CDFR 2000 Chapter 2 Book Notes
CDFR 2000 Chapter 2 Book Notes CDFR 2000
Popular in Child Development I: Prenatal through Middle Childhood
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Popular in Child Development and Family Relations
Carmyn L Watkins
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This 18 page Class Notes was uploaded by AmberNicole on Monday September 12, 2016. The Class Notes belongs to CDFR 2000 at East Carolina University taught by Dr. Archana Hegde in Fall 2016. Since its upload, it has received 7 views. For similar materials see Child Development I: Prenatal through Middle Childhood in Child Development and Family Relations at East Carolina University.
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Chapter 2: Genetic and Environmental Foundations Foundations of development: heredity and environment Directly observable characteristics are called phenotypes o They depend in part on the individual's genotype- the complex blend of genetic information that determines our species and influences all our unique characteristics Genetic Foundations Nucleus contains rodlike structures called chromosomes, which store and transmit genetic information Human chromosomes come in 23 matching pairs (an exception is the XY pair in males) o Each member of a pair corresponds to the other in size, shape, and genetic functions o One is inherited from the mother and one from the father The Genetic Code Chromosomes are made up of a chemical substance called deoxyribonucleic acid (DNA) Each ring of the ladder consists of a pair of chemical substances called bases o A and T o C and G A gene is a segment of DNA along the length of the chromosome Protein-coding genes directly affect our body's characteristics, lie along the human chromosomes o They send instructions for making a rich assortment of proteins to the cytoplasm, the area surrounding the cell nucleus Proteins, which trigger chemical reaction throughout the body, are the biological foundation on which our characteristics are build Regulator genes modify the instructions given by protein-coding genes, greatly complicating their genetic impact Individuals around the world are about 99.6% genetically identical It takes a change in only a single DNA base pair to influence human trait Biological events of profound developmental significance are the result of both genetic and nongenetic forces The Sex Cells Gametes (sex cells): sperm and ovum o A gamete contains only 23 chromosomes, half as many as a regular body cell o Gametes are formed through a cell division process called meiosis, which halves the number of chromosomes normally present in body cells When sperm and ovum unite at conception, the resulting cell, called a zygote, will again have 46 chromosomes Meiosis ensures that a constant quantity of genetic material is transmitted from one generation to the next o In Meiosis, the chromosomes pair up and exchange segments, so that genes from one are replaced by genes from another The genetic variability produced by meiosis is adaptive: It increases the chances that at least some members of a species will cope with ever-changing environments and will survive In the male, four sperm are produced when meiosis is complete About 1 to 2 million eggs are present in the female at birth, 40,000 remain at adolescence, and approximately 350 to 450 will mature during a woman's childbearing years Boy or Girl? 22 of the 23 pairs of chromosomes are matching pairs, called autosomes (meaning not sex chromosomes) rd The 23 pair consists of sex chromosomes o In females, this pair is called XX o In males, it is called XY The X is a relatively large chromosome, where as the Y is short and carries little genetic material When gametes form in males, the X and Y chromosomes separate into different sperm cells The gametes that form in females all carry an X chromosome Multiple Offspring Fraternal, or dizygotic, twins, the most common type of multiple offspring, resulting from the release and fertilization of two ova A zygote that has started to duplicate separates into two clusters of cells that develop into two individuals o These are called identical, or monozygotic, twins because they have the same genetic makeup Most twins catch up in development by early or middle childhood Parental energies are further strained after the birth of triplets, whose early development is slower than that of twins Maternal factors linked to fraternal twinning Ethnicity o Occurs in 6 to 9 per 1,000 births among Asians and Hispanics, 9 to 12 per 1,000 births among white Europeans, and 11 to 18 or more per 1,000 births among black Africans Family history of twinning o Occurs more often among women whose mothers and sisters gave birth to fraternal twins, suggesting a hereditary influence through the female line Age o Rises with maternal age, peaking between 35 and 39 years, and then rapidly falls Nutrition o Occurs less often among women with poor diets; occurs more often among women who are tall and overweight or of normal weight as opposed to slight body build Number of births o Is more likely with each additional birth Fertility drugs and in vitro fertilization o Is more likely with fertility hormones and in vitro fertilization (see page 62 of textbook), which also increase the chances of bearing triplets, quadruplets, or quintuplets Patterns of Gene-Gene Interactions Two forms of each gene occur at the same place on the chromosomes, on inherited from the mother and one from the father Each form of a gene is called an allele o If the alleles from both parents are alike, the child is homozygous and will display the inherited trait o If the alleles are different, the child is heterozygous, and relationships between the alleles determine the phenotype Dominant-Recessive pattern In many heterozygous pairings, dominant-recessive inheritance occurs: Only one allele affects the child's characteristics o It is called dominant The second allele, which has no effect, is called recessive A child who