National Academies Press: OpenBook

Development During Middle Childhood: The Years From Six to Twelve (1984)

Chapter: 2 The Biological Substrate and Physical Health in Middle Childhood

« Previous: 1 Introduction
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 24
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 25
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 26
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 27
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 28
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 29
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 30
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 31
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 32
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 33
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 34
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 35
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 36
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 37
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 38
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 39
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 40
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 41
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 42
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 43
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 44
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 45
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 46
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 47
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 48
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 49
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 50
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 51
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 52
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 53
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 54
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 55
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 56
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 57
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 58
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 59
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 60
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 61
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 62
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 63
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 64
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 65
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 66
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 67
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 68
Suggested Citation:"2 The Biological Substrate and Physical Health in Middle Childhood." National Research Council. 1984. Development During Middle Childhood: The Years From Six to Twelve. Washington, DC: The National Academies Press. doi: 10.17226/56.
×
Page 69

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

CHAPTER 2 The Biological Substrate and Physical Health in Middle Childhoocl Jack P. Shonkoff T n industrialized societies, schoolmate children are generally the healthiest Isegment of the population. In general, they are not exposed to the nu- tritional deficiencies and infections that plague so many children in devel- oping countries, and they have not yet experienced the myriad changes of adolescence or the increased risks of major diseases that adults face. For children ages 6-12, health issues are best defined in the context of the developmental tasks of this period. Whereas acute illnesses are generally brief and followed by the resumption of normal routines, chronic impair- ments and catastrophic diseases demand sophisticated medical treatments in conjunction with attention to the child's personal and social development. Moreover, although more research is needed on socioeconomic class differ' ences in health status and use of health services, and although poverty continues to pose a major threat to the physical and mental well-being of children in the United States, the most far-reaching basic research concerns from a public health perspective go beyond the domain of the organized health care system and involve the more pervasive matter of life-style. Accidents accounted for half the deaths of children ages 5-14 in the United States in 1978, and more than 50 percent of them were related to motor vehicles (Bureau of the Census, 1982~. Multiple risk factors for the most common adult diseases have been shown to include a number of behaviors whose antecedents are germinated, if not sprouted, during middle childhood. Exercise and attitudes toward physical fitness, coping with stress, tobacco and alcohol abuse, and dietary habits are some of the life-style characteristics that appear to warrant particular preventive attention during this age period. 24

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH 25 This chapter provides an overview of the current research regarding health and illness during middle childhood. It reviews existing knowledge of the biological substrate of human function during this period. It also explores the problem of conceptualizing health and illness and analyzes it in the context of the child's emerging life-style and sense of his or her own health status both during the school years and in the future. An agenda for further study is proposed. THE BIOLOGICAL SUBSTRATE Physical Maturation Despite significant individual differences, the rate of increase in stature during middle childhood is generally similar and regular until the onset of puberty. Skeletal maturity, as measured by bone age, is the most useful biological indicator of overall physiologic maturation. Its determination is based on the predictable, ordered appearance of primary and secondary centers of ossification that develop in the growth regions (epiphyses) of bones. Although some variability related to ethnic factors has been docu- mented, measured differences in maturity are primarily related to variations in rate and not sequence. Thus, the order of epiphyseal ossification is gov' erned largely by genetic factors. The rate of skeletal maturation, however, is influenced by both nature and nurture; for example, lower socioeconomic status as well as a wide range of pathological processes have been shown to correlate with delays in bone age, and girls demonstrate a faster rate of maturation than boys by approximately 20 percent (Sinclair, 19781. In general, skeletal maturation parallels skeletal growth and, therefore, height, with both ending when hormonal influences cause the epiphyses to fuse in late adolescence. The onset of puberty heralds the beginning of reproductive maturity and provides a useful biological marker for the onset of adolescence. Pubertal changes have been reported to occur earlier in children from higher socio- economic groups, those living in urban rather than rural areas, and children living at lower altitudes (Benson and Migeon, 1975~. A later onset of puberty has been documenter! for children who are malnourished, those living in larger families, and girls engaged in strenuous exercise such as competitive athletics and dance (Frisch et al., 1980~. Generally speaking, however, genetic factors appear to have a greater effect than environmental influences on the onset of puberty, an event that is largely related to a child's overall level of maturation and body size and that correlates better with bone age than chronological age.

26 DEVELOPMENT DURING MIDDLE CHILDHOOD Although the sequence of pubertal changes is relatively predictable, their timing is extremely variable. The normal range of onset is ages 8-14 in females and ages 9-15 years in males, with girls generally beginning two years earlier than boys (Benson and Migeon, 1975~. In girls, puberty begins with a growth spurt, usually the first noticeable event, and is soon accom- panied by enlargement of breast tissue and generally followed by menarche two years later. The onset of puberty in boys is typically marked by an increase in testicular size followed by a growth spurt. The peak growth velocity for both sexes (10.3 cm per year for boys and 9.0 cm per year for girls) is achieved 2 to 3 years after the beginning of the pubertal process (Smith, 19771. In general, the rate of maturation of boys is slower and less predictable than that of girls, and their age at the onset of puberty is more variable. For both sexes, pubertal changes before the thirteenth birthday are not uncommon. Growth and development studies over the past 200 years have demon- strated a so-called secular trend toward an earlier age of menarche in the industrialized world. Data also suggest larger increments of growth, greater size for age during childhood, and earlier final height attainment (Smith, 19771. Despite questions about the reliability of past data collection methods, these trends appear to be accurate and the differences statistically significant. The age of menarche occurred 2-3 months earlier per decade during the past 150 years in Europe and the United States, with a leveling off of growth and age of menarche as standards of living increased (Wyshak and Frisch, 1982~. More equitable socioeconomic conditions have also resulted in the elimination of discrepancies associated with social class and urban-rural differences. The current average age of menarche in the United States of 12.8 years has been relatively stable since 1947. The reasons for this secular trend are not well understood. The reduction of such growth-retarding factors as poor nutrition and chronic illness has been cited most often, and recently documented trends toward a later age of menarche in Bangladesh appear to support this hypothesis (Chow~hury et al., 1978~. Whether this historical acceleration in the rate of general body maturation has been associated with comparable changes in the rate of brain development and level of performance of children growing up in industrialized societies is unknown. Preliminary data do suggest, however, that variations in age of onset of puberty may have developmental and behavioral consequences during adolescence. In a study of more than 5,000 white males and females ages 12-17 (Duke et al., 1982), late-mat-tiring males scored lower on education-related variables and early-maturing males scored higher than those in the middle maturity groups. These differences were found to be independent of measured intelligence and weaker at age

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH 27 12 than at older ages. No consistent and statistically significant differences related to maturational status were found among females. Other studies, reporting inconsistent findings that imply disadvantages for early-maturing girls as well as late-maturing boys, suggest that cultural context and social class may be important determinants of the influences on behavior of the differential timing of physical maturation (CIausen, 1975; Jones et al., 1971~. Interactions among academic achievement, personal and social develop- ment, and physiologic maturity are not well understood. Further studies of these relationships, particularly regarding the early onset of pubertal changes in the middle childhood years, are needed. Developmental Neurobiology Although the biology of physical growth and maturation during the middle childhood years is generally understood, the basic development and regu- lation of the nervous system and its relationship to behavior remain a com- plex mystery. The bulk of our knowledge regarding the process of neuromaturation comes from gross and microscopic anatomical studies that have demonstrated the highly regulated progression of cell proliferation, migration, and differentiation that characterizes the early development of the central nervous system in a wide variety of animal species. The relatively invariant timing of this process and the intricate coordination of its multiple interacting cellular systems strongly supports the assumption that early neu- romaturation is largely controlled by a genetically determined regulatory system. That environmental factors can influence this process has been documented by a substantial body of data showing reduced cell numbers during the proliferation stage and reduced cell size during the differentiation stage in the face of severe and prolonged undernutrition. Moreover, rela- tionships between differential visual experiences in early infancy and sub- sequent morphological changes in the brain suggest that behaviorally mediated contingencies can also have a significant effect on this highly controlled biological process (Hube! et al., 1977~. Since the average human brain is 65 percent of its adult size at birth and 90 percent by age 2, it is not suprising that anatomical studies alone have provided relatively little insight into the neuromaturational process beyond infancy. Thus, further understanding has required a shift in focus from structure to function. Available data on the biochemical and physiological mediators of human behavior, however, are extremely primitive, and their clinical applicability remains obscure. Several areas of investigation, espe- cially the concepts of neurotransmission and neuromodulation, appear wor- thy of examination in relation to the development of school-age children.

28 DEVELOPMENT DURING MIDDLE CHILDHOOD Neurotransmission, the process whereby individual nerve cells commu- nicate, involves the highly specific synthesis, storage, release, uptake, and degradation of discrete chemical substances that cross synaptic clefts and relay excitatory or inhibitory messages to postsynaptic receptor sites. Neu- romodulation refers to the process whereby a specific substance simulta- neously affects large numbers of neurons, thereby modifying a number of neurotransmitter actions. Hormonal influences provide a classic example of this latter activity. Hormonal Influences Hormonal influences on the central nervous system have been studied in a wide variety of animal species. Accumulated data suggest that specific hormones may exert differential effects on the brain, depending on its ma- turational status. During the critical early stages of development, for ex- ample, the influence may be inductive or organizational. In the mature central nervous system, excitatory, activational, and inhibitory effects are noted. School-age children and comparable groups among other vertebrate species have been less well studied than the perinatal and adult organisms. Among the studies of hormonal influences on animal behavior, data on androgen effects are of particular interest for human development in middle childhood. The secretion of adrenal androgens in children begins to increase between ages 7 and 8, well before the dramatic rise in their plasma levels that accompanies the onset of puberty. The developmental and behavioral influences of these prepubertal androgens deserve further investigation. Studies in rats, chickens, and rhesus monkeys strongly suggest that the organization and maintenance of social rank is, at {east in part, affected by gonadal hormones. Positive correlations among aggressive behavior, social rank, and plasma androgen levels in males, and perhaps in females, have been extensively documented for a wide variety of species (Flickinger, 1966; Kling, 1975; Lloyd, 1971; Rose et al., 1971~. The degree to which exper- iential factors modify the physiological effects of sex hormones is still unclear. Edwards and Rowe (1975) acknowledge that the specific expression of be- haviors is related to environmental circumstances, but they view aggressive urges themselves as hormonally mediated, internal events. The relative validity of such assertions for human behavior is unclear, although evidence suggests that the influence of social experience increases as one ascends the phylogenetic tree (Lloyd, 1975~. Studies by Olweus et al. ( 1980) documented strong correlations between plasma testosterone levels in pubertal boys and the intensity of their aggressive responses to provocation and weak corre- lations with aggressive attitude for unprovoked aggression. They suggest that

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH 29 further investigation requires careful delineation of different aggressive di- mensions as well as avoidance of omnibus measures. The neuromaturational timing of ancirogen influences is particularly in- triguing. In many animal species, androgens exert an early organizing effect on brain architecture as well as on subsequent patterns of function. Mor- phologic differences between male and female brains in rats and rhesus monkeys, for example, have been well described (Bubenik and Brown, 1973; Raisman and Field, 1971), In humans, gestational plasma levels of testos- terone have been directly correlated with aggressive postnatal behavior for children of both sexes (Kling, 1975), and girls exposed to increased andro- genic stimulation in utero (e.g., newborns with acirenogenital syndrome) have been notes! to later demonstrate more tomboy behavior than average female children (Ehrhardt, 1975; Money, 1973~. A recent study describing impaired spatial ability in men with idiopathic hypogonadotrophic hypo- gonadism (characterized by an isolatecT, severe pubertal androgen deficiency), normal spatial skills in men with hypogonadism acquired during or after an otherwise normal puberty, ant] the failure of exogenous androgens to reverse the deficits in the postaclolescent idiopathic group suggests that androgens may have a permanent organizing influence on cognitive function before or during puberty (Hier and Crowley, 1982~. Although a number of meth- odological questions were raised about the collection and analysis of these data (Kagan, 1982) and adult male superiority on tests of spatial reasoning has been well documented (Maccoby end Jacklin, 1974), the hypothesis that these sex differences are mediated by a specific androgen effect just before or during puberty requires further evaluation. The classic paradigm for hormonal research with experimental animals has involved extirpation of the gland, subsequent replacement therapy, and evaluation of behavior under both conditions. Aside from the ethical re- strictions imposed on human research, most studies have been flawed meth- odologically because they have excluded females and have failed to delineate potentially confounding factors in the physical and social environment. Despite the limitations of available data, a substantial body of evidence suggests that gonadal hormones, gonadotropins, and adrenal hormones in- fluence and are affected by social interactions among groups of experimental animals and may play an important role in the regulation of human social behavior (Lloyd, 1975; Rose et al., 1971~. Future research in this area will demand sophisticated multidisciplinary collaboration in order to adequately investigate levels of interaction between neurohormonal regulation and the social-emotional milieu. In addition to their association with aggression and dominance, adrenal steroids have been shown to be mobilized in response to a variety of aversive

