Now does each cow have the same amount to eat, or does one cow have more?
Now are the sticks the same length, or is one longer?
Now are there the same number of pennies in each row, or does one row have more?
Now is there the same amount of water in each glass, or does one glass have more?
Stretch out the top row of pennies, push together the bottom row.
Move one stick to the left and the other to the right.
Roll one ball so that it looks like a sausage.
Spread out the squares in one field.
Number
Length
Mass
Area
Type of conservation Starting configuration Final configurationTransformation
Figure 4.2 ❚ Children in the preoperational stage of development typically have difficulty solving conservation problems, in which important features of an
object (or objects) stay the same despite changes in physical appearance.
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children believe that there must be more juice now than before. Because preopera- tional thinking is characterized by centration, these youngsters ignore the fact that the change in the level of the juice is always accompanied by a change in the diameter of
the beaker. In other conservation problems, preoperational children also tend
to focus on only one aspect of the problem. In conservation of num- ber, for example, preoperational children concentrate on the fact that, after the transformation, one row of objects is now longer than the other. In conservation of length, preoperational children concentrate on the fact that, after the transformation, the end of one stick is far- ther to the right than the end of the other. Thus, preoperational chil- dren’s “centered” thinking means that they overlook other parts of the problem that would tell them the quantity is unchanged.
Appearance as Reality A fi nal feature of preoperational thinking is that preschool children believe that an object’s appearance tells what the object is really like.
For instance, many a 3-year-old has watched with quiet fascination as an older brother or sister put on a ghoulish costume only to erupt in frightened tears when their sibling put on scary makeup. The scary made-up face is reality, not just something that looks
frightening but really isn’t. Confusion between appearance and reality is not limited to cos-
tumes and masks. It is a general characteristic of preoperational thinking. Consider the following cases where appearances and reality confl ict:
A boy is angry because a friend is being mean but smiles be- ■ cause he’s afraid the friend will leave if he reveals his anger.
A glass of milk looks brown when seen through sunglasses. ■
A piece of hard rubber looks like food (e.g., like a piece of ■ pizza).
Older children and adults know that the boy looks happy, the milk looks brown, and the object looks like food but that the boy is really angry, the milk is really white, and the object is really rubber. Preop- erational children, however, confuse appearance and reality, thinking the boy is happy, the milk is brown, and the piece of rubber is edible.
The defi ning characteristics of preoperational thought are sum- marized in ● Table 4.1.T H I N K A B O U T I T
Children with low birth weight often
have delayed intellectual development.
According to Piaget, what form might
the delay take?
● TA B L E 4 . 1
Characteristics of Preoperational Thinking
Characteristic Definition Example
Egocentrism Child believes that all people see A child gestures during a telephone the world as he or she does conversation, not realizing that the listener cannot see the gestures
Centration Child focuses on one aspect of a In conservation of liquid quantity, child pays attention problem or situation but ignores to the height of the liquid in the beaker but ignores other relevant aspects the diameter of the beaker
Appearance as reality Child assumes that an object Child believes that a person smiling at another person really is what it appears to be is really happy even though the other person is being mean
In conservation problems, preschool children
typically do not believe that the quantity of a
liquid remains the same when it is poured into a
taller, more slender beaker.
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For young children, appearance is often reality
and so they are frightened when familiar people
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| Evaluating Piaget’s Theory
Because Piaget’s theory is so comprehensive, it has stimulated much research. Much of this work supports Piaget’s view that children actively try to understand the world around them and organize their knowledge and that cognitive development includes major qualitative changes (Brainerd, 1996; Flavell, 1996). One important contribution of Piaget’s theory is that many teachers and parents have found it a rich source of ideas about ways to foster children’s development.
Guidelines for Fostering Cognitive Development Piaget’s theory has several straightforward implications for the conditions that pro- mote cognitive growth.
Cognitive growth occurs as children construct their own understanding of ■ the world, so the teacher’s role is to create environments where children can discover for themselves how the world works. A teacher shouldn’t simply try to tell children how addition and subtraction are complementary but instead should provide children with materials that allow them to discover the com- plementarity themselves.
Children profi t from experience only when they can interpret this experience ■ with their current cognitive structures. It follows, then, that the best teaching experiences are slightly ahead of the children’s current level of thinking. As youngsters begin to master basic addition, don’t jump right to subtraction but go to slightly more diffi cult addition problems.
Cognitive growth can be particularly rapid when children discover inconsis- ■ tencies and errors in their own thinking. Teachers should therefore encourage children to look at the consistency of their thinking but then let children take the lead in sorting out the inconsistencies. If a child is making mistakes in borrowing on subtraction problems, a teacher shouldn’t correct the error di- rectly but should encourage the child to look at a large number of these errors to discover what he or she is doing wrong.
Criticisms of Piaget’s theory Although Piaget’s contributions to child development are legendary, some elements of his theory have held up better than others (Siegler & Alibali, 2005).
Piaget’s theory underestimates cognitive competence in infants and young chil- ■ dren and overestimates cognitive competence in adolescents. In Piaget’s theory, cognitive development is steady in early childhood but not particularly rapid. In contrast, a main theme of modern child-development science is that of the extraordinarily competent infant and toddler. By using more sensitive tasks than Piaget’s, modern investigators have shown that infants and toddlers are vastly more capable than expected based on Piaget’s theory. For example, in a few pages we’ll see that infants have much greater understanding of objects than Piaget believed. Paradoxically, however, Piaget overestimated cognitive skill in adolescents, who often fail to reason according to formal operational principles and revert to less sophisticated reasoning.
Piaget’s theory is vague with respect to processes and mechanisms of change ■ . One important shortcoming is that many of the key components of the theory, such as accommodation and assimilation, are too vague to test scientifi cally. Consequently, scientists abandoned them in favor of other cognitive processes that could be evaluated more readily and hence could provide more convinc- ing accounts of children’s thinking.
Piaget’s stage model does not account for variability in children’s performance ■ . An even more important criticism is that cognitive development is nowhere near as stagelike as Piaget believed. In Piaget’s view, each stage of intellectual development has unique characteristics that leave their mark on everything a
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child does. Preoperational thinking is defi ned by egocentrism and centration; formal operational thinking is defi ned by abstract and hypothetical reasoning. Consequently, children’s performance on diff erent tasks should be very consis- tent. On the conservation and the three-mountains tasks, for instance, accord- ing to Piaget a 4-year-old should always respond in a preoperational way: He should say the water is not the same after pouring, and that another person sees the mountains the same way he does. In fact, children’s thinking falls far short of this consistency. A child’s thinking may be sophisticated in some domains but naïve in others (Siegler, 1981). This inconsistency does not sup- port Piaget’s view that children’s thinking should always refl ect the distinctive imprint of their current stage of cognitive development.
Piaget’s theory undervalues the influence of the sociocultural environment on ■ cognitive development. Returning to the metaphor of the child as scientist, Piaget describes the child as a lone scientist, constantly trying to figure out by herself how her theory coordinates with data. In reality, a child’s effort to un- derstand her world is a far more social enterprise than Piaget described. Her growing understanding of the world is profoundly influenced by interactions with family members, peers, and teachers, and it takes place against the back- drop of cultural values. Piaget did not ignore these social and cultural forces entirely, but they are not prominent in his theory.
These criticisms do not mean that Piaget’s theory is invalid or should be abandoned. As noted previously, it remains the most complete account of cognitive development. However, in recent years researchers have attempted to round out our understanding of cognitive development using other theoretical perspectives, such as the informa- tion-processing approach examined later in this chapter.
| Extending Piaget’s Account: Children’s Naive Theories
Piaget believed that children, like scientists, formulate theories about how the world works. Children’s theories are usually called “naive theories” because, unlike real sci- entifi c theories, they are not created by specialists and are rarely evaluated by formal experimentation. Naive theories are nevertheless valuable because they allow children (and adults) to understand new experiences and predict future events.
In Piaget’s view, children formulate a grand, comprehensive theory that attempts to explain an enormous variety of phenomena—including reasoning about objects, people, and morals, for example—within a common framework. More recent views retain the idea of children as theorists but propose that children, like real scientists, develop specialized theories about much narrower areas. For example, according to the core knowledge hypothesis, infants are born with rudimentary knowledge of the world; this knowledge is elaborated based on children’s experiences (Carey & Spelke, 1994). Some of the theories young children fi rst develop concern physics, psychology, and bi- ology. That is, infants and toddlers rapidly develop theories that organize their knowl- edge about properties of objects, people, and living things (Wellman & Gelman, 1998).
We examined children’s developing theory of mind in Chapter 3; in the next few pages, we’ll look at children’s naive theories of physics and biology.
Naive Physics As adults, we know much about objects and their properties. For example, we know that if we place a coff ee cup on a table, it will remain there unless moved by another person; it will not move by itself or simply disappear. And we don’t release a cof- fee cup in midair because we know that an unsupported object will fall. Child-devel- opment researchers have long been interested in young children’s understanding of objects, in part because Piaget claimed that understanding of objects develops slowly and takes many months to become complete. However, by devising some clever pro- cedures, other investigators have shown that babies understand objects much earlier
core knowledge hypothesis
infants are born with rudimentary knowl-
edge of the world, which is elaborated
based on experiences
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than Piaget claimed. Renée Baillargeon (1987, 1994), for example, assessed object per- manence by using a procedure in which infants fi rst saw a silver screen that appeared to be rotating back and forth. After an infant became familiar with this display, one of two new displays was shown. In the “realistic” event, a red box appeared in a position behind the screen, making it impossible for the screen to rotate as far back as it had previously. Instead, the screen rotated until it made contact with the box, then rotated forward. In the “unrealistic” event, shown in ❚ Figure 4.3, the red box appeared but the screen continued to rotate as before. The screen rotated back until it was fl at, then rotated forward, again revealing the red box. The illusion was possible because the box was mounted on a movable platform that allowed it to drop out of the way of the mov- ing screen. However, from the infant’s perspective, it appeared as if the box vanished behind the screen, only to reappear.
The disappearance and reappearance of the box violates the idea that objects exist permanently. Consequently, an infant who understands the permanence of objects should fi nd the unrealistic event a truly novel stimulus and look at it longer than the realistic event. Baillargeon found that 4½-month-olds consistently looked longer at the unrealistic event than at the realistic event. Infants apparently thought that the unre- alistic event was novel, just as we are surprised when an object vanishes from a magi- cian’s scarf. Evidently, then, infants have some understanding of object permanence early in the fi rst year of life.
Of course, understanding that objects exist independently is just a start; objects have many other important properties, and infants know many of them. Infants know,
1.The silver screen is lying flat on the table and the red box is fully visible
3.The silver screen is now vertical, blocking the red box.
4.The silver screen continues to rotate, blocking the red box, which has started to drop through the trap door.
6.The silver screen is rotating back toward the infant but still blocks the red box.
7.The silver screen is again flat and the box fully visible to the infant.
5.The silver screen is completely flat, apparently having “rotated through” the red box which is actually now under the table.
2.The silver screen has begun to rotate, but the red box is largely visible.
Figure 4.3 ❚ Infants are surprised to see the silver screen rotate flat, which suggests that they understand the
“permanence” of the orange box. Data from Baillargeon (1987).
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for instance, that objects move along connected, continuous paths and that objects cannot move “through” other objects (Hespos & Baillargeon, 2001a; Spelke, 1994). In- fants look longer at objects that violate these properties than at objects that are consis- tent with them. For example, imagine one ball that rolls through a hole in a wall and a second ball that rolls directly through a solid wall. By 5 months, infants look much longer at the second ball, apparently because they are surprised when objects move in ways not predicted by their naive theory of physics. By the middle of the fi rst year, babies also understand that one object striking a second object will cause the latter to move (Kotovsky & Baillargeon, 1998; Spelke, 1994).
Later in their fi rst year, infants who are shown the two situations illustrated in ❚ Figure 4.4 they will look intently at the object that appears unsupported, apparently because it violates their expectations about what happens to unsupported objects (Baillargeon, 1998). And infants are surprised when a tall object is completely hidden when placed behind a shorter object, apparently because it violates their expectations about concealment (Walden et al., 2007; Wang & Baillargeon, 2005).
These amazing demonstrations attest to the fact that the infant is indeed an ac- complished naive physicist (Baillargeon, 2004). Of course, the infant’s theories are far from complete, since physical properties can be understood at many diff erent levels (Hood, Carey, & Prosada, 2000). Using gravity as an example, infants can expect that unsupported objects will fall, elementary-school children know that such objects fall due to gravity, and physics students know that the force of gravity equals the mass of an object times the acceleration caused by gravity. Obviously, infants do not under- stand objects at the level of physics students. However, the important point is that infants rapidly create a reasonably accurate theory of some basic properties of objects, a theory that helps them to expect that objects such as toys will act in predictable ways.
A realistic configuration in which the small box rests on the larger one
An impossible configuration in which the small box has no apparent means of support
Figure 4.4 ❚ Infants are surprised when an unsupported
box doesn’t fall, which suggests that they have
some understanding that objects should be
supported. Data from Baillargeon (1998).
Naive Biology Fundamental to adults’ naive theories is the distinction between living and nonliving things. Adults know that living things, for example, are made of cells, inherit proper- ties from parents, and move spontaneously. Adults’ theories of living things begin in infancy, when youngsters fi rst distinguish animate objects (e.g., people, insects, other animals) from inanimate objects (e.g., rocks, plants, furniture, tools). Motion is critical in early understanding of the diff erence between animate and inanimate objects: That is, infants and toddlers use motion to identify animate objects, and by 12–15 months they have determined that animate objects are self-propelled, can move in irregular paths, and act to achieve goals (Biro & Leslie, 2007; Rakison & Hahn, 2004).
By the preschool years, children’s naive theories of biology have come to include many of the specifi c properties associated with living things (Wellman & Gelman, 1998). Many 4-year-olds’ theories of biology include the following elements.
Movement ■ : Children understand that animals can move themselves but that inanimate objects can be moved only by other objects or by people. Shown an animal and a toy hopping across a table in exactly the same manner, pre- schoolers claim that only the animal can move itself (Gelman & Gottfried, 1996).
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Growth ■ : Children understand that, from their fi rst appearance, animals get bigger and physically more complex but that inanimate objects do not change in this way. They believe, for example, that sea otters and termites become larger as time goes by but that teakettles and teddy bears do not (Rosengren et al., 1991).
Internal parts ■ : Children know that the insides of animate objects contain diff erent materials than the insides of inanimate objects. Preschool children judge that blood and bones are more likely to be inside an animate object but that cotton and metal are more likely to be inside an inanimate object (Simons & Keil, 1995).
Inheritance ■ : Children realize that only living things have off spring that re- semble their parents. Asked to explain why a dog is pink, preschoolers believe that some biological characteristic of the parents probably made the dog pink; asked to explain why a can is pink, preschoolers rely on mechanical causes (e.g., a worker used a machine), not biological ones (Springer & Keil, 1991; Weissman & Kalish, 1999). And both U.S. and Brazilian children believe that a baby pig that is adopted by a cow will grow up to look like and behave like a pig (Sousa, Altran, & Medin, 2002).
Illness ■ : Preschoolers believe that permanent illnesses such as color blindness or food allergies are more likely to be inherited from parents but that tempo- rary illnesses such as a sore throat or a runny nose are more likely to be trans- mitted through contact with other people (Raman & Gelman, 2005).
Healing ■ : Children understand that, when damaged, animate things heal by regrowth whereas inanimate things must be fixed by humans. Preschool- ers know that hair will grow back when cut from a child’s head but must be repaired by a person when cut from a doll’s head (Backscheider, Shatz, & Gelman, 1993).
By 4 years, children’s understanding of living things is so sophisticated that children aren’t fooled by lifelike robots: 4-year-olds know that robots are machines that (a) do not eat or grow and (b) are made by people and can break (Jipson & Gelman, 2007).
A fundamental part of young children’s theory of living things is a commitment to teleological explanations: children believe that livings things and parts of living things exist for a purpose. Lions exist so that people can see them in a zoo. Fish have smooth skin so that they won’t cut other fi sh that swim alongside them (Keleman, 2003). One view is that teleological explanations are based on children’s knowledge that objects such as tools and machines are usually made with a purpose in mind. Children may follow a similar logic in thinking that living things (and their parts) were designed with a specifi c purpose in mind (Keleman & DiYanni, 2005). This teleological think- ing echoes the animistic thinking described on page 132: children attribute their own intentions and goals to other living objects.
Young children’s theories of living things are also rooted in essentialism: children believe that all living things have an essence that can’t be seen but gives a living thing its identity. All birds share an underlying “bird-ness” that distinguishes them from dogs, which of course share an underlying “dog-ness.” And bird-ness is what allows birds to fl y and sing (Gelman, 2003). Young children’s essentialism explains why 4-year-olds believe that a baby kangaroo adopted by goats will still hop and have a pouch and why they believe that a watermelon seed planted in a cornfi eld will produce watermelons (Gelman & Wellman, 1991). The baby kangaroo and the watermelon seed have kangaroo-ness and watermelon-ness that cause properties of kangaroos and wa- termelons to emerge in maturity.
Most children in Western cultures do not have well-defi ned ideas about what es- sences are. They believe that essences are inside an animal because they think that re- moving an animal’s inside parts changes the animal’s identity: for example, a dog that has blood and bones removed is no longer a dog (Gelman & Wellman, 1991). But their ideas about essences are limited to a vague notion of “inside parts.” However, preschool children living in a Native American community in Wisconsin—the Menominee—
teleological explanations
children’s belief that living things and
parts of living things exist for a purpose
essentialism
children’s belief that all living things have
an essence that can’t be seen but gives a
living thing its identity
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have more refi ned ideas. Blood relations matter a great deal in this community be- cause, for example, regulations regarding school funding and hunting are based in part on the number of “full-blooded” Menominee living in the community. Preschool Menominee children believe that a baby cow raised by pigs would grow up look and act like a cow, which is the usual essentialist response. But, when told that a baby cow received a complete blood transfusion from its adoptive pig parent, now preschool children believed that the cow would grow up to be a pig. For Menominee preschool- ers, blood is the essence of cow-ness or pig-ness (Waxman, Medin, & Ross, 2007).
Where do children get this knowledge of living things? Some of it comes just by watching animals, which children love to do. But parents also contribute: When read- ing books about animals to preschoolers, mothers frequently mention the properties that distinguish animals, including self-initiated motion (e.g., “the seal is jumping in the water”) and psychological properties (e.g., “the bear is really mad!”). Such talk helps to highlight important characteristics of animals for youngsters (Gelman et al., 1998).
Of course, although preschoolers’ naive theories of biology are complex, their theo- ries aren’t complete. Preschoolers don’t know, for instance, that genes are the biological basis for inheritance (Springer & Keil, 1991). Preschoolers’ theories include some mis- conceptions: They believe that body parts have intentions—that the heart “wants” to pump blood and bones “want” to grow (Morris, Taplin, & Gelman, 2000). And, although preschoolers know that plants grow and heal, they nevertheless don’t consider plants to be living things. It’s not until 7 or 8 years of age that children routinely decide that plants are alive. Preschoolers’ reluctance to call plants living things may stem from their belief in goal-directed motion as a key property of living things. This is not easy to see in plants, but when 5-year-olds are told that plants move in goal-directed ways—for example, tree roots turn toward a source of water or a venus fl y-trap closes its leaves to trap an insect—they decide that plants are alive after all (Opfer & Siegler, 2004).
Despite these limits, children’s naive theories of biology, when joined with their naive theory of physics, provide powerful tools for making sense of their world and for understanding new experiences.
Recall answers: (1) accommodation, (2) schemes, (3) “out of sight, out of mind,” (4) to use
symbols, (5) egocentric, (6) animism, (7) infants and young children, (8) grow
Test Yourself
RECALL
1. The term refers
to modifi cation of schemes based on
experience.
2. According to Piaget, are psychological
structures that organize experience.
3. Piaget believed that infants’ understanding of objects could
be summarized as .
4. By 18 months, most infants talk and gesture, which shows
that they have the capacity .
5. Preschoolers are often , meaning that
they are unable to take another person’s viewpoint.
6. Preoperational children sometimes attribute thoughts
and feelings to inanimate objects; this is called
.
7. One criticism of Piaget’s theory is that it underestimates
cognitive competence in .
8. Most 4-year-olds know that living things move,
, have internal parts, resemble their
parents, and heal when injured.
INTERPRET
Piaget championed the view that children participate actively
in their own development. How do the sensorimotor child’s
contributions diff er from the formal-operational child’s
contributions?
APPLY
Based on what you know about Piaget’s theory, what would
his position have been on the continuity–discontinuity issue
discussed in Chapter 1?
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W hen Claire, a bubbly 3-year-old, is asked how old she’ll be on her next birthday,
she proudly says, “Four!” while holding up fi ve fi ngers. Asked to count four objects,
whether they’re candies, toys, or socks, Claire almost always says, “1, 2, 6, 7 . . . SEVEN!” Claire’s
older brothers fi nd all this very funny, but her mother thinks that, the obvious mistakes not-
withstanding, Claire’s behavior shows that she knows a lot about numbers and counting. But
what, exactly, does Claire understand? That question has her mother stumped!
T O D AY, MAN Y D EVELO PMEN T ALIST S BO RRO W FRO M C O MPUT ER SC IEN C E T O FO R MULAT E their ideas about human thinking and how it develops (Kail & Bisanz, 1992; Plunkett, 1996). As you recall from Chapter 1, this approach is called information processing. In this section, we’ll see what information processing has revealed about young chil- dren’s thinking and, along the way, see what to make of Claire’s counting.
| General Principles of Information Processing
In the information-processing view, human thinking is based on both mental hard- ware and mental software. Mental hardware refers to mental and neural structures that are built in and that allow the mind to operate. Mental software refers to mental programs that are the basis for performing particular tasks. According to informa- tion-processing psychologists, it is the combination of mental hardware and mental software that allows children to accomplish a specifi c task. Information-processing psychologists claim that, as children develop, their mental software becomes more complex, more powerful, and more effi cient.
In the next few pages, we’ll look at the development of many important cognitive processes in infants, toddlers, and preschoolers, beginning with attention.
| Attention
Hannah was only 3 days old and was often startled by the sounds of traffi c outside her family’s apartment. Hannah’s parents worried that she might not get enough sleep. Yet, within a few days, traffi c sounds no longer disturbed Hannah; she slept blissfully. Why was a noise that had been so troubling no longer a problem? The key is attention, a process that determines which sensory information receives additional cognitive processing.
Hannah’s response was normal not only for infants but also for children and ado- lescents. When presented with a strong or unfamiliar stimulus, an orienting response usually occurs: A person startles, fi xes the eyes on the stimulus, and shows changes in heart rate and brain-wave activity. Collectively, these responses indicate that the in- fant has noticed the stimulus. Remember, too, that Hannah soon ignored the sounds of trucks. After repeated presentations of a stimulus, people recognize it as familiar and the orienting response gradually disappears. Habituation is the diminished re- sponse to a stimulus as it becomes more familiar.
4.2 INFORMATION PROCESSING DURING INFANCY AND EARLY CHILDHOOD
L E A R N I N G O B J E C T I V E S
What is the basis of the information-processing approach? ❚
How well do young children pay attention? ❚
What kinds of learning take place during infancy? ❚
Do infants and preschool children remember? ❚
What do infants and preschoolers know about numbers? ❚
mental hardware
mental and neural structures that are
built-in and that allow the mind to operate
mental software
mental “programs” that are the basis for
performing particular tasks
attention
processes that determine which infor-
mation will be processed further by an
individual
orienting response
an individual views a strong or unfamiliar
stimulus, and changes in heart rate and
brain-wave activity occur
Infants (and older children) pay attention to loud
stimuli at first but then ignore them if they aren’t
interesting or dangerous.
© L
IU J
IN /
A FP
/ G
et ty
Im ag
es
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The orienting response and habituation are both useful to infants. On the one hand, orienting makes the infant aware of potentially important or dangerous events in the environment. On the other hand, constantly responding to insignifi cant stimuli is wasteful, so habituation keeps infants from devoting too much energy to biologi- cally nonsignifi cant events (Rovee-Collier, 1987).
Preschool children gradually learn how to focus their attention, but as compared to older children and adults they are often not very attentive (Ruff , Capozzoli, & Weiss- berg, 1998). Preschoolers are easily distracted by extraneous information. However, we can help children to pay attention better. One straightforward approach is to make rel- evant information stand out. For example, closing a classroom door may not eliminate competing sounds and smells entirely, but it does make them less noticeable. When preschoolers are working at a table or desk, we can remove other objects that are not necessary for the task. Another useful tactic, particularly for young children, is to re- mind them to pay attention to relevant information and to ignore the rest.
| Learning
An infant is always learning. For example, a 5-month-old learns that a new toy makes a noise every time she shakes it. Infants are born with many mechanisms that enable them to learn from experience. This learning can take several forms, including habitu- ation, classical conditioning, operant conditioning, and imitation.
Classical Conditioning Some of the most famous experiments in psychology were conducted with dogs by the Russian physiologist Ivan Pavlov. Dogs salivate when fed. Pavlov discovered that, if something always happened just before feeding—for example, if a bell sounded— then dogs would begin to salivate to that event. In classical conditioning, a neutral
stimulus elicits a response that was originally produced by another stimulus. In Pavlov’s experiments, the bell was a neutral stimulus that did not naturally cause dogs to salivate. However, by repeatedly pair- ing the bell with food, the bell began to elicit salivation. Similarly, in- fants will suck refl exively when sugar water is placed in their mouth with a dropper; if a tone precedes the drops of sugar water, infants will suck when they hear the tone (Lipsitt, 1990).
Classical conditioning is important because it gives infants a sense of order in their environment. That is, through classical conditioning, infants learn that a stimulus is a signal for what will happen next. A youngster may smile when she hears the family dog’s collar because she knows the dog is coming to play with her. Or a toddler may frown when he hears water running in the bathroom because he realizes this means it’s time for a bath.
Infants and toddlers are defi nitely capable of classical condition- ing when the stimuli are associated with feeding or other pleasant events. It is much more diffi cult to demonstrate classical conditioning in infants and toddlers when the stimuli are aversive, such as loud noises or shock (Fitzgerald & Brackbill, 1976). Yet because adults care for and protect very young children, learning about potentially dan- gerous stimulation is not a common biological problem for infants and toddlers (Rovee-Collier, 1987).
Operant Conditioning In classical conditioning, infants form expectations about what will happen in their environment. Operant conditioning focuses on the relation between the consequences of behavior and the likelihood that the behavior will recur. When a child’s behavior leads to pleasant consequences, the child will probably behave similarly in the future;
Children often smile as they hear the family dog
coming closer, which is a by-product of classical
conditioning.
© M
yr le
en F
er gu
so n
C at
e /
Ph ot
oE di
t habituation
becoming unresponsive to a stimulus that
is presented repeatedly
classical conditioning
a form of learning that involves pairing a
neutral stimulus and a response originally
produced by another
operant conditioning
view of learning, proposed by B. F.
Skinner, that emphasizes reward and
punishment
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when the child’s behavior leads to unpleasant consequences, the child will probably not repeat the behavior. When a baby smiles, an adult may hug the baby in return; this pleasing consequence makes the baby more likely to smile in the future. When a baby grabs a family heirloom, an adult may become angry and shout at the baby; these un- pleasant consequences make the baby less likely to grab the heirloom in the future.
Imitation Older children, adolescents, and young adults learn much simply by watching others be- have. For example, children learn new sports moves by watching pro athletes, they learn how to pursue romantic relationships by watching TV, and they learn how to play new computer games by watching peers. Infants, too, are capable of imitation (Barr & Hayne, 1999). A 10-month-old may imitate an adult waving her fi nger back and forth or imitate another infant who knocks down a tower of blocks.
More startling is the claim that even newborns imitate. Meltzoff and Moore (1989, 1994) found that 2- to 3-week-olds would stick out their tongue or open and close their mouth to match an adult’s acts. This work is controversial because other researchers do not consistently obtain these results. In addition, because the newborns’ behavior is not novel—newborns are already capable of sticking out their tongues as well as opening and closing their mouths—some researchers do not consider this to be a “true” form of imitation (Anisfeld, 1991, 1996). This work may well be describing an early, limited form of imitation; over the course of the fi rst year of life, infants are able to imitate a rapidly expanding range of behaviors.
| Memory
Young babies remember events for days or even weeks at a time. Some of the studies that opened our eyes to the infant’s ability to remember used the following method devised by Rovee-Collier (1997, 1999). A ribbon from a mobile is attached to a 2- or 3-month-old’s leg; within a few minutes, the babies learn to kick to make the mobile move. When Rovee-Collier brought the mobile to the infants’ homes several days or a couple of weeks later, babies would still kick to make the mobile move. If Rovee-Collier waited several weeks to return, most babies forgot that kicking moved the mobile. When that happened, Rovee-Collier gave them a reminder—she moved the mobile herself without attaching the ribbon to their foot. Then she would return the next day, hook up the apparatus, and the babies would kick to move the mobile.
Rovee-Collier’s experiments show that three important features of memory exist as early as 2 and 3 months of age: (1) an event from the past is remembered, (2) over time, the event can no longer be recalled, and (3) a cue can serve to dredge up a mem- ory that seems to have been forgotten.
From these humble origins, memory improves rapidly in older infants and tod- dlers. Youngsters can recall more of what they experience and can remember it longer (Courage & Howe, 2004; Pelphrey et al., 2004). When youngsters are shown novel ac- tions with toys and later are asked to imitate what they saw, toddlers can remember more than infants and remember the actions for longer periods (Bauer, 2007). For
Newborns imitate an adult’s facial expressions.
A nd
re w
M el
tz of
f
Several days after infants have learned that kick-
ing moves a mobile, they will kick when they see
the mobile, showing that they remember the
connection between kicking and the mobile’s
movements.
C ou
rt es
y of
D r.
C ar
ol yn
R ov
ee -C
ol lie
r
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example, if shown how to make a rattle by fi rst placing a wooden block inside a con- tainer and then putting a lid on the container, toddlers are more likely than infants to remember the necessary sequence of steps.
These improvements in memory can be traced, in part, to growth in the brain regions that support memory (Bauer, 2007; Richmond & Nelson, 2007). On the one hand, the brain structures primarily responsible for the initial storage of informa- tion, including the hippocampus and amygdala, seem to develop very early—by age 6 months. On the other hand, the structure responsible for retrieving these stored memories, the frontal cortex, develops much later—into the 2nd year. What’s more, part of the hippocampus is not mature until about 20–24 months. Development of memory during the fi rst 2 years therefore refl ects growth in these two diff erent brain regions. In other words, as the hippocampus and prefrontal cortex mature over the fi rst 24 months, children’s memory skills gradually improve.
Autobiographical Memory A novel feature of memory emerges in the preschool years. Autobiographical memory refers to people’s memory of the signifi cant events and experiences of their own lives. You can access your own autobiographical memory by answering these questions:
Who was your teacher in fourth grade?
Where (and with whom!) was your fi rst kiss?
Was your high-school graduation indoors or outdoors?
In answering these questions you searched your memory, just as you would search your memory to answer such questions as “What is the capital of Ohio?” and “Who in- vented the sewing machine?” However, answers to questions about Ohio and sewing machines are based on general knowledge that you have not experienced personally; answers to questions about your fourth-grade teacher, your fi rst kiss, and your high- school graduation are based on knowledge unique to your own life. Autobiographical memory is important because it helps people construct a personal life history. In ad- dition, autobiographical memory allows people to relate their experiences to others, creating socially shared memories (Conway & Pleydell-Pearce, 2000; Nelson, 1993).
Autobiographical memory originates in the preschool years. According to one in- fl uential theory (Nelson & Fivush, 2004), autobiographical memory emerges gradually as children acquire the component skills. Infants and toddlers have the basic memory skills that enable them to remember past events. Layered on top of these memory skills during the preschool years are language skills and a child’s sense of self. Lan- guage allows children to become conversational partners. After infants begin to talk, parents often converse with them about past and future events, particularly about per- sonal experiences in the child’s past and future. Parents may talk about what the child did today at day care or remind the child about what the child will be doing this week- end. In conversations like these, parents teach their children the important features of events and how events are organized (Fivush et al., 2006). Children’s autobiographical memories are richer when parents talk about past events in detail and encourage their children to participate in these conversations. In contrast, when parents’ talk is lim- ited to direct questions that can be answered “yes” or “no,” children’s autobiographical memories are less extensive.
The richness of parent–child conversations also helps to explain a cultural dif- ference in autobiographical memory. Compared to adults living in China, Japan, and Korea, Europeans and North Americans typically remember more events from their early years and remember those events in more detail (Wang, 2006). This diff erence in early memories can be traced to cultural diff erences in parent–child conversational styles: the elaborative style is less common among Asian parents, which means that Asian youngsters have fewer opportunities for the conversations about past events that foster autobiographical memory (Wang, 2007).
How does an emergent sense of self contribute to autobiographical memory? Dur- ing the fi rst two years, infants rapidly acquire a sense that they exist independently in
autobiographical memory
memories of the signifi cant events and
experiences of one’s own life
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space and time. An emerging sense of self thus provides coherence and continuity to children’s experience. Children realize that the self who went to the park a few days ago is the same self who is now at a birthday party and is the same self who will read a book with dad before bedtime. The self provides a personal timeline and anchors a child’s recall of the past (and anticipation of the future). In sum, a sense of self, lan- guage skills that enable children to converse with parents about past and future, and basic memory skills all contribute to the emergence of autobiographical memory in preschool children.
Research on children’s autobiographical memory has played a central role in cases of suspected child abuse. When abuse is suspected, the victim is usually the sole wit- ness. To prosecute the alleged abuser, the child’s testimony is needed. But can pre- schoolers accurately recall these events? We’ll try to answer this question in the Cur- rent Controversies feature.
Current Controversies Preschoolers on the Witness Stand
Regrettably, child abuse
is all too common in
America today. When
abuse is suspected, the victim is usually the sole
eyewitness. But when preschool children are in-
volved, can they provide reliable testimony?
Answering this question is not as easy as it
might seem. One obstacle to accurate testimony
is that young children are often interviewed
repeatedly during legal proceedings, which can
cause them to confuse what actually happened
with what others suggest may have happened.
When the questioner is an adult in a position
of authority, children often believe that what is
suggested by the adult actually happened (Ceci
& Bruck, 1995, 1998; Lampinen & Smith, 1995).
They will tell a convincing tale about “what really
happened” simply because adults have led them
to believe things must have happened that way.
Young children’s storytelling can be so convinc-
ing that—even though enforcement officials and
child protection workers believe they can usually
tell if children are telling the truth—profession-
als often cannot distinguish true and false re-
ports (Gordon, Baker-Ward, & Ornstein, 2001).
Perhaps you doubt that interviewers routinely
ask the leading or suggestive questions that are
the seeds of false memories. But analyses of vid-
eotapes of actual interviews reveal that trained
investigators often ask children leading questions
and make suggestive comments (Lamb, Steinberg,
& Esplin, 2000).
Adults aren’t the only ones who taint chil-
dren’s memories; peers can too! When, for
example, some children in a class experience an
event (e.g., a class field trip, a special class visi-
tor), they often talk about the event with class-
mates who weren’t there; later,
these absent classmates readily
describe what happened and
often insist they were actually
there (Principe & Ceci, 2002;
Principe et al., 2006).
Preschool children are par-
ticularly suggestible. Why? One
idea is that preschool children
are more suggestible because
of limited source-monitoring
skills (Poole & Lindsay, 1995).
Older children, adolescents,
and adults often know the
source of information that they
remember. For example, a father recalling his
daughter’s piano recitals will know the source of
many of his memories: Some are from personal
experience (he attended the recital), some he
saw on videotape, and some are based on his
daughter’s descriptions. Preschool children are
not particularly skilled at such source monitor-
ing. When recalling past events, preschoolers
are often confused about who did or said what;
when confused in this manner, they frequently
assume that they must have experienced some-
thing personally. Consequently, when preschool
children are asked leading questions (e.g.,
“When the man touched you, did it hurt?”),
this information is also stored in memory but
without the source. Because preschool children
are not skilled at monitoring sources, they have
trouble distinguishing what they actually expe-
rienced from what interviewers imply that they
experienced.
Although preschoolers are easily misled, they
can provide reliable testimony. Here are some
guidelines for improving the reliability of child
witnesses (Ceci & Bruck, 1995, 1998; Gordon
et al., 2001):
• Warn children that interviewers may
sometimes try to trick them or suggest
things that didn’t happen.
• Interviewers’ questions should evaluate
alternative explanations of what happened
and who was involved.
• Children should not be questioned repeat-
edly on a single issue.
Following these guidelines can foster the con-
ditions under which preschoolers (and older
children, too) are more likely to provide ac-
curate testimony. More important, with greater
understanding of the circumstances that give rise
to abuse—a topic of Chapter 7—we should be
able to reduce its occurrence considerably.
When questioned by a person in a position of
authority, young children often go along with an
adult’s description of events.
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| Learning Number Skills
Powerful learning and memory skills allow infants and preschoolers to learn much about their worlds. This rapid growth is well illustrated by research on children’s un- derstanding of the concept of number. Basic number skills originate in infancy, long before babies learn the names of numbers. Many babies experience daily variation in quantity. They play with two blocks and see that another baby has three; they watch as a father sorts laundry and fi nds two black socks but only one blue sock, and they eat one hot dog for lunch while an older brother eats three.
From these experiences, babies apparently come to appreciate that quantity or amount is one of the ways in which objects in the world can diff er. That is, research suggests that 5-month-olds can distinguish two objects from three and (though less often) three objects from four (Canfi eld & Smith, 1996; Wynn, 1996). Apparently, in- fants’ perceptual processes enable them to distinguish diff erences in quantity. That is, just as colors (reds, blues) and shapes (triangles, squares) are basic perceptual proper- ties, small quantities (“twoness” and “threeness”) are as well.
What’s more, young babies can perform simple addition and subtraction. In exper- iments using the method shown in ❚ Figure 4.5, infants view a stage with one mouse. A screen hides the mouse and then a hand appears with a second mouse, which is placed behind the screen. When the screen is removed and reveals one mouse, 5-month-olds look longer than when two mice appear. Apparently, 5-month-olds expect that one mouse plus another mouse should equal two mice, and they look longer when this ex- pectancy is violated (Wynn, 1992). Likewise, when the stage fi rst has two mice and one of them is removed, infants are surprised when the screen is removed and two mice are still on the stage. These experiments only work with very small numbers, indicat- ing that the means by which infants add and subtract are quite simple and probably unlike the processes that older children use (Mix, Huttenlocher, & Levine, 2002).
Finally, scientists have shown that infants can compare quantities. One way to relate two quantities is by their ratio; amazingly, 6-month-olds are sensitive to ratio (McCrink & Wynn, 2007). Once they are shown stimuli that feature two blue circles for every yellow circle (e.g., 8 blue and 4 yellow or 30 blue and 15 yellow) infants look longer when they’re next shown stimuli that have a ratio of four blue circles to every yellow circle (e.g., 36 blue and 9 yellow). Infants can also detect the larger of two quan- tities. If 10-month-olds watch an adult place two crackers in one container but three crackers in a second container, the infants usually reach for the container with more crackers (Feigenson, Carey, & Hauser, 2002).
Sequence of events 1 � 1 � 1 or 2
1. Object placed on stage 2. Screen comes up 3. Second object added 4. Hand leaves empty
or: impossible outcomeThen either: possible outcome
5. Screen drops… revealing 2 objects 5. Screen drops… revealing 1 object
Figure 4.5 ❚ Infants are surprised when they see objects
added or removed but the original number
of objects are still present when the screen
is removed; this pattern suggests some basic
understanding of addition and subtraction.
Adapted from Figure 1 in Karen Wynn, “Addition and Subtraction by Human Infants,” Nature, vol. 358
(August 27, 1992), 749. Reprinted by permission.
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Learning to Count By 2 years of age, most youngsters know some number words and have begun to- count. This counting, however, is usually full of mistakes. They might count “1, 2, 6, 7”—skipping 3, 4, and 5. Gelman and Meck (1986) charted preschoolers’ understand- ing of counting. They simply placed several objects in front of a child and asked, “How many?” By analyzing children’s answers to many of these questions, Gelman and Meck discovered that, by age 3, most children have mastered three basic principles of counting—at least when it comes to counting up to fi ve objects.
One-to-one principle ■ : There must be one and only one number name for each object that is counted. A child who counts three objects as “1, 2, a” understands this principle because the number of names matches the number of objects to be counted, even though the third name is a letter.
Stable-order principle ■ : Number names must be counted in the same order. A child who counts in the same sequence—for example, consistently counting four objects as “1, 2, 4, 5”—shows understanding of this principle.
Cardinality principle ■ : The last number name differs from the previous ones in a counting sequence by denoting the number of objects. Typically, 3-year- olds reveal their understanding of this principle by repeating the last number name, often with emphasis: “1, 2, 4, 8 . . . EIGHT!”
During the preschool years, children master these basic principles and apply them to increasingly larger sets of objects. By age 5, most youngsters can apply these counting principles to as many as nine objects. Of course, children’s understanding of these principles does not mean that they always count accurately. To the contrary, children can apply all these principles consistently while counting incorrectly. They must mas- ter the conventional sequence of number names and the counting principles to learn to count accurately.
This turns out to be easier when infants are frequently exposed to number words at home (Levine et al., 2008). It’s also easier when youngsters learn languages that use plural nouns. English, for ex- ample, usually indicates plural by adding “s” to a noun. But in some languages (e.g., Japanese), the noun is the same regardless of the num- ber of objects; toddlers speaking these languages learn number words more slowly (Sarnecka et al., 2007).
Learning the number names beyond 9 is easier because the count- ing words can be generated based on rules for combining decade number names (20, 30, 40) with unit names (1, 2, 3, 4). Later, similar rules are used for hundreds, thousands, and so on. By age 4, most youngsters know the numbers to 20, and some can count to 99. Usu- ally, they stop counting at a number ending in 9 (29, 59), apparently because they don’t know the next decade name (Siegler & Robinson, 1982).
Learning to count beyond 10 is more complicated in English than in other languages. For example, eleven and twelve are completely irregular names, following no-rules. Also, the remaining “teen” number names diff er from the 20s, 30s, and the rest in that the decade number name comes after the unit (thir-teen, four-teen) rather than before (twenty-three, thirty-four). Also, some decade names only loosely correspond to the unit names on which they are based: twenty, thirty, and fi fty only resemble two, three, and fi ve; they are not the same.
In contrast, the Chinese, Japanese, and Korean number systems are almost perfectly regular. Eleven and twelve are expressed as ten-one and ten-two. There are no special names for the decades: Two-ten and two-ten-one are names for 20 and 21. These simpli- fi ed number names help explain why youngsters growing up in Asian countries count more accurately than U.S. preschool children of the same age (Miller et al., 1995). Fur- thermore, the direct correspondence between the number names and the base-ten sys- tem makes it easier for Asian youngsters to learn base-ten concepts (Miura et al., 1988).
one-to-one principle
counting principle that states that there
must be one and only one number name
for each object counted
stable-order principle
counting principle that states that number
names must always be counted in the
same order
cardinality principle
counting principle that the last number
name denotes the number of objects being
counted
Preschool children in Asian countries often learn
to count at younger ages than children in North
America because, in many Asian languages, num-
ber names correspond directly to the base-ten
system. ©
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Thus far we have not considered the impact of social context on children’s think- ing. In the next section we’ll examine a theory developed by Vygotsky, who believed that cognitive development has its roots in social interactions.
V ictoria, a 4-year-old, enjoys solving jigsaw puzzles, coloring, and building towers with blocks.
While busy with these activities, she often talks to herself. For example, once as she was
coloring a picture, she said, “Where’s the red crayon? Stay inside the lines. Color the blocks
blue.” These remarks were not directed at anyone else; after all, Victoria was alone. Why did
she say these things? What purpose did they serve?
H UMAN D EVELO PMEN T IS O FT EN REFERRED T O AS A JO UR N EY T H AT T AK ES PEO PLE ALO N G MAN Y D IFFEREN T PAT H S. For Piaget and for information-processing psychologists, chil- dren make the journey alone. Other people (and culture in general) certainly infl uence the direction that children take, but fundamentally the child is a solitary adventurer- explorer, boldly forging ahead. Lev Vygotsky (1896–1934), a Russian psychologist, pro-
Recall answers: (1) less noticeable, (2) let her view a moving mobile, (3) interviewers may
try to trick them, (4) cardinality
Test Yourself
RECALL
1. One way to improve preschool chil-
dren’s attention is to make irrelevant
stimuli .
2. Four-month-old Tanya has forgotten that kicking moves a
mobile. To remind her of the link between kicking and the
mobile’s movement, we could .
3. Preschoolers’ testimony is more likely to be reliable if
interviewers test alternative hypotheses and avoid re-
peated questioning and if we warn the children that
.
4. When a child who is counting a set of objects repeats the
last number, usually with emphasis; this indicates the
child’s understanding of the principle
of counting.
INTERPRET
Do the developmental mechanisms in the information-pro-
cessing perspective emphasize nature, nurture, or both? How?
APPLY
Describe how research on children’s eyewitness testimony il-
lustrates connections among emotional, cognitive, and social
development.
L E A R N I N G O B J E C T I V E S
What is the zone of proximal development? How does it ❚ help explain how children accomplish more when they col-
laborate with others?
Why is scaffolding a particularly effective way of teaching ❚ youngsters new concepts and skills?
When and why do children talk to themselves as they solve ❚ problems?
4.3 MIND AND CULTURE: VYGOTSKY’S THEORY
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posed a very diff erent account: Development is an apprenticeship in which children advance when they collaborate with others who are more skilled. According to Vy- gotsky (1934/1986), children rarely make much headway on the developmental path when they walk alone; they progress when they walk hand in hand with an expert partner.
For Vygotsky and other sociocultural theorists, the social nature of cognitive devel- opment is captured in the concept of intersubjectivity, which refers to mutual, shared understanding among participants in an activity. For example, when parents and chil- dren play board games together, they share an understanding of the goals of their activity and of their roles in playing the games. Such shared understanding allows parents and children to work together in complementary fashion on the puzzles. Such interactions typify guided participation, in which cognitive growth results from chil- dren’s involvement in structured activities with others who are more skilled than they. Through guided participation, children learn from others how to connect new experi- ences and new skills with what they already know (Rogoff , 2003). Guided participation is shown when a child learns a new video game from a peer or an adolescent learns a new karate move from a partner.
Vygotsky died of tuberculosis at the age of 37, so he never had the opportunity to develop his theory fully. He did not pro- vide a complete theory of cognitive development throughout childhood and adolescence (as Piaget did), nor did he give defi ni- tive accounts of cognitive change in specifi c domains (as infor- mation-processing theorists do). However, many of his ideas are infl uential, largely because they fi ll in some gaps in the Piaget- ian and information-processing accounts. In the next few pages, we’ll look at three of Vygotsky’s most important contributions— the zone of proximal development, scaff olding, and private speech—and learn more about why Victoria talks to herself.
| The Zone of Proximal Development
Four-year-old Ian and his father often solve puzzles together. Al- though Ian does most of the work, his father encourages him, sometimes fi nds a piece that he needs, or shows Ian how to put parts together. When Ian tries to assemble the same puzzles by himself, he can rarely complete them. The diff erence between what Ian can do with assistance and what he does alone defi nes his zone of proximal development. That is, the zone is the area between the level of performance a child can achieve when working independently and a higher level of performance that is possible when working under the guidance or direction of more skilled adults or peers (Wertsch & Tulviste, 1992). For ex- ample, elementary-school children are often asked to solve arith- metic story problems. Many youngsters have trouble with these problems, often because they simply don’t know where to begin. By structuring the task for them—“fi rst decide what you’re sup- posed to fi gure out, then decide what information you’re told in the problem”—teachers can help children accomplish what they cannot do by themselves. Thus, just as training wheels help children learn to ride a bike by allowing them to concentrate on certain aspects of bicycling, collaborators help children perform more eff ectively by providing structure, hints, and reminders.
The idea of a zone of proximal development follows naturally from Vygotsky’s basic premise: Cognition develops fi rst in a social setting and only gradually comes under the child’s independent control. What factors aid this shift? This leads us to the second of Vygotsky’s key contributions.
intersubjectivity
mutual, shared understanding among
participants in an activity
guided participation
children’s involvement in structured ac-
tivities with others who are more skilled,
typically producing cognitive growth
zone of proximal development
diff erence between what children can
do with assistance and what they can do
alone
Young children can often accomplish far more
with some adult guidance than they can accom-
plish alone; Vygotsky referred to this difference
as the zone of proximal development.
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| Scaffolding
Have you ever had the good fortune to work with a master teacher, one who seemed to know exactly when to say something to help you over an obstacle but otherwise let you work uninterrupted? Scaffolding is a style in which teachers gauge the amount of assistance they off er to match the learner’s needs. Early in learning a new task, children know little, so teachers give much direct instruction about how to do all the diff erent elements of a task. As the children catch on, teachers need to provide much less direct instruction; they are more likely to be giving reminders.
Worldwide, parents attempt to scaff old their children’s learning, but not always using the same methods. Rogoff and her colleagues (1993) observed mothers in four countries—Guatemala, India, Turkey, and the United States—as they showed their toddlers how to operate a novel toy. In all cultures, most mothers attempted to scaf- fold their children’s learning, either by dividing a diffi cult task into easier subtasks or by doing parts of the task themselves, particularly the more complicated parts. How- ever, mothers in diff erent cultures accomplish scaff olding in diff erent ways. Mothers in Turkey and the United States relied primarily on verbal instruction. Mothers in India and Guatemala used verbal instruction but also used touches (e.g., nudging a child’s elbow) or gaze (e.g., winking or staring) to guide their youngsters. Evidently, parents worldwide try to simplify learning tasks for their children, but they use diff erent methods.
The defi ning characteristic of scaff olding—giving help but not more than is needed—clearly promotes learning (Cole, 2006). Youngsters do not learn readily when they are constantly told what to do or when they are simply left to struggle through a problem unaided. However, when teachers collaborate with them, allowing children to take on more and more of a task as they master its diff erent elements, they learn more eff ectively (Murphy & Messer, 2000). Scaff olding is an important technique for transferring skills from others to the child, both in formal settings such as schools and in informal settings such as the home or playground.
| Private Speech
Remember Victoria, the 4-year-old in the vignette who talked to herself as she colored? Her behavior demonstrates private speech: comments that are not intended for others but are designed to help children regulate their own behavior (Vygotsky, 1934/1986). Thus, Victoria’s remarks are simply an eff ort to help herself color the picture.
Vygotsky viewed private speech as an intermediate step toward self-regulation of cognitive skills. At fi rst, children’s behavior is regulated by speech from other people that is directed toward them. When youngsters fi rst try to control their own behavior and thoughts without others present, they instruct themselves by speaking aloud. Pri- vate speech seems to be children’s way of guiding themselves, of making sure that they do all the required steps in solving a problem. Finally, as children gain ever greater skill, private speech becomes inner speech, which was Vygotsky’s term for thought (Behrend, Rosengran, & Perlmutter, 1992).
If private speech functions in this way, can you imagine when a child would be most likely to use it? We should see children using private speech more often on diffi cult tasks than on easy tasks, because children are most likely to need extra guid- ance on harder tasks. Also, children should be more likely to use private speech after a mistake than after a correct response. These predictions are generally supported by research (Berk, 2003), which suggests the power of language in helping children learn to control their own behavior and thinking.
Thus, Vygotsky’s work has characterized cognitive development not as a solitary undertaking but as a collaboration between expert and novice. His work reminds us of the importance of language, which we’ll examine in detail in the last section of this chapter.
scaff olding
a style in which teachers gauge the
amount of assistance they off er to match
the learner’s needs
private speech
a child’s comments that are not intended
for others but are designed instead to help
regulate the child’s own behavior
Young children often regulate their own behav-
ior by talking to themselves, particularly while
performing difficult tasks.
© T
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ch al
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y
T H I N K A B O U T I T
Vygotsky emphasized cognitive
development as collaboration. How
could such collaboration be included
in Piaget’s theory? In information
processing?
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N abina is just a few weeks away from her fi rst birthday. For the past month, she has
seemed to understand much of her mother’s speech. If her mom asks, “Where’s
Garfi eld?” (the family cat), Nabina scans the room and points toward Garfi eld. Yet Na-
bina’s own speech is still gibberish: She “talks” constantly, but her mom can’t understand a
word of it. If Nabina apparently understands others’ speech, why can’t she speak herself?
AN EX T R AO RD IN AR Y H UMAN AC H IEVEMEN T O C C UR S SO O N AFT ER T H E FIR ST BIR T H - D AY: Most children speak their fi rst word, which is followed in the ensuing months by several hundred more. This marks the beginning of a child’s ability to communicate orally with others. Through speech, youngsters impart their ideas, beliefs, and feelings to family, friends, and others.
Actually, the fi rst spoken words represent the climax of a year’s worth of language growth. To tell the story of language acquisition properly and explain Nabina’s seemingly strange behavior, we must begin with the months preceding the fi rst words.
| The Road to Speech
When a baby is upset, a concerned mother tries to console it. This familiar situ- ation is rich in language-related information. The infant, not yet able to talk, is conveying its displeasure by one of the few means of communication available to it—crying. The mother, for her part, is using both verbal and nonverbal measures to cheer her baby, to send the message that the world is really not as bad as it may seem now.
The situation also raises two questions about infants as nonspeaking crea- tures. First, can babies who are unable to speak understand any of the speech that
Recall answers: (1) zone of proximal development, (2) scaffolding, (3) private speech
Test Yourself
RECALL
1. The is the
diff erence between the level of per-
formance that youngsters can achieve
with assistance and the level they can
achieve alone.
2. The term refers to a style in which
teachers adjust their assistance to match a child’s needs.
3. According to Vygotsky, is an in-
termediate step between speech from others and inner
speech.
INTERPRET
How would scaff olding that’s appropriate for infants dif-
fer from the the scaff olding that’s appropriate for preschool
children?
APPLY
Review Piaget’s description of the conditions that foster cog-
nitive development (page 135). How would a comparable list
derived from Vygotsky’s theory compare?
4.4 LANGUAGE
L E A R N I N G O B J E C T I V E S
When do infants first hear and make speech sounds? ❚
When do children start to talk? How do they learn word ❚ meanings?
How do young children learn grammar? ❚
How well do youngsters communicate? ❚
A baby’s first form of communication—
crying—is soon joined by other, language-based
ways of communicating.
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is directed at them? Second, how do infants progress from crying to more eff ective methods of oral communication, such as speech? Let’s start by answering the fi rst question.
Perceiving Speech Even newborn infants hear remarkably well (page 109), and newborn babies prefer to listen to speech over comparably complex nonspeech sounds (Vouloumanos & Werker, 2007). But can babies distinguish speech sounds? To answer this question, we fi rst need to know more about the elements of speech. The basic building blocks of language are phonemes, which are unique sounds that can be joined to create words. Phonemes include consonant sounds, such as the sound of t in toe and tap, along with vowel sounds such as the sound of e in get and bed. Infants can distinguish many of these sounds, some of them as early as 1 month after birth (Aslin, Jusczyk, & Pisoni, 1998).
How do we know that infants can distinguish between diff erent vowels and conso- nants? Researchers have devised a number of clever techniques to determine whether babies respond diff erently to distinct sounds. In one approach, a rubber nipple is con- nected to a tape recorder so that sucking turns on the tape and sound comes out of a loudspeaker. In just a few minutes, 1-month-olds learn the relation between their sucking and the sound: They suck rapidly to hear a tape that consists of nothing more than the sound of p as in pin, pet, and pat (pronounced “puh”).
After a few more minutes, infants seemingly tire of this repetitive sound and suck less often, which represents the habituation phenomenon described on page 141. But after the tape is changed to a diff erent sound—such as the sound of b in bed, bat, or bird (pronounced “buh”)—babies begin sucking rapidly again. Evidently, they recog- nize that the sound of b is diff erent from p because they suck more often to hear the new sound (Jusczyk, 1995).
Of course, the language environment for young infants is not solely auditory; much exposure to language comes from face-to-face interaction with adults. These interactions provide many visual cues about sounds and infants’ use of these cues: Shown a video of an adult saying “ba,” infants notice when the adult looks to be saying “sha” even though the audio still presents “ba” (Patterson & Werker, 2003).
THE IMPACT OF LANGUAGE EXPOSURE. Not all languages use the same set of pho- nemes, so a distinction that is important in one language may be ignored in another. For example, French and Polish (unlike English) diff erentiate between nasal and non- nasal vowels. To hear the diff erence, say the word rod. Now repeat it, but holding your nose. The subtle diff erence between the two sounds illustrates a nonnasal vowel (the fi rst version of rod) and a nasal one (the second).
Because an infant might be exposed to any of the world’s languages, it would be adaptive for young infants to be able to perceive a wide range of phonemes. In fact, research shows that infants can distinguish phonemes that are not used in their na- tive language. For example, Japanese does not distinguish the consonant sound of r in rip from the sound of l in lip, and Japanese adults trying to learn English have great diffi culty distinguishing these sounds. At about 6–8 months, Japanese and American infants can distinguish these sounds equally well. However, by 10–12 months, percep- tion of r and l improves for American infants—presumably because they hear these sounds frequently—but declines for Japanese babies (Kuhl et al., 2006).
Newborns apparently are biologically capable of hearing the entire range of pho- nemes in all languages worldwide. But as babies grow and are more exposed to a particular language, they begin to notice only the linguistic distinctions that are mean- ingful in their own language (Maye, Weiss & Aslin, 2008). Thus, specializing in one language apparently comes at the cost of making it more diffi cult to hear sounds in other languages (Best, 1995). This pattern of greater specialization in speech percep- tion is very reminiscent of the profi le for face perception (pages 113–116). With greater exposure to human faces, babies development a more refi ned notion of a human face, just as they develop a more refi ned notion of the sounds that are important in their native language.
phonemes
unique sounds used to create words; the
basic building blocks of language
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IDENTIFYING WORDS. Of course, hearing individual phonemes is only the fi rst step in perceiving speech. One of the biggest challenges for infants is identifying recurring patterns of sounds—words. Imagine, for example, an infant overhearing this conver- sation between a parent and an older sibling:
sibling: Jerry got a new bike. parent: Was his old bike broken? sibling: No. He’d saved his allowance to buy a new mountain bike.
An infant listening to this conversation hears bike three times. Can the infant learn from this experience? Yes. When 7- to 8-month-olds hear a word repeatedly in diff er- ent sentences, they later pay more attention to this word than to words they haven’t heard previously. Evidently, 7- and 8-month-olds can listen to sentences and recognize the sound patterns that they hear repeatedly (Houston & Jusczyk, 2003; Saff ran, Aslin, & Newport, 1996). By 6 months, infants pay more attention to content words (e.g., nouns, verbs) than to function words (e.g., articles, prepositions), and they look at the correct parent when they hear “mommy” or “daddy” (Shi & Werker, 2001; Tincoff & Jusczyk, 1999).
In normal conversation, there are no silent gaps between words, so how do in- fants pick out words? Stress is one important clue. English contains many one-syllable words that are stressed and many two-syllable words that have a stressed syllable fol- lowed by an unstressed syllable (e.g., dough′-nut, tooth′-paste, bas′-ket). Infants pay more attention to stressed syllables than unstressed syllables, which is a good strategy for identifying the beginnings of words (Mattys et al., 1999; Thiessen & Saff ran, 2003). And infants learn words more readily when they appear at the beginning and ends of sentences, probably because the brief pause between sentences makes it easier to identify fi rst and last words (Seidl & Johnson, 2006).
Of course, stress is not a foolproof sign. Many two-syllable words have stress on the second syllable (e.g., gui-tar′, sur-prise′), so infants need other methods to identify words in speech. One method is statistical. Infants notice syllables that go together fre- quently (Jusczyk, 2002). For example, in a study by Aslin, Saff ran, and Newport (1998), 8-month-olds heard the following sounds, which consisted of four three-syllable artifi - cial words, said over and over in random order:
pa bi ku go la tu da ro pi ti bu do da ro pi go la tu pa bi ku da ro pi . . . .
We’ve underlined the words and inserted gaps between them so you can see them more easily, but in the study there were no breaks at all—just a steady fl ow of syl- lables for 3 minutes. Later, infants listened to these words less than to new words that were novel combinations of the same syllables. They had detected pa bi ku, go la tu, da ro pi, and ti bu do as familiar patterns and hence listened to them less than to new “words” like tu da ro, even though the latter were made up from syllables they’d already heard.
Yet another way that infants identify words is through their emerging knowledge of how sounds are used in their native language. For example, think about these two pairs of sounds: s followed by t and s followed by d. Both pairs of sounds are quite com- mon at the end of one word and the beginning of the next: bus takes, kiss took; this dog, pass directly. However, s and t occur frequently within a word (stop, list, pest, stink) but s and d do not. Consequently, when d follows an s, it probably starts a new word. In fact, 9-month-olds follow rules like this one because—when they hear novel words em- bedded in continuous speech—they’re more likely to identify the novel word when the fi nal sound in the preceding word occurs infrequently with the fi rst sound of the novel word (Mattys & Jusczyk, 2001). Thus, infants use many powerful tools to identify words in speech. Of course, they don’t yet understand the meanings of these words; they just recognize a word as a distinct confi guration of sounds.
Parents (and other adults) often help infants master language sounds by talking in a distinctive style. In infant-directed speech, adults speak slowly and with exaggerated changes in pitch and loudness. If you listen to a mother talking to her baby, you will
infant-directed speech
speech that adults use with infants that is
slow and has exaggerated changes in pitch
and volume; it is thought to aid language
acquisition
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notice that she alternates between speaking softly and loudly and be- tween high and low pitches and that her speech seems emotionally ex- pressive (Liu et al., 2007; Trainor, Austin, & Desjardins, 2000). Infant- directed speech is also known as motherese because this form of speaking was fi rst noted in mothers, although it’s now known that most caregivers talk this way to infants.
Infant-directed speech may attract infants’ attention more than adult-directed speech (Kaplan et al., 1995; Lewkowicz, 2000b) because its slower pace and accentuated changes provide infants with more (and more salient) language clues. For example, infants can segment words more eff ectively when they hear them in infant-directed speech (Thies- sen, Hill, & Saff ran, 2005). In addition, infant-directed speech includes especially good examples of vowels (Kuhl et al., 1997), which may help infants learn to distinguish these sounds. When talking to infants, speak- ing clearly is a good idea. In one study (Liu, Kuhl, & Tsao, 2003), infants who could best distinguish speech sounds had mothers who spoke most clearly.
Infant-directed speech, then, helps infants perceive the sounds that are fundamental to their language. But how do infants accomplish the next step, producing speech? We answer this question next.
Steps to Speech As any new parent can testify, newborns and young babies make many sounds— they cry, burp, and sneeze. Language-based sounds don’t appear immediately. At two months, infants begin to produce vowel-like sounds, such as “ooooooo” or “ahhhhhh,” a phenomenon known as cooing. Sometimes infants become quite excited as they coo, perhaps refl ecting the joy of simply playing with sounds.
After cooing comes babbling, speechlike sound that has no meaning. A typical 6-month-old might say “dah” or “bah,” utterances that sound like a single syllable con- sisting of a consonant and a vowel. Over the next few months, babbling becomes more elaborate as babies apparently experiment with more complex speech sounds. Older infants sometimes repeat a sound, as in “bahbahbah,” and begin to combine diff erent sounds, such as “dahmahbah” (Hoff , 2005).
Babbling is not just mindless playing with sounds; it is a precursor to real speech. We know this, in part, from video records of people’s mouths while speaking. When adults speak, their mouth is open somewhat wider on the right side than on the left side, refl ecting the left hemisphere’s control of language and muscle movements on the body’s right side (Graves & Landis, 1990). Infants do the same when they babble but not when making other nonbabbling sounds, which suggests that babbling is fun- damentally linguistic (Holowka & Petitto, 2002).
Other evidence for the linguistic nature of babbling comes from studies of devel- opmental change in babbling: At roughly 8 to 11 months, infants’ babbling sounds more like real speech because infants stress some syllables and vary the pitch of their speech (Snow, 2006). In English declarative sentences, for example, pitch fi rst rises and then falls toward the end of the sentence. In questions, however, the pitch is level and then rises toward the end of the question. Older babies’ babbling refl ects these patterns: Babies who are brought up by English-speaking parents have both the declarative and question patterns of intonation in their babbling. Babies exposed to a language with diff erent patterns of intonation, such as Japanese or French, refl ect their language’s intonation in their babbling (Levitt & Utman, 1992).
The appearance of intonation in babbling indicates a strong link between percep- tion and production of speech: Infants’ babbling is infl uenced by the characteristics of the speech that they hear. Beginning in the middle of the fi rst year, infants try to reproduce the sounds of language that others use in trying to communicate with them (or, in the case of deaf infants with deaf parents, the signs that others use). Hearing dog, an infant may fi rst say “dod” and then “gog” before fi nally saying “dog” correctly. In the same way that beginning typists gradually link movements of their fi ngers with
cooing
early vowel-like sounds that babies
produce
babbling
speechlike sounds that consist of vowel–
consonant combinations; common at
about 6 months
When mothers and other adults talk to young
children, they often use infant-directed speech in
which they speak slowly and with exaggerated
changes in pitch and loudness.
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particular keys, through babbling infants learn to use their lips, tongue, and teeth to produce specifi c sounds, gradually making sounds that approximate real words (Poul- son et al., 1991). Fortunately, learning to produce language sounds is easier for most babies than the cartoon suggests!
These developments in production of sound, coupled with the 1-year-old’s ad- vanced ability to perceive speech sounds, clearly set the stage for the infant’s fi rst true words.
| First Words and Many More
Recall that Nabina, the 1-year-old in the vignette, looks at the family cat when she hears its name. This phenomenon is common in 10- to 14-month-olds. They appear to understand what others say despite the fact that they have yet to speak. In response to “Where is the book?” children will go fi nd the book. They grasp the question, even though their own speech is limited to advanced babbling (Fenson et al., 1994; Hoff - Ginsberg, 1997). Evidently, children have made the link between speech sounds and particular objects, even though they cannot yet manufacture the sounds themselves. As fl uent adult speakers, we forget that speech is a motor skill requiring perfect timing and tremendous coordination.
A few months later, most youngsters utter their fi rst words. These words typically have a structure, borrowed from their advanced babbling, that consists of a consonant- vowel pair that may be repeated. Mama and dada are common examples of this type of construction. Other common words in early vocabularies denote animals, food, and toys (Caselli et al., 1995; Nelson, 1973). Also common are words that denote actions (e.g., go). By the age of 2, youngsters have a vocabulary of a few hundred words; by 6, a typical child’s vocabulary includes more than 10,000 words (Anglin, 1993). However, children diff er markedly in the size of their vocabulary. At 16-months, vocabularies typically range from as few as 10 words to as many as 150; at 2½ years, from 375 words to 650 (Fenson et al., 1994).
The Grand Insight: Words as Symbols To make the transition from babbling to real speech, infants need to learn that speech is more than just entertaining sound. They need to know that particular sounds form words that can refer to objects, actions, and properties. Put another way, infants must recognize that words are symbols—entities that stand for other entities.
A vivid account of this insight came from Helen Keller, an American essayist. Born in 1880 and left blind and deaf from an illness during infancy, she had no means of communicating with other people. When Helen was 7 years old, a tutor attempted to teach her words by spelling them in her hands. For Helen, the hurdle was to link the fi nger spelling with concepts she already knew; in her case, awareness came suddenly (Keller, 1965, p. 21):
Someone was drawing water and my teacher placed my hand under the spout. As the cool stream gushed over one hand she spelled into the other the word water, fi rst slowly, then rapidly. I stood still, my whole attention fi xed upon the
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T H I N K A B O U T I T
Compare and contrast the steps in
learning to make speech sounds with
Piaget’s account of the sensorimotor
period
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motions of her fi ngers. Suddenly I felt a misty consciousness as of something forgotten—a thrill of returning thought; and somehow the mystery of language
was revealed to me. I knew then that “w-a-t-e-r” meant the wonder- ful and cool something that was fl owing over my hand. That living word awakened my soul, gave it light, hope, joy, set it free!
When do youngsters who can hear and see have this insight? Piaget believed that it occurs at roughly 18 months of age and that it marks the beginning of transition from the sensorimotor to the preopera- tional stage. However, a glimmer of understanding of symbols occurs earlier, soon after the fi rst birthday. By this age, children have already formed concepts such as “round, bouncy things” or “furry things that bark,” based on their own experiences. With the insight that speech sounds can denote these concepts, infants begin to identify a word that goes with each concept (Reich, 1986).
If this argument is correct then we should fi nd that children use symbols in other areas, not just in language. They do. Gestures are symbols, and infants begin to gesture shortly before their fi rst birth- day (Goodwyn & Acredolo, 1993). Young children may smack their lips to indicate hunger or wave “bye-bye” when leaving. In these cases, gestures and words convey a message equally well.
What’s more, gesture sometimes paves the way for language. Be- fore knowing an object’s name, infants often point to it or pick it up for a listener, as if to say “I want this!” or “What’s this?” In one study, 50% of all objects were fi rst referred to by gesture and, about 3 months later, by word (Iverson & Goldin-Meadow, 2005). After children know that objects have names, a gesture is a convenient substitute for pronouns like “it” or “that” and often causes an adult to say the object’s name.
What’s What? Fast Mapping of Words After children develop the insight that a word can symbolize an ob- ject or action, their vocabularies grow, but slowly at fi rst. A typical
15-month-old, for example, may learn two to three new words each week. However, at about 18 months, many children experience a naming explosion during which they learn new words—particularly names of objects—much more rapidly than before. Children now learn ten or more new words each week (Fenson et al., 1994).
This rapid rate of word learning is astonishing when we realize that most words have many plausible but incorrect referents. To illustrate, imagine what’s going through the mind of a child when her mother points to a fl ower and says, “Flower. This is a fl ower. See the fl ower.” This all seems crystal clear to you and incredibly straightfor- ward. But what might the child learn from this episode? Perhaps the correct referent for “fl ower.” But a youngster could, just as reasonably, conclude that “fl ower” refers to a petal, to the color of the fl ower, or to the mother’s actions in pointing at the fl ower.
Surprisingly, though, most youngsters learn the proper meanings of simple words in just a few presentations. Children’s ability to connect new words to referents so rap- idly that they cannot be considering all possible meanings for the new word is termed fast mapping. How can young children learn new words so rapidly? Researchers be- lieve that many distinct factors contribute to young children’s rapid word learning (Hollich, Hirsh-Pasek, & Golinkoff , 2000).
JOINT ATTENTION. Parents encourage word learning by carefully watching what in- terests their children. When toddlers touch or look at an object, parents often label it for them. When a youngster points to a banana, a parent may say, “Banana, that’s a banana.” And parents usually simplify the task for children by using just one label for an object (Callanan & Sabbagh, 2004).
Of course, to take advantage of this help, infants must be able to tell when parents are labeling instead of just conversing. In fact, when adults label an unfamiliar object, 18- to 20-month-olds assume that the label is the object’s name only when adults show
Helen Keller became deaf and blind in infancy
but learned to speak at 7 years of age. ©
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a child’s connections between words and
referents that are made so quickly that he
or she cannot consider all possible mean-
ings of the word
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signs that they are referring to the object. For example, toddlers are more likely to learn the name of an object or action when adults look at the object or action while saying its name than when adults look elsewhere while labeling (Diesend- ruck et al., 2004; Poulin-Dubois & Forbes, 2002). Thus, beginning in the toddler years, parents and children work together to create condi- tions that foster word learning: Parents label objects and youngsters rely on adults’ behavior to interpret the words they hear.
Although joint attention helps children to learn words, it is not required: Children learn new words that are used in ongoing con- versation and when they overhear others using novel words (Akhtar, Jipson, & Callanan, 2001). And when speakers appear unfamiliar with a novel person or object, 4- and 5-year-olds are less likely to learn new words—as if they doubt the speakers know what they’re talking about (Jaswal & Neely, 2007; Pasquini et al., 2007).
CONSTRAINTS ON WORD NAMES. Joint attention simplifi es word learning for children, but the problem still remains: How does a tod- dler know that banana refers to the object that she’s touching, as opposed to her activity (touching) or to the object’s color? Many re- searchers believe that young children follow several simple rules that limit their conclusions about what labels mean.
A study by Au and Glusman (1990) shows how researchers have identifi ed rules that young children use. Au and Glusman presented preschoolers with a stuff ed animal with pink horns that otherwise resembled a monkey and called it a mido. Mido was then repeated several times, always referring to the monkeylike stuff ed animal with pink horns. Later, these youngsters were asked to fi nd a theri in a set of stuff ed animals that included several mido. Never having heard of a theri, what did the children do? They never picked a mido; instead, they selected other stuff ed animals. Knowing that mido referred to monkeylike animals with pink horns, evidently they decided that theri must refer to one of the other stuff ed animals.
Apparently children were following this simple but eff ective rule for learning new words:
If an unfamiliar word is heard in the presence of objects that already have ■ names and objects that don’t, the word refers to one of the objects that doesn’t have a name.
Researchers have discovered several other simple rules that help children match words with the correct referent (Hoff , 2005; Woodward & Markman, 1998):
A name refers to a whole object, not its parts or its relation to other objects, ■ and refers not just to this particular object but to all objects of the same type (Hollich et al., 2007). For example, when a grandparent points to a stuffed ani- mal on a shelf and says “dinosaur,” children conclude that dinosaur refers to the entire dinosaur, not just its ears or nose, not to the fact that the dinosaur is on a shelf, and not to this specific dinosaur but to all dinosaurlike objects.
If an object already has a name and another name is presented, the new name ■ denotes a subcategory of the original name. If the child who knows the mean- ing of dinosaur sees a brother point to another dinosaur and hears the brother say “T-rex,” the child will conclude that T-rex is a special type of dinosaur.
Given many similar category members, a word applied consistently to only ■ one of them is a proper noun. If a child who knows dinosaur sees that one of a group of dinosaurs is always called “Dino,” the child will conclude that Dino is the name of that dinosaur.
Rules like these make it possible for children like Nabina, the child in the vignette, to learn words rapidly because they reduce the number of possible referents. The child
One of the challenges for theories of language
learning is to explain how children figure out
that the parent’s words refer to the object, not
to its color or texture and not to the parent.
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being shown a fl ower follows these rules to decide that fl ower refers to the entire ob- ject, not its parts or the action of pointing to it.
SENTENCE CUES. Children hear many unfamiliar words embedded in sentences con- taining words they already know. The other words and the overall sentence structure can be helpful clues to a word’s meaning.
For example, when a parent describes an event using familiar words but an un- familiar verb, children often infer that the verb refers to the action performed by the subject of the sentence (Fisher, 1996; Woodward & Markman, 1998). When youngsters hear, “The man is juggling,” they will infer that juggling refers to the man’s actions with the bowling pins because they already know man and because -ing refers to on- going actions.
As another example of how sentence context aids word learning, look at the blocks in ❚ Figure 4.6 and point to the “boz block.” You probably pointed to the middle block. Why? In English, adjectives usually precede the nouns they modify, so you inferred that boz is an adjective describing block. Since the before boz implies that only one block is boz, you picked the middle one, having decided that boz means “winged.” Tod- dlers, too, use sentence cues like these to judge word meanings. Hearing “This is a zav,” 2-year-olds will interpret zav as a category name; but hearing “This is Zav” (without the article a), they interpret zav as a proper name (Hall, Lee, & Belanger, 2001).
Figure 4.6 ❚ “The boz block” probably refers to the
middle block because “the” implies that only
one block is “boz” and the middle block is
the only one with wings.
COGNITIVE FACTORS. The naming explosion coincides with a time of rapid cogni- tive growth, and children’s increased cognitive skill helps them to learn new words. As children’s thinking becomes more sophisticated and, in particular, as they start to have goals and intentions, language becomes a means to express those goals and to achieve them. Thus, intention provides children with an important motive to learn language—to help achieve their goals (Bloom & Tinker, 2001).
In addition, young children’s improving attentional and perceptual skills also pro- mote word learning. Smith (2000), for example, argues that shape plays a central role in learning words. Infants and young children spontaneously pay attention to an ob- ject’s shape, and they use this bias to learn new words. In Smith’s theory, children fi rst associate names with a single object: “ball” is associated with a specifi c tennis ball, and “cup” is associated with a favorite sippy cup. As children encounter new balls and new cups, however, they hear the same words applied to similarly shaped objects and reach the conclusion that balls are round and cups are cylinders with handles. With further experience, children derive an even more general rule: Objects that have the same shape have the same name. From this, children realize that paying attention to shape is an easy way to learn names. Consistent with this theory, the shape bias and the naming explosion typically occur at about the same time (Gershkoff -Stowe & Smith, 2004).
DEVELOPMENTAL CHANGE IN WORD LEARNING. Some of the word-learning tools described in the past few pages are particularly important at diff erent ages (Hirsh- Pasek & Golinkoff , 2008). Before 18 months, infants learn words relatively slowly— often just one new word each day. At this age, children rely heavily on simple at- tentional processes (e.g., the shape bias) to learn new words. But by 24 months, most children are learning many new words daily. This faster learning refl ects children’s greater use of language cues (e.g., constraints on names) and a speaker’s social cues. At any age, infants and toddlers rely on a mixture of word-learning tools, but with age they gradually move away from attentional cues to language and social cues.
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NAMING ERRORS. Of course, these rules for learning new words are not perfect; ini- tial mappings of words onto meanings are often only partially correct (Hoff & Naigles, 2002). A common mistake is underextension, defi ning a word too narrowly. Using car to refer only to the family car and ball to a favorite toy ball are examples of underex- tension. Between 1 and 3 years, children sometimes make the opposite error, overex- tension, defi ning a word too broadly. Children may use car to also refer to buses and trucks or use doggie to refer to all four-legged animals.
The overextension error occurs more frequently when children are producing words than when they are comprehending words. Two-year-old Jason may say “dog- gie” to refer to a goat but nevertheless correctly point to a picture of a goat when asked. Because overextension is more common in word production, it may actually refl ect another fast-mapping rule that children follow: “If you can’t remember the name for an object, say the name of a related object” (Naigles & Gelman, 1995). Both underexten- sion and overextension disappear gradually as youngsters refi ne meanings for words after increased exposure to language.
Individual Differences in Word Learning The naming explosion typically occurs at about 18 months, but like many develop- mental milestones, the timing of this event varies widely for individual children. Some youngsters have a naming explosion as early as 14 months, but for others it may be as late as 22 months (Goldfi eld & Reznick, 1990). Another way to make this point is to look at variation in the size of children’s vocabulary at a specifi c age. At 18 months, for example, an average child’s vocabulary would have about 75 words, but a child in the 90th percentile would know nearly 250 words and a child in the 10th percentile fewer than 25 words (Fenson et al., 1994).
This range in vocabulary size for typical 18-month-olds is huge—from 25 to 250 words! What can account for this diff erence? Heredity contributes: Twin studies fi nd that vocabulary size is more similar in identical twins than in fraternal twins (Dionne et al., 2003). But the diff erence is fairly small, indicating a relatively minor role for genetics.
More important are two other factors. One is phonological memory, the ability to remember speech sounds briefl y. This is often measured by saying a nonsense word to children—“ballop” or “glistering”—and asking them to repeat it immediately. Chil- dren’s skill in recalling such words is strongly related to the size of their vocabulary (Gathercole et al., 1992). Children who have diffi culty remembering speech sounds ac- curately fi nd word learning particularly challenging, which is not surprising because word learning involves associating meaning with an unfamiliar sequence of speech sounds.
However, the single most important factor in growth of vocabulary is the child’s language environment. Children have larger vocabularies when they are exposed to much high-quality language. The more words that children hear, the better. Specifi - cally, children learn more words when their parents’ speech is rich in diff erent words and is grammatically sophisticated (Hoff , 2003; Hoff & Naigles, 2002) and when par- ents respond promptly and appropriately to their children’s talk (Tamis-Lemonda & Bornstein, 2002).
BILINGUALISM. Millions of American children grow up in bilingual households; these youngsters usually speak English and another language. When infants learn two languages simultaneously, they often progress somewhat slowly at fi rst. They mix words from the two languages and are less skilled at using language-specifi c sounds to guide word learning (Fennell, Byers-Heinlein, & Werker, 2007). Soon, however, they separate the languages, and bilingual children reach most language milestones at about the same age as monolingual children (Pettito et al., 2001). When each language is considered separately, bilingual children often have somewhat smaller vocabularies than monolingual children (Umbel et al., 1992). However, because bilingual young- sters often know words in one language but not the other, their total vocabulary (i.e., words known in both languages plus words known in either language but not both)
underextension
when children defi ne words more nar-
rowly than adults do
overextension
when children defi ne words more broadly
than adults do
phonological memory
ability to remember speech sounds briefl y;
an important skill in acquiring vocabulary
T H I N K A B O U T I T
Gavin and Mitch are both 16-month-
olds. Gavin’s vocabulary includes about
14 words, but Mitch’s has about 150
words, more than 10 times as many as
Gavin. What factors contribute to this
difference?
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is greater than that of monolingual children. What’s more, bilingual children also bet- ter understand that words are simply arbitrary symbols. Bilingual youngsters, for in- stance, are more likely than monolingual children to understand that, as long as all English speakers agreed, dog could refer to cats and cat could refer to dogs (Bialystok, 1988; Campbell & Sais, 1995).
WORD LEARNING STYLES. As youngsters expand their vocabulary, they often adopt a distinctive style of learning language (Bates, Bretherton, & Snyder, 1988; Nelson, 1973). Some children have a referential style; their vocabularies mainly consist of words that name objects, persons, or actions. For example, Rachel, a referential child, had 41 name words in her 50-word vocabulary but only two words for social interaction or ques- tions. Other children have an expressive style; their vocabularies include some names but also many social phrases that are used like a single word, such as “go away,” “what’d you want?” and “I want it.” Elizabeth, an expressive child, had a more balanced vocabu- lary, with 14 words for social interactions and questions and 24 name words.
Referential and expressive styles represent end points on a continuum; most chil- dren are somewhere in between. For children with referential emphasis, language is primarily an intellectual tool: a means of learning and talking about objects (Masur, 1995). In contrast, for children with expressive emphasis, language is more of a social tool: a way of enhancing interactions with others. Of course, both of these functions— intellectual and social—are important functions of language, which explains why most children blend the referential and expressive styles of learning language.
Encouraging Language Growth How can parents and other adults help children learn words? For children to expand their vocabularies, they need to hear others speak. Not surprisingly, then, children learn words more rapidly if their parents speak to them frequently (Huttenlocher et al., 1991; Roberts, Burchinal, & Durham, 1999). Of course, sheer quantity of parental speech is not all that matters. Parents can foster word learning by naming objects that are the focus of a child’s attention (Dunham, Dunham, & Curwin, 1993). Parents can name diff erent products on store shelves as they point to them. During a walk, parents can label the objects—birds, plants, vehicles—that the child sees.
Parents can also help children learn words by reading books with them. Reading together is fun for parents and children alike and provides opportunities for children to learn new words. However, the way that parents read makes a diff erence. When parents carefully describe pictures as they read, preschoolers’ vocabularies increase (Reese & Cox, 1999). Asking children questions during reading also helps (Sénéchal, Thomas, &-Monker, 1995). When an adult reads a sentence (e.g., “Arthur is angling”),
then asks a question (e.g., “What is Arthur do- ing?”), a child must match the new word (an- gling) with the pictured activity (fi shing) and say the word aloud. When parents read with- out questioning, children can ignore words they don’t understand. Questioning forces children to identify meanings of new words and practice saying them.
Watching television can help word learning under some circumstances. For example, pre- school children who frequently view Sesame Street often have larger vocabularies by the time they enter kindergarten than do preschool- ers who watch Sesame Street less often (Rice et al., 1990). Other kinds of television programs— notably cartoons—do not have this positive infl uence.
What accounts for the diff erence? The key to success is encouraging children to become
referential style
language-learning style of children whose
vocabularies are dominated by names of
objects, persons, or actions
expressive style
language-learning style of children whose
vocabularies include many social phrases
that are used like one word
Children can learn words from TV programs that
actively engage them in language-related activi-
ties such as naming, singing, or counting.
© 1
99 4
D on
P er
du e
/ C
hi ld
re n’
s Te
le vi
si on
W or
ks ho
p
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actively involved in language-related activities. Video segments that encourage young- sters to name objects, to sing, and to count help children increase their vocabulary. Ap- parently, the fundamental principle is much the same for television and for parents: Children expand their vocabularies when they have experiences that engage and chal- lenge their emerging language talents.
| Speaking in Sentences: Grammatical Development
Within months after children say their fi rst words, they begin to form simple two- word sentences. Such sentences are based on “formulas” that children fi gure out from their own experiences (Braine, 1976; Radford, 1995). Armed with a few formulas, chil- dren can express an enormous variety of ideas:
Formula Example
actor + action Mommy sleep, Timmy run action + object Gimme cookie, throw ball possessor + possession Kimmy pail, Maya shovel
Each child develops a unique repertoire of formulas, refl ecting his or her own experi- ences. However, the formulas listed here are commonly used by many children grow- ing up in diff erent countries around the world.
From Two Words to Complex Sentences Children rapidly move beyond two-word sentences, fi rst doing so by linking two-word statements together: “Rachel kick” and “Kick ball” become “Rachel kick ball.” Even longer sentences soon follow; sentences with 10 or more words are common in 3-year- olds’ speech. For example, at 1½ years, Laura Kail would say, “Gimme juice” or “Bye-bye Ben.” As a 2½-year-old, she had progressed to “When I fi nish my ice cream, I’ll take a shower, okay?” and “Don’t turn the light out—I can’t see better!”
Children’s two- and three-word sentences often fall short of adults’ standards of grammar. Youngsters will say, “He eating” rather than “He is eating,” or “two cat” rather than “two cats.” This sort of speech is called telegraphic because, like telegrams of days gone by, children’s speech includes only words directly relevant to meaning, and noth- ing more. Before cell phones and e-mail, people sent urgent messages by telegraph, and the cost was based on the number of words. Consequently, telegrams were brief and to the point, containing only the important nouns, verbs, adjectives, and adverbs—much like children’s two-word speech. The missing elements, grammatical morphemes, are words or endings of words (such as -ing, -ed, or -s) that make a sentence grammatical. During the preschool years, children gradually acquire the grammatical morphemes, fi rst mastering those that express simple relations like -ing, which is used to denote that the action expressed by the verb is ongoing. More complex forms, such as appro- priate use of the various forms of the verb to be, are mastered later (Peters, 1995).
Children’s use of grammatical morphemes is based on their growing knowledge of grammatical rules, not simply memory for individual words. This was fi rst demon- strated in a landmark study by Berko (1958) in which preschoolers were shown pictures of nonsense objects like the one in ❚ Figure 4.7. The experimenter labeled it, saying, “This is a wug.” Then youngsters were shown pictures of two of the objects, and the experimenter said, “These are two.” Most children spontaneously said, “wugs.” Because both the singular and plural forms of this word were novel for these youngsters, they could have generated the correct plural form only by applying the familiar rule of adding -s.
Children growing up in homes where English is spoken face the problem that their native tongue is highly irregular, with many exceptions to the rules. Sometimes chil- dren apply rules to words that are exceptions to the rule, errors called overregulariza- tions. With plurals, for example, youngsters may incorrectly add an -s instead of using an irregular plural—two “mans” instead of two “men.” With the past tense, children may add -ed instead of using an irregular past tense: “I goed home” instead of “I went home” (Marcus et al., 1992; Mervis & Johnson, 1991).
telegraphic speech
speech used by young children that con-
tains only the words necessary to convey
a message
grammatical morphemes
words or endings of words that make a
sentence grammatical
overregularization
grammatical usage that results from ap-
plying rules to words that are exceptions
to the rule
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These examples give some insight into the complexities of mastering the grammatical rules of one’s language. Not only must children learn an extensive set of specifi c rules, they must also absorb—on a case-by-case basis—all of the exceptions. Despite the enormity of this task, most children have mastered the basics of their na-
tive tongue by the time they enter school. How do they do it? Biological, psychologi- cal, and sociocultural forces all contribute.
How Do Children Acquire Grammar? Most youngsters can neither read nor do arithmetic when they enter kindergarten, but virtually all have mastered the fundamentals of grammar of their native tongue. How do they do it? Theorists have proposed several diff erent answers to this question.
THE BEHAVIORIST ANSWER. Probably the simplest explanation for learning gram- mar is that children imitate the grammatical forms they hear. In fact, B. F. Skin- ner (1957) and other learning theorists once claimed that all aspects of language— sounds, words, grammar, and communication—are learned through imitation and reinforcement (Whitehurst & Vasta, 1975).
Critics were quick to point to some fl aws in this theory. One problem is that most of children’s sentences are novel, which is diffi cult to explain in terms of sim- ple imitation of adults’ speech. For example, when young children create questions by inserting a wh word at the beginning of a sentence (“What she doing?”), who are they imitating? Also troublesome is that, even when children imitate adult sen-
tences, they do not imitate adult grammar. In simply trying to repeat “I am drawing a picture,” young children will say “I draw picture.” Finally, linguists (see, e.g., Chomsky, 1957, 1995) have argued that grammatical rules are far too complex for toddlers and preschoolers to infer them solely on the basis of speech that they hear.
THE LINGUISTIC ANSWER. Many scientists believe that children are born with mech- anisms that simplify the task of learning grammar (Slobin, 1985). According to this view, children are born with neural circuits in the brain that allow them to infer the grammar of the language that they hear. That is, grammar itself is not built into the child’s nervous system, but processes that guide the learning of grammar are. Many fi ndings indirectly support this view:
1. If children are born with a “grammar learning processor,” then specific regions of the brain should be involved in learning grammar. As we dis- cussed on page 96, the left hemisphere of the brain plays a critical role in understanding language.
2. If learning grammar depends on specialized neural mechanisms that are unique to humans, then eff orts to teach grammar to nonhumans should fail. This prediction has been tested by trying to teach grammar to chim- panzees, the species closest to humans on the evolutionary ladder. The result: Chimps master a handful of grammatical rules governing two-word speech, but only with massive eff ort that is completely unlike the preschool child’s learning of grammar (Savage-Rumbaugh et al., 1993; Seyfarth & Cheney, 1996).
3. The period from birth to about 12 years is a critical period for acquiring language generally and mastering grammar particularly. If children do not acquire language in this period, they never truly master language later (Newport, 1991; Rymer, 1993).
4. The mastery of grammar is closely related to vocabulary growth in a way that suggests both are part of a common, emerging language system (Dixon & Marchman, 2007). For example, one idea is that, as children learn words, they learn not only a word’s meaning but also about the kinds of sentences in which a word appears and its position in those sentences. They learn the meaning of “teacher” and that “teacher” can appear as the actor and object in transitive sentences. Grammar than emerges naturally as children learn more and more words.
This is a wug.
Now there is another one. There are two of them. There are two ____________.
Berko, 1958.
Figure 4.7 ❚ When shown the two birds, young children
usually refer to them as two “wugs,” spon-
taneously adding an s to “wug” to make it
plural.
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Although these fi ndings are consistent with the idea that children have innate gram- mar-learning mechanisms, they do not prove the existence of such mechanisms. Con- sequently, scientists have continued to look for other explanations.
THE COGNITIVE ANSWER. Some theorists (Braine, 1992) believe that children learn grammar through powerful cognitive skills that help them rapidly detect regularities in their environment, including patterns in the speech they hear. According to this ap- proach, it’s as if children establish a huge spreadsheet that has the speech they’ve heard in one column and the context in which they heard it in a second column; periodically infants scan the columns looking for recurring patterns (Maratsos, 1998). For example, children might be confused the fi rst time they hear -s added to the end of a familiar noun. However, as the database expands to include many instances of familiar nouns with an added -s, children discover that -s is always added to a noun when there are multiple instances of the object. Thus, they create the rule: noun + -s = plural. With this view, children learn language by searching for regularities across many examples that are stored in memory, not through an inborn grammar-learning device.
Scientists who subscribe to this view argue that infants’ impressive ability to ex- tract regularities in the speech sounds that they hear (described on page 153) would work just as eff ectively to extract regularities in sentence structure. In the Spotlight on Research feature, we describe a study showing that infants can indeed infer gram- mars quickly.
Spotlight on Research Infants Infer Grammatical Rules From Speech
Who were the investiga-
tors, and what was the
aim of the study? Accord-
ing to a cognitive account of grammar learning,
as long as children have adequate exposure to
different grammatical forms, they can infer the
underlying grammatical rules. For example, re-
peated exposure to phrases such as “my car,”
“your hat,” “her keys,” and “his book” should be
enough for children to infer two categories of
words—possessive pronouns and objects—and
infer that “possessive pronoun + object” is a legal
sentence. LouAnn Gerken (2005) conducted a
study to determine whether infants can, in fact,
infer grammatical rules in this manner.
How did the investigators measure the topic
of interest? Gerken created nonsense words
and divided them into two arbitrary categories:
Examples of “A” words were le, ji, and wi; ex-
amples of B words were di, li, and je. Infants heard
“sentences” consisting of an A word, the same A
word repeated, and a B word:
le le di,
ji ji li,
wi wi je.
These were repeated over and over for two
minutes. Test trials came next: Infants heard
different sentences, some consisting of new
sounds that followed the AAB rule (e.g., ko ko
di) as well as others made up of new sounds
that did not follow the AAB rule (e.g., ko di ko).
These new sentences were played, one at a time,
through loudspeakers to the infant’s left or right.
Each sentence was played as long as the infant
looked in the direction of the loudspeaker; the
experimenter measured the length of the baby’s
looking.
Who were the children in the study? Gerken
tested 32 9-month-olds.
What was the design of the study? This study
was experimental: The independent variable was
whether the strings played on test trials had the
same structure (AAB) as the sentences played
originally. The dependent variable was the length
of time that infants looked in the direction of the
loudspeaker that was playing the sentence. The
study was not developmental (only 9-month-olds
participated and they were tested just once), so
it was neither cross-sectional nor longitudinal.
Were there ethical concerns with the study? No.
The task posed no danger to the infants, who
were seated on a caregiver’s lap throughout
testing.
What were the results? Infants looked longer in
the direction of the loudspeaker that presented
strings matching the original grammar (13.51
seconds) than in the direction of the loudspeaker
presenting strings that did not match the original
grammar (10.14 seconds). In other words, hav-
ing heard strings such as le le di, they preferred
a novel “grammatical” string like ko ko di over a
novel “ungrammatical” string like ko di ko.
What did the investigators conclude? This work
and other similar studies (e.g., Marcus et al.,
1999) shows that infants are remarkably skilled
at identifying the rules that generate simple
sequences of words. With just two minutes of
exposure to strings like le le di and ji ji li, infants
extracted the AAB rule that generated sentences
and then recognized that a new string, ko ko di,
followed the rule but ko di ko did not.
What converging evidence would strengthen
these conclusions? The grammars used here were
quite simple, and each category included only a
small number of words. Obviously, even relatively
simple English sentences have more complex
rules than these, and the number of words that
can belong to each category is enormous. Con-
sequently, a valuable step would be extending this
work to grammars that are more representative
of the ones that children actually master.
To enhance your understanding of this re-
search, go to www.cengage.com/psychology/
kail to complete critical thinking questions
and explore related websites.
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Thus, from a surprisingly young age, infants are able to infer underlying rules—at least from sequences of speech sounds.
THE SOCIAL-INTERACTION ANSWER. This approach is eclectic, drawing on each of the views we’ve considered. From the behaviorist approach, it takes an emphasis on the environment; from the linguistic approach, that language learning is distinct; and from the cognitive view, that children have powerful cognitive skills they can use to master language. The unique contribution of this perspective is emphasizing that much language learning takes place in the context of interactions between children and adults, with both parties eager for better communication (Bloom & Tinker, 2001). Children have an ever-expanding repertoire of ideas and intentions that they wish to convey to others, and caring adults want to understand their children, so both parties work to improve language skills as a means toward better communication. Thus, im- proved communication provides an incentive for children to master language and for adults to help them.
None of these accounts provides a comprehensive explanation of how grammar is mastered. But many scientists believe the fi nal explanation will include contributions from the linguistic, cognitive, and social-interaction accounts. That is, children’s learn- ing of grammar will be explained in terms of some mechanisms specifi c to learning grammar, children actively seeking to identify regularities in their environment, and linguistically rich interactions between children and adults (MacWhinney, 1998).
| Communicating With Others
Imagining two preschoolers arguing is an excellent way to learn what is needed for eff ective communication. Both youngsters probably try to speak at the same time; their remarks may be rambling or incoherent; and they neglect to listen to each other altogether. These actions reveal three key elements in eff ective oral communication with others (Grice, 1975):
People should take turns, alternating as speaker and listener. ■
When speaking, your remarks should be clear from the listener’s perspective. ■
When listening, pay attention and let the speaker know if his or her remarks ■ don’t make sense.
Complete mastery of these elements is a lifelong pursuit. Af- ter all, even adults often miscommunicate with one another, violating each of these prescriptions in the process. However, youngsters grasp many of the basics of communication early in life.
Taking Turns Many parents begin to encourage turn-taking long before in- fants have said their fi rst words (Field & Widmayer, 1982):
parent: Can you see the bird? infant: (cooing) ooooh. parent: It is a pretty bird. infant: ooooh. parent: You’re right, it’s a cardinal.
Soon after 1-year-olds begin to speak, parents encourage their youngsters to participate in conversational turn-taking. To help their children along, parents often carry both sides of the conversation to show how the roles of speaker and listener are alternated (Hoff , 2005):
parent: (initiating conversation) What’s Kendra eating? parent: (illustrating reply for child) She’s eating a cookie.
Arguments can often be traced to people’s
failure to follow the fundamental conversational
rules of taking turns, speaking clearly, and listen-
ing carefully.
S us
an J
oh ns
/ P
ho to
R es
ea rc
he rs
, I nc
.
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Help of this sort is needed less often by age 2, when spontaneous turn- taking is common in conversations between youngsters and adults (Barton & Tomasello, 1991). By 3 years of age, children have progressed to the point that, when a listener fails to reply promptly, the child will often repeat his or her remarks to elicit a response and keep the conver- sation moving (Garvey & Berninger, 1981).
Speaking Effectively When do children fi rst try to initiate communications with others? In fact, what appear to be the fi rst deliberate attempts to communicate typically emerge at 10 months (Bates et al., 1979; Golinkoff , 1993). In- fants at this age may touch or point to an object while simultaneously looking at another person. They continue this behavior until the person acknowledges them. It’s as if the child is saying, “This is a neat toy! I want you to see it, too.”
Beginning at 10 months, an infant may point, touch, or make noises to get an adult to do something. An infant in a playpen who wants a toy that is out of reach may make noises while pointing to the toy. The noises capture an adult’s atten- tion, and the pointing indicates what the baby wants (Blake, O’Rourke, & Borzellino, 1994). The communication may be a bit primitive by adult standards, but it works for babies! And mothers typically translate their baby’s pointing into words, so that gesture paves the wave for learning words (Goldin-Meadow et al., 2007). After the fi rst birthday, children begin to use speech to communicate and often initiate conversations with adults (Bloom et al., 1996). Toddlers’ fi rst conversations are about themselves, but their conversational scope expands rapidly to include objects in the environment (e.g., toys, food). Later, conversations begin to include more abstract notions, such as hypo- thetical objects and past or future events (Foster, 1986).
Of course, young children are not always skilled conversational partners. At times their communications are confusing, leaving a listener to wonder, “What was that all about?” Every message—whether an informal conversation or a formal lecture— should have a clear meaning. But saying something clearly is often diffi cult because clarity can only be judged by considering the listener’s age, experience, and knowledge of the topic, along with the context of the conversation. For example, think about the simple request, “Please hand me the Phillips screwdriver.” This message may be clear to older listeners who are familiar with variants of screwdrivers, but it is vague to younger listeners, to whom all screwdrivers come from the same mold. Of course, if the toolbox is fi lled with Phillips screwdrivers of assorted sizes, the message is am- biguous even to a knowledgeable listener.