inherits a homozygous pair of dominant alleles (DD) and a child who inherits a heterozygous pair (Db) will both be dark-haired, even though their genotypes differ o Blonde hair can result only from having two recessive alleles (bb) o Still, heterozygous individuals with just one recessive allele (Db) can pass that trait to their children. Therefore, they are called carriers of the trait One of the most frequently occurring recessive disorders is phenylketonuria, or PKU, which affects the way the body breaks down proteins contained in many foods o Damages the central nervous system o By 1 year, infants with PKU suffer from permanent intellectual disability o All U.S. states require that each newborn be given a blood test for PKU o Children who receive this treatment nevertheless show mild deficits in certain cognitive skills, such as memory, planning, decision making, and problem solving, because even small amounts of phenylalanine interfere with brain functioning o But as long as dietary treatment begins early and continues, children with PKU usually attain an average level of intelligence and have a normal lifespan Some dominant disorders do persist such as Huntington disease o Huntington disease is a condition in which the central nervous system degenerates o Symptoms usually do not appear until age 35 or later, after the person has passed the dominant allele to his or her children Examples of dominant and recessive diseases Autosomal Diseases Cooley's anemia o Pale appearance, delayed physical growth, and lethargic behavior begin in infancy o Recessive o 1 in 500 births to parents of Mediterranean descent o Frequent blood transfusions; death form complications usually occurs by adolescence Cystic fibrosis o Lungs, liver, and pancreas secrete large amounts of thick mucus, leading to breathing and digestive difficulties o Recessive o 1 in 2,000 to 2,500 Caucasian births; 1 in 16,000 births to North Americans of African descent o Bronchial drainage, prompt treatment of respiratory infection, dietary management. Advances in medical care allow survival with good life quality into adulthood Phenylketonuria (PKU) o Inability to metabolize the amino acid phenylalanine, contained in many proteins, causes severe central nervous system damage in the first year of life o Recessive o 1 in 8,000 births o Placing the child on a special diet results in average intelligence and normal lifespan. Subtle difficulties in memory, planning, decision making, and problem solving are often present Sickle cell anemia o Abnormal sickling of red blood cells causes oxygen deprivation, pain, swelling, and tissue damage. Anemia and susceptibility to infections, especially pneumonia, occur. o Recessive o 1 in 500 births to North Americans of African descent o Blood transfusions, painkillers, prompt treatment of infection. o No known cure; 50% die by age 55 o 85% of affected children make it to adulthood Tay-Sachs disease o Central nervous system degeneration, with onset at about 6 months, leads to poor muscle tone, blindness, deafness, and convulsions o Recessive o 1 in 3,600 births to Jews of European descent and to French Canadians o No treatment; death occurs by 3-4 years of age Huntington's disease o Central nervous system degeneration leads to muscular coordination difficulties, mental deterioration, and personality changed o Symptoms usually do not appear until age 35 or later o Dominant o 1 in 18,000 to 25,000 births to North Americans o No treatment; death occurs 10 to 20 years after symptom onset Marfan syndrome o Tall, slender build; thin, elongated arms and legs; and heart defects and eye abnormalities, especially of the lens o Excessive lengthening of the body results in a variety of skeletal defects o Dominant o 1 in 5,000 to 10,000 births o Correction of heart and eye defects sometimes possible o Death from heart failure in early adulthood is common X-Linked Diseases Duchenne muscular dystrophy o Degenerative muscle disease o Abnormal gait, loss of ability to walk between ages 7 and 13 years o Recessive o 1 in 3,000 to 5,000 male births o No treatment; death from respiratory infection or weakening of the heart muscle usually occurs in adolescence Hemophilia o Blood fails to clot normally o Can lead to severe internal bleeding and tissue damage o Recessive o 1 in 4,000 to 7,000 male births o Blood transfusions o Safety precautions to prevent injury Diabetes insipidus o Insufficient production of the hormone vasopressin results in excessive thirst and urination o Dehydration can cause central nervous system damage o Recessive o 1 in2,500 male births o Hormone replacement treatment Incomplete dominance pattern Incomplete dominance is a pattern of inheritance in which both alleles are expressed in the phenotype, resulting in a combined trait, or one that is intermediate between the two Only 8% of African Americans are carriers of sickle cell compared with 20% of black Africans X-Linked Pattern When a harmful allele is carried on the X chromosome, X-linked inheritance applies Males are more likely to be affected because their sex chromosomes do not match Rates of miscarriage, infant and childhood deaths, birth defects, learning disabilities, behavior disorders, and intellectual disability all are higher for boys The female, with two X chromosomes, benefits from a greater variety of genes In many Western countries, including the United States, Canada, and European nations, the proportion of male births has declined in recent decades Social and cultural factors can substantially modify the male to female birth sex ratio, in either direction They can readily undermine the ratio's assumed evolutionary role: compensating for males' greater genetic vulnerability Genomic imprinting In genomic imprinting, alleles are imprinted, or chemically marked through regulatory processes within the genome, in such a way that one pair member (either the mother's or the father's) is activated, regardless of its makeup The imprint is often temporary; it may be erased