30 DEVELOPMENT DURING MIDDLE CHILDHOOD social stimuli, including crowding and defeat Floyd, 1975~. In fact, brain- mediated interactions between the endocrine and autonomic nervous systems appear to play a vita! role in the physiological response of humans to stress. The most commonly reported consequences of a stressful stimulus include increases in serum corticosteroid, catecholamine (epinephrine), growth hor- mone, and prolactin, with a corresponding fall in serum testosterone (Rose, 1980~. Although increased epinephrine release by the adrenal medulla shows no evidence of a habituation effect, even after the organism shows behavioral adaptation to a repeated stressor, the hypothalamic-mediated release of in- creased corticosteroid by the adrenal cortex diminishes with repetition of the stress stimulus. Recent neuropeptide research on hypothalamic-pituitary- adrenocortical system function (Sowers, 1980) and investigations of the stress-induced effects of the hypothalamic-limbic-midbrain circuits on en- docrine and autonomic nervous system responses (Usdin et al., 1980) have contributed to the rapidly increasing body of data documenting the physi- ological reactions produced by a variety of stressors, including situations that elicit a sense of threat, alarm, or distress as well as novelty, uncertainty, or unpleasantness (Hennessy and Levine, 1979~. These same neuroendocrine circuits have also been shown to be significantly involved in mediating adaptive functions of memory, appraisal, and motivational-emotional re- sponses. The contribution of these hormones to specific patterns of reaction and adaptation to social pressures and stress, however, remains to be elu- cidated and may ultimately provide critical insight into individual differences in resilience displayed by school-age children. Possible implications of these findings for health in middle childhood are discussed later in this chapter. Neurotransmission Perhaps the most promising area in research on brain-behavior relations is the current focus on the identification and functional understanding of neurotransmitters. The study of these substances, some of which have prob- ably not yet been discovered, directly addresses the question of how nerve cells communicate with each other and, therefore, how they produce such complex behaviors as coordinated ambulation, creative problem solving, and affective experiences. Neurotransmitters are the mediators of a highly regulated biological sys- tem. Virtually every neuron and tract in the brain is believed to exert its action through the release of a neurotransmitter, and virtually every recipient neuron has neurotransmitter receptor sites. Moreover, neurotransmitter sys- tems are continually reorganized during the development of the organism. Thus, whereas neuromaturation in the fetus and young infant may be dem

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH 31 onstrated by observable changes in brain morphology, the maturational process in the older child may very well be characterized by significant modifications in neurotransmitter circuitry (Johnston and Singer, 1982~. In fact, it is reasonable to hypothesize that the relative plasticity of an immature nervous system may be related to the degree to which production and receptor sites can be modified to accommodate to different neurotransmitters. This hypothesis has particular relevance for the issue of age changes in respon- siveness to psychopharmacotherapy. Chemical substances that have been identified as neurotransmitters (amino acids, peptides, and biogenic amines such as dopamine, norepinephrine, epinephrine, and serotonin) have been the object of preliminary investi- gations whose potential findings may ultimately illuminate some of the neurological enigmas and developmental vicissitudes of the school-age pe- riod. Research with adults, for example, has shown that circulating epi- nephrine plays an important role in the coping behavior of healthy persons exposed to a variety of psychosocial stressors (Rose, 1980~. Under conditions of low and moderate behavioral arousal, a direct correlation has been reported between catecholamine secretion and efficiency of performance. Studies with children suggest that, among normal youngsters, those who secrete relatively more epinephrine tend to be socially and emotionally better adjusted than those with lower secretions (Frankenhaeuser and Johansson, 1975~. Lambert et al. (1969) reported that 8-year-old children with higher secretions of epinephrine were judged as being quicker and livelier, more decisive, open, curious, playful, and candid than their peers with lower epinephrine output. This trend was more pronounced for boys than for girls. The implications of these data for understanding differences in vulnerability and resilience are discussed later in this chapter. Preliminary evidence linking several neurological and functional disorders with abnormalities of specific neurotransmitter metabolism have provided the impetus for many clinical studies but no conclusive results. The report of elevated platelet serotonin in a subgroup of children with autism (Schain and Freedman, 1961), for example, and the recently described (though not replicated) improvement in behavior and cognitive function after pharma- cologic reduction of elevated blood levels in three autistic youngsters (Geller et al., 1982) has renewed interest in the role of serotonin in the development of the central nervous system without clarifying the pathophysiology of autistic behavior. The continuing search for the neurochemical bases of attention'6eficit disorders is particularly illustrative of the frustrations that have plagued investigators in this area. The successful therapeutic use of dextroamphe- tamine and methy~phenidate in appropriately selected children has been

32 DEVELOPMENT DURING MIDDLE CHILDHOOD interpreted as indirect evidence for a catecholaminergic defect, inasmuch as these medications augment the function of catecholamines (Weeder, 1971~. Rodent studies in which the selective destruction of neurons rich in catecholamine was followed by clinical hyperactivity providecl further sup- port for this hypothesis (Shaywitz et al., 1976~. However, the marked het- erogeneity of the children clinically diagnosed as having attention deficits, the demonstration of decreased reaction time and improved performance on cognitive tests in "normal" prepubertal boys treated with dextroamphetamine (Rapoport et al., 1978), and the unavailability of a specific diagnostic test have thwarted attempts to characterize precisely the neurochemical basis of this clevelopmental disability. Pathogenetic mechanisms for well-docu- mentec] toxins, such as lead (NeedIeman et al., 1979), and objects of spec- ulation. such as food additives (Denny, 1982), remain to be elucidated. The neurophysiological mechanisms underlying the entire spectrum of learning disorders in school-age children are the subject of an extensive literature whose review is beyond the scope of this chapter. Although all learning is essentially mediated through brain function, the relevance of most available neuroscientific data for the practical management of school dysfunction is currently unclear. Repeated attempts to reliably link atypical electroencephalographic patterns and clinical signs of neuromaturational delay (so-called soft signs) with attention deficits and learning disabilities, for example, have yielded inconsistent results (Adams et al., 1974; Barlow, 1974; Lewis and Freeman, 1977; Touwen, 1972~. Although voluminous data on cerebral lateralization and hemispheric dominance have clearly dem- onstrated the linear, sequential, analytic, ant! verbal characteristics of left- brain function and the spatial, simultaneous, holistic, and intuitive nature of processing on the right, the translation of such findings into effective strategies for educational intervention has not been achieved. Neuropsy- chological assessment offers a promising vehicle for elucidating the biological basis for differences in learning style and proficiency among school-age chil- ciren. Its applicability for educational planning and curriculum design, how- ever, is unlikely to be realized unless neuroscientists, clinicians, and educators cooperate in the design, implementation, and analysis of collaborative in- vestigation. The study of neurotransmission, neuromodulation, and neuropsychology is in its infancy. Attempts to study interactions among multiple biochemical systems and the phenomenon of localized instead of whole-brain effects underline the technical complexity of this research. New technologies, such as positron emission tomography (PET scanning), offer methods for exam- ining neurotransmitter receptors in living patients (Wagner, 1980~. Their utility awaits the test of time.

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH 33 It is reasonable to expect that basic neurobiological research will ul- timately elucidate the biochemical and physiological bases for a host of neurological disorders, specific learning difficulties, and behavioral dys- functions that afflict children in middle childhood. Furthermore, it is perhaps not unthinkable that neurotransmitter and neuroendocrine pro- files might ultimately provide insight into the biological bases for indi- viclual differences in temperament, coping style, ant] overall resilience and vulnerability throughout the life cycle. For the present and the near future, the application of neurochemical and neuropsychological assess- ment techniques to the study of the human nervous system is just begin- ning. In the more distant future, knowledge of brain-behavior relations might very well form the basis for a highly sophisticated system of diag- nostic assessment and prescriptive intervention for the developmental and behavioral concerns of school-age children. CONCEPTS OF HEALTH, ILLNESS, AND DISEASE A consideration of health issues of school-age children must begin with a clarification of what is meant by the terms health, illness, and disease. Perhaps the most pervasive metaphor in the history of medicine has been the concept of health as a state of equilibrium or balance. This concept provided an organizing principle for Hippocratic medicine in the fifth and fourth centuries B.C. and formed the basis for Galen's second-century A.D. popularization of the interaction of the four body humors, which dominated medical theory for several hundred years (Mechanic, 1978~. It is also clearly reflected in the ancient Chinese concepts of yin and yang (WalInofer and Von Rot- tauscher, 1972) and in the traditional health beliefs of many native American groups who believe that physical and mental health are a reflection of one's harmony with the earth (Primeaux, 1977~. The biological principle of ho- meostasis reflects the enduring influence of this concept of dynamic equi- librium in contemporary biomedical science. Despite the persistence of this seemingly universal principle, a satisfactory operational definition of health or welIness has not been developed. Dubos (1968:67) described health as a "modus vivendi enabling imperfect men to achieve a rewarding and not too painful existence while they cope with an imperfect world. " Parsons ~ 1972: 117) defined health as "the state of optimum capacity of an individual for the effective performance of the roles and tasks for which he has been socialized." The frequently quoted definition of the World Health Organization describes "a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity" (Constitution of the World Health Organization, 1958:459~.

34 DEVELOPMENT DURING MIDDLE CHILDHOOD From the literary to the political, such definitions underscore the wide- spread agreement on the importance of viewing health as a social concept (Lewis, 1953~. As noted by Mechanic (1978:53~: [EIven physical wellbeing is dependent on the context in which we live, our associations with others, and the physical and social assaults to which our living situation exposes us.... Moreover, even from a practical standpoint, we must come to appreciate that in the long run our wellbeing is less dependent on the elegance and sophistication of medical practice than on how we choose to live and what is done to the environment in which we live. The implications of this mode! for the health and development of school- age children are discussed later in this chapter. The phenomenon of sickness has been relatively easier to characterize. Its analysis has been significantly enhanced by those who have specified a differentiation between the concept of illness and that of disease. Eisenberg ( 1977:11 ) succinctly summarized this critical distinction by noting that "pa- tients suffer 'illnesses'; physicians diagnose and treat 'diseases.' " That is to say, disease refers to abnormality in the structure and/or function of body organs, whereas illness refers to the human experience of an uncomfortable change in one's state of being with or without an undesirable impairment of social function (Fabrega, 1974; Kleinman et al., 19781. Thus, disease and illness do not always coexist. Half of all adult visits to a physician's office are for symptoms whose biological basis is not identified (Stoeckle et al., 1964~. Many children with congenital heart disease never experience cardiac symptoms and therefore are not ill. Illness in any given individual is often distinct from the course of his or her disease. Among the many factors that contribute to these distinctions, the degree to which the human experience of poor health is affected by social and cultural influences has been extensively studied. Cultural Influences Physical illness implies a state of being that is undesirable, uncomfortable, or damaging in relation to the values and usual life situations characteristic of a given ecocultural niche. Thus, individual differences in perceptions, experiences, and coping patterns are significantly modified by systematic variations in the systems of meaning used to explain the phenomenon of sickness (Fabrega, 1972; Kleinman et al., 1978; Spector, 1979~. A seizure disorder may be variably regarded as a simple disease, a stigmatizing defect, or a reflection of supernatural powers (Mechanic, 19781. In some societies, obesity is the object of envy and desire; others define it as a health risk or

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH 35 a frank disease. Scoliosis in a school-age air! is understood and experienced in dramatically different ways by an African believer in demons (Hughes and Bontemps, 1958) and a middIe-cIass family in the United States. Many pathological conditions are not defined as illnesses in those societies in which their prevalence is almost universal (Dubos, 1965~. Studies of cultural variations in acknowledging symptoms and seeking medical assistance within the United States have documented important social class and ethnic differences (Beecher, 1956; Koos, 1954; Zborowski, 1952; Zola, 1966~. Analyses of these findings, however, have not distin- guished among differences in objective symptoms, varied interpretations of the same symptoms, variations in willingness to express concerns or to seek help, or the use of different vocabulary for expressing distress (Mechanic, 1972~. Moreover, individual differences within apparently homogeneous groups have been shown to be "vast and impressive" (Mechanic, 1978:35~. The cultural context of health and illness and the particular dilemma of contemporary health care in the United States have been critically examiner! by Eisenberg (1976:186), who noted: Illness experience is patterned by culture. Medical lore is integral to every existing human culture. Every human group has a body calf beliefs about illness and healing. As culture evolves over time, folk knowledge becomes the special prerogative calf healers. The shaman car healer in traditional societies does what the physician does in Western societies. He diagnoses; he prescribes ritual actions designed to overcome illness; he casts a prognosis; and he legitimates the mysteries of death. He names and explains just as we name and explain, although he and we employ very different explanatory systems. The explanatory system of American medicine is the biomedical mode! of health and disease. Its benefits have been dramatic and far-reaching. Its boundaries, however, have become increasingly apparent, especially with regard to the salient health issues of middle childhood. A critical exami- nation of the biomedical model, in contrast to the proposed enhancements of a biopsychosocial orientation, provides a method for taking a broad look at the physical health needs of school-age children. The Biomedical Model The biomedical model, which continues to dominate Westem medicine, is governed by the philosophical traditions of reductionism and mind-body dualism. The former concept is manifested in the belief that all human illness, including complex behavioral dysfunction, can be explained ulti- mately by a disordered biochemical or neurophysiological process. Studies of neurotransmission and neuromodulation reflect this orientation. Mind

36 DEVELOPMENT DURING MIDDLE CHILDHOOD body dualism, which has its roots in the work of Descartes in the seventeenth century, separates somatic from mental and interpersonal functions and pays little attention to the psychological, social, and behavioral aspects of disease. As a scientific framework for the study of the molecular biology of patho- logical processes, the biomedical mode! has been extraordinarily productive. Its contribution to our understanding of the etiology and pathogenesis of human disease, as well as to the development of rational therapeutic inter- ventions, continues to strengthen the technical efficacy of Western medical care. A growing appreciation of the diversity of clinical signs and symptoms demonstrated by many well-defined diseases, however, highlights the in- completeness of the traditional biomeclical model. Congenital cytomega- lovirus, fetal alcohol syndrome, and lead intoxication, for example, are some of the many conditions whose organic etiology has been identified but whose developmental and behavioral manifestations are highly variable. The dem- onstration that a significant proportion of that variability may be attributed to psychosocial factors suggests the need for a reassessment of the traditional categorization of diseases solely according to their biological causes the single cause:single disease illusion. Thus, Achenbach's discussion (in this volume) of the relative merits of nosological versus multivariate approaches for the classification of psychopathology has relevance for so-called physical disease as well. Critics of the biomedical mode! have charged that it embodies a simplistic view of the human body as a machine and conceptualizes disease as the result of a defective part or overall mechanical breakdown. By forcing a dichotomous choice between disease and nondisease, it fails to acknowledge the continuum from optimal function through degrees of dysfunction that characterizes human well-being. Moreover, its relative disregard for the social and psychological determinants of human illness has stimulated the demand for a broader biopsychosocial mode! of health and disease (Engel, 19771. The Biopsychosocial Orientation The biopsychosocial approach provides a "framework within which can be conceptualized and related, as natural systems, all the levels of organi- zation pertinent to health and disease from subatomic particles through molecules, cells, tissues, organs, organ systems, the person, the family, the community, the culture, and ultimately the biosphere" (Engel, 1979:266~. In the tradition of viewing health as a state of relative balance and harmony, it provides a vehicle for analyzing the integrity of each component level as well as their reciprocal interactions within a dynamic hierarchical system that extends from molecule to culture.

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH 37 Unlike the biomedical model, which restricts its factor analytic approach to the patient and his or her component parts, the biopsychosocial orien- tation is based on a general systems theory, which demands a sophisticated analysis of social and cultural levels of organization as well as the interacting systems linking each component in the overall hierarchy. The analytic techniques employed successfully at any given level are likely to differ, as will the approaches used to understand the collective system (Weiss, 1967~. The obvious gain in comprehensiveness provides! by this proposed mode! has been described by Enge! (1979:266~: Health, disease, illness and disability thus are conceptualized in terms of the relative intactness and functioning of each component system on each hierarchical level. Overall health reflects a high level of intraand inter-systemic harmony. Such harmony may be disrupted at any level, that of the cell, the organ, the person, or the community. Whether the resulting disturbance is contained at the level at which it was initiated or whether other levels become implicated is a function of the capacity of that system to adjust to change.... Such contrasts between smooth functioning and disruption provide the bases upon which health, disease, illness and disability may be differentiated. The potential richness of a biopsychosocial orientation is most compelling. Although the availability of sophisticated analytic techniques for the entire hierarchy as well as for each of its component levels is highly variable, the mode! itself represents a critical conceptual advancement over its more narrow predecessor. As Eisenberg (1976:186) observed: "Our worship of restricted disease models resembles a ritual or magical belief more than it does scientific logic." The biopsychosocial orientation demands the appli- cation of science to those aspects of health and disease that concern the patient as an individual and as a social being, dimensions that heretofore have been considered part of the more subjective art of medicine. It offers a far richer framework for studying the health of school-age children. Developmental Considerations The universality of illness and the clearly delimited nature of the "sick" role make these phenomena "a strategic arena in which to consider role learning, attitude formation, and other aspects of the process of acquiring general social orientation" (Campbell, 1975:92) during the school-age years. The diversity of opinion regarding concepts of health and illness among scholars and the lay adult public, however, raises a number of intriguing questions regarding middle childhood. How does an understanding of health and illness develop during this period? What are the cognitive and affective factors that determine the contents of children's beliefs? How are evolving concepts influenced by family, peers, school, media, and personal expert'

38 DEVELOPMENT DURING MIDDLE CHILDHOOD ences with sickness? Simply stated, what do children think about health and illness, where do those thoughts come from, and how do they evolve into adult concepts? The earliest attempts to address these questions were methodologically unsophisticated and without theoretical content beyond that provided by the psychoanalytic model. Most studies described children's feelings about their own illnesses and often focused on the emotional impact of associated experiences, such as hospitalization (Prugh et al., 1953~. The most common observation reported by clinical researchers was that children often thought they were responsible for their own ill health and viewed disease as a pun- ishment for wrongdoing (Beverly, 1936; Freud, 1952; Langford, 1948; Lynn et al., 19621. In a more recent study of 408 healthy children from first-, third-, and fifth-grade classes, however, Broclie ~ 1974) confirmed this finding in only one-quarter of the sample. He found, rather, that nonanxious chil- dren frankly rejected the notion of illness as punishment. With increasing interest in the development of health-related concepts, attention has shifted toward explorations of children's ideas about illness ant! not just their affective responses. Nagy (1951), one of the first inves- tigators to explore children's theories of illness, found very little appreciation before age 12 of the multiplicity of causal factors of disease. More recently, Campbell ~ 1975) devised a listing of ~ 1 illness themes ranging from relatively immature somatic sensations ("feeling bad," "stomach ache") to more so- phisticated levels concerned with dispositional states ("irritable," "un- happy") and role functioning ("don't want to go to school," "stay home from worked. Although greater precision in definition and greater emphasis on alterations in role performance and/or psychosocial disposition were found with increasing age, Campbell's data were still essentially descriptive and not articulated in terms of a unified theoretical model. Current investigators, moving beyond a simple cataloging of responses, have begun to analyze children's explanations of illness within a framework that reflects the sequence and structure of the major stages of cognitive development as formulated by Jean Piaget and Heinz Werner (Bibace and Walsh, 1981; Perrin and Gerrity, 1981 ). Generally speaking, these studies demonstrate that kindergarten children display magical thinking, that fourth- grade children believe that illness is caused by germs without any insight into the issue of host susceptibility, and that eighth-grade children under- stand the concept of multiple interacting mechanisms for etiology and treat- ment. Concepts of illness causality were noted to lag behind but closely parallel the development of concepts of physical causality in the youngsters studied, with illness prevention appearing to be more difficult to understand than causation or treatment. Differences in patterns of decalage were not

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH 39 found to be related to sex or socioeconomic status (Perrin and Gerrity, 1981). The most sophisticated theoretical formulation of developing concepts of illness currently available is that of Bibace and Walsh ( 1980, 1981 ). Through an analysis of the cognitive processes underlying children's ideas about illness at different ages, they have constructed a mode! consonant with Piaget's stages of cognitive development, which includes two subtypes of explanation within each of three major categories: phenomenism and contagion in the preoperational stage, contamination and interrtatization during the stage of concrete operations, and physiological and psychophysiologic conceptualization during the formal operations period. Consistent data from a series of studies confirmed the usefulness of this classification, and frequency distributions of the responses of normal children validated its ordered developmental sequence (Bibace and Walsh, 1981~. The development of concepts of health, compared with those of illness, has been less well studied, possibly because being well is more abstract and therefore more difficult for a child to define than is the idea of being hurt or sick (Nenhauser et al., 1978~. Nevertheless, children as young as 6 have been found to articulate positive ideas about health. In a study of 264 elementary school students, for example, first graders tended to define health as a series of specific practices (e.g., "eating the right foods" and "getting enough exercise"), and fourth graders tended to focus more on themes related to being in good shape and feeling good. Seventh graders (12-year-olds) showed evidence of an emerging perception of health as "Iong-term-in- volving the body, mind, and in some cases, the environment" (Natapoff, 1978:999~. Although available data regarding health (as opposed to illness) concepts are limited and largely descriptive and further study in this area is clearly needed it would appear reasonable to hypothesize that children's ideas about health are influenced in large part by their level of cognitive development. The implications of this hypothesis for the challenges of health promotion and education during middle childhood are considered later. Available data on the degree to which the development of concepts of health and illness may be modified by environmental influences are incon- elusive and contradictory. Although maternal attitudes and behavior re- garding child health do influence children's patterns of illness behavior, the degree of variance in children's responses that can be explained by mothers' responses is often extremely small and therefore less influential than antic- ipated (Mechanic, 1964~. Campbell (1975) concluded that children's con- cepts do not result from direct matemal teaching and noted that "a more casual learning process may be involved, one in which mother's perspectives may make a difference only insofar as they impinge on and thus modify

40 DEVELOPMENT DURING MIDDLE CHILDHOOD children's relevant responses" (p. 991. In a subsequent study of short-term patients on a pediatric ward, however, Campbell (1978) attributed more weight to matemal influences, especially in the later childhood years, and noted that children's reports of their own illnesses were tied to age and sex roles and were significantly related to parental socioeconomic status. Al- though Natapoff (1978) found no significant socioeconomic differences in children's views of health, other data suggest that such influences may be relevant. For example, the prevalence of belief in health-related television commercials reported for poor children anti their parents was 20 to 30 percent higher than that found among middIeor uppercase families (Lewis and Lewis, 1974~. The relative and interacting contributions of these and other relevant variables have not been studied adequately. Personal experience with illness is another important variable whose im- pact has not been well delineated. In a study of chronically ill hospitalized children ages 5-13, Brewster (1982) compared performance on high-affect cognitive tasks (ilIness causality and ideas regarding the intent of medical procedures) with that on low-affect tasks (e.g., conservation, physical cau- sality, etc. ~ and found no significant differences in the mean scores for any age group. Campbell (1975) interviewed an acutely hospitalized, essentially normal group of children ages 6-12 and found that past experience with sickness did affect the level of sophistication of children's concepts of illness but noted that the differences were contingent on age. That is to say, children under age 9.5 whose health was rated poorer than that of their parents had the least sophisticated concepts, while more mature responses were obtained from the older group. The influence of past experience with disease on conceptual development regarding health and illness clearly requires further . . . Investigation. Relationships among concepts of health and illness, affective responses, and health-related behaviors are complex and not well understood. Radius et al. (1980) studied the health beliefs of 249 children ages 6-17 and found health issues to be a meaningful concern for the majority, regardless of age, sex, or participation in risk-taking behaviors. Gochman (1971) interviewed 108 children ages 7-18 and found health to be of relatively low salience. We know very little about the genesis of health beliefs. Our understanding of the conditions under which they are acquired and the factors that promote individual differences is severely limited. We know even less about how to change health beliefs at different ages. In fact, available data show them to be relatively well established and difficult to alter by the end of the school- age years (Weisenberg et al., 1980~. Finally, we have little evidence that health beliefs are important determinants of health-promoting behaviors during middle childhood and the early adolescent period.

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH 41 The study of the development of concepts of health and illness of school- age children is in its infancy. Its importance is best appreciated in the context of recent attitudinal and substantive changes in the delivery of medical care for children in the United States ages 6-12. Middle childhood is regarded increasingly as a significant period of transition toward independent inter- action with the health care system. Routine well-child examinations are shifting from parent-physician dialogue to more extensive discussion with children about their own health maintenance. Youngsters with chronic diseases or handicapping conditions are encouraged to assume growing re- sponsibility for decisions regarding their own care. For some children, in- creasing autonomy is beneficial; for others it may be premature and detrimental. Further investigation regarding individual differences in this process of trans- ferring responsibility is needed. Theoretical frameworks within which such matters can be facilitated and analyzed are being constructed. Greater understanding of the developmental unfolding of these issues will be particularly important in communicating more appropriately with school-age children, thereby enhancing our ability to meet the challenges of health promotion, education, and management of chronic illnesses and disabling conditions during this dynamic period of expanding self-understanding and self-regulation. PHYSICAL HEALTH AND THE EMERGING SENSE OF SELF The school-age years mark an important period of growing awareness of oneself. For the child between ages 6 ant! 12, the construction of the self- concept is both intimately private and intensely social. The intersection of this emerging sense of personal identity with issues related to physical health falls in the realm of what eventually becomes known as life-style. The concept of life-style implies a pattern of behavior and values that extends over a period of time. Though hardly immutable, one's life-style tends to include habitual characteristics whose modifiability is presumed to be inversely related to age. Thus, as an organizing construct for thinking about health, the early development of life-style during the school-age years is particularly salient. Its association with the major causes of death in childhood (accidents) and in adult life (cardiovascular and malignant dis- eases) underlines its influence on both immediate and {ong-term health concems. Health Promotion and the Evolution of Personal Life-Styles Increasing evidence suggests that the ways in which people live and the patterns of behavior and adaptation they exhibit play a major role in de

42 DEVELOPMENT DURING MIDDLE CHILDHOOD termining their health status throughout the life cycle. A recent Institute of Medicine report, based on the views of more than 400 leaders in the biomedical and social sciences, noted (Hamburg et al., 1982:~: The heaviest burdens of illness in the United States today are related to aspects of individual behavior, especially long-term patterns of behavior often referred to as "life' style." As much as 50 percent of mortality from the 10 leading causes of death in the United States can be traced to lifestyle. As public health initiatives have shifted emphasis from the treatment of acute illness to the prevention of chronic disease, the modification of det- rimental behavior patterns has received growing attention. Difficulties in altering long-standing adult behaviors have led to a logical interest in ex- panded efforts on behalf of children. Physical exercise, eating patterns, and self-induced vulnerability are some of the life-style elements that have been targeted for such efforts. Physical Exercise Vigorous exercise on a regular basis, as a health-enhancing behavior, has gained considerable popular support. Although the often cIaimec} salutary effects of exercise on emotional well-being have not been extensively studied, the association between physical activity and lowered risk of clinical com- plications secondary to atherosclerosis has been well documented (Dawber, 1980; Thomas et al., 1981~. The mechanism through which physical activity may affect morbidity and mortality from cardiovascular disease has not been well elucidated. Whether inactivity is an independent risk factor or whether it has multiple effects through interactions with other variables remains to be determined. Studies of serum lipid profiles in adults, for example, have demonstrated greater risk for coronary artery disease when low-density lipoproteins (LDL-cholesterol) are elevated and an apparent protective effect from high-density liproproteins (HDL-cholesterol) (National Heart, Lung, and Blood Institute, 19811. El- evations of serum HDL-cholestero! in association with physical exercise have been clearly demonstrated in adults and replicated in a controlled study of girls ages 8-10 (Gilliam and Burke, 1978; GIomset, 19801. The significance of this particular mechanism in the pathogenesis of cardiovascular disease is not known. Although the cardiovascular benefits for adults of fitness from aerobic exercise have been established (Paffenbarger and Hyde, 1980), little is known about the long-term effects of physical training by children. Rowland ~ 1981:7- 8) noted:

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH 43 The basic premise for the promotion of physical fitness rests upon the assumption that repeated aerobic exercise (training) will produce a series of physiologic changes (training effect or fitness), and that these alterations can be translated into objective benefits to the individual. That repeated aerobic exercise produces such changes in adults is well documented, but in children it remains controversial. Whether the relatively high levels of fitness found in school~age children compared with adults are related to differences in activity level or genetically determined differences in physiological development is currently unclear (Hamilton and Andrew, 1976; Hovell et al., 1978~. Although relevant physiological measures in competitive swimmers and track stars are advanced for age, the observed differences may not be secondary to training but rather a result of the fact that genetically endowed athletes are more likely to be successful in sports. In addition, although the process of atherosclerosis begins in early childhood and continues throughout the life cycle, it is not at all clear whether physical fitness during childhood has any effect on the rate of decline of cardiovascular function or the risk of coronary artery disease in later life. That physical activity during the adult years does appear to be important for cardiovascular health, however, highlights the importance of reinforcing it in the emerging life-style of the schoolmate child. Most children naturally enjoy participation in physical exercise. Concems have been voiced, however, that the sedentary influences of modem society are resulting in decreasing childhood fitness. Only one out of every three school children participates in a daily program of physical education (Select Pane} for the Promotion of Child Health, 1981). Interest in organized sports for young people, however, has increased over the past 10 years and is now estimated to involve over 8 million American children (Goldberg et al., 1978~. Participation in physical activity, nevertheless, dramatically declines with increasing age. One of six persons in the United States ages 10-17 was classified as physically underdeveloped by the standards of the President's Council on Physical Fitness and Sports (1977~. In 1974 the President's Council estimated that almost half of adult Americans did not participate in any form of exercise (Apple and Cantwell, 1979~. The growing popularity of both organized and informal efforts to promote physical fitness, however, has probably improved these statistics substantially. The need to promote continued involvement in physical activity beyond the school-age years is clear. Critics have argued that the traditional system of recreation and school activities has focused on the athletically gifted or early~maturing child and has emphasized the acquisition of skills in such sports as baseball, basketball, and football, which have limited cardiovascular benefits and are less likely to be pursued in adulthood (Pate and Blair, 1978~.

44 DEVELOPMENT DURING MIDDLE CHILDHOOD Concerns about overemphasis on performance in competitive athletics have also been raised regarding psychological stress and predisposition to injury (Rowland, 19811. Epiphyseal fractures in football players and little league pitchers (Adams, 1965), for example, with their potential risk of distorting subsequent long~bone growth, are some of the specific injuries that have stimulated the growth of sports medicine as a new pediatric specialty (Micheli and Smith, 19821. Increasing female participation in organized sports pro- grams has raised additional questions for study. The well-known phenom- enon of delayed menarche in young track stars and ballet dancers, for example, has been shown to be reversible after cessation of vigorous training, but ultimate fertility and endocrine status after many years of competition remain unknown (Warren, 1980; Frisch et al., 1980~. The American Academy of Pediatrics' Committee on the Pediatric Aspects of Physical Fitness, Recre- ation and Sports (1975) specifically examined the issue of sex differences and subsequently endorsed coeducational sports programs in the prepubes- cent years, noting that young girls can effectively compete against boys in any sport when matched for weight, skills, size, and physical maturation. Current knowledge regarding physical activity in childhood is limited. The long-term benefits and risks of a variety of activity profiles have not been described. The frequency, intensity, ant] duration of exercise necessary for fitness has been well defined for adults but not for children at different ages. The well'documentec! value of routine, vigorous aerobic exercise for adults, in conjunction with the decline in physical fitness often seen with advancing age, underscores the critical need for physical education programs during the school-age years that are oriented toward high-level activity involving sustained exercise of the large muscle groups, that place emphasis more on endurance than on speed, and that introduce the kinds of sports and aerobic activity that can be continued into the adult years. The differ- ential benefits of individual sports, their specific impact on self-esteem and evolving attitudes toward recreational exercise among children of varying athletic abilities, and the developmental consequences of the competitive pressures of organized sports during middle childhood clearly require further study. Eating Patterns American eating patterns have changed dramatically over the past 30 years. In response to recommendations to decrease cholesterol and fat intake, our consumption of eggs and milk fats have each dropped 30 percent, the per capita consumption of lard has fallen by 80 percent, and that of butter by 55 percent (Page and Friend, 1978; StamIer, 1978~. Conversely, the use

BIOLOGICAL SUBSTRATE AND PHYS1CALHEALTH 45 of margarines and vegetable oils has increased markedly, and overall trends show a significant decrease in the proportion of calories in the average American diet contributed by fat (Rizek and Jackson, 1980~. This shift in eating habits has been accompanied by a 7 percent drop in average serum cholesterol levels, with a greater decrease among the higher educated seg- ment of the population (bevy, 1979~. Over the past 20 years, however, food processing and refinement have grown, and the proliferation of "conve- nience" foods has dramatically increased, and sales by fast-food restaurants have increased 305 percent (Select Pane! for the Promotion of Child Health, 1981). Few available data specifically address the eating patterns of school-age children. A detailed survey of the diets of children under age 13 in the Bogalusa Heart Study, however, showed overall consumption of foods high in saturated fat, sucrose, and sodium, with snack foods high in fat, salt, and sugar accounting for approximately one-third of the total caloric intake. Moreover, although correlations between diet and serum lipid levels have not been demonstrated in adults, they were documented in the children studied in Bogalusa (Berenson et al., 1982~. These findings clearly conflict with the total population data described above. Whether they are represen- tative of other childhood samples requires further study. The development of eating patterns is generally established in infancy and early childhood (Lowenberg, 1977) and heavily influenced by cultural ant] familial factors. Preliminary studies of the emergence of concepts of nutrition suggest that kindergarten children understand that "good" and "bad" foods can influence health and growth, but comprehension of how nutritional factors relate to later physical status is not apparent until the sixth grade (WelIman and Johnson, 1982~. The potential impact of television on this process is worthy of particular attention. One study of children's programs revealed that 68.5 percent of the commercial messages were for food, of which 25 percent were for cereal, 25 percent for candy and sweets, and 8 percent for snacks and other foods. Ten percent of the advertisements were for quick meals and eating places, and sugar cereals outnumbered unsugared cereals by a ratio of 3 to ~ (Barcus, 1975; National Science Foundation, 19771. Children ages 5-10 have been noted to attend more closely to commercials than those ages 11-12 (Ward et al., 1972), while older children are more likely to question commercials (Blatt et al., 1972~. McNeal (1969) and Yankelovich (1970) found that children attempted to influence parental buying practices on the basis of what they heard on television commercials, and mothers were noted to be more likely to honor requests for food than for other products (Berey and PolIay, 1968~. The excessive focus of television commercials on food prod

46 DEVELOPMENT DURING MIDDLE CHILDHOOD ucts has been clearly documented. However, we know relatively little about the extent of their impact on eating patterns in middle childhood, nor have we adequately evaluated the potential usefulness of this medium for more nutrition education. A better understanding of these and other influences on food preferences in early and middle childhood requires further study. A detailed review of the nutritional status of school-age children in the United States is beyond the scope of this paper. Owen and Lippman ( 1977), in reviewing three national surveys and a number of regional and local studies, found a low prevalence of clinical signs suggestive of significant nutritional deficits, although iron deficiency continues to be a major prob- lem, and overall nutritional status consistently correlates directly with so- cioeconomic status or income. The developmental consequences of intrauterine and early childhood malnutrition have been studied extensively. Speculation regarding an association between chronic undernutrition and developmental vulnerability, including the possible effects of iron-deficiency anemia on scholastic achievement, suggests a need for further investigation (Webb and Oski, 1973). Perhaps the most important health-related problem associated with eating behavior during the school-age years is obesity (Merritt, 1982~. Although definitions of obesity vary, a weight that is 20 percent or more above average for a given age, height, and gender is a commonly accepted standard (Van Itallie, 19791. Despite the failure to elucidate the role of obesity as an independent risk factor for cardiovascular disease in adult life, obesity is closely associated with a number of well-documented vuInerabilities, in- cluding hypertension, hypercholesterolemia, and diabetes mellitus (Ham- burg et al., 1982~. In addition, overweight individuals are cosmetically handicapped and frequently victimized by social discrimination, which may have long-term psychological sequelae for a vulnerable school-age child (Nathan, 1973~. Although the differential diagnosis of obesity includes a long list of patho- logical conditions, more than 90 percent of obese children are fat because they consume more calories than they expend. Some inequality in energy balance may have major genetic determinants (Weil, 1981 ), but most obesity is caused by excessive eating. A greatly reduced activity level is another factor associated with obesity in children (Mayer, 1975; Rowland, 1981~. Whether this correlation is a causal one-and, if so, in which direction it operates is currently unclear. Some inactive children may be predisposed to obesity. Many obese children are secondarily inactive. In both cases the progressive decrease in activity level that often accompanies a weight in- crease results in lower energy needs, which then require even fewer calories

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH 47 per day. The importance of physical activity in the treatment of obesity is I. . crltlca . Relationships between childhood and adult obesity have not been clearly delineated. Charney et al. (1976) reviewed medical records from infancy through age 30 for an adult population in Rochester, New York, and reported a relative risk factor for obesity of 2.5 (chance of a fat infant becoming a fat adult) and an attributable risk value of 50 percent (chance of a fat adult having been a fat child). Few data are available on the factors that perpetuate or counteract the progression of obesity from childhood to adulthood. The central importance of two major lifestyle issues in its pathogenesis, eating patterns and activity level, suggests that successful intervention in the school' age years will contribute to improved health in adult life. The validity of this hypothesis, however, remains to be documented. The possible contri' button of a range of underlying psychological disturbances (e.g., depression, anxiety) to both the initiation and the continuation of excessive weight gain during middle childhood requires extensive investigation. Self-lnduced Vulnerability Cigarette smoking, excessive alcohol consumption, and drug abuse con- tribute to a significant percentage of adult disease and death. Although the prevalence of such behaviors is relatively low in the preadolescent years, school-age children provide a natural population for early prevention efforts. The problem of cigarettes is particularly compelling. Of all the major risk factors for serious illness, disability, and premature death in the United States, the U.S. Public Health Service (1979) noted that smoking may be the most important preventable one. Unfortunately, the process through which young people first become smokers has been inadequately studied (Blaney, 1981 ). Cigarette smoking is a major contributor to the development of lung cancer and chronic bronchitis and accounts for nearly 50 percent of adult excess mortality from cardiovascular disease. Although an augmented risk of cor- onary artery disease is associated with the onset of smoking before age 20, large numbers of teenagers and young adults continue to adopt the habit, especially females. As noted by Blaney (1981:192~: Obviously, reaching children before they begin smoking, or at least reaching young adolescents before they become addicted smokers, is the most logical way to reduce the health risks from smoking. Yet it is for this period of early smoking onset where data are most lacking. in other words, we cannot readily explain why children start to smoke or what means are most effective in preventing or reducing their smoking.

48 l DEVELOPMENT DURING MIDDLE CHILDHOOD Although cigarette smoking in adolescents and adults has been stuclied extensively, relatively few investigations have looked specifically at the school-age years. Moreover, most attitudinal studies are cross-sectional, gen- erated inconsistent data on the stability and predictability of individual beliefs, and do not address questions regarding the genesis of observed dif- ferences (Downey and O'Rourke, 1976; Laoye et al., 1972~. Investigations of peer and parental influences have largely focused on older adolescents, thereby precluding an examination of their differential impact and inter- action with other variables at successive times in the process through which one changes from a school-age nonsmoker to an adolescent or young adult smoker (Banks et al., 1978; Levitt and Edwards, 19701. Evidence that sibling variables may be highly significant requires more systematic examination (Banks et al., 1978; Lanese et al., 1972~. The fact that knowledge of the health risks of tobacco neither deters people from smoking nor changes existing smoking habits has been consis- tently demonstrates] for adolescents ant! adults (Allegrante et al., 1977; Laoye et al., 1972~. Although children as young as 7 or 8 have been shown to understand the danger, their appreciation of its personal implications may not be clear (Bland et al., 1975; Schneider and Vanmastrigt, 1974~. Sug- gestions that immediate and short-term risks be emphasized have not con- sistently led to a more effective impact on smoking by children (Bland et al., 1975; Bynner, 1970~. The relevance of these findings for the design and implementation of health education programs for preadolescents is clear. Despite a large body of literature on smoking prevention efforts, very few programs have been based on a firm theoretical framework and systematic evaluation has been sparse (Evans et al., 1979; Green, 1979~. Recent at- tempts to directly address the issue of peer pressure have provided a poten- tially fruitful avenue for further study. Using the concept of psychological inoculation, high school students have been trained to teach behavioral techniques to junior high school students to help them resist temptations and pressures from their peers. Preliminary findings from a series of controlled studies demonstrate significant impact on reported smoking behaviors, with effects persisting for almost 3 years (McAlister et al., 1979; Telch et al., 19821. Data reflecting comparable influences on alcohol consumption and marijuana use suggest the need for replication and further analysis of this model of behavioral change (McAlister et al., 1980~. Persistent Impairment and the Challenge of Functional Adaptation While most school-age children enjoy unparalleled good health, a sig- nificant minority suffer chronic illness or disability. Although the definition of a chronic disorder has varied, it generally refers to an illness that interferes

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH 49 with ordinary activity and that lasts for more than three months in a given year or requires one or more months of continuous hospitalization. In a large epidemiologic survey of more than 5,000 children in Great Britain, Pless and Douglas (1971) used these criteria and calculated a prevalence rate of 112 per 1,000, exclusive of mental deficiencies. Males were found to out- number females by 1.4 to 1, and the distribution of illness severity was reported to be 54 percent milcI, 34 percent moderate, and 12 percent severe. Other prevalence rates cited in the literature vary, clepending on the sam- pling procedures or definitions used, and range from 5 to 20 percent, in- cluding such diverse disorders as asthma, diabetes mellitus, meningomyelocele, juvenile arthritis, seizure disorclers, cystic fibrosis, and childhood malig- nancy. In a review of three epidemiologic surveys, Pless and Roghmann (1971) observed that "about one child in 10 will experience one or more chronic illnesses by the age of 15 and up to 30 percent of these children may be expected to be handicapped by secondary social and psychological maladjustments" (p. 357~. The comprehensive management of the multiple needs of chronically impaired children and their families is now recognized as an increasingly important pediatric responsibility during the school-age years (Hobbs et al., 1983; Task Force on Pediatric Education, 1978~. A large number of studies have explored the developmental-behavioral impact of chronic disease on affected children. For the child between ages 6 and 12, who is frequently judged according to academic, athletic, and social competence, the psychological burden of a persistent disorder can be particularly weighty. Sperling (1978) noted that deficits in ability or di- minished physical attractiveness cause profound threats to self-esteem and perpetuate an atmosphere of stress. A higher incidence of psychiatric prob- lems and behavioral disorders among such children has been reported by many investigators (Mattson, 1972; McAnarney et al., 1974; Pless and Roghmann, 1971~. Conversely, other studies have failed to document higher rates of emotional disturbance (Bedell et al., 1977; Gayton et al., 1977~. Pless and Pinkerton (1975) summarized a large body of literature that re- veated a higher incidence of maladjustment among chronically ill children as well as evidence of successful adaptation in a substantial number. Sex, age at onset of disease, its course and severity, the visibility and specific consequences of associated handicaps, individual coping styles, and the quality of the parent-child relationship are some of the many variables that have been correlated with overall adjustment (Hewett et al., 1970; Mattson and Gross, 1966~. Major methodological limitations in many studies, in- cluding absence of control groups and subjective methods of data collection, have contributed to the inconclusive and contradictory nature of the cur- rently available data.

50 DEVELOPMENT DURING MIDDLE CHILDHOOD The literature on family impact is more voluminous but no less equivocal. Increased stress, problems of diminished parental self-esteem, persistent anx- iety, depressive feelings, and marital discord have been reported repeatedly (Aply et al., 1967; Boles, l9S9; Holt, 1958; Marcus, 1977; Turk, 1964~. Other studies have noted more adaptive outcomes (Gayton et al., 1977; Vance et al., 1980~. In a review of more than 50 reports on the impact of a handicapped child on the family, Murphy (1982) found only 16 controlled analytical studies, 11 of which involved parents of moderately to profoundly retarded children. Moreover, only 8 of the studies included a control group of healthy children, while the others compared handicapped populations. Vance et al. (1980) reviewed the literature on the methodological and conceptual problems of families and placed particular emphasis on the ap- propriate selection of control groups and the formulation of interview ques- tions. Despite their limitations, however, the available data suggest that a chronically impaired child is a stressor to which different families adapt with varying degrees of success. Recent attempts have been made to measure differential impacts with greater precision and reliability (Stein and Riess- man, 1982~. More studies are needec] to identify those variables that predict . a. specific outcomes. Questions regarding the impact of childhood chronic illness on healthy siblings have received increased attention in recent years. Although some studies have reported positive effects, such as increased understanding of problems and favorable responses to increased responsibilities (Caldwell and Guze, 1960; Hunt, 1973), most investigators have found increased guilt, anxiety, resentment, feelings of rejection, somatic complaints, and malad- justment in school (Mattson, 1972; Tew and Laurence, 1973~. Lavigne and Ryan ~ 1979) reported siblings of children attending hematology, cardiology, and especially plastic surgery clinics to be more withdrawn socially and more irritable than children without chronically ill family members. In addition, although neither the age nor the sex of the healthy sibling appeared to correlate with adverse outcome, the interaction between the two was noted to be significant. By contrast, Breslau et al. (1981) studied the psychological functioning of siblings of children with cystic fibrosis, cerebral palsy, mye- lodyplasia, and multiple handicaps and found no relation to type or severity of disability but did find an interaction between age and sex that completely contradicted that reported by l~avigne and Ryan (1979~. Furthermore, al- though global ratings of behavioral symptoms were not different from those of control subjects, subscales measuring interpersonal aggression with peers and within the school revealed significantly higher scores among siblings of disabled children. Breslau et al. (1981) highlighted this finding, pointing out the danger of overemphasizing mean differences in global ratings on behavior inventories without examining differences in specific behavioral

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH 51 domains. Although recent studies regarding sibling effects have demonstrated greater methodological sophistication, a great deal more work is needed to identify the factors that account for differences and similarities between siblings of disabled children and those with healthy brothers and sisters. Perhaps the most exciting new conceptualization in the literature on chronic impairment is reflected in a recent monograph from the Carnegie Council on Children (Gliedman and Roth, 1980~. In a sharp indictment of the use of normative models of development to study the adaptation of handicapped children and their families, Gliedman and Roth make the following observation (pp. 58-59~: IDlevelopmentalists have made a crucial oversight. They take it for granted that theories constructed for able-bodied children can correctly interpret the developmental signifi- cance of the handicapped child's behavior. The importance of this research shortcoming cannot be emphasized too much. Because of stigma and misunderstanding, handicapped children often live in a social world that is radically different from the one inhabited by their able-bodied peers, and their physical or mental disabilities often impose sharp constraints on the ways that they can obtain and analyze experience. These social and biological differences raise a fundamental theoretical question for the field of child development: do some handicapped children develop according to a healthy logic of their own? By ignoring this question developmentalists more than imperil the value of their research; they run the risk of sometimes perpetuating the traditional deviance analysis of disability in a more subtle and more socially acceptable form. lt is simply not enough to apply mainstream developmental theories to disability. Psychologists must first assess the ap- plicability of these theories to each of the many groups of children with handicaps. Support for this challenge is derived from varied yet related literature dealing with issues ranging from ethnic biases in "standardized" develop- mental models (Labov, 1972) to the dysfunctional use of conventional male- derived theories of personality and moral development in women's studies (Gilligan, 1979) and the necessity of constructing altemative models of normative development for children who are congenitally blind (Fraiberg, 1977) or deaf (Klima and Bellugi, 1979~. The need for a new family sociology or anthropology "to locate those factors of family life that correlate with an handicapped child's achieving independence and self-respect later in life" (Gliedman and Roth, 1980:61) was also emphasized. Gliedman and Roth (1980) conceptualize`] the predicament of the de- veloping handicapped child as a "cruel experiment of nature." They offer the intriguing suggestion that the social experiences of the disabled child be exploited as an opportunity to test the universality of theories of devel- opment, including the relative influences of nature and nurture, in a unique type of cross-cultural research (p. 64~: lt is conceivable that the handicapped child may provide the investigator with an opportunity to study groups of children who do not pose such profound cross-cultural

52 DEVELOPMENT DURING MIDDLE CHILDHOOD problems because they belong to his own culture, yet who are subjected to an array of socialization experiences that are even more alien to the norms of an able~bodied Amer' ican childhood than those of a child who grows up in a non-Western culture. Should this prove to be the case, the implications for constructing meaningful tests of theories of child development would be staggering. For years psychologists have rushed off to far- away places in the hope of testing the relative importance of nature and nurture, the universality of Piaget's stages of cognitive development, Kohlberg's stages of moral de- velopment, and various psychodynamic theories of emotional development. Is it possible that all this time the best groups of children with whom to explore these and other crucial developmental issues have been quite literally staring us in the face? Is it possible that the study of the handicapped child represents the best way to deepen our under- standing of how all children grow up? It is clear that new and creative frameworks are needed to deepen our understanding of how chronically ill and handicapped children grow up. Particularly for those whose impairments are highly visible, normative cri- teria for examining social interaction and the development of self-concept preclude nondeviant judgments. The increasing body of literature regarding successful coping and positive adaptation among many handicapped children and their families suggests the possibility that altemative pathways of de' velopment may be operative for the disabled population. Gliedman and Roth have made a valuable contribution in raising these issues and in plant- ing the seeds for what may be the ultimate cross-cultural study. AN AGENDA FOR FURTHER INVESTIGATION The salience of physical health as a developmental issue in the middle childhood years is both trivial and central. School-age children are among the healthiest members of American society, and their physical well-being is generally assumed. It is ironic, however, that this apparently uneventful interval in the life cycle may be the most sensitive period for the development of many of the functional patterns that significantly influence health status during the adult years. Moreover, for children with chronic impairments, the impact of diminished physical health may exert a pervasive influence on the developmental process. This chapter has provided an overview of current knowledge regarding a selection of physical health issues for school-age children. The preliminary nature of available data and the significant number of conceptual and in- formational gaps were noted earlier in this chapter. This final section pro- poses avenues for additional investigation and suggests how the matter of physical health can be studied in the context of development during middle childhood. Three integrating themes will be addressed childhood per- spectives on health and disease, the phenomena of vulnerability and resi- lience, and the challenges of health education.

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH The Child's View of Health and Illness 53 During the years from 6 to 12, cognitive maturation, the development of literacy skills, and a host of social experiences facilitate children's acquisition of knowledge and growing sophistication about the world in which they live. At the same time, and perhaps of more importance, the school-age child is developing a concept of himself or herself as an individual and a sense of how and where he or she fits within that world. The degree to which perceptions of personal well-being and physical integrity are con- sciously incorporated into one's developing construction of self and the extent to which that process is influenced by a variety of constitutional and environmental variables remain largely unexplored. Further elucidation of these issues will provide critical data needed to guide the evolution of a personal health care system in which cross-generational communication succeeds and school-age children are guided to function as independent consumers. We know very little about what the concept of health means to a school- age child who has never experienced serious illness. We know even less about those variables that contribute to the individual differences in belief patterns that have been described in the limited studies conducted thus far. While some investigators have suggested that basic values and perceptions regarding health and illness are fairly uniform among Westem cultures, others have highlighted the importance of subgroup differences related to a number of demographic variables (Gochman and Sheiham, 1978; Wright, 1982~. Several observers have characterized health beliefs as highly resistant to modification; others have examined the potent influences of such agents of change as parents and television. Perhaps the greatest limitation of our current knowledge of children's ideas about health is its static nature. Currently available data have almost all been collected cross-sectionally. Rather than further documentations of significant correlations between already established views of health and spe- cific demographic or experiential variables, there is a compelling need for well-designed longitudinal studies that employ multivariate analytic tech- niques and that demonstrate the differential impact and interactional effects of clusters of variables at different points in time. Only then, when we are able to better describe the formation of health concepts and the way in which specific factors influence their unfolding and manifestations, will we be able to communicate effectively with school-age children about the rel- evance to their health of particular behaviors and life-style issues. For children with acute illnesses or chronic diseases, the need for further research on their views of health and sickness has both immediate and long- term importance. Not only is the existing literature on the influences of

54 DEVELOPMENT DURING MIDDLE CHILDHOOD chronic health impairment on development during middle childhood in- conclusive and frequently contradictory, but it has also only begun to provide the data needed to promote the kind of direct communication with children that will facilitate optimal comprehensive care. Common problems such as passive acceptance and poor compliance regarding treatment are character- istic of many children with chronic illnesses. Explanations of the etiologies of symptoms, the rationale for specific therapeutic interventions, and the reasons for particular diagnostic studies or hospitalizations are some of the many critical areas of physician~patient communication that require devel- opmentally appropriate conceptualizations that are just beginning to be de- scribed and that demand extensive further study. A facilitation of increasing personal responsibility and involvement in decision making is highly de- pendent on an understanding of the developmental procession of a chron- ically ill child's ideas about his or her disorder. In summary, investigators have just begun to explore children's views of health and illness in a systematic and theoretically guided fashion. The current scarcity of such data reflects a pediatric clinical tradition of infor- mation sharing with parents and less effective communication with children (Pantell et al., 1982~. Changing trends toward viewing children as more active and informed participants in their own medical care have stimulated demands for a better understanding of how their health-related concepts mature. Increasing interest in the conscious promotion of healthful life- styles as early as possible has similarly emphasized the need for guidelines on how to talk effectively with young children. The recently demonstrated inability of pediatricians to correctly discriminate typical illness concepts at different ages in the middle childhood years (Perrin and Perrin, 1983) un- derlines the need for a genetic epistemology of health and disease concepts. Practically speaking, we can neither raise health-promoting consciousness nor comprehensively manage persistent illnesses in school-age children until we can leam to speak and understand their language. The Enigma of Resilience and Vulnerability Individual differences in susceptibility to physical as well as psychiatric disease have been acknowledged clinically for a long time, and attempts to elucidate the mechanisms for these differences have been undertaken by both biomedical and social scientists. A great deal of research, most of it oriented toward studies of animals and adults, has specifically looked at the biology of stress responses as a vehicle for understanding the phenomenon of differential vulnerability to illness. A brief review of current knowledge in this highly active area of biobehavioral research, some of which was

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH 55 described earlier in this chapter, suggests a number of possible applications to the study of health in school-age children. The fact that stress has been implicated as a risk factor for a large number of physical diseases is well established for both adults and children (Elliot and Eisdorfer, 1982; Heise! et al., 1973; Meyer and Haggerty, 1962; Rahe and Arthur, 1978~. The details of how certain stressors contribute to specific pathologies in a given individual, however, are far from being elucidated (Hamburg et al., 1982~. Genetically determined variations in catecholamine or corticosteroid metabolism or neuroregulator activity in the brain, for example, might very well play a major role in individual differences in susceptibility to particular diseases (Voge! and MotuIsky, 1979~. Such dif- ferences could be mediated through differential perceptions of external or intemal stimuli, variations in the responses of end organs to hormonal influences, or the actual nature of the hormones released (Hamburg et al., 1982~. Correlations between stressors and pathology, however, almost never reflect simple cause-effect relationships. Rather, they are related to complex interactions among a variety of environmental influences and constitutional factors that mediate individual physiological responses to stress. Hamburg et al. (1982) noted that "the relations doubtless will be difficult to disen- tangle, but the problems are too important and the prospects tOO promising to justify neglect" (p. 74~. The assertion that individual variation in resistance to illness undoubtedly has a biological basis does not diminish the significance of environmental contributions to the pathogenesis of much organic morbidity, particularly in relation to socioeconomic variables. Poor children miss more school days because of illness and are hospitalized more frequently and for longer du- rations than other children (Egbuonu and Starfield, 1982~. Children who live in crowded substandard housing have greater exposure to infectious diseases. Black children ages 5-14 have higher mortality rates than their white peers and are 24 percent more likely to die in accidents. In 1976, 76 percent of white children were immunized against measles compared with 61 percent of nonwhites. Data collected from 1971 to 1974 revealed unfilled, decayed teeth in 42 percent of black children ages 6-11, in contrast to a rate of 29 percent among whites (Select Pane! for the Promotion of Child Health, 1981~. Many biological risk factors for mild mental retardation, such as malnutrition and increased body lead burden, are more prevalent in lower socioeconomic classes (Shonkoff, 1982~. For those interested in the nature-nurture dynamics of resilience and vulnerability regarding illness or disability in school-age children, efforts might be directed toward the elucidation of psychosocial protective factors

56 DEVELOPMENT DURING MIDDLE CHILDHOOD that appear to facilitate more adaptive responses to stress. Recent studies suggest that social supports, such as a caring family and friends, provide a critical buffer against stressful experiences, perhaps by promoting effective coping strategies that help individuals defuse stressful stimuli and restore the state of physiological balance needed to maintain good health (Cobb, 1976; Haggerty, 1980; Rutter, 1981; Werner and Smith, 19821. Relations among life stresses, the availability of support systems, socioeconomic group differ- ences in disease prevalence rates, and long-term health issues are particularly worthy of further investigation in this regard. More careful study of potential stress reducers, their distribution in pop- ulation groups, and their interactions with individual characteristics of chil- dren and environmental variables should lead to a richer understanding of the phenomena of resilience and vulnerability. The benefits and growth- promoting aspects of stress also demand critical analysis. The middle child- hood period offers an extensive array of issues around which such investi- gations could be organized. A great deal remains to be reamed about the relationships among stresses, such as family disruption or reorganization and school pressures regarding individual achievement, and health disturbances, such as persistent somatic complaints (e.g., headaches, recurrent abdominal pain) and psychosomatic disorders (e.g., asthma, chronic inflammatory bowel disease). Stresses accompanying important social changes in the family, school, and peer context are discussed extensively in several chapters of this volume. Studies of their impact on the physical health of school-age children will considerably expand our knowledge of human adaptation. Whither Health Education, The need for effective health education for school-age children is uni- versally accepted. Successful efforts require prior consideration of a variety of issues, including precise definition of goals and objectives, specific iden- tification of target groups, choice of dissemination modes, and design and implementation of strategies for evaluation. Most health education activities have not addressed all these concerns in a systematic manner. Perhaps the most important issue from the perspective of basic research on school-age children is related to the need for reliable outcome data. Although the possibility of affecting health-related behavior in adult pop- ulations has been demonstrated (Maccoby et al., 1977; Puska, 1973), the efficacy of most childhood health education regarding behavior change has been disappointing (Berberian, 1976; lammarino, 1980; Levy, 1980~. Bar- tlett ( 1981: 1387) noted:

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH 57 Evaluation studies of even the best developed school health education curricula generally reveal that these programs are very successful in increasing knowledge, somewhat sue' cessful in improving attitudes, and infrequently successful in facilitating lifestyle changes. The effects of school health education on such pupil outcomes as decision~making and social interaction abilities have seldom, if ever, been measured. Additionally, limited evidence suggests the possibility that school health education programs are more likely to achieve significant improvement in health behaviors when they are directed toward diseases with high perceived susceptibility and severity, and/or include high involvement of students and parents. A recently reported pilot test of a family~oriented cardiovascular risk reduction program based on social reaming theory offers a promising mode! of a controlled, systematically evaluated behavioral intervention for families with schoolbags children (Nader et al., 1983~. Preliminary data demonstrate ing significant differences in reported dietary choices support the need for further efforts to both implement and carefully measure such educational efforts. The agenda for evaluating health education programs is a full one. Data are needed to identify "the tasks that are appropriate for reaming about weliness at various points along the developmental continuum and those tasks that will enhance an individual's motivation to work toward weliness" (Ng et al., 1981:50~. The likelihood that altemative formats and strategies will be variably effective at different ages demands a developmental approach to the establishment of goals and process and outcome measures. The fact that knowledge alone does not ensure appropriate behavior suggests that the conceptualization of health education in the school years must move beyond the domains of cognitive and educational psychology and into the realms of social psychology, anthropology, and sociology. SUMMARY Physical health in middle childhood is intimately related to interactions among a child's biological function, socioeconomic environment, and the evolution of his or her personal lifestyle. As such, it is determined by physiological mechanisms as well as the imperatives of the ecocultural niche. The importance of this interplay among constitutional, genetic, and psy- chosocial influences is equally critical for both the maintenance of well' being and the natural history of illness or disability. In short, an understanding of health requires an understanding of the way people live. As it relates to adaptation and function, health can be viewed as a lens through which biological integrity and the negotiation of devel' opmental tasks can be analyzed throughout the life cycle.

58 DEVELOPMENT DURING MIDDLE CHILDHOOD Middle childhood embodies a particularly rich host of transitions. From the perspective of traditional health care delivery needs, this period is rel- atively unevenly. As a stage of human development, however, the school- age years are rich in health-related issues. As our concepts of health and illness are broadened, the heretofore neglected years from 6 to 12 emerge as fertile ground for expanded basic research. REFERENCES Adams, ]. 1965 Little League shoulder: Osteochondrosis of the proximal humeral epiphysis in boy basebaI1 pitchers. California Medicine 105:22. Adams, R., Kocsis, J., and Estes, R. 1974 Soft neurological signs in learning-disabled children and controls. American Journal of Diseases of Children 128:614-618. Allegranee, ]., O'Rourke, T., and Tuncalp, S. 1977 A muleivariate analysis of selected psychosocial variables on the development of sub- sequent youth smoking behavior. Journal of Drug Education 7:237-248. American Academy of Pediatrics, Committee on the Pediatric Aspects of Physical Fitness, Rec reation and Spores 1975 Participation in spores by girls. Pediatrics 55:563. Aply, J., Barbour, R., and Wesemacoet, I. 1967 Impact of congenital heart disease on the family: Preliminary report. British Medical Journal 1: 103. Apple, D., and Canewell, J. 1979 Medicine for Sport. Chicago: Year Book Medical Publishers, Inc. Banks, M., Bewley, B., Bland, J., Dean, J., and Pollard, V. 1978 Long-eerm study of smoking by secondary school children. Archives of Disease in Childhood 53:12-19. Barcus, F. 1975 Weekend Commercial Ch~ldTen's Television-1975. Newronville, Mass.; Action for Chil- dren's Television. Barlow, C. 1974 "Soft signs" in children with learning disorders. American Journal of Diseases of Children 128:605-606. Bareleee, E. 1981 The contribution of school health education to community health promotion: What can we reasonably expect? American Journal of Public Health 71:1384-1391. Bedell, J., Giordani, B., Amour, J., Tavormina, ]., and Boll, T. 1977 Life stress and the psychological and medical adjustment of chronically ill children. Journal of Psychosomatic Research 21:237. Beecher, H. 1956 Relationship of the significance of wound to the pain experienced. Journal of the American Medical Association 161 1609-1613. Benson R., and Migeon, C. 1975 Physiological and pathological puberty, and human behavior. In B. Eleftheriou and R. Sprote, eds., Hormonal Correlates of Behavior. Vol. 1. New York: Plenum Press.

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALI7I 59 Berberian, R. 1916 The effectiveness of drug education programs: A critical review. Health Education Mon- ographs 4:377-398. Berenson, G., Frank, G., Hunter, S., Srinivasan, S., Voors, A., and Webber, L. 1982 Cardiovascular risk factors in children: Should they concern the pediatrician? Amencan Jourr~il of Diseases of Children 136:855-862. Berey, L., and Pollay, R. 1968 The influencing role of the child in family decision making. Journal of Marketing Research 5:70. Beverly, B. 1936 Effect of illness on emotional development. Journal of Pediamcs 8:533-543. Bibace, R., and Walsh, M. 1980 Development of children's concepts of illness. Pediarncs 66:912-917. 1981 Children's conceptions of illness. In R. Bibace and M. Walsh, eds., New Directions for Child Development: Cluldren's Conceptions of Heakh, Illness, Bodily Functions. No. 14. San Francisco: Jossey-Bass. Bland, I., Bewley, B., Banks, M., and Pollard, V. 1975 Schoolchildren's beliefs about smoking and disease. Health Educanon Journal 34:71-78. Blaney, N. 1981 Cigarette smoking in children and young adolescents: Causes and prevention. Advances in Behavioral Pediarucs. Vol. 2. Greenwich, Conn.: JAI Press. Blatt, I., Spencer, L., and Ward, S. 1972 A cognitive developmental study of children's reactions to television advertising. In E. Rubinstein, G. Comstock, and I. Murray, eds., Television and Social Behavior. Vol. 4. Television in Day lo Day Life: Patterns of Use. Washington, D.C.: U.S. Govemment Printing Office. Boles, G. 1959 Personality factors in mothers of cerebral palsy children. Genetic Psychology Monographs 59:159. Breslau, N., Weitzman, M., and Messenger, K. 1981 Psychologic functioning of siblings of disabled children. Pediarncs 67:344-353. Brewster, A. 1982 Chronically ill hospitalized children's concepts of their illness. Pediatrics 69:355-362. Brodie, B. 1974 Views of healthy children toward illness. Amencan Journal of Public Health 64:1156- 1159. Bubenik, G., and Brown, G. 1973 Morphologic sex differences in primate brain areas involved in regulation of reproductive activity. E=enenna 29:619. Bureau of the Census 1982 Current Population Reports, P-23, No. 114, ChaTaCtenSnCS of Amencan Children and Youth: 1980. Washington, D.C.: U.S. Department of Commerce. Available from the U.S. Government Printing Office. Bynner, J. 1970 Behavioral research into children's smoking. Some implications for anti-smoking strategy. Royal Society of Health Journal 90: 159-163. Caldwell, B., and Guze, S. 1960 A study of the adjustment of parents and siblings of institutionalized and non-institu- tionalized retarded children. A7r~an Journal of Mental Defic~y 64:845.

60 Campbell, DEVELOPMENT DURING MIDDLE CHILDHOOD J 1975 Illness is a Faint of view: The development of children's concepts of illness. Child Development 46:92-100. 1978 The child in the sick role: Contributions of age, sex, parental status, and parental values. Journal of Health and Social Behavior 19:35-51. Charney, E., Goodman, H., and McBride, M. 1976 Childhood antecedents of adult obesity Do chubby infants become obese adults? New England Journal of Medicine 295:6. Chc~wdbury, A., Huffman, S., and Curlin, G. 1978 Malnutrition, menarche, and marriage in rural Bangladesh. Social Biology 24:316-325. Clausen, ]. 1975 The social meaning calf differential physical and sexual maturation. In S. Dragstin and G. Elder, eds., Adolescence in the Life Cycle. New York: Halsted. Cobb, S. 1976 Social support as a moderator of life stress. Psychosomatic Medicine 38:300-314. Constitution of the World Health Organization 1958 In The First Ten Years of the WHO. Geneva: Palais des Nations. Dawber, T. 1980 The Framingham Study: Epidemiology of Atherosclerotic Disease. Cambridge, Mass.: Harvard University Press. Denny, F. 1982 Defined diets and childhood hyperactivity: Consensus conference. Journal of the American Medical Association 248:290-292. Downey, A., and O'Rourke, T. 1976 The utilization of attitudes and beliefs as indicators of future smoking behavior. Journal of Drug Education 6:283-295. Dubos, R. 1965 Man Adapting. New Haven, Conn.: Yale University Press. 1968 Medicine, Man and Environment. New York: Praeger Publishers. Duke, P., Carlsmith, J., Jennings, D., Martin, ]., Dvmbusch, S., Gross, R., and Siegel-Gorelick, B. 1982 Educational correlates of early and late sexual maturation in adolescence. Journal of Pediatrics 100:633-637. Edwards, D., and Rowe, F. 1975 Neural and endocrine control of aggressive behavior. In B. Eleftheriou and R. Sprott, eds., Hormonal Correlates of Behavior. New York: Plenum Press. Egbuonu, L., and Starfield, B. 1982 Child health and social status. Pediatrics 69:550-557. Ehrhardt, A. 1975 Prenatal hormonal exposure and psychosexual differentiation. In E. Sachar, ea., Topics in Psychoendocrinology. New York: Grune & Stratton. Eisenberg, L. 1976 Medical ecology: The epidemiology of handicap. Birth. Defects: Original Article Series 12(4):181-188. 1977 Disease and Illness. Culture, Medicine, and Psychiatry 1:9-23. Elliott, G., and Eisdorfer, C. 1982 Stress and Human Health. New York: Springer. Engel, G. 1977 The need for a new medical model: A challenge for biomedicine. Science 196:129-135. 1979 The biomedical model: A Procrustean bed? Man and Medicine 4(4):257-275.

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH 61 Evans, R., Henderson, A., Hill, P., and Raines, B. 1979 Smoking in children and adolescents: Psychosocial determinants and prevention strap egies. In Smoking and Health: A Report of the Surgeon General. Available from the U.S. Government Printing Office. DHEW Publication No. (PHS) 79-50066. Washington, D.C.: U.S. Department of Health, Education, and Welfare. Fabrega, H. 1972 The study of disease in relation to culture. Behavioral Science 17:183-203. 1974 Disease and Social Behavior. Cambridge, Mass.: MIT Press. Flickinger, G. 1966 Response of the testes to social interaction among grouped chickens. General and Com- parative Endocrinology 6:89. Fraiberg, S. 1977 Insights From the Blind. New York: Basic Books. Fr~nkenh~ft~ser. M.. and lohansson. G. 1975 Behavior and catecholamines in children. In L. Levi, ea., Society, Stress and Disease. Vol. 2. Childhood and Adolescence. London: Oxford University Press. Freud, A. 1952 The role of bodily illness in the mental life of children. In P. Eissler, ea., Psychoanalytic Study of the Child. New York: International Universities Press. Frisch, R., Wyshak, G., and Vincent, L. 1980 Delayed menarche and amenorrhea in ballet dancers. New England Journal of Medicine 303:17-19. Gayton, W., Friedman, S., Tavormina, ]., and Tucker, F. 1977 Children with cystic fibrosis: I. Psychological test findings of patients, siblings, and parents. Pediatrics 59:888-894. Geller, E., Ritvo, E., Freeman, B., and Yuwiler, A. 1982 Preliminary observations on the effect of fenfluramine on blood serotonin and symptoms in three autistic boys. New England Jounce of Medicine 307:165-169. Gilliam, T., and Burke, M. 1978 Effects of exercise on serum lipids and lipoproteins in girls, ages 8 to 10 years. Artery 4:203. Gilligan, C. 1979 Woman's place in man's life cycle. Harvard Education Review 49(4). Gliedman, J., and Roth, W. 1980 The Unexpected Minority: Handicapped Children in American Society. New York: Harcourt Brace Jovanovich. Glomset, ]. 1980 High-density lipoproteins in human health and disease. Advances in Internal Medicine 25:91. Gochman, D. 1971 Some correlates of children's health beliefs and potential health behavior. Journal of Health and Social Behavior 12: 148-154. Goehman, D., and Sheiham, A. 1978 Cross national consistency in children's beliefs about vulnerability. International Jourrm1 of Health Education 21 (3): 189- 193. Goldberg, B., Veras, G., and Nicholas, ]. 1978 Sports medicine: Pediatric perspective. New York State Journal of Medicine 78: 1406. Green, D. 1979 Youth education. In Smoking and Health: A Report of the Surgeon General. DHEW Pub- lication No. (PHS) 79~50066. Washington, D.C.: U.S. Government Printing Office.

62 Haggerty, R. DEVELOPMENT DURING MIDDLE CHILDHOOD 1980 Life stress, illness and social supports. Developmental Medicine and Child Neurology 22:391- 400. Hamburg, D., Elliott, G., and Parron, D., eds. 1982 Health and Behatnor: Frontiers of Research in the Biobehauioral Sciences. Report of a study from the Institute of Medicine. Washington, D.C.: National Academy Press. Hamilton, P., and Andrew, G. 1976 Influence of growth and athletic training on heart and lung functions. European Journal of Applied Physiology 36:27. Heisel, I., Ream, S., Raitz, R., Rappaport, M., and Coddington, R. 1973 The significance of life events as contributing factors in the diseases of children. III. A study of pediatric patients. Journal of Pediatrics 83:119- 123. Hennessy, I., and Levine, S. 1979 Stress, arousal, and the pituitary-adrenal system: A psychoendocrine hypothesis. In I. Srague and A. Epstein, eds., Progress in Psychobiology and Physiological Psychology. New York: Academic Press. Hewett, S., Newson, J., and Newson, E. 1970 The Family and the Handicapped Child. Chicago: Aldine. Hier, D., and Crowley, W. 1982 Spatial ability in androgen~deficient men. New England Journal of Medicine 306:1202- 1205. Hobbs, N., Perrin, J., and Ireys, H. 1983 Summary of Findings and Recommendations. Public Policies Affecting Chronically III Children and Their Families. Nashville: Center for the Study of Families and Children, Institute for Public Policy Studies, Vanderbilt University. Holt, K. 1958 The influence of a retarded child upon family limitation. Journal of Mental Deficiency Research 2:28. Hovell, M., Bursick, J., and Sharkey, R. 1978 An evaluation of elementary students' voluntary physical activity during recess. Research Quarterly of the American Association of Health and Physical Education 49:460. Hubel, D., Wiesel, T., and LeVay, S. 1977 Plasticity of oculardominance columns in monkey striate cortex. Philosophical Transactions of the Royal Society of London 278:411. Hughes, L., and Bontemps, A. 1958 The Book of Negro Forbore. New York: Dodd, Mead. Hunt, G. 1973 Implications of the treatment of myelomeningocele for the child and his family. Lancet 2:1308. Iammarino, N. 1980 The state of school heart health education: A review of the literature. Health Education Quarterly 7:298-320. Johnston, M., and Singer, H. 1982 Brain neurotransmitters and neuromodulators in pediatrics. Pediatrics 70:57-68. Jones, M., Bayley, N. and Macfarlane, I., eds. 1971 The Course of Human Development. Toronto: John Wiley & Sons. Kagan, J. 1982 The idea of spatial ability. New England Journal of Medicme 306:1225-1227 (Editorial). Kleinman, A., Eisenberg, L., and Good, B. 1978 Culture, illness, and care Clinical lessons from anthropologic and cross-cultural re- search. Annals of Intemal Medicine 88:251-258.

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH Klima, E., and Bellugi, V. 1979 The Signs of Language. Cambridge, Mass.: Harvard University Press. Kling, A. 63 1975 Testosterone and aggressive behavior in man and non-human primates. In B. Eleftheriou and R. Sprott, eds., Hormonal Correlates of Behavior. New York: Plenum Press. Koos, E. 1954 Labov, W. 1972 Language in the Inner City: Studies in the Black English Vernacular. Philadelphia: University of Pennsylvania Press. Lambert, W., Johansson, G., Frankenhaeuser, M., and Klachenberg-Larsson, I. 1969 Catecholamine excretion in young children and their parents as related to behavior. Scandinavian Journal of Psychology 10:306-318. Lanese, R., Banks, R., and Keller, M. 1972 Smoking behavior in a teenage population: A multivariate conceptual approach. Amer' ican Journal of Public Health 62:807-813. Langford, W. 1948 Physical illness and convalescence: Their meaning to the child. .1Ou~1 of Pediatrics The Health of Regionville. New York: Columbia University Press. 33:242-250. Laoye, J., Creswell, W., and Stone, D. 1972 A cohort study of 1,205 secondary school students. Journal of School Heals 42:47-52. Lavigne, I., and Ryan, M. 1979 Psychologic adjustment of siblings of children with chronic illness. Pediatrics 63:616- 627. Levitt, E., and Edwards, J. 1970 A multivariate study of correlative factors in youthful smoking. Developmental Psychology 2:5- 11. Levy, R. 1979 Testimony before the Subcommittee on Nutrition of the Committee on Agriculture, Nutrition, and Forestry, United States Senate, 96th Congress, May 22. Levy, S. 1980 Nutrition~education research: An interdisciplinary evaluation and review. Health Edu' cation Quarterly 7: 107- 126. Lewis, A. 1953 Health as a social concept. British Journal of Sociology 2:109-124. Lewis, C., and Lewis, M. 1974 The impact of television commercials on health related beliefs and behaviors of children. Pediatrics 53:431-435. Lewis, D., and Freeman, J. 1977 The electroencephalogram in pediatric practice: Its use and abuse. Pediatrics 60:324 330. Lloyd, J. 1971 Weights of testes, thymi, and accessory reproductive glands in relation to rank in paired and grouped house mice. Proceedings of the Royal Society of Experimental Biology and Medicine 137:19. 1975 Social behavior and hormones. In B. Eleftheriou and R. Sprott, eds., Hormonal Correlates of Behavior. New York: Plenum Press. Lowenberg, M. 1977 The development of food patterns in young children. In P. Pipes, ea., Nutrition in Infancy and Childhood. Saint Louis: C.V. Mosby.

64 Lynn, D., Glaser H., and Harrison, G. DEVELOPMENT DURING MIDDLE CHILDHOOD 1962 Comprehensive medical care for handicapped children: III. Concepts of illness in children with rheumatic fever. American Journal of Diseases of Children 103:42-50. Maccoby, E., and Jacklin, C. 1974 The Psychology of Sex Differences. Stanford, Calif.: Stanford University Press. Maccoby, N., Farquhar, J., Wood, P., and Alexander, I. 1977 Reducing the risk of cardiovascular disease: Effects of a community-based campaign on knowledge and behavior. Journal of Community Health 3: 100- 114. Marcus, L. 1977 Patterns of coping in families of psychotic children. American Journal of Orthopsychiatry 47:388-395. Mattson, A. 1972 Long-term physical illness in childhood: A challenge to psychosocial adaptation. Pediatrics 50:801-811. Mattson, A., and Gross, S. 1966 Social and behavioral studies on hemophiliac children and their families. Journal of Pediatrics 68:952. Mayer, J. 1975 Obesity during childhood. In M. Winick, ea., Childhood Obesity. New York: John Wiley & Sons. McAlister, A., Perry, C., Killen, J., Slinkard, L., and Maccoby, N. 1980 Pilot study of smoking, alcohol and drug abuse prevention. American Journal of Public Health 70:719-721. McAlister, A., Perry, C., and Maccoby, N. 1979 Adolescent smoking: Onset and prevention. Pediatrics 63:650-658. McAnamey, E., Pless, I.B., Satterwhite, B., and Friedman, S. 1974 Psychological problems of children with chronic juvenile arthritis. Pediatrics 53:523- 528. McNeal, ]. 1969 An exploratory study of consumer behavior of children. In I. McNeal, ea., Dimensions of Commercial Behavior. New York: Appleton-Century-Crofts. Mechanic, D. 1964 The influence of mothers on their children's health attitudes and behavior. Pediatrics 39:444-453. 1972 Social psychologic factors affecting the presentation of bodily complaints. New England Journal of Medicine 286:1132- 1139. 1978 Medical Sociology. Second edition. New York: Free Press. Merritt, R. 1982 Obesity. Current Problems in Pediatrics 12(11). Meyer, R., and Haggerty, R. 1962 Streptococcal infections in families: Factors altering individual susceptibility. Pediatrics 29:539. Micheli, L., and Smith, A. 1982 Sports injuries in children. Current Problems in Pediatrics 12(9). Money, J. 1973 Effects of prenatal androgenization and deandrogenization on behavior in human beings. In W. Ganong and L. Martini, eds., Frontiers in Neuroendocrinology. New York: Oxford University Press. Murphy, M. 1982 The family with a handicapped child: A review of the literature. Journal of Developmental and Behavioral Pediatrics 3(2):73-81.

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH 65 Nader, P., Baranowski, T., Vanderpool, N., Dunn, K., Dworkin, R., and Ray, L. 1983 The Family Health Project: Cardiovascular risk reduction education for children and parents. Joutnal of Developmental and Behavioral Pediatrics 4:3-10. Nagy, M. 1951 Natapoff, I. 1978 Children's ideas on the origin of illness. Health Education Journal 9:6. Children's views of health: A developmental study. American Journal of Public Health 68:995-1000. Nathan, S. 1973 Body image in chronically obese children as reflected in figure drawings. Journal of Personality Assessment 37:456-462. National Heart, Lung, and Blood Institute 1981 Arteriosclerosis, 1981. DHHS Publication No. (NIH) 81 2034. Washington, D.C.: U.S. Department of Health, Education, and Welfare. Available from the U.S. Government Printing Office. National Science Foundation 1977 Research on the Effects of Television Advertising in Children: A Review of the Literature and Recommendations for Future Research. Washington, D.C.: National Science Foundation. Needleman, H., Gunnoe, C., Leviton, A., Reed, R., Peresie, H., Maher, C., and Barrett, P. 1979 Deficits in psychologic and classroom performance of children with elevated dentine lead levels. New England Journal of Medicine 300:689-695. Neuhauser, C., Amsterdam, B., Hines, P., and Steward, M. 1978 Children's concepts of healing: Cognitive development and locus of control factors. American Journal of Orthopsychiatry 48:335-341. big, L., Davis, D., Manderscheid, R., and Elkes, J. 1981 Toward a conceptual formulation of health and well being. In L. Eng and D. David, eds., Strategies for Public Health. New York: Van Nostrand Reinhold. Olweus, D., Mattson, A., Schalling, D., and Low, H. 1980 Testosterone, aggression, physical, and personality dimensions in normal adolescent males. Psychosomatic Medicine 42:253-269. Owen, G., and Lippman, G. 1977 Nutritional status of infants and young children: U.S.A. Pediatric Clinics of North America 24(1):211-227. Paffenbarger, R., and Hyde, R. 1980 Exercise as protection against heart attack. New England Journal of Medicine 302:1026. Page, L., and Friend, B. 1978 The changing United States diet. BioScience 28:192-197. Pantell, R., Stewart, T., Dias, J., Wells, P., and Ross, W. 1982 Physician communication with children and parents. Pediatrics 70:396-401. Parsons, T. 1972 Definitions of health and illness in the light of American values and social structure. In E. Jaco, ea., Patients, Physicians, and illness. Second edition. New York: Free Press. Pate, R., and Blair, S. 1978 Exercise and the prevention of atherosclerosis: Pediatric implications. In W. Strong, ea., Atherosclerosis: Its Pediatric Aspects. New York: Grune & Stratton. Perrin, E., and Gerrity, P. 1981 There's a demon in your belly: Children's understanding of illness. Pediatrics 67:841- 849. Perrin, E., and Perrin, J. 1983 Clinicians' assessments of children's understanding of illness. American Journal of Diseases of Cluldren 137:874-878.

66 DEVELOPMENT DURING MIDDLE CHILDHOOD Pless, I.B., and Douglas, M. 1971 Chronic illness in childhood: Part I. Epidemiological and clinical characteristics. Pedi- atucs 47:405-414. Pless, I.B., and Pinkerton, P. 1975 Chronic Childhood Disorder: Promoting Patterns of Adjustment. London: Henry Klimpton Publishers. Primeaux, 1977 Pless, I.B., and Roghmann, K. 1971 Chronic illness and its consequences: Observations based on three epidemiologic surveys. Journal of Pediatrics 79:351-359. President's Council on Physical Fitness and Sports 1977 The Physically Underdeveloped Child. Washington, D.C.: U.S. Government Printing Of- fice. M. American Indian health care practices: A cross-cultural perspective. Nursing Clinics of North America 12:57. Prugh, D., Staub, E., Sands, H., Kirschbaum, R., and Lenihan, E. 1953 A study of the emotional reactions of children and families to hospitalization and illness. American Journal of Orthopsychiatry 23:70- 106. Puska, P. 1973 The North Karelia project: An attempt at community prevention of cardiovascular disease. World Health Organization Chronicle 27:55-58. Radius, S., Dielman, T., Becker, M., Rosenstock, I., and Horvath, W. 1980 Health beliefs of the school-aged child and their relationship to risk taking behaviors. luternational Journal of Health Education 23(4):227-235. Rahe, R., and Arthur, R. 1978 Lite change and illness studies: Past history and future directions. Journal of Human Stress 4:3-15. Raisman, G., and Field, P. 1971 Sexual dimorphism in the preoptic area of the rat. Science 173:731. Rapoport, ]., Buchsbaum, M., Zahn, T., Weingartner, H., Ludlow, C., and Mikkelsen, E. 1978 Dextroamphetamine: Cognitive and behavioral effects in normal prepubertal boys. Science 199:560-562. Rizek, R., and Jackson, E. 1980 Current Food Consumption Practices and Nutrient Sources in the American Diet. Hyattsville, Md.: Consumer Nutrition Center, Human Nutrition Science and Education Adminis- tration, U.S. Department of Agriculture. Rose, R. 1980 Endocrine responses to stressful psychological events. Psychiatric Clinics of North America 3:251-276. Rose, R., Holaday, J., and Bernstein, I. 1971 Plasma testosterone, dominance rank and aggressive behavior in rhesus monkeys. Nature 231:366. Rowland, T. 1981 Physical fitness in children: Implications for the prevention of coronary artery disease. Current PToble7ns in Pediatrics (9). Rutter, M. 1981 Stress, coping and development: Some issues and some questions. Journal of Child Psy- chology and Psychiatry 22:323-356. Schain, R., and Freedman, D. 1961 Studies on 5-hydroxyindole metabolism in autistic and other mentally retarded children. Journal of Pediatrics 58:315-320.

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH 67 Schneider, F., and Vanmastrigt, L. 1974 Adolescent-pre~adolescent differences in beliefs and attitudes about cigarette smoking. Journal of Psychology 87:71 -81. Select Panel for the Promotion of Child Health 1981 Better Health for OUT Children: A National Strategy. DHHS (PHS) Publication No. 79- 55071. Washington, D.C.: U.S. Department of Health and Human Services. Shaywitz, B., Yager, R., and Klopper, J. 1976 Selective brain dopamine depletion in developing rats: An experimental model of min- imal brain dysfunction. Science 191:305. Shonkoff, J. 1982 Biological and social factors contributing to mild mental retardation. In K. Heller, W. Holtzman, and S. Messick, eds., Placing Children in Special Education: A Strategy for Equity. Panel on Selection and Placement of Students in Programs for the Mentally Retarded, Committee on Child Development and Public Policy, National Research Council. Washington, D.C.: National Academy Press. Sinclair, D. 1978 Human Growth After Birth. Third edition. London: Oxford University Press. Smith, D. 1977 Growth and Its Disorders. Philadelphia: W.B. Saunders. Sowers, ]., ed. 1980 Hypothalamic Hormones. Stroudsburg, Pa.: Dowden, Hutchinson and Ross. Spector, R. 1979 Cultural Diversity in Health and Illness. New York: Appleton-Century-Crofts. Sperling, E. 1978 Psychological issues in chronic illness and handicap. In E. Gellert, ea., Psychosocial Aspects of Pediatric Care. New York: Grune & Stratton. Stamler, J. 1 978 Introduction to risk factors in coronary artery disease. In H. McIntosh, ea., Baylor College of Medicine Cardiology Series (3). Northfield: Medical Communications. Stein, R., and Riessman, C. 1980 The development of an impact-on-family scale: Preliminary findings. Medical care 18:465- 472. Stoeckle, ]., Zola, I., and Davidson, G. 1964 The quantity and significance of psychological distress in medical patients. Journal of Chronic Disease 17:959-970. Task Force on Pediatric Education 1978 The Future of Pediatric Education. Evanston, Ill.: American Academy of Pediatrics. Telch, M., Killen, J., McAlister, A., Perry, C., and Maccoby, N. 1982 Long-term follow up of a pilot project on smoking prevention with adolescents. louTnal of Behavioral Medicine 5:1-8. Tew, B., and Laurence, K. 1973 Mothers, brothers, and sisters of patients with spine bifida. Developmental Medicine and Child Neurology 15 (Suppl. 29):69-76. Thomas, G., Lee, P., Franks, P., and Paffenbarger, R., eds. 1981 Exercise and Health: The Evidence and the Implications. Cambridge, Eng.: Oelgeschlager, Gunn, and Hain. Tc~uwen, B. 1972 Laterality and dominance. Developmental Medicine and Child Neurology 14:747-755. Turk, ]. 1964 Impact of cystic fibrosis on family functioning. Pediatrics 34:67.

68 DEVELOPMENT DURING MIDDLE CHILDHOOD U.S. Public Health Service 1979 Smoking and Health: A Report of the Surgeon General. DHEW Publication No. (PHS) 79- 50066. Washington, D.C.: U.S. Department of Health, Education, and Welfare. Avail able from the U.S. Govemment Printing Office. Usdin, E., Kvetnansky, R., and Kopin, I., eds. 1980 Carecholamines and Stress: Recent Advances. New York: Elsevier/Noreh Holland. Vance, J., Fazan, L., Satterwhite, B., and Pless, I.B. 1980 Effects of nephrotic syndrome on the family: A controlled study. Pediatrics 65:948-955. Van Itallie, T. 1979 Obesity: Adverse effects on health and longevity. American Journal of Clinical Nutrition 32:2723-2733. Vogel, F., and Motulsky, A. 1979 Human Genetics: Problems and Approaches. Berlin: Springer-Verlag. Wagner, H. 1980 Nuclear imaging: New developments. Hospital Practice 15:117. Wallnofer, H., and Von Rottauscher, A. 1972 Chinese Folk Medicine. New York American Library. Ward, S., Levinson, D., and Wackman, D. 1972 Children's attention to television commercials. In E. Rubinstein, G. Comseock, and ]. Murray, eds., Television and Social Behavior. Vol. 4. Television in Day to-Day Life: Pattems of Use. Washington, D.C.: U.S. Government Printing Office. Warren, M. 1980 The effects of exercise on pubertal progression and reproductive function in girls. Jourrml of Clinical Endocrinology and Metabolism 51:1150. Webb, T., and Oski, F. 1973 Iron deficiency anemia and scholastic achievement in young adolescents. ]ournal of Pediarrics 82:827-830. Weil, W. 1981 Obesity in children. Pediatrics in Review 3:180-189. Weisenberg, M., Kegeles, S., and Lund, A. 1980 Children's health beliefs and acceptance of a dental preventive activity. Journal of Health and Social Behavior 21:59-74. Weiss, P. 1967 1 + 2 = 2: When one plus one does not equal ewo. In G. Quarton, T. Melnechok, and F. Schmidt, eds., The Neurosciences: A Study Program. New York: Rockefeller Uni versity Press. Wellman, H., and ]ohnson, C. 1982 Children's understanding of food and its functions: A preliminary study of the devel- opment of concepes of nutrition. Journal of Applied Developmental Psychology 3:135-148. Wender, P. 1971 Minimal Brain Dysfunction in Children. New York: Wiley Interscience. Werner, E., and Smith, R. 1982 Vulnerable But Invincible-A Study of Resil~ent Children. New York: McGraw-Hill. Wright, E. 1982 Children's perceptions of vulnerability to illness and dental disease. Community Dentistry and Oral Epidemiology (10) 1 :29-32. Wyshak, G., and Frisch, R. 1982 Evidence for a secular trend in age of menarche. New England]ournal of Medicine 306:1033- 1035. Yankelovich, D. 1970 Mothers' Atritudes Toward Children's Programs and Commercials. Newton Center, Mass.: Action for Children's Television.

BIOLOGICAL SUBSTRATE AND PHYSICAL HEALTH Zborowski, M. 1952 Cultural components in responses to pain. Joumal of Social Issues 8:16-30. Zola, I. 1966 Culture and symptoms: an analysis of patients' presenting complaints. American Socio- logical Review 31:615-630. 69

Next: 3 Cognitive Development in School-Age Children: Conclusions and New Directions »
Development During Middle Childhood: The Years From Six to Twelve Get This Book
×
Buy Paperback | $125.00
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

For the first time, a report focuses specifically on middle childhood--a discrete, pivotal period of development. In this review of research, experts examine the physical health and cognitive development of 6- to 12-year-old children as well as their surroundings: school and home environment, ecocultural setting, and family and peer relationships.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!