Consistently constructing clear messages is a fi ne art, which we would hardly ex- pect young children to have mastered. By the preschool years, however, youngsters have made their initial attempts to calibrate messages, adjusting them to match the listener and the context. For example, preschool children give more elaborate mes- sages to listeners who lack access to critical information than to listeners who have this information (Nadig & Sedivy, 2002; O’Neill, 1996). For example, a child describing where to fi nd a toy will give more detailed directions to a listener whose eyes were covered when the toy was hidden. And, if listeners appear to misunderstand, 2- and 3-year-olds will clarify their messages (Shwe & Markman, 1997). These fi ndings show that preschoolers are already sensitive to the importance of the listener’s skill and un- derstanding in formulating a clear message.
Listening Well Sometimes messages are vague or confusing; in such situations, a listener needs to ask the speaker to clarify the message. Preschoolers do not always realize when a message is ambiguous. Told to fi nd “the red toy,” they may promptly select the red ball from a pile that includes a red toy car, a red block, and a red toy hammer. Instead of asking the speaker to refer to a specifi c red toy, preschool listeners often assume they know
In early parent–child “conversations,” parents
usually carry both sides of the conversation, al-
ternating as speaker and listener.
© T
on y
Fr ee
m an
/ P
ho to
Ed it
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which toy the speaker had in mind (Beal & Belgrad, 1990). During the elementary- school years, youngsters gradually master the many elements involved in determining whether another person’s message is consistent and clear (Ackerman, 1993).
Improvement in communication skill is yet another astonishing accomplishment in language during the fi rst 5 years of life; changes are summarized in ● Table 4.2. By the time children are ready to enter kindergarten, they use language with remarkable profi ciency and are able to communicate with growing skill.
● TA B L E 4 . 2
Major Milestones of Language Development
Age Milestones
Birth to 1 year Babies hear phonemes; they begin to coo and then babble About the 1st birthday Babies begin to talk and to gesture, showing they have begun to use symbols
1–2 years Vocabulary expands rapidly (due to fast mapping); reflective and expressive language learning styles appear; two-word sentences emerge in telegraphic speech; and turn-taking is evident in communication
3–5 years Vocabulary continues to expand; grammatical morphemes are added; and children begin to adjust their speech to listeners but, as listeners, often ignore problems in messages they receive
T H I N K A B O U T I T
Compare Piaget’s theory, Vygotsky’s
theory, and the information-processing
approach in their emphasis on the role
of language in cognitive development.
Recall answers: (1) Phonemes, (2) infant-directed speech, (3) intonation, (4) referential,
(5) overextension, (6) social-interaction, (7) provide more elaborate messages
Test Yourself
RECALL
1. are fundamen-
tal sounds used to create words.
2. Infants’ mastery of language sounds may be fostered by
, in which adults speak slowly and
exaggerate changes in pitch and loudness.
3. Older infants’ babbling often includes ,
a pattern of rising and falling pitch that distinguishes
statements from questions.
4. Youngsters with a(n) style have
early vocabularies dominated by words that are names and
use language primarily as an intellectual tool.
5. In , a young child’s meaning of a
word is broader than an adult’s meaning.
6. Answers to the question, “How do children ac-
quire grammar?” include linguistic, cognitive, and
infl uences.
7. When talking to listeners who lack critical information,
preschoolers .
INTERPRET
How do the various explanations of grammatical development
diff er in their view of the child’s role in mastering grammar?
APPLY
According to Piaget’s theory, preschoolers are egocentric. How
should this egocentrism infl uence their ability to communi-
cate? Are the fi ndings we have described on children’s com-
munication skills consistent with Piaget’s view?
4.1 The Onset of Thinking: Piaget’s Account
According to Piaget, how do schemes, assimilation, and accom-
modation provide the foundation for cognitive development
throughout the life span?
In Piaget’s view, children construct their own under- ■ standing of the world by creating schemes, categories of related events, objects, and knowledge. Infants’ schemes are based on actions, but older children’s and adolescents’ schemes are based on functional, conceptual, and abstract properties.
Schemes change constantly. In assimilation, experiences ■ are readily incorporated into existing schemes. In accommodation, experiences cause schemes to be modified.
When accommodation becomes much more common ■ than assimilation, this signals that schemes are inadequate and so children reorganize them. This reorganization pro- duces four different phases of mental development from infancy through adulthood.
S U M M A RY
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How does thinking become more advanced as infants progress
through the sensorimotor stage?
The first 2 years of life constitute Piaget’s sensorimotor ■ period. Over these 2 years, infants begin to adapt to and explore their environment, understand objects, and learn to use symbols.
What are the distinguishing characteristics of thinking during
the preoperational stage?
From 2 to 7 years of age, children are in Piaget’s preop- ■ erational period. Although now capable of using symbols, their thinking is limited by egocentrism—the inability to see the world from another’s point of view. Preopera- tional children are also centered in their thinking and sometimes confuse appearance with reality.
What are the strengths and weaknesses of Piaget’s theory?
One important contribution of Piaget’s theory is the view ■ that children actively try to understand their world. An- other contribution is specifying conditions that foster cognitive development.
However, the theory has been criticized because it under- ■ estimates infants’ and preschoolers’ competence, is vague regarding processes of change, does not account for vari- ability in performance, and undervalues the influence of the sociocultural environment.
How have contemporary researchers extended Piaget’s theory?
In contrast to Piaget’s idea that children create a compre- ■ hensive theory that integrates all their knowledge, the modern view is that children are specialists who generate naive theories in particular domains, including physics and biology. Infants understand many properties of ob- jects; they know how objects move, what happens when objects collide, and that objects fall when not supported.
Infants understand the difference between animate and ■ inanimate objects. As preschoolers, children know that— unlike inanimate objects—animate objects move them- selves, grow, have distinct internal parts, resemble their parents, and repair through healing.
4.2 Information Processing During Infancy and Early Childhood
What is the basis of the information-processing approach?
According to the information-processing view, cognitive ■ development involves changes in mental hardware and in mental software.
How well do young children pay attention?
Infants use habituation to filter unimportant stimuli. ■ Compared to older children, preschoolers are less able to pay attention to task-relevant information. Their atten- tion can be improved by making irrelevant stimuli less noticeable.
What kinds of learning take place during infancy?
Infants are capable of many forms of learning, ■ including classical conditioning, operant conditioning, and imitation.
Do infants and preschool children remember?
Infants can remember and can be reminded of events ■ they seem to have forgotten. Memory improves during infancy, reflecting growth of the brain. Autobiographical memory emerges in the preschool years, reflecting chil- dren’s growing language skills and their sense of self.
Preschoolers sometimes testify in cases of child abuse. ■ When questioned repeatedly, they often have difficulty distinguishing what they experienced from what others may suggest they have experienced. Inaccuracies of this sort can be minimized by following certain guidelines when interviewing children, such as warning them that interviewers may try to trick them.
What do infants know about numbers?
Infants are able to distinguish small quantities, such as ■ “twoness” from “threeness.” By 3 years of age, children can count small sets of objects and in so doing adhere to the one-to-one, stable-order, and cardinality principles.
Learning to count to larger numbers involves learning ■ rules about unit and decade names. This learning is more difficult for English-speaking children compared to chil- dren from Asian countries because names for numbers are irregular in English.
4.3 Mind and Culture: Vygotsky’s Theory
What is the zone of proximal development? How does it help
explain how children accomplish more when they collaborate
with others?
Vygotsky believed that cognition develops first in a social ■ setting and only gradually comes under the child’s inde- pendent control. The difference between what children can do with assistance and what they can do alone consti- tutes the zone of proximal development.
Why is scaffolding a particularly effective way of teaching
youngsters new concepts and skills?
Control of cognitive skills is most readily transferred to the ■ child through scaffolding, a teaching style in which teach- ers let children take on more and more of a task as they master its different components. Scaffolding is common worldwide, but the specific techniques for scaffolding chil- dren’s learning vary from one cultural setting to the next.
When and why do children talk to themselves as they solve
problems?
Children often talk to themselves, particularly when the ■ task is difficult or after they have made a mistake. Such private speech is one way that children regulate their be- havior, and it represents an intermediate step in the trans- fer of control of thinking from others to the self.
4.4 Language
When do infants first hear and make speech sounds?
Phonemes are the basic units of sound from which words ■ are constructed. Infants can hear phonemes soon after birth. They can even hear phonemes that are not used in
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their native language, but this ability diminishes after the first birthday.
Infant-directed speech is adults’ speech to infants that is ■ slower and has greater variation in pitch and loudness. Infants prefer infant-directed speech, perhaps because it gives them additional language clues.
Newborns’ communication is limited to crying, but babies ■ coo at about 3 months of age. Babbling soon follows, con- sisting of a single syllable; over several months, infants’ babbling comes to include longer syllables as well as into- nation.
When do children start to talk? How do they learn word
meanings?
After a brief period in which children appear to under- ■ stand others’ speech but do not speak themselves, most infants begin to speak around the first birthday. The first use of words is triggered by the realization that words are symbols. Soon after, the child’s vocabulary expands rapidly.
Most children learn the meanings of words much too rap- ■ idly for them to consider all plausible meanings system- atically. Instead, children use certain rules to determine the probable meanings of new words. The rules do not always yield the correct meaning. An underextension is a child’s meaning that is narrower than an adult’s meaning; an overextension is a child’s meaning that is broader.
Individual children differ in vocabulary size, differences ■ that are due to phonological memory and the quality of the child’s language environment. Bilingual children learn language readily and better understand the arbi- trary nature of words. Some youngsters use a referential word-learning style that emphasizes words as names and that views language as an intellectual tool. Other children use an expressive style that emphasizes phrases and views language as a social tool.
Children’s vocabulary is stimulated by experience. Both ■ parents and television can foster the growth of vocabu- lary. The key ingredient is to actively involve children in language-related activities.
How do young children learn grammar?
Soon after children begin to speak, they create two-word ■ sentences that are derived from their own experiences. Moving from two-word to more complex sentences in- volves adding grammatical morphemes. Children first master grammatical morphemes that express simple rela- tions and later those that denote complex relations. Mas- tery of grammatical morphemes involves learning not only rules but also exceptions to the rules.
Behaviorists proposed that children acquire grammar ■ through imitation, but that explanation is incorrect. To- day’s explanations come from three perspectives: the lin- guistic perspective emphasizes inborn mechanisms that allow children to infer the grammatical rules of their na- tive language, the cognitive perspective emphasizes cog- nitive processes that allow children to find recurring pat- terns in the speech they hear, and the social-interaction perspective emphasizes social interactions with adults in which both parties want improved communication.
How well do young children communicate?
Parents encourage turn-taking even before infants begin ■ to talk, and later they demonstrate both the speaker and listener roles for their children. By 3 years of age, children spontaneously take turns and prompt one another to take their turn.
Preschool children adjust their speech in a rudimentary ■ fashion to fit the listener’s needs. However, preschoolers are unlikely to identify ambiguities in another’s speech; instead, they are likely to assume they knew what the speaker meant.
scheme (128)
assimilation (129)
accommodation (129)
equilibration (129)
sensorimotor period (130)
object permanence (130)
egocentrism (131)
animism (132)
centration (132)
core knowledge hypothesis (136)
teleological explanations (139)
essentialism (139)
mental hardware (141)
mental software (141)
attention (141)
orienting response (141)
habituation (141)
classical conditioning (142)
operant conditioning (142)
autobiographical memory (144)
one-to-one principle (147)
stable-order principle (147)
cardinality principle (147)
intersubjectivity (149)
guided participation (149)
zone of proximal development (149)
scaff olding (150)
private speech (150)
phonemes (152)
infant-directed speech (153)
cooing (154)
babbling (154)
fast mapping (156)
underextension (159)
overextension (159)
phonological memory (159)
referential style (160)
expressive style (160)
telegraphic speech (161)
grammatical morphemes (161)
overregularization (161)
K E Y T E R M S
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Websites
Visit the Human Development companion website for all URLs.
The Human Development Book Companion Website ■
See www.cengage.com/psychology/kail for practice quiz questions, Internet exercises, glossary, fl ashcards, and more. Also accessible from the Wadsworth Psychology Study Center (www.cengage.com/login).
The Jean Piaget Society ■
This website includes biographical information about Piaget, suggested readings on Piaget’s life and theory, and articles about cognitive development.
The American Speech-Language-Hearing Association ■
At this website, you will fi nd information about commu- nication and communication disorders.
The American Sign Language Browser ■
The browser has a dictionary that shows the signs for many words and also has links to sites where you can learn more about American Sign Language.
Go to www.cengage.com/login to link to CengageNOW, your online study tool. First take the Pre-Test for this chapter to get your Personalized Study Plan, which will identify topics you need to review and direct you to online resources. Then take the Post-Test to determine what concepts you have mas- tered and what you still need to work on.
Readings
FLAVELL, J. H., MILLER, P. H., & MILLER, S. A. (2001). Cognitive development (4th ed.). Englewood Cliff s, NJ: Pren- tice-Hall. This book, written by a trio of leading researchers, describes cognitive development during infancy and the pre- school years. Piaget’s and Vygotsky’s theories are presented, as is the information-processing perspective. This is prob- ably the best general-purpose reference book on cognitive development for undergraduates.
GOLINKOFF, R. M., & HIRSH-PASEK, K. (1999). How babies talk: The magic and mystery of language in the fi rst three years of life. New York: Dutton/Penguin. This engag- ing book, written by two specialists in child language, shows how children master language in the fi rst 3 years of life. It is fi lled with many entertaining examples of children’s talk.
POOLE, D. A., & LAMB, M. E. (2003). Investigative inter- views of children: A guide for helping professionals. Wash- ington, DC: American Psychological Association. Written by leading experts on the proper use of children as witnesses, the authors describe how best to ensure that interviews with child witnesses are conducted sensitively and professionally.
SIEGLER, R. S., & ALIBALI, M. W. (2005). Children’s think- ing (4th ed.). Upper Saddle River, NJ: Prentice-Hall. The au- thors are leading proponents of the information-processing approach to cognitive development, and this book refl ects that orientation. They discuss Piaget’s theory and language, but the best coverage is given to information-processing top- ics such as memory, problem solving, and academic skills.
L E A R N M O R E A B O U T I T
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