in the next generation, and it may not occur in all individuals The number of genes subjected to genomic imprinting is believed to be less than 1% Imprinting is involved in several childhood cancers and in Prader-Willi syndrome, a disorder with symptoms of mental disability and severe obesity It may also explain why Huntington disease, when inherited from the father, tends to emerge at an earlier age and to progress more rapidly Genomic imprinting can also operate on the sex chromosomes, as fragile X syndrome – the most common inherited cause of intellectual disability Mutation Although less than 3 percent of pregnancies result in the birth of a baby with a hereditary abnormality, these children account for about 20% of infant deaths and contribute substantially to lifelong impaired physical and mental functioning Mutation: a sudden but permanent change in a segment of DNA High doses of radiation over a long period of time impairs DNA Germline mutation takes place in the cells that give rise to gametes o Defective DNA is passed on to the next generation Somatic mutation o Normal body cells mutate, an event that can occur at any time of life o DNA defect appears in every cell derived form the affected body cell, eventually becoming widespread enough to cause a disease (such as cancer) or disability o Somatic mutation may be involved in these disorders as well Help individuals adapt to unexpected environmental challenges Polygenic inheritance Many genes affect the characteristic in question Chromosomal abnormalities Most chromosomal defects result from mistakes during meiosis, when the ovum and sperm are formed Down Syndrome (trisomy 21) Most common chromosomal disorder, occurring in 1 out of every 700 live births In 95% of cases, it results from a failure of the twenty-first pair of chromosomes to separate during meiosis, so the new individual receives three of these chromosomes rather than the normal two In less frequent forms, an extra broken piece of a twenty-first chromosome is attached to another chromosome (called translocation pattern) An error occurs during the early stages of cell duplication, causing some but not all body cells to have the defective chromosomal makeup (called mosaic pattern) o Because the mosaic type involves less genetic material, symptoms may be less extreme Live until around the age of 60 More than half of affected individuals who live past age 40 show symptoms of Alzheimer's disease, the most common form of dementia o Genes on chromosome 21 are linked to this disorder Environmental factors affect how well children with Down syndrome fare 5-10% of cases, the extra genetic material originates with the father Abnormalities of the sex chromosomes Abnormalities of the sex chromosomes usually lead to fewer problems Cognitive challenges are usually very specific o Verbal difficulties- for example, with reading and vocabulary- are common among girls with triple X syndrome and boys with Klinefelter syndrome, both of whom inherit an extra X chromosome o In contrast, girls with Turner syndrome, who are missing an X, have trouble with spatial relationships Sex Chromosomal Disorders XYY Syndrome o Extra Y chromosome o Above-average height o Large teeth o Sometimes severe acne o Intelligence, male sexual development, and fertility are normal o 1 in 1,000 male births o No special treatment necessary Triple X syndrome (XXX) o Extra X chromosome o Tallness and impaired verbal intelligence o Female sexual development and fertility are normal o 1 in 500 to 1,250 female births o Special education to treat verbal ability problems Klinefelter syndrome (XXY) o Extra X chromosome o Tallness, body fat distribution resembling females, incomplete development of sex characteristics at puberty, sterility, and impaired verbal intelligence o 1 in 900 male births o Hormone therapy at puberty to stimulate development of sex characteristics o Special education to treat verbal ability problems Turner Syndrome (XO) o Missing X chromosome o Short stature, webbed neck, incomplete development of sex characteristics at puberty, sterility, and impaired spatial intelligence o 1 in 2,500 to 8,000 female births o Hormone therapy in childhood to stimulate physical growth and at puberty to promote development of sex characteristics o Special education to treat spatial ability problems Reproductive Choices Genetic counseling and prenatal diagnosis help people make informed decisions about conceiving, carrying a pregnancy to term, or adopting a child Genetic Counseling Genetic counseling is a communication process designed to help couples assess their chances of giving birth to a baby with a hereditary disorder and choose the best course of action in view of risks and family goals As genetic age rises beyond age 35, the rates of Down syndrome and other chromosomal abnormalities increase sharply Older parental age present heightened risk of DNA mutations as well After age 40, it is associated with increased risk of several serious psychological disorders o These include hallucinations, delusions, and irrational behavior; and bipolar disorder, marked by alternating periods of elation and depression Pedigree is a picture of the family tree in which affected relatives are identified Autism, schizophrenia, and bipolar disorder have each been linked to an array of DNA-sequence deviations (called genetic markers) distributed across multiple chromosomes New genomewide testing methods, which look for these genetic markers, have enabled genetic counselors to estimate risk for these conditions Seems to depend on environmental conditions Geneticists have begun to identify rare repeats and deletions of DNA bases that are more consistently related to mental illness The Pros and Cons of Reproductive Technologies One-sixth of all couples who try to conceive discover that they are infertile Donor Insemination and In Vitro Fertilization o Donor insemination: injection of sperm from an anonymous man into a woman- has been used to overcome male reproductