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COMMUNICATING AND LEARNING 125 example, are significantly more likely as adults to display a host of behav- iors that are destructive to themselves and others, including substance abuse, unemployment, low income, welfare dependency, delinquency, and crime (Haveman and Wolfe, 1984; Hawkins and Lishner, 1987; Hinshaw, 1992; Loeber and Stouthamer-Loeber, 1987; Rutter et al., 1998; Steinberg et al., 1984). One of the most significant insights about educational attainment in recent years is that educational outcomes in adolescence and even beyond can be traced back to academic skills at school entry (Chen et al., 1996; Cunningham and Stanovich, 1997; Luster and McAdoo, 1996; Weller et al., 1992). Academic skills at school entry can, in turn, be traced to capa- bilities seen during the preschool years and the experiences in and out of the home that foster their development. Childrenâs cognitive skills before they enter kindergarten show strong associations with achievement in elemen- tary and high school (Hess and Hahn, 1974; Stevenson and Newman, 1986) and during early adulthood (Baydar et al., 1993). Preschool general cognitive ability has also been shown to predict high school completion (Brooks-Gunn et al., 1993). This evidence underpins the national commit- ment to school readiness and has fueled the proliferation of public pre- kindergarten programs (Schulman et al., 1999). It is important to note that children who start school lagging behind their peers in language and cognitive abilities are not doomed to be school failures and dropouts. To the contrary, early interventions can make sub- stantial contributions to the academic skills of young children (see Chapter 13). Moreover, the associations found between early and later achievement leave substantial unexplained variance. This means that there is plenty of room for children to defy the odds, and many do. Both language development and the emergence of early learning capa- bilities appear to be relatively resilient processes. This means that they are relatively protected from adverse circumstances, that it may take more to undermine these processes than is the case for other aspects of develop- ment, and that they can show surprising recovery if children exhibiting delays are placed in more advantageous environments. Nevertheless, some aspects of language and cognition appear to be less resilient and more open to environmental influence than others, including vocabulary and attentional capacities. These aspects are particularly important to school success, in part because of what they can set in motion once a child enters formal schooling. They are also characterized by striking socioeconomic differences and therefore contribute to inequities in childrenâs life chances. Moreover, the prospects for children with serious delays in language and cognition resulting from developmental disabilities and specific disorders can be seriously constrained and are heavily dependent on early detection and intervention. This chapter illustrates these points first with a discussion
126 FROM NEURONS TO NEIGHBORHOODS of what is now known about the development of communication and lan- guage, and then with a discussion of how children learn about the world and come to view themselves as competent individuals. LANGUAGE ACQUISITION AND COMMUNICATION Starting from the first day of life, the development of communication skills, language, and literacy are significant accomplishments. The childâs first word is a cause for celebration. Parents watch in amazement as these words multiply exponentially, turn into phrases and then sentences, and ultimately allow them to have almost adult like conversations with their preschoolers. The transition from a newborn who can barely keep his eyes focused on a book to a preschooler who laughs and cries when his parent reads or tells a story, moves his fingers along a page and pretends to read, and, in some cases, can read himself is equally impressive. Almost all chil- dren learn to talk without explicit instruction, suggesting that language acquisition is a relatively resilient process, although they do not all learn to talk well, suggesting that language acquisition includes some more fragile elements. In contrast, reading as a component of literacy is a much more fragile process. Not everyone achieves fluent reading, and instruction seems to be essential. Indeed, some cultures donât even have a written system. The development of reading is addressed in a pair of recent reports from the National Research Council: Preventing Reading Difficulties in Young Chil- dren (National Research Council, 1998a) is written primarily for a research audience, and Starting Out Right (National Research Council, 1998b) is geared to parents and practitioners. Only recently has information about trends in young childrenâs literacy development become available, and the data span only 6 years (Nord et al., 1999). Unfortunately, the information comes exclusively from parent re- ports, which can contain biases, but the sample is nationally representative. They tell us that 3- to 5-year-olds in 1999 have somewhat better knowledge of the alphabet and are able to count a bit higher (i.e., 57 versus 52 percent in 1993 can count to 20 or higher) than their counterparts in 1993, but they are no more likely to be able to write their own names or to read or pretend to read. Moreover, the majority of the statistically significant changes are for children who are less at risk of school failure, namely, those who are not poor and whose mothers speak English. The somewhat good overall news must thus be tempered by the fact that the children for whom we most want to see progress are still being left behind. In this discussion, we do not attempt to recount all of the accomplishments of young children in the realm of literacy; rather, we focus on the ways in which (and for whom) language development is and is not resilient, the role of the environmentâ particularly that provided by the parentâand implications for intervention.
COMMUNICATING AND LEARNING 127 To study the process of language learning, the most common technique is to do nothing more than observe children as they talk. Early studies consisted of diaries that researcher parents made of their own childâs first utterances. The goal was to write down all of the new utterances that the child produced. Diary studies were later replaced by audio and video samples of talk from a number of children, usually over a period of years. The most famous of these studies is Roger Brownâs longitudinal observa- tions of Adam, Eve, and Sarah (Brown, 1973). Because transcribing and analyzing child talk is so labor-intensive, language acquisition studies typi- cally focus on a small number of children, often interacting with their primary caregiver at home. Naturalistic observations of childrenâs talk can be supplemented with experimental probes that are used with larger num- bers of children. For example, Berko (1958) gave children nonsense words and asked them to generate novel forms in different contexts (e.g., âThis is a wug. Now there are two of them. There are two ____?â The child who understands English plurals should supply the word âwugsâ). Unlike many areas of developmental research, language acquisition studies have been conducted across the globe, although typically the studies focus on a small number of children in each culture (see Slobin, 1985). Language Learning is a Resilient Process Language learning turns out to be remarkably similar across cultures. Children exposed to markedly different languages follow similar develop- mental trajectories as they learn their native language. Six-month-old in- fants can distinguish the full range of sounds used in the worldâs languages, but by age 1 they have lost many of these distinctions as they focus in on their own cultureâs language. Children the world over produce their first words between 10 and 15 months (âmine,â âshoeâ); they then learn that the word can be composed of smaller, meaningful parts (morphology, e.g.,âshoeâ + âsâ) and that the word is a building block for larger, mean- ingful phrases and sentences (syntax, e.g., âmy shoeâ). Most 18-month- olds have begun a word-learning explosion, acquiring (on average) 9 new words a day, every day, throughout the preschool years (Carey, 1978). They also begin to produce two-word strings that are highly similar across languages in two respects. First, the content is the same. Children note the appearance and disappearance of objects, their properties, locations, and owners and comment on the actions done to and by objects and people. Second, the words in these short sentences are consistently ordered in ways that mirror adult word orders (e.g., âdrink juice,â âMommy giveâ). By the time children are 3 years old, full sentences are the norm (âI wish I could sit on a horse and ride him to every house in the worldâ; Hoff- Ginsberg, 1997). These sentences often involve elaborating one element of
128 FROM NEURONS TO NEIGHBORHOODS a single proposition (âbaby drinking big bottleâ) or combining two propo- sitions with a conjunction (âmaybe you can carry that and I can carry thisâ). Three-year-olds can also show some remarkably subtle capabilities for language comprehension. For example, consider a child who is told that a little girl fell and ripped her dress in the afternoon and reported the event to her mother later that night. When 3-year-olds are asked, âWhen did the girl say she ripped her dress?â they will provide one of two possible answers (in the afternoon, or at night), but when asked âWhen did the girl say how she ripped her dress?â they will provide only one (at night). By age 4 or 5, children all over the world have mastered the fundamental (and many of the fine points) of the grammatical system of their native language, includ- ing verb declensions, gender agreement, embedded clauses, and the like (Brown, 1973; Slobin, 1985). This common trajectory of language acquisition is particularly striking given the variability in input that children receive across cultures. In all cultures, language is one of the most powerful symbolic systems through which children learn to understand and interpret human behavior (Harwood et al., 1995). How language is used in the context of social interaction is just as important as what is said. For example, in some cultures, children are commonly spoken to directly as participants in con- versation; in other cultures, children primarily overhear talk that is directed toward others. Despite large differences of this sort, children proceed quite uniformly with the task of language learning (Ochs and Schieffelin, 1984). Another example is cross-cultural research on narrative constructions, which reveals both considerable overlap across cultures in the narratives that caregivers use with their children and also striking differences that have an impact on the child. For example, Taiwanese mothers tend to tell narratives that make explicit reference to moral rules and point out the childâs wrongdoing. European-American mothers, by contrast, emphasize the entertainment function over the didactic function and go to great lengths to portray the child in a positive light (Miller et al., 1996). Children who hear stories of this sort not only learn how to build their own culturally appropriate narratives, but they also learn the social value of their behav- iors, as noted in Chapter 7. Language learning proceeds apace even when the child is faced with learning two languages simultaneously (de Houwer, 1995; Hakuta, 1986; National Research Council and Institute of Medicine, 1997). Children be- coming bilingual from birth are not dramatically slowed in their develop- ment and appear to develop each language as they would had it been their only tongue. The problematic issue in the case of bi- or multilingualism is less one of language acquisition than of language retention, which can be made difficult when one language is not used or valued by nonfamily adults or institutions, such as the schools, peer groups, and the broader society
COMMUNICATING AND LEARNING 129 (National Research Council and Institute of Medicine, 1997, 1998b). For example, language loss (of Spanish) among Mexican-American children increases rapidly across first-, second-, and third-generation children (Hakuta and DâAndrea, 1992). Finally, although language development is markedly delayed among children raised in low-stimulating orphanages (Rutter, 1981a), once placed in supportive families, children develop lan- guage even with the added challenge, in most of the cases that have been studied, of learning a new language. Thus, language learning is apparently a very robust process. Where does this robustness come from? One way to address this question is to systematically vary either the learner or the learning environment, observ- ing the effects of these variations on subsequent language development. As an example from another species, Marler raised two closely related but genetically distinct varieties of sparrows from the egg in identical environ- ments, exposing them to a common collection of songs typical for both (Marler, 1990). He found that the two varieties learned different songs out of the same collection, each variety apparently zeroing in on different as- pects of the input. The range of possible outcomes in the learning process, for this species and for this skill, appears to have been narrowed by the organism itself. For obvious ethical reasons, researchers cannot deliberately manipulate the conditions under which human language is learned. One can, however, take advantage of variations that occur naturally in language-learning con- ditions in order to explore the boundary conditions under which language learning is possible. And many studies have done just that, each exploring a particular deviation from typical language-learning circumstances and its effect on the development of language (Gleitman and Newport, 1995). Three types of deviations from the norm might be expected to have effects on the language-learning process: (1) deviations in the environment that affect the quantity or quality of the linguistic input children receive (e.g., children raised under conditions of relative deprivation of access to linguistic input), (2) deviations in the organism that affect the way children process their linguistic input (e.g., intermittent conductive hearing loss, which affects the way the child processes speech), and (3) deviations in the organism that affect the general endowment of the learner (e.g., children with Down syndrome, autism). Interestingly, in many cases, the cause of the deviation does not appear to be what is importantâjust its effect. Thus, deviations in the language-learning environment often lead to the same effectsâor noneffectsâon childrenâs language as deviations in the organism. In general, language learning is remarkably resilient even under ex- tremely altered learning circumstances. However, there are some condi- tions that are not compatible with the development of language indepen-
130 FROM NEURONS TO NEIGHBORHOODS dent of the learner, and some learners who are not capable of language acquisition independent of their environment. As one example, children raised under conditions of extreme social and linguistic deprivation do not develop language during their periods of deprivation (Brown, 1958; Skuse, 1988); many of them, however, do achieve some linguistic proficiency after recovery and rehabilitation, findings that bear on the issue of a critical period for language learning, discussed below. As another example, some children with severe autism are deviant in every aspect of speech, language, and communication despite apparently normal language input (Fay, 1988). Thus, there appear to be both environmental and organic limits on lan- guage learning in children. Perhaps the clearest example of the resilience of language comes from the fact that it is not tied exclusively to spoken language (Klima and Bellugi, 1979). Children who are exposed to a conventional sign language such as American Sign Language from birth acquire that language as effortlessly, and along the same developmental course, as children acquiring a spoken language (Newport and Meier, 1985). This fact is notable, as it suggests that children are completely âequipotential across modalityâ with respect to language learning. In other words, if language is offered via hand and eye, it is learned and processed as easily as if it is presented via mouth and ear. Thus, in an appropriate environment, deaf children are not at all handicapped with respect to language learning, and the capacity for lan- guage learning appears to be modality independent. However, most deaf children are not born into an environment in which signing is the language of communication. About 90 percent of deaf children are born to hearing parents and thus are not immediately exposed to a sign language. If exposed only to input from a spoken language, profoundly deaf children (even if given intensive training) are not likely to acquire that spoken language (Mayberry, 1992), suggesting that the visual channel cannot compensate for a lack of auditory input in the acquisition of spoken language. It is important to point out, however, that deaf children who cannot learn spoken language do indeed communicateâeven if their hearing par- ents do not expose them to conventional sign language until later in life. Such children have no usable linguistic input, although in other respects their home environments are quite typical. Despite these childrenâs lack of a language model, they learn to use their hands to communicateâthey ges- ture, as do all humans when they communicate. However, the deaf childrenâs gestures are structured very differently from the gestures that speakers typically produce to supplement their talk (Goldin-Meadow et al., 1996) (see Box 6-1). The deaf childrenâs gestures resemble the early com- munication systems of children learning conventional languages, signed or spoken (Goldin-Meadow, 1997). For example, the childrenâs gestures are
COMMUNICATING AND LEARNING 131 BOX 6-1 The Resilience of Language What happens if a child has hearing losses so severe that he or she cannot learn the surrounding spoken language, and does not have ac- cess to sign language? Such a child might not be able to communicate at all. It turns out, however, that the need to communicate is so strong that such children invent gesture systems to get their ideas and desires across. Deaf children who have not seen sign language and cannot learn speech have been studied in both Taiwan and the United States (Goldin- Meadow and Mylander, 1998). Both Chinese and American children pro- duce gestures to communicate with the hearing individuals in their worlds, and do so to fulfill many of the functions typically assumed by languageâ to make requests, comments, and queries, and even to describe events in the past and future. Moreover, children in both cultures often convey their messages via strings of gestures, akin to sentences, rather than single gesturesâand those âsentencesâ do not follow either English or Mandarin work order. For example, the child pictured below first gestures the action, âeatâ and then the actor, âyouâ and then âyouâ again for empha- sis. A typical pattern for English or Mandarin would be âyou eatâ rather than âeat you.â used to request and to make comments about the present and the nonpresent and even to âtalkâ about their own gestures. The gestures display sentence- level structure (following order and deletion regularities, and with struc- tures for both simple and complex gesture sentences), word-level structure (hand shape and motion morphemes), and grammatical categories (distinc- tions among nouns, verbs, and adjectives). These characteristics are not found in the spontaneous gestures their hearing parents use when commu- nicating with them, and thus may be the default system that children them- selves bring to the language-learning situation. The fact that children will produce a communication system with structural properties, even without guidance from a conventional language model, suggests that these proper- ties are not maintained in human language merely by being transmitted from one generation to the next. Rather, these particular linguistic proper-
132 FROM NEURONS TO NEIGHBORHOODS ties can be introduced de novo by a child attempting to communicate with other people. Language learning also proceeds in the face of variation in the amount and consistency of linguistic input that children receive, and in the commu- nicative situation in which language is learned, whether that variation is caused by environmental or organic factors. For example, hearing children of deaf parents, who themselves are not fluent speakers, can acquire spoken language normally if they receive as little as 5 to 10 hours per week of exposure to hearing speakers (Schiff-Myers, 1988). Moreover, hearing chil- dren do not reproduce the idiosyncrasies of their deaf parentsâ speech, but rather regularize their language toward the norms of the spoken language they are learning. Twins most often share their language-learning situation with one another, making the typical twin situation triadic (e.g., a parent and two children) rather than dyadic. Nevertheless, normal language devel- opment is observed in most twin pairs, although mild delays are common (Mogford, 1988). As an example of variation in input created by internal or organic factors, children who have intermittent conductive hearing losses that cause their intake of linguistic input to vary in amount and pattern, for the most part, acquire language normally (Klein and Rapin, 1988). Chil- dren who are blind from birth might be expected to have difficulty learning language simply because they map the words they hear onto a world that is not informed by vision. In fact, they have little difficulty with grammatical development, suggesting that the formal learning involved in acquiring a grammatical system does not depend in any crucial respect on the precise mapping between that system and the world (Landau and Gleitman, 1985). Finally, language learning can even survive some rather major alter- ations in the basic endowment of the learner. Language development can proceed normally after focal brain damage even if the left cerebral cortex is removed, provided the brain damage necessitating this operation is sus- tained very early in life (Feldman, 1994). It appears that speech and lan- guage are affected by brain injury only when the damage occurs bilaterally (i.e., to both hemispheres). In the face of unilateral damage prior to age 5 or 6, aphasic symptoms may result initially, but are not permanent. In fact, extensive left-hemisphere damage sustained prenatally or in the immediate postnatal period, i.e., before the onset of speech, has not been reported to result in any lasting language deficits despite some delays in the develop- ment of speech (Gadian et al., 1999; Rasmussen and Milner, 1977; Taylor, 1991; Vargha-Khadem and Mishkin, 1997; Vargha-Khadem and Polkey, 1991). Indeed, Bates and colleagues have reported that even significant focal brain injuries that occur perinatally to the left hemisphere appear to spare most language functions (see, e.g., Bates and Roe, in press). More- over, language development does not proceed in lockstep with the develop- ment of other mental abilities. For example, children with Down syndrome
COMMUNICATING AND LEARNING 133 are delayed in language learning relative to mental age (Fowler et al., 1994). Yet children with Williams syndrome (a rare metabolic disorder), who are as mentally retarded in terms of IQ as children with Down syndrome, display considerably better grammatical skills (Bellugi et al., 1988). Thus, low intelligence does not, in all cases, preclude grammatical development. The inverse is true, as well: language difficulties do not inevitably imply cognitive difficulties. For example, children with specific language impairment, by definition, have no cognitive disabilities but do have diffi- culty learning language. As a final piece of evidence, adults, who are cognitively mature, typically have difficulty learning a second language (Johnson and Newport, 1989), suggesting that cognitive maturity is not sufficient to guarantee grammatical development (and after some sensitive period may even become an impediment, as discussed below). In general, in fact, the growth of cognitive, language, and literacy skills is much more domain-specific, constrained, and modular than previously thought (Chris- tian et al., in press). A similarly complex pattern holds for social skills. For example, children with Down syndrome are relatively adept socially (in comparison to children with autism) yet have difficulty learning grammar (Fowler et al., 1994). In contrast, autistic childrenâs social interactions are atypical, yet when they are able to learn language, their grammatical skills are intact (Tager-Flusberg, 1994). Language learning is robust in the same way that developing an attach- ment to a caregiver is robust. Only in aberrant conditions of care, such as extreme neglect or institutional deprivation, do children fail to form attach- ments to anyone (see Chapter 9). However, not all infants develop secure attachmentsâsecure attachments are formed in a more restricted set of circumstances. Similarly, children acquire language with very little environ- mental support (deaf children inventing their own gesture systems are a good example). However, the specific language that they learn and certain qualities of their language depend on specific features of the environment in which they learn language. And these aspects of language are often instru- mental to subsequent cognitive and social growth. Children can be at risk in society, not because they do not have mastery of a language, but because they do not have complete mastery of the dominant language of their society, particularly at the time of formal school entry. Not All Language Learning Is Resilient It is important to recognize that language is not a unitary phenomenon. Certain aspects of language may turn out to be more susceptible to varia- tions in learning conditions (both internal and external) than others. If, across a variety of exceptional circumstances, the same components of language tend to be delayed while others remain intact, one might begin to
134 FROM NEURONS TO NEIGHBORHOODS argue that certain components of language are resilient in the face of either environmental or organic deviations from the typical language-learning circumstances, while other components of language are relatively fragile (Goldin-Meadow, 1982). For example, clinical notes on language develop- ment in children who have been adopted from institutions suggest that despite becoming proficient in the language of their new homes, these children may not use language as readily for expressing emotion, requesting aid from adults, or expressing ideas and fantasy (Provence and Lipton, 1962). It is not known if they are as likely as other children to use language to guide problem solving, although this might be one reason for their poorer executive functioning (Gunnar, in press). Perhaps the most dramatic example of how language is vulnerable to environmental influences concerns the role of the timing of language inputs in language proficiency. This literature is highly relevant to current debates about critical or sensitive periods in development. There is, in fact, a con- siderable amount of evidence suggesting that early exposure to a language results in greater proficiency in that language than late exposure. For ex- ample, deaf children of hearing parents, as mentioned earlier, are typically not exposed to a conventional sign language at birth and may not receive their first exposure to such a system until adolescence or later. These indi- viduals thus provide an excellent âexperiment of natureâ to test the effects of learning a first language at varying times in the life course. Findings from these studies suggest that certain aspects of languageâmorphological prop- erties, for example, which involve how smaller parts of words make up bigger words and affect word meaning (e.g., âeatâ + âingâ = âeatingâ)âare affected by the age at which the learner is first exposed to sign language. An example of a morphological property in sign is movement added to a sign such as âeatâ to create the meaning âeat continuously over time.â Late learners, although perfectly capable of conversing in sign, do not have complete productive control over many of the complex morphological prop- erties of the language (Newport, 1991). Interestingly, however, certain properties of languageâsuch as the order of signs in a sentenceâappear to be completely unaffected by the age at which the learner is first exposed to the language. In other words, native-like competence is possible for sign order whether or not the learner is exposed to sign early in lifeâbut is far less likely for morphological properties. Similar patterns arise in second-language learning (Newport, 1991). Learners who are first exposed to their second language after puberty find that certain aspects of that language (often morphological aspects) are difficult, if not impossible, to master even after decades of use, while others (like word order) are relatively easy to control. For example, learning to systematically produce endings such as â-edâ in âwalked,â which adds the past meaning, or âsâ in âshoes,â which adds the plural meaning, is far more
COMMUNICATING AND LEARNING 135 difficult for late learners than learning that âcats chase miceâ has a different meaning from âmice chase cats.â We see the same trend when we look at Genie, a child who experienced extreme deprivation for the first 13 years of her life. During this deprivation, Genie made essentially no progress in developing a communication system (she had, after all, no one to talk to). After discovery and rehabilitation, Genie was found to make progress in acquiring certain components of language (word order among them), but little progress in acquiring other components of language, including mor- phology (Curtiss, 1977; Goldin-Meadow, 1978). This developmental pattern again suggests that certain components of language may be resilientâhere in the face of variations in the timing of acquisitionâwhile other components may be relatively fragile. The ability to learn the fragile components of language does not drop off precipitously. Rather, there appears to be a decline after age 6 or 7âa decline that begins to plateau and become less steep in late adolescence. Importantly, unlike early learners who tend to follow the same developmental trajectory (that is, there is strikingly little variability across them), late learners vary quite a bit. Some achieve native-like competence even on the fragile properties of language, while others do not. This research is providing a much more refined understanding of the ways in which early language experience pro- vides a foundation for later language facility. Studies of brain activity patterns (using event-related brain potentials, called ERPs, which measure electrical activity recorded at the scalp) provide further evidence that language is not a single entity and that developmental mechanisms may differ for different properties of language (see Neville and Mills, 1997). For example, Neville and her colleagues have found, in nor- mal, right-handed, monolingual adults, that nouns and verbs (words that provide semantic informationâthat is, about meaning) elicit a markedly different pattern of brain activity than do prepositions and conjunctions (functional words that provide grammatical information). These findings suggest that different neural systems mediate the processing of semantic and grammatical information in adults (in particular, a greater role for more posterior temporal-parietal systems in semantic processing and for anterior temporal systems within the left hemisphere in grammatical pro- cessing). Impressively, these findings are robust across languages, including sign languages (although there appears to be more right-hemisphere in- volvement in processing a sign language like American Sign Language than in processing a spoken language like English). The work of Neville and her colleagues also bears on issues of the timing of environmental inputs. In studies of cerebral organization in indi- viduals who learned English at different times in the life span, Neville and colleagues have found that aspects of semantic and grammatical processing differ markedly in the degree to which they depend on the timing of lan-
136 FROM NEURONS TO NEIGHBORHOODS guage input (Neville and Mills, 1997). In particular, in a group of Chinese- English bilinguals, delays as long as 16 years in exposure to English had very little effect on the organization of the brain systems important in lexical semantics. That is, the brain system underlying the organization of nouns and verbs was disrupted very little. However, delays of only 4 years had significant effects on aspects of brain organization linked to grammati- cal processing. Brain organization underlying function words, such as prepo- sitions and conjunctions, was severely disrupted. Similar patterns have been found in studies of congenitally deaf individuals who learned English late and as a second language (American Sign Language was their first lan- guage). Deaf individuals displayed ERP responses to nouns and to semanti- cally anomalous sentences that were indistinguishable from those of nor- mally hearing individuals. However, the same deaf individuals displayed aberrant ERP responses to grammatical information. These findings sug- gest that the systems that mediate the processing of at least some types of grammatical information are much more modifiable byâand therefore vul- nerable toâvariations in language experience. This is demonstrated again below, in the discussion of interventions with children with specific lan- guage disorder. In general, it seems important that practitioners consider the data gen- erated from studies of the effectsâand noneffectsâof exceptional circum- stances on language learning, for they provide important information on the boundary conditions of language learning. Moreover, these phenomena are the anchor points for theories of language development that take into account the resilience of language learning within more normal ranges of both environmental and organic variation. The Impact of Linguistic Input on Language Learning and Language Production As noted earlier, conventional language input is not essential for a young child to develop a language-like system and use it to communicate with others. However, a language model may play a central role in deter- mining how often and when those linguistic properties are used. We noted above, for example, the infrequent use of language to express emotions among children who had been institutionalized. Another example concerns the ability to communicate about objects and events in other than the here and now. Deaf children who are not exposed to usable linguistic input (because their parents do not know American Sign Language, for example) not only use gesture to convey information about the here and now, but they also use it to converse about past, future, and hypothetical events (Morford and Goldin-Meadow, 1997). Linguistic input is thus not essen- tial for a child to communicate about the nonpresent. However, the amount
COMMUNICATING AND LEARNING 137 and nature of the linguistic input a child receives has large effects on how often the child actually uses talk about the nonpresent, particularly the past. And the amount and type of talk children hear, in turn, can influence how well they remember events in the past (Reese et al., 1993). A great deal of attention is now being paid to research indicating that the amount of talk mothers direct to their children is strongly associated with the childrenâs vocabulary growth (Hart and Risley, 1995; Huttenlocher et al., 1991), as well as with the childrenâs performance on measures of emergent literacy and print-related skills (De Temple and Snow, 1992). For example, during the period from 11 to 18 months, children in one study heard, on average, 325 utterances addressed to them per hour (Hart and Risley, 1995). But the range was enormousâone child heard as many as 793 utterances per hours, another as few as 56. And these differences tend to be stable over time. The amount of speech children heard from their parents at 18 months was strongly correlated with the amount of speech they heard at age 3. Moreover, these differences tended to be associated with socioeconomic status, although it is important to recognize that the sample of 42 participating families was small and not representative and so cannot provide firm evidence regarding social class differences. Often researchers videotape mothers and their young children to ex- plore parental verbal input and child output. One study (Hoff-Ginsberg, 1991), for example, videotaped mothers while they dressed, fed, and played with their 18- to 29-month-old children. They all talked when they played with their children, but there were big differences in how much they talked and whether they used a rich vocabulary and asked questions during dress- ing and feeding. The children whose mothers talked more during the mun- dane activities had larger vocabularies, indicating the importance of inte- grating conversations throughout the day. Although differences in motherâs talk are associated with their social class, it is critical to recognize that other characteristics that can be more easily targeted by early interventions are as strongly related to childrenâs accomplishments as the advantages conferred by socioeconomic status. A composite of parental behaviors that included âjust talking,â âtrying to be nice,â âtelling children about things,â âgiving children choices,â and âlis- teningâ accounted for over 60 percent of the variance in the rate of childrenâs vocabulary growth and vocabulary use and almost 60 percent of the variance in their IQ scores at age 3 (Hart and Risley, 1995). Moreover, it is important to recognize that even the large differences in mother talk and child vocabulary that characterized the children in this study had more specific than pervasive effects on the childrenâs school-related outcomes. For example, while the childrenâs vocabulary use at age 3 was strongly associated with their vocabulary test and reading comprehension scores in third grade, the rate of vocabulary growth was not associated with childrenâs
138 FROM NEURONS TO NEIGHBORHOODS third grade scores in the academic skill areas of reading, writing, spelling, or arithmetic. It is important to recognize that this research on language input focuses largely on white, middle class children in the United States and on mothersâ speech directed to their children. It does not explore the role that talk around and about the child might play in language acquisition. This may be particularly important in other cultures, in which children are more likely to be involved in relationships in which skilled conversation takes place around them, but is not directed at them (Rogoff et al., 1993). For example, in a Mayan Indian community studied by Rogoff and her colleagues, adults communicated to their children primarily through shared activity and group conversations, rather than in the context of one-on-one lessons or explana- tions directed to the child. Although, as we noted earlier, virtually all children learn language, the issue is whether there are qualitative differ- ences across individuals that are correlated with differing types of input. It is also important to note that this area of research is open to the criticism that it has not considered the sizeable role that genetic influences undoubtedly play in the development of verbal abilities. Mothers who talk more to their children may also share genetic endowments that facilitate language learning. One study, which took advantage of the fact that twins tend to lag behind singletons in language development, ruled out a variety of competing hypotheses to conclude that the quality and complexity of mother-child communicative interaction was responsible for the twin-single- ton differences in language development (Rutter et al., 2000). Measures of mother-child verbal interaction at 20 months predicted language level at 36 months in both twins and singletons, and they accounted for the twin- singleton differences in language level. Nevertheless, the relative inattention to genetic factors in this area of research is a shortcoming that needs to be addressed. Evidence of the importance of verbal input during the years when verbal development is proceeding rapidly has also emerged from research on child care. Children whose teachers talk with them a lot (and many donât!) have higher scores on tests of both verbal and general ability. This is especially the case when the talking consists of the teacher encouraging, questioning, and guiding the childrenâs exploration and learning. Positive inputs are positive inputs, whether they happen at home or in child care. Vocabulary size, in turn, is highly correlated with IQ. Thus, environmental input can play a large role in determining the rate at which children acquire and use a particular aspect of language, and rate of acquisition and use may be an important factor in cognitive growth and cognitive functioning. Furthermore, taking vocabulary as an example, the individual differ- ences that characterize children at school entry are enormous. In one large, longitudinal study, children tested at kindergarten when they were 5 years
COMMUNICATING AND LEARNING 139 old displayed receptive vocabularies (i.e., word comprehension, as distinct from the ability to produce words) that ranged from the level of a typical 1 year, 9-month-old to the level of a 10 year, 8-month-old (Morrison et al., 1997, 1998). These individual differences not only emerge early, but they also appear to be stable over time. It is hard to imagine that such striking differences would not affect how children fare and are treated during their early years of school, in ways that perpetuate the initial differences. In fact, childrenâs scores on early literacy tasks at kindergarten entry consistently predict academic performance throughout the first three years of formal schooling and beyond (Morrison et al., 1995; Stevenson et al., 1976). Simi- lar patterns have also been reported for early mathematical abilities (Na- tional Research Council, 2000). That these early emerging and quite stable individual differences in language skill are consistently linked to the social class of childrenâs families lends them even greater importance in a society that established its educa- tional system in part to promote equity of opportunity. There is some evidence to suggest that socioeconomic factors exert their most powerful effects on childrenâs achievement during early childhood and that these early influences contribute to sustaining socioeconomic effects on achieve- ment throughout the school years and beyond. It is also important to note that these aspects of early language develop- ment (e.g., vocabulary, semantics), unlike morphology, grammar, and pho- nology, do not show critical or sensitive periods. In these domains, children can, in principle, catch up given appropriate and sufficient exposure. As Hart and Risley point out, however, the amount of additional exposure a child needs to catch up increases over time. With each passing year, the gap widens and, at some point, may become insurmountable for all practical purposes. The studies just described explore the effects of linguistic input on child output by examining the natural range of variation found in mother talk to children. But what would happen if one were to augment the amount of input children typically receive? As an example, Nelson (1977) enriched the input children received in forming questions and found that this enriched experience selectively increased the childrenâs production of this type of construction. However, it is not clear from such studies whether the en- riched input is actually teaching children a new construction or merely teaching them to produce an already known construction in a particular context. Thus enriched input may be important, not to establish a particu- lar construction in a childâs linguistic repertoire, but to influence the pro- duction of that construction in a given context. Given that production of language is what teachers hear and base their judgments of competence on, strategies that improve production warrant substantial attention in early invention programs.
140 FROM NEURONS TO NEIGHBORHOODS In another example of an enrichment study, Goodwyn and Acredolo (1998) attempted to accelerate young childrenâs production and compre- hension of spoken words by teaching them symbols in another modalityâ gestures. The findings suggest that gesture training does indeed accelerate word use and word understanding at the beginning stages of language learning, although the gains appear to be short-lived. The important find- ing, however, is that gesture training does absolutely no harm to word learning and, in fact, has the potential to enrich parent-child early commu- nications. Many parents in the gesture-training condition reported that the gestures improved communication with their children and made them feel more involved in their childrenâs lives. Enriched input may be important, again, not for direct benefits to language learning, but, in this instance, for the indirect effects it has on parent-child interaction. It is clear that, under typical circumstances, parents do not need to arrange linguistic inputs according to a particular plan in order for lan- guage learning to proceed on course. They do not need to think about when to introduce particular syntactic constructions (e.g., questions, imperatives, passives) into the talk they use with their children. Parents across the globe seem intuitively to provide children with input that is adequate for them to learn how to talk. To the extent that problems arise, it is generally not because parents are doing the wrong things, but because they are not doing enough of the right things. The more children are talked to, the more they themselves talk and the more elaborate that talk becomes (Hart and Risley, 1995). But what happens when language learning goes awry? How can one tell, and what does one do? How, as we noted in the core concepts outlined in Chapter 1, can we distinguish persistent impairments from typical varia- tions and maturational or otherwise transient delays? Language Impairment A language impairment during childhood is usually defined as a signifi- cant limitation in language ability as indicated by poor performance on language tests (the psychometric criterion) and concern about the childâs language skills on the part of family members and educators. Both criteria are used in considering whether a child is language impaired. The language tests used for this purpose are typically comprehensive batteries that in- clude semantic (e.g., vocabulary) abilities and grammatical abilities, as mea- sured in both comprehension and production. Some comprehensive tests at the preschool-age level assess phonological abilities (i.e., speech pronuncia- tion and clarity) as well. As children reach school age, narrative abilities are sometimes included in tests. Although pragmatic abilitiesâthe social uses of languageâare important, these abilities have not yet been incorporated into tests of language ability.
COMMUNICATING AND LEARNING 141 How frequent is language disability? In the most extensive epidemio- logical study conducted to date, the prevalence of specific language impair- mentâchildren with language problems but no other documented develop- mental problemsâat age 5 was determined to be 7.4 percent (Tomblin et al., 1997). This figure is somewhat higher than previous estimates, in part because earlier studies have relied on clinically referred children. Studies relying principally on clinically referred children also report a lower per- centage of girls with specific language impairment than was reported in the epidemiological study. Boys with a language disorder may be more likely to be referred than girls simply because of the kinds of behaviors that they exhibit in response to their communication difficulties. Boys frequently react with more exuberance and activity to being misunderstood than do girls. By the late preschool years, it is not always easy to distinguish children whose language problems constitute a true disorder and may persist from children whose abilities fall on the extreme low end of a normal distribu- tion and who may catch-up to their expected levels of language develop- ment over time. Children with persistent language impairments are at risk for social and academic problems, making the task of distinguishing them from those with more transient delays extremely important. Recent re- search has uncovered at least two measures that might serve as clinical markers of a true impairment. One measures the use of finite verb mor- phologyâforms such as the present third person singular verb inflection â-sâ (âhe walksâ), the past inflection â-edâ (âhe walkedâ), and the copula and auxiliary forms such as âis,â âare,â and âam.â These forms are ex- traordinarily weak in many English-speaking children with specific lan- guage impairment (e.g., Leonard et al., 1997; Oetting and Horohov, 1997; Rice and Wexler, 1996). Even by school age, they are not used with consis- tency by many of these children (e.g., Marchman et al., 1999). The second measure is a task in which the child is asked to repeat multisyllabic nonsense words (e.g., Gathercole and Baddeley, 1990; Kamhi et al., 1988; Montgomery, 1995). Both of these measures show excellent sensitivity and specificity in distinguishing children with specific language impairment from their normally developing peers (for finite verb morphol- ogy, see Bedore and Leonard, 1998; Rice, 1998; for nonsense word repeti- tion, see Bishop et al., 1996; Dollaghan and Campbell, 1998). It is interest- ing that verb morphology, a property of language that is vulnerable to variations in learning conditions, as discussed above, is also implicated in specific language impairment. Thus, children with clinically significant language difficulties are not just less good language-learners than children who are developing on course; they appear to have particular deficits that lead to their language difficul- ties. There is, moreover, some evidence that the combination of genetic and
142 FROM NEURONS TO NEIGHBORHOODS environmental factors at the extreme of language delay is different from those operating in the normal range. In a large twin study, Dale and col- leagues (1998) found that language delay at age 2 is highly heritable and that language delay is much more heritable than individual differences within the normal range of language ability. These findings suggest that extreme language delay is qualitatively different from typical language learn- ing, and that it reflects a strong genetic contribution. However, two caveats are important with regard to this study. First, age 2 is much too early to determine whether the language deficit will or will not persist and, in many cases, it probably will not. Second, there was severe attrition from the sample of young mothers and of mothers who were socially disadvantaged or less well educated than average. As a result, the results, interesting and potentially important though they are, were based on a sample that was not representative of environmental risk. Moreover, it is essential to stress the point, made in the broader discussion of genetic influences in Chapter 2, that genetic causes do not imply that language delay is inevitable or un- changeable. Interventions can be implemented that affect the course of language delay. What Can be Done? Most of the therapy procedures designed for children with specific language impairment focus directly on language itself. Approaches to lan- guage difficulties range from structured, drill-like techniques to what may appear to be relatively unstructured play. For example, in imitation-based approaches, the clinician produces the exact sentence or phrase required of the child, and the child is asked to repeat it. In conversational recasting, the clinician and child participate in play activities. The clinician responds to utterances produced by the child in a manner that serves as a relevant conversational turn and contains some linguistic form serving as the focus of therapy. Focused approaches of this sort are adopted when there are specific therapy goals, such as assisting the child in the production of par- ticular semantic or grammatical forms. However, more intensive programs that children attend for several mornings per week, 3 hours per morning, are also available. In these programs, specific approaches may take up a portion of the childâs day, but much of the time is spent in group activities that have both education/enrichment and general language stimulation as goals. How effective are these therapies? The controls used to evaluate pro- grams vary from study to study. The gains of children who receive treat- ment are compared with gains made by similar children in no-treatment control groups or by children receiving therapy unrelated to the linguistic forms of interest. In other cases, a multiple-baseline design has been used in
COMMUNICATING AND LEARNING 143 which the childâs progress is assessed on forms that have been explicitly taught, as well as forms that were not part of the instruction. Still other studies have made use of statistical estimation as a means of determining the amount of gain that could be expected by maturation alone, so that added gains attributed to therapy can be deciphered. Each of the therapy approaches described above has been shown to be effective (Farran, 2000; Leonard, 1998; McLean and Cripe, 1997). The gains with these approaches are greater than can be expected through maturation without therapy. In addition, each approach leads to the childrenâs use of target forms in sen- tences that were not explicitly taught, and in speaking contexts that differ from those used during therapy. In spite of this generally positive picture, two important qualifications must be made. First, the more specific the focus of therapy, the narrower the scope of the rules or patterns that are learned. For example, therapy that concentrates on helping the child use âwh-â questions, such as âWhere is the girl taking the dog?â and âWhy is the man crying?â will result in the childâs use of similar untaught questions, but gains may not be seen in other details of the childâs grammar (e.g., Wilcox and Leonard, 1978). More intensive programs tend to avoid this problem but, of course, intensive programs are just thatâprograms that not only occupy a good portion of the childâs week, but can also extend for as long as 2 years. The second qualification is that, whereas most children in therapy begin to progress at an accelerated rate, the gains are often not enough to bring them to age-appropriate ability levels. It is not unusual for children to remain a full standard deviation behind their peers (Rice and Hadley, 1995). Indeed, there appears to be great stability in language impairments over time. For example, in a 14-year follow up study, Johnson and col- leagues (1999) found that 73 percent of the children who were language impaired at age 5 continued to perform in this range at age 19. Long-term outcomes were better for those with initial speech impairments than for those with language impairmentsâthat is, for those whose impairments involved problems with speech sounds rather than problems with the struc- tural aspects of language. In addition, interventions that are successful in facilitating grammatical expression in preschoolers with language impair- ments do not always minimize the risk that these children have in their social adjustment and academic achievement upon entering school (Fey et al., 1995). One last intervention must be mentioned. In recent years, an approach developed by Tallal, Merzenich, and their colleagues has attracted consid- erable attention (Merzenich et al., 1996; Tallal et al., 1996). This treatment approach is based on earlier findings that children with specific language impairment have significant difficulty on tasks requiring them to process auditory information that is presented rapidly, and auditory information in
144 FROM NEURONS TO NEIGHBORHOODS which contrastive stimuli differ only in acoustic details that are brief in duration. The approach takes the form of computer games in which the children must first make discriminations based on stimuli of greater dura- tion and intensity. As the children progress through the program, the stimuli begin to approximate their typical duration and intensity values. Impressive gains on standardized tests of language have been reported for children who participated in this program. Because measures of language in natural settings, such as spontaneous speech samples, have not yet been part of the testing protocol with this approach, it is difficult to determine if the test gains made by children with this approach are gains in language ability or gains in attention skills. Is early intervention better than later intervention? The working as- sumption is yes, but it has been difficult to test empirically. Some portion of the children diagnosed with specific language impairment at young ages will, in fact, grow out of itâthese are the late talkers who will catch up to peers even without intervention. It is always difficult to know whether intervention was effective, or whether the child just grew out of his or her problems. For example, following a period of intervention, 28-month-olds with expressive language limitations were found to make larger gains in expressive language ability than a comparable group of children not receiv- ing intervention; by 34 months, these children approximated age-level ex- pectations. However, 10 months later, the control children, too, caught up to age level (Whitehurst et al., 1992). Unfortunately, therapy effectiveness as a function of age has not been investigated systematically, in large part because of the problems inherent in diagnosing children with specific lan- guage impairment at an early age. When should parents take language and speech delays seriously? Chil- dren are often regarded as being late talkers if at 24 months they use fewer than 50 words and produce no word combinations (Paul, 1991; Rescorla, 1989; Thal and Bates, 1988). However, many of these late talkers will be normal language users in 1 to 3 years. For example, 50 percent of late talkers are likely to exhibit typical language use by age 3, and another 25 percent will be functioning normally when they enter school (Rescorla and Schwartz, 1990; Thal and Tobias, 1992). Thus, a good proportion of chil- dren who have language difficulties at a young age will grow out of those problems even without intervention. Early language delay is not sufficient for a child to have severe language problems later in development. How- ever, early language delay does appear to be a necessary condition for later language problems. Most, if not all, children with specific language impair- ment have a history of slow, protracted language development (Trauner et al., 1995). Virtually all such children come from the ranks of the late- talking.
COMMUNICATING AND LEARNING 145 Considerable research has been aimed at discovering the factors that distinguish late talkers who will and will not outgrow their language limita- tions. No factor has proven foolproof. However, several factors are asso- ciated with better as opposed to poorer outcomes. Children with age- appropriate language comprehension who use recognitory gestures (e.g., pretending to drink from an empty cup) are more likely to outgrow their language difficulties (Thal and Bates, 1988; Thal et al., 1991). In contrast, children with family members who have a language-related problem or a history of such a problem are less likely to outgrow their language difficul- ties and more likely to be diagnosed as having a specific language impair- ment (Tallal et al., 1989; Tomblin, 1989; van der Lely and Stollwerck, 1996; Weismer et al., 1994). Given the difficulty in discriminating children who will grow out of language difficulties from those who will not, the most prudent (although perhaps not the most cost-efficient) strategy may be to intervene whenever a child shows early language impairment. There is, of course, always the possibility that labeling children as âlanguage delayedâ may affect how others view them and may, in the end, have adverse effects on them. Very little is known about this potential problem. However, it is known that intervention can do considerable good. It may be important to foster these benefits as early as possible, before the gap in language development widens. Of particular significance is evidence showing that wide individual differences at school entry in vocabulary and other early literacy skills are seldom reduced as children move through school, and they can be exacer- bated. This is true for children within the normal variation of language ability as well as for those with specific language delays. Evidence discussed below with respect to early learning that these initial differences set in motion very negative chains of events reveals the critical importance of language interventions that start prior to school entry. Moreover, early intervention that moves children toward normal linguistic functioning as quickly as possible may be able to forestall some of the problems with social skills that are demonstrated by children who are slow to develop language. Indeed, early intervention can have benefits, not only in vocabu- lary and multiword combinations, but also in areas not specifically targeted for intervention, such as social skills, speech intelligibility, and parental stress (Robertson and Weismer, 2000). Early intervention may be impor- tant, not because doors remain permanently closed without it, but because with it, doors swing open that might otherwise have been inaccessible at that moment in the childâs development.
146 FROM NEURONS TO NEIGHBORHOODS THINKING AND LEARNING DURING EARLY CHILDHOOD As with language learning, childrenâs early capacities to make sense of the world around them and learn from their experiences appear to be relatively robust features of early development. Studies that examine cul- tural variation often find similar developmental progressions across cul- tures in cognitive development, although this is not uniformly true (Avis and Harris, 1991; Diamond, 1991; Fernald et al., 1989; Flavell et al., 1983; Gelman, 1998; Slobin, 1997). This may be due to certain fundamental commonalities in cultures across the world, such as opportunities to inter- act with other people, to observe physical events, to observe countable numbers of things, and to hear language. Moreover, despite dramatically delayed cognitive development among children reared in highly depriving institutions, their recovery upon adoption into stable and loving families is equally dramatic (see Chapter 9). At the same time, however, some aspects of early learning are more susceptible to variations in childrenâs environ- ments, as well as to early insults arising from exposures to prenatal toxins and other damaging influences (see Chapter 8). Finally, early interventions can have significant effects on what children know and can do at school entry and, perhaps as a result, sometimes have lasting influences on their school trajectories. We first portray aspects of early cognitive development and learning that proceed apace for almost all children who grow up in supportive early environments. We then describe aspects of early learning that are character- ized by individual differences and discuss the debate about early learning and sensitive periods. Next, following a brief discussion of early achieve- ment motivation, we review what is known about features of environments that foster or undermine early learning, including the influence of socioeco- nomic status. We close with a discussion of measuring early cognitive devel- opment. A companion report from the National Research Council titled Eager to Learn: Educating Our Preschoolers (National Research Council, 2000) discusses what science now tells us about instruction and teaching during the early years. Early Intellectual Competence Infancy, toddlerhood, and the preschool years are times of intense intellectual engagement. Even 30 years ago, it would have seemed absurd to suggest that infants have memories, that they explore cause-and-effect se- quences, or that they can engage in numerical reasoning. Today, thanks to the efforts of scientists who have developed new techniques for studying cognitive development, we know that they have these and many other amazing mental capacities.
COMMUNICATING AND LEARNING 147 Children from birth to age 5 engage in making sense of the world on many levels: language, human interactions, counting and quantification, spatial reasoning, physical causality, problem solving, categorization. In- deed, even preverbal infants show surprisingly sophisticated understand- ings in each of these areas. Complex human reasoning is thus rooted in early childhood. For example, infants less than a month of age can imitate othersâ gestures that are no longer in view, such as sticking out their tongues or opening their mouths (Meltzoff and Moore, 1989). By 9-12 months of age, infants can learn new behaviors simply by watching others, such as remembering how to unlock a container up to 24 hours after observing a peer do it (Bauer and Wewerka, 1995; Mandler and McDonough, 1995; Meltzoff, 1988). Six- to eight-month-olds can represent numbers: they match the number of objects visually depicted on a display with the number of drumbeats emanating from a loudspeaker (Starkey et al., 1983), and, when shown first one toy and then another hidden behind a screen, 5- month-olds expect to see two toys when the screen is lifted (Wynn, 1992). By the second half of the first year of life, infants have already learned about the properties of physical objects (Baillargeon et al., 1995). They know, for example, that objects cannot pass through one another and that objects fall when they are not supported. Within the first year of life, infants become highly attuned to causal relations between objects. They distinguish events involving a causal se- quence from other, noncausal events. For example, babies are more sur- prised when a video of one object colliding into another is run backward than when an object changing color is run backward (Leslie and Keeble, 1987). Furthermore, babies are aware of the effects of their own behaviors, in that they prefer consequences that they control directly over those that are uncontrollable (e.g., Parritz et al., 1992). For example, a child interact- ing with a noisy mechanical monkey perceives it as mildly threatening when it moves unpredictably, but enjoys it when he himself controls the toyâs movements (Gunnar-vonGnechten, 1978). Similarly, infants 12 and 18 months old respond more positively to strangers who act in predictable ways that allow them more control than to strangers who are less predict- able (Mangelsdorf, 1992). In addition to distinguishing cause from effect, infants can distinguish accidental from intentional actions (Leslie and Keeble, 1987; Oakes and Cohen, 1990; Tomasello et al., 1996). In one study, 18-month-old children viewed an adult attempting to perform a series of target actions (e.g., pulling the ends off a tube) (Meltzoff, 1995). The adult was shown trying, but failing, to perform the target acts. When children imitated the event, they imitated the intended actionânot the observed behavior. In a control experiment, children viewed a machine performing the same failed target acts. In this case, children did not attempt to perform the target acts at all.
148 FROM NEURONS TO NEIGHBORHOODS These results suggest that 18-month-olds situate people, but not machines, within a psychological framework that differentiates between the surface behavior of people and a deeper level involving goals and intentions. This feature of imitative learning, which appears to be unique to human beings (see Tomasello, 1996), has been highlighted as crucial to the acquisition of cultural knowledge. As Tomasello notes (2000:37): âChildren grow into cognitively competent adults in the context of a structured social world full of material and symbolic artifacts . . . structured social interactions . . . and cultural institutions such as families and religionsâ (see also Rogoff and Chavajay, 1995). The capacity to learn from others, by perceiving their goals and attempting to reproduce their strategies to achieve the same goals, initiates for the 1-year-old the process of being socialized as a mem- ber of a particular cultural group that reflects the accumulated wisdom of its ancestors. Surprisingly, given the usual image of toddlers as egocentric, this men- talistic framework also allows even 2 1/2-year-olds to take on the perspec- tive of another person, for example, recognizing that someone may have different tastes or preferences from their own (Flavell et al., 1990; Repacholi and Gopnik, 1997). By age 5, this has developed into a full-blown theory of mind, in which children can predict othersâ intentions, deceive others suc- cessfully, and recognize that beliefs donât always correspond to reality. The appearance-reality distinction is understood quite broadly by age 4 or 5, extending to childrenâs way of reasoning about categories of objects and animals in the real world. Thus, 4-year-olds recognize that everyday catego- ries (such as dinosaurs or living things) are not just perceptually based. They can readily learn that a pterodactyl is a dinosaur, not a bird, and infer from this information that it behaves like other dinosaurs (Gelman and Markman, 1986). Given the wealth of abilities present even in infancy, it is not surprising that researchers now describe babies as âwired to learn,â âcomputers made of neurons,â and as âhaving inborn motivation to develop competencies.â The policy issue is therefore not one of getting children ready to learn, but rather one of appreciating that they are born to learn and crafting policies and programs that actively build on their considerable capabilities (see National Research Council, 2000). Childrenâs intrinsic drive to master the environment is probably no more evident than in relation to their efforts to understand and control the world around them. Indeed, infantsâ need to be active agents in their own learning becomes abundantly evident when you take away their control over stimulation. By a year of age, give a baby a metal spoon and a bunch of pots to bang on and she will happily make a considerable din. Let her hit a panel to turn on a toy monkey that claps cymbals loudly and she will do so with much glee. Record when she hits the panel, though, and use her record of hits to turn the toy (unpredictably) on
COMMUNICATING AND LEARNING 149 for another child and, instead of smiles and laughter, that child will likely cry and attempt to escape to the safety of her parentâs lap. Provide a beep before the toy comes on each time (to add predictability), and although the child lacks control, she will be less likely to cry and try to escape, but she still wonât be likely to smile and reach for the toy. This clever research suggests that early learning environments should be set up to provide ample opportunities for young children to be active agents in their own learning and to receive predictable responses from their surroundings. But not all aspects of cognitive development emerge with such predict- ability. As with language development, cognitive development consists of numerous components, some of which appear to be more affected by vary- ing early environments than others. Unfortunately, the majority of research on cognitive development, particularly during the earliest years of life, has focused on the identification of universal patterns. By the time children are on the verge of school entry, however, research exploring individual differ- ences becomes more prominent. Virtually all children develop the capacity to understand causality, adopt the perspective of another person, and sort objects by categories. But just as children arrive at school with widely varying vocabularies, they also arrive at school with vast individual differences in their understanding of number concepts, familiarity with the alphabet and its relationship to sounds and printed words, capacity to reason through problems, knowl- edge of different notational forms (i.e., print, 3-D models, maps), and even familiarity with question-answer formats (National Research Council, 1998a, 2000). Another example of individual differences is provided by research on early conceptual development. While all preschoolers, for ex- ample, can categorize objects, only children who have been exposed to substantial knowledge about dinosaurs can sort them according to whether they are meat-eaters or not, land-dwellers or not, and so on (Gobbo and Chi, 1986). One of the more striking differences among children starting kindergar- ten is in the area of executive functioning, discussed in the previous chapter. Some children are far more capable than others of the self-regulatory, sequencing, planning, and organizational skills that the research refers to as executive functioning. Deficits in any of these processes typically result in problems in school (Lyon, 1996), and they can create a snowball effect, with problems growing greater over time and extending to other areas of cognitive, academic, social, and emotional development. Year after year of failing to âstop, look, listenâand thinkâ (Douglas, 1980:71) will inevitably diminish the richness of childrenâs intellectual growth and experience and will interfere with their ability and motivation to be effective problem solvers.
150 FROM NEURONS TO NEIGHBORHOODS Are There Sensitive Periods in Cognitive Development? Perhaps a surprising point to many interested in early cognition is that there is no evidence for critical or sensitive periods in any aspect of cogni- tive development, in contrast to recent discoveries regarding processes in perception and language that are linked to the timing of inputs. This is not to say that sensitive periods in cognition do not exist; rather, scientific tools have not yet identified them if they do exist. Indeed, scientists have gener- ally not even studied sensitive periods in cognitive development. Thus, there is an absence of relevant studies, rather than an absence of positive evi- dence. This gap reflects the difficulty of manipulating, in any precise way, the timing of input deemed relevant to cognitive development. Consider, as a contrasting example, studies of sensitive periods in lan- guage acquisition. The most successful of these studies exploit certain ex- periments of nature, in which children are effectively barred from linguistic input (for example, due to deafness in a nonsigning environment). The problems inherent in studying comparable cases in cognition are multiple. First, everyday interactions and observations are rich with evidence that children exploit to further their cognitive growth (e.g., other faces or voices to imitate; sights and sounds to remember; problems to solve, including even those so mundane as an infant attempting to find her fingers to suck; similarities and differences to note and classify). Thus, it is difficult to imagine a context in which a child could be deprived utterly of cognitive input. Second, those cases in which cognitive deprivation of some sort does occur tend to be confounded with social, emotional, and language depriva- tion (for example, children who suffer extreme isolation). One implication of this gap is that strong claims regarding inherently irreversible effects of early experience on later cognition in humans, no matter how appealing, are not scientifically well founded. In addition to the lack of evidence regarding sensitive periods for cog- nition, it is clear that important intellectual developments take place throughout childhood and even adulthood. To give just one striking ex- ample: researchers studying memory capacity have been able to train ordi- nary adults to achieve prodigious memory feats. In one well-documented case study (Kliegl et al., 1987), two young adults were trained, over a period of many months, to extend their digit span (that is, the number of single-digit numbers they could recall without error, after hearing them spoken aloud only once, without any opportunities to study, practice, or rehear the list). They started with a digit span of typical length (about 7, the length of a telephone number) and by hours of practice extended it over tenfold. In other words, by the end of training they could hear any new list of 80 single-digit numbers, one time only, and repeat the entire list, flaw- lessly, in order.
COMMUNICATING AND LEARNING 151 More usual (yet still remarkable) examples concern the striking growth of scientific knowledge and reasoning, mathematical understanding, and reading and writing skills of children past age 5, typically in school con- texts. Likewise, although children from birth to age 3 engage in complex reasoning, it is well documented that major developments continue into early school age and well beyond. For example, there is a major shift between the ages of 3 and 7 in childrenâs understanding of social relation- ships, in their understanding of biological principles (Carey, 1985), in their capacity to be self-reflective, and in their capacity to self-regulate. Learning is characterized by remarkable plasticity over the life span; learning during the earliest years is not unique. This picture is complicated, however, by the recognition that early developmental sequences may provide important foundations for later de- velopment. Consider, for example, the case of early motor development. Researchers Joseph Campos and his colleagues have discovered that in- fantsâ experience with crawling appears to affect their fear of heights. In particular, crawling experience predicts wariness of heights, controlling for age; experience moving about in a walker leads to wariness of heights; lack of locomotor experience (due to physical disability) yields lack of wariness of heights; and regardless of the age when infants began to crawl, it is the duration of locomotor experience and not age that predicts avoidance of heights (Campos et al., 1992a). Another quite different example of the importance of early sequences concerns the implications of impoverished verbal communication for devel- opment of reasoning about othersâ mental states. In one study (Peterson and Siegal, 1999), normal 4-year-olds were compared with a sample of deaf children averaging 9 years of age and to a sample of autistic (hearing) children averaging 9 years of age. The deaf children included a group of deaf signers from hearing families, none of whom had experienced daily conversational access to fluent signers, as well as children with access to more enriched conversations (either in homes with at least one native deaf signer or as oral deaf children with a moderate to severe hearing loss and the assistance of amplifying hearing aids). All children participated in a series of experimental tasks designed to tap their understanding of othersâ mental states. For example, in one task, children discovered that a candy box actually (and unexpectedly) contained pencils inside. They were then asked to predict what a naive observer would think was inside the closed box. A correct understanding of mental states would lead a child to answer âcandyâ; an incomplete understanding would lead a child to answer âpen- cilsâ (i.e., the child would attribute his or her own belief state to that of the naive observer). Results indicated that native deaf signers performed as well as the hearing children. Oral deaf children also performed well. In contrast, the
152 FROM NEURONS TO NEIGHBORHOODS signing children from hearing homes, all of whom had limited access to enriched conversations, and the autistic children performed much more poorly, at about half the level of the other two groups. These results suggest that the availability of discourse about invisible mental states contributes to childrenâs capacity to make sophisticated inferences about these constructs. The authors also suggest the possibility of a neurobiological basis for these group differences in performance, as deaf children who have been restricted in early conversational exposure differ in their patterns of language-related brain activity from both hearing adults and deaf native signers (Marschark, 1993; Neville et al., 1997). Findings such as these certainly do not argue for a sensitive period of development. Nonetheless, they emphasize the importance of early screening of sensory, perceptual, and motor abilities. These seemingly mundane skills are the foundation for later learning and problem solving and, if not addressed early, can constrain or alter conse- quent aspects of learning. Motivational Dimensions of Early Learning The vast majority of young children think they are just wonderful, capable of doing almost anything, and headed for success (Harter and Pike, 1984; Stipek, 1992). Most kindergarten children, for example, will tell you that they are the smartest child in their class (Stipek, 1993). Even when they approach tasks on which they have previously failed, young children usu- ally predict that they will succeed (Stipek and Hoffman, 1980; Stipek et al., 1984). Why is this so? Ironically, the self-confidence of most preschoolers derives, in part, from their limited capabilities to distinguish among their strengths and weaknesses, to recognize that ability is not infinitely mal- leable (i.e., they confuse effort and ability), and to use social comparisons to make realistic judgments of their skills and competencies. Indeed, one rea- son why young children are so buoyantly optimistic about themselves is that when they compare what they can do with what they were able to do when they were younger, they can easily see how much more competent they are now (Frey and Ruble, 1990). In effect, they conclude that âevery day, in every way, I am getting better and better!â Young children thus appear to be disposed toward positive motivation- related cognitions. This applies across the board to children from families with both high and low socioeconomic status (Stipek and Ryan, 1997). But not all young children display this positive bias, and not all aspects of achievement motivation in the early years are so robust. Achievement mo- tivation encompasses a set of constructs, including: (1) mastery motivation, or the childâs propensity to explore, manipulate, persist, and derive pleasure in mastery-related behaviors and achievement (White, 1959); (2) intrinsic motivation, or the childâs engagement in an activity without pressure or
COMMUNICATING AND LEARNING 153 rewards for doing so (Deci and Ryan, 1985; Lepper, 1981); and (3) cogni- tive aspects of motivation, including expectations for success, challenge seeking, and self-perceptions of competence (Atkinson, 1964). Despite the optimistic and positive picture of young childrenâs motiva- tion, their positive beliefs decline precipitously upon school entry (Stipek and Hoffman, 1980; Stipek and Tannatt, 1984; Wigfield et al., 1997). While some studies find that girls are more likely than boys to succumb to declining self-perceptions of their abilities (Entwisle and Baker, 1983; Ladd and Price, 1986), this is not always the case (Phillips, 1984), at least during the elementary years. A blend of developmental and contextual factors seems to be involved, including childrenâs developing ability to make social comparisons, exposure in school to explicit and comparative standards for performance, and individual differences in the tendency to ascribe failure to oneâs ability or to more transient (i.e., effort) or external (i.e., the test was unfair) factors. Researchers have, however, continued to search for early indicators of motivational problems. Individual differences in facets of behavior that are closely aligned with motivational tendencies can be detected as early as 6 months of age (see MacTurk and Morgan, 1995 and Morgan and Harmon, 1984 for reviews). Some infants, for example, persist in goal-directed behavior and seem to derive more pleasure from attaining goals (e.g., slipping a ball into a hole) than do other infants. These early differences, moreover, are closely tied to constructs assessed in the literature on temperament, such as inhibition around novel stimuli, persistence, and sustained attention (Fox et al., in press; Kagan et al., 1987). It is possible that individual differences seen in infantsâ mastery-related behaviors reflect differences in temperament. Whether these differences set in motion interactions that, over time, lead to motivational differences in the preschool and elementary years remains to be seen. Longitudinal studies of motivation that follow children from in- fancy into school are, surprisingly, missing in the developmental literature, despite recognition of the critical role played by motivational tendencies in childrenâs achievement (see Stipek and Greene, in press). The one chink in the armor of motivational resilience that has been detected in children as young as age 4 concerns their reactions to failure. Carol Dweck and her colleagues have examined a broad set of negative cognitions, behaviors, and emotional variables that they refer to as learned helplessness (Cain and Dweck, 1995; Diener and Dweck, 1978, 1980; Dweck, 1991; Smiley and Dweck, 1994). Children who display learned helplessness are highly impaired by failure experiences, showing displays of negative affect, challenge avoidance, and low expectancies for future suc- cess. Some preschoolers exhibit learned helplessness in achievement-related contexts. In one of the studies that first demonstrated this, children first completed a series of puzzles in which three unsolvable puzzles were fol-
154 FROM NEURONS TO NEIGHBORHOODS lowed by a fourth solvable puzzle, which all children were given sufficient time to complete. They were then again presented with all four puzzles and asked to choose a puzzle to work on. About one-third to one-half of the children not only chose the puzzle that they had previously completed (thus avoiding the puzzles on which they failed), but also expressed a coherent set of negative attitudes about their ability and future achievement. For ex- ample, they indicated that they would not be able to complete puzzles in the future even if given more time, were likely to describe themselves as ânot so goodâ at puzzles even when they had said they were âgoodâ at puzzles prior to failure, and to express âvery sadâ feelings about their performance. These individual differences among preschoolers emerged despite the fact that there were no prior differences among the children in puzzle-solving ability, in the number of pieces they fit into unsolvable puzzles, or in post- failure puzzle-solving ability. Moreover, the children who were negatively affected by failure generalized their diminished self-confidence to tasks that were unrelated to puzzles. Unlike older children, however, preschoolers who display learned help- lessness do not show performance decrements following failure; in fact, their use of effective problem-solving strategies seems to bounce back once presented with a solvable task. Still, their negative self-appraisals may have implications for their orientations to learning as elementary students. In one study (Smiley and Dweck, 1994), children who responded negatively to failure as 4-year-olds were found to have significantly lower expectations for success and poorer appraisals of their abilities as third and fourth graders than did the children whose motivation was not impaired as preschoolers. In sum, many aspects of achievement motivation fail to show indi- vidual differences prior to school entry, suggesting that young children either lack the cognitive abilities or experiences that can lead some to give up easily, anticipate poor performance, and disparage their abilities. Yet there is some evidence that children as young as age 4 are sensitive to failure experiences and, although subsequent performance does not appear to be affected, their internalized views of themselves as effective students do appear to remain vulnerable over time. Early Learning Environments The exciting discoveries that have characterized research on cognitive development have led some to argue that young mindsâso active and capableârequire special, heightened cognitive stimulation. Certainly, as more is learned about the remarkable capabilities of young children and their eagerness to learn, one naturally wants to provide them with environ- ments that will support them in their task of becoming the most competent
COMMUNICATING AND LEARNING 155 children, and ultimately adults, that they can be. As mentioned earlier, this does not imply that specific inputs are required at specific times during early development. But what is known about how best to ensure that childrenâs early learning is on track? And to what extent do efforts to accelerate learning have lasting effects? Early Learning and Early Environments There is no question that enriched inputs can lead to enhanced learn- ing, at least on a short-term basis. To give a trivial example, a 4-year-old child who is coached on the names of different species of birds can develop a more extensive vocabulary of bird names than a child who does not receive such input. However, it is not clear what the longer-term implica- tions of such inputs are, nor which skills are being transmitted. It is also not clear that early learning is any more efficient, enduring, or effective than later learning. For example, there is to date no scientific evidence that teaching children to count at age 2 versus age 4 has any implications for their mathematical understanding or later mathematical achievement. More- over, as discussed below, some activities embarked on in the name of enrichment may actually have some unintended detrimental effects. As much as parents and other caregivers may wish for a toy or a tape or a lesson that would accelerate cognitive development, there isnât one yet. In fact, there is no magic bullet for brain stimulation and early learning. For example, there is no credible scientific foundation to the popular belief that listening to classical music will raise a childâs IQ (see Box 6-2). Rather, it appears that, just as the vast majority of children all around the world grow up in homes and communities that provide them with the inputs they need to develop language, most grow up in environments that support their natural inclinations and abilities to learn. Indeed, childrenâs curiosity about how the world works and their basic understandings in these domains routinely emerge without special prompting or instruction. Children, for example, spontaneously begin organizing objects into categories before 2 years of age, neatly sorting a pile of toys into cars and marbles and blocks (Sugarman, 1981; Waxman, 1999). Likewise, 2-year-olds spontaneously count arrays of objects, both in the service of solving problems (i.e., has someone taken one of my marbles?) and because it is fun for its own sake (Gelman and Gallistel, 1978). All they need are the small objects to ma- nipulate and the opportunity to play with them. Accordingly, the literature on early learning environments is not about accelerating learning with expensive toys and explicit early instruction. Instead, it focuses on how adults interact with young children and set up relatively ordinary environments to support and foster early learning. While this sounds like a subtle distinction, it captures the difference between a
156 FROM NEURONS TO NEIGHBORHOODS BOX 6-2 The Mozart Effect Does listening to classical music improve a young childâs cognitive performance? Belief in the so-called Mozart effect has already had far- reaching consequences for public policy, not to mention the musical choices of first-time parents. In Georgia and Tennessee, for example, a classical music CD is given to every new mother, and in Florida, a new law requires that children in state-run child care facilities listen to classical music daily. Many parents are now wondering whether they should be playing classical music to their infants and toddlersâor whether their fail- ure to do so earlier has blunted untapped intellectual potential in their offspring. The possible effects of classical music on cognitive performance were first suggested by a study of college students showing that adults who listened to a Mozart sonata performed slightlyâthough significantlyâbet- ter on a brief spatial reasoning task than did students listening to a relax- ation tape or sitting in silence (Rauscher et al., 1993). The effect on performance was measured immediately after exposure to the music; longer-term effects were not studied. Many studies have attempted to replicate and extend these findings, but there has been no research with infants or toddlers, none involving assessments of brain functioning, and few examining effects of more than a dayâs duration. Even research with adults that has used the same particular Mozart sonata as the original study (Sonata for Two Pianos in D Major, K 448) has yielded inconsistent findings, with some researchers replicating the effect for performance on a brief spatial-temporal reasoning task but most failing to do so, and oth- ers finding that the effect can be induced by other pleasant events, such as listening to a story (Chabris, 1999). There have been no studies with infants or young children showing long-term cognitive gains attributable to early exposure to classical music. In the end, although listening to music and learning to play a musical instrument may have important benefits for children, it is important to realize that there is no shortcut on the path toward developing early intel- lectual skills. child who is taught to recite the alphabet and a child who is read to every night and becomes interested in letters and words because they are associ- ated with the joy of being in her fatherâs lap, seeing beautiful pictures, and hearing a wonderful story. As with every other task of early development that we have discussed, the elements that support early learning revolve around relationships and the resources they provide for children. This literature emphasizes parentsâ interactions with their young children, their beliefs about learning and their
COMMUNICATING AND LEARNING 157 childrenâs capabilities, the home learning environment, and family organi- zation. We discuss these aspects of the childâs environment in more depth in Part III. Here, it is important to note that these features of families account for sizeable differences in the learning opportunities that children are exposed to prior to school entry and, in turn, for the wide disparities in knowledge and abilities that characterize kindergarteners (Duncan et al., 1994). Child care and preschool experiences also matter, as do childrenâs peer groups and the degree to which their communities support and provide opportunities for learning. Cognitive outcomes have, in fact, been a central focus of research on the effects of child care and more comprehensive early interventions. There is ample documentation in this literature of early envi- ronmental influences on concurrent cognitive development and, in some cases, on later learning and such important outcomes as special education placement and staying at grade level in school (see Chapters 11 and 13). But even for children who spend hours every day in child care or preschool, the home environment accounts for the lionâs share of the variation in what young children know and are ready to learn when they start kindergarten (NICHD Early Child Care Research Network, 2000). Motivation and Early Environments There is also evidence regarding the effects of early learning environ- ments on motivational aspects of early development (see Phillips and Stipek, 1993; Stipek and Greene, in press). Studies have found systematic effects of both the home environment and the instructional and social climate of early childhood education programs on a variety of motivation-related outcomes. For example, infantsâ mastery motivation has been associated with the number of toys in the home that are responsive to infantsâ manipulations and with maternal physical and auditory stimulation (Busch-Rossnagel et al., 1995; Yarrow et al., 1982), as well as to parental support of autonomy in task situations (e.g., nonintrusive assistance and encouragement) (Frodi et al., 1985; Grolnick et al., 1984). For toddlers and preschoolers, intrusive behavior on behalf of parents and teachers discourages mastery behavior, as does criticism and directive comments instead of using praise, giving suggestions and information, and demonstrating effective strategies (Fagot, 1973; Farnham-Diggory and Ramsey, 1971; Hamilton and Gordon, 1978; Henderson, 1984). These same relations appear to hold for young children with disabilities (Hauser-Cram, 1996). With regard to classroom settings, although there is minimal variation in achievement motivation among preschool-age children, the variation that exists is significantly associated with classroom context. Specifically, highly didactic, performance-oriented early childhood classrooms have been
158 FROM NEURONS TO NEIGHBORHOODS found to depress young childrenâs motivation. Children in these classrooms characterized by strong teacher control over activities, discouragement of collaborative work, a strong emphasis on getting correct answers, and relatively low levels of teacher warmth have been found to rate their abili- ties lower, to avoid challenging tasks, to expect poorer performance from themselves, and to show less enjoyment while working on achievement tasks compared with children in classrooms characterized by minimal pres- sure to perform, ample child choice in activities, encouragement of collabo- ration, and more nurturant teacher-child interactions (Stipek et al., 1995, 1998). They also showed more evidence of stress (e.g., nail biting, frown- ing, turning away from a task) and were less compliant in the classroom. It remains to be seen if highly didactic instruction in preschool has enduring effects on motivation or achievement. This research also fails to untangle the influence of didactic instruction and low levels of nurturance, because they were highly associated. Perhaps didactic instruction in the context of more nurturant teacher-child interactions would not be harmful to motiva- tion. In light of the very early age at which children in the United States are first exposed to a school-like setting (see Chapter 11), there has been a growing appreciation of the importance of studying children whose home language or culture differs substantially from the norm in early childhood classrooms. How do these differences manifest themselves in childrenâs classroom behavior, motivation to learn, and achievement? A child who has been taught that it is disrespectful to ask questions of adults or who is unaccustomed to playing in mixed-sex peer groups is likely to feel some initial discomfort and confusion in classrooms that embody different rules and norms for behavior. Japanese students, for example, are more reluctant than their counterparts in the United States to ask questions because this suggests that they did not work hard enough to understand the material or that they are implicitly criticizing the teachersâ ability to communicate in- formation (see Greenfield and Cocking, 1994). Parentsâ beliefs about when and how children learn school-related skills and the social rules that guide learning interactionsâtermed âfunds of knowledgeââare also based in culture (Moll et al., 1992), and they affect how much parents emphasize explicit early learning opportunities that map onto what kindergarten teach- ers in the United States expect children to know and be able to do (Goldenberg et al., 1992; Heath, 1983; Laosa, 1980; Shanahan and Rodriguez-Brown, 1993). Classroom adaptations that are designed to ac- commodate young childrenâs differing approaches to learning have been found to reduce disruptive and inattentive behaviors (Au and Mason, 1981; Gallimore et al., 1974; Vogt et al., 1987; Weisner et al., 1989), but effects on achievement remain to be demonstrated. In sum, despite the generally positive motivational orientations of young
COMMUNICATING AND LEARNING 159 children, both home and classroom environments, as well as the lack of âfitâ between them, have the capacity to undermine their natural optimism and enjoyment of learning. Motivation suffers when parental behavior is intrusive, highly directive, and critical, and when teachers stress individual performance and deemphasize interpersonal warmth. The Contribution of Family Socioeconomic Status Of all aspects of childrenâs early environments, the familyâs socioeco- nomic status (SES) is most powerfully associated with childrenâs cognitive skills when they enter school. We consider this literature separately and return to these issues in Chapter 10. Because lifelong educational attain- ments can be traced back to academic skills at school entry, these class- related differences at the beginning of school are cause for serious concern (Stevenson and Newman, 1986; Stipek, in press). Thus, even though there is no evidence that early cognitive attainments are characterized by sensitive periods that are inherent to development, school entry can be viewed as an important social transition when SES-linked individual differences can be- come solidified and amplified or initial gaps can be narrowed. In this sense, what children know and can do at school entry matter, not because devel- opment becomes less amenable to environmental influence once the pre- school years have passed, but because there is, in effect, a manufactured critical transition at which point individual differences begin to predict longer-term patterns of learning and achievement. Indeed, there is good evidence to suggest that the long-term prediction of academic achievement, school dropout, and even adult literacy from the socioeconomic status of oneâs family during the early childhood years is attributable to the effects of social class on early school achievement (Stipek, in press). For example, when researchers explore causal sequences in their data (e.g., does A explain C, or does A explain B, which then explains C?) they find, for example, that the significant effect of income on early adult literacy is mediated or influenced by the effects of income on early child- hood cognitive level, which in turn predicts adult literacy (Baydar et al., 1993). Similarly, while mothersâ SES-linked interactions with these young children predict the childrenâs achievement in sixth grade, an even stronger relationship is found between childrenâs preschool academic skills and their sixth grade achievement (Hess et al., 1984). As we discuss in Chapter 10, SES during the early childhood years appears to be more predictive of educational attainments than SES during other periods of childhood. Several mechanisms have been proposed to explain the long-term pre- dictive power of a childâs academic skills at school entry and, in particular, the extent to which class-linked differences at school entry are perpetu- atedâeven exacerbatedâas children move through school. These include
160 FROM NEURONS TO NEIGHBORHOODS effects of childrenâs initial performance on teachersâ expectations for their subsequent learning, teacher behaviors and decisions that derive from these expectations, associations between low academic skills and conduct prob- lems that further impede learning, and self-defeating perceptions and ex- pectations that children hold for themselves that undermine effort, persis- tence, and therefore learning (Stipek, in press). These processes are not the focus of this report. They do, however, further illustrate the importance of narrowing the gap prior to school entry between children whose families occupy different economic niches in society. Measurement Issues The learning capacities of young children, discovered by researchers over the past 30 years, complicate efforts to measure early intellectual and cognitive development. Yet the measurement of early learning and cogni- tion, primarily with global measures of developmental status or IQ, has been a staple of efforts to evaluate the effects of early interventions. This final discussion raises concerns about traditional approaches to assessing the effectiveness of early interventions and identifies alternative constructs that would provide firmer evidence of effective programs. We return to these questions when we discuss the early intervention literature in Chap- ter 13. IQ tests are not, in fact, well suited for studying development. They are not designed, for example, to capture the enormous cognitive growth that is taking place during the early years in such areas as increased knowledge, memory, speed of processing, and sequencing and planning abilities. Rather than assessing individual growth over time, or growth in response to an intervention, the IQ is designed to be stable over time and to assess the relative standing of an individual with respect to others of the same age. Indeed, because the IQ is hard to push around, an intervention that finds reliable improvements in IQ has accomplished something noteworthy, par- ticularly if these improvements endure over time (which they seldom do). Standard IQ tests are also not designed to assess intelligence in infancy, and scores within the normal range on standard measures of infantsâ devel- opmental status (such as the Bayley Scales of Infant Development) have poor predictive value for later functioning. Indeed, later IQ cannot be reliably predicted by early measures of ability until the child is about 4 years of age. In contrast, the speed with which infants habituate to stimuli and their preference for novelty are predictive of later childhood IQs (Bornstein, 1989; Fagan, 1984; McCall and Carriger, 1993; Rose et al., 1992; Thompson et al., 1991). Finally, many of the early intellectual abilities that have been the focus of research on cognitive development over the past 30 years are not evalu-
COMMUNICATING AND LEARNING 161 ated directly by standard IQ tests. These include childrenâs regulatory and attentional capacities, certain aspects of memory, and abilities that relate to theory of mind. Moreover, as researchers have learned more about what can go wrong with cognitive development, it becomes imperative to assess the specific dimensions of early cognitive functioning that can reveal serious problems and register the effects of efforts to intervene. For example, un- derstanding of othersâ intentions and mental states seems to be a quite separate intellectual domain, which is impaired in autism but spared in Down syndrome. Children with autism also display failures to engage in protodeclarative pointing, low rates of direct eye contact with others, low levels of pretend play, language delays, and deficits in reasoning about othersâ mental states (Baron-Cohen, 1995; Tager-Flusberg, 1989). The re- search on early biological insults, reviewed in Chapter 8, further calls atten- tion to the importance of assessing the attention, memory, and abstract thinking abilities that appear to be affected by a number of these insults, as well as by prolonged exposure to stress. These are not the outcomes that are typically measured in research on early intervention, despite their relevance to the populations that are typically targeted by these initiatives. SUMMARY AND CONCLUSIONS The years from birth to school entry mark a period of remarkable linguistic and intellectual growth. Children make the transition from hav- ing no language at all to understanding and expressing the subtleties of intentionality, cause and effect, and emotional states. The motivation and capacity of the newborn to act on and learn about the surrounding world and the people in it flourish during the early childhood years and ultimately transform the newborn into a 5-year-old who is usually well prepared to embark on the formal school curriculum. At the same time, there is no evidence to confirm or disconfirm that the age of 3 or 5 marks the end of a sensitive period in human cognition and, with respect to language develop- ment, evidence for sensitive periods is largely restricted to pronunciation and the complex morphological properties of language. In fact, both lan- guage development and early learning appear to be relatively resilient pro- cesses, largely protected from adverse circumstances and quick to recover when these circumstances are removed, and to be characterized by lifelong capacities for growth and learning. Nevertheless, some critical aspects of language and learning remain vulnerable to environmental variation even within the normal range that encompasses families at different socioeconomic levels in society. Indeed, evidence reviewed in Part III, suggests that young childrenâs academic at- tainments may be even more susceptible to the negative influence of poverty than is the case for older children (at least up to adolescence). These less
162 FROM NEURONS TO NEIGHBORHOODS resilient aspects include the extent of the childâs vocabulary, language pro- ficiency (i.e., uses of language), understanding of number concepts, famil- iarity with letter-sound associations, and executive functioning. Impor- tantly, these are precisely the aspects of early communication and learning that distinguish children at school entry and are thus strong candidates for the aspects of early school performance that become consolidated over time, accounting for linkages between preschool capabilities and educa- tional outcomes in adolescence and beyond. Early interventions can attenu- ate these individual differences at school entry, although the subsequent school environment plays a crucial role in either sustaining or undermining early gains. Children with specific disabilities (as contrasted with transitory developmental delays) can also benefit to varying degrees from specially designed interventions, although the early initiation of these efforts may be especially important (as has been demonstrated by research on deaf chil- dren) and the extent to which normal functioning can be approached re- mains unclear (as illustrated by children with specific language impair- ments). Despite the substantial interest that research on the developing brain has stimulated in finding materials that can accelerate early talking and learning, there is no evidence that any specialized kind of short-term input improves intelligence or learning in an appreciable way. Put in crude terms, there is no magic bullet to boost intelligence. Likewise, there is no scientific evidence that any sort of mobile, toy, computer program, or baby class has a long-term impact on reasoning, intelligence, or learning. Rather, under typical circumstances, parents around the globe seem intuitively to talk to children in ways that work quite well in fostering language development and to provide children with the interactions and materials that promote early learning. To the extent that problems arise, it is usually not that parents are doing terribly wrong things, but that they are not doing quite the right things or enough of them. This includes talking to children more and using more elaborate talk, taking advantage of everyday interactions to introduce number concepts, and not only spending more time reading but also exploring the words and pictures in the book.
E163 Making Friends and Getting Along with Peers 7 stablishing relationships with other children is one of the major developmental tasks of early childhood (see Rubin et al., 1998, for an excellent review). How well children fare at this task appears to matter. It matters to the children themselves, creating a context in which they evaluate their self-worth, competence, and view of the world as pleasant or hostile (Harter, 1982; Ladd and Price, 1986). It matters to their future, as the patterns of peer interaction in early childhood increasingly predict whether children will walk pathways to competence or deviance in the tasks of middle childhood and adolescence (Barclay, 1966; Kupersmidt and Coie, 1990; Ollendick et al., 1992). And it matters to the other children a child comes into contact with, as the experience of children in peer groups depends in good measure on the nature of the other children with whom they interact (Wright et al., 1986). Yet playing nicely, making friends, and being a good friend are not all that easy for young children. These tasks confront them with increasing demands on their developing cognitive and emotional capacities (Howes and Matheson, 1992). Developmental psychologists use a variety of techniques to understand the landscape of early peer relations. Teachers and parents have often been used as informants. However, their ratings correlate only modestly (Achenbach et al., 1987). Teacher and parent ratings reflect how adults, not children, think about what it means to be competent, nice, or fun to play with (Rubin et al., 1998). Direct observation helps get beyond prob- lems of adult interpretation, and it has been a staple of research on early peer relations. Several observational instruments have been used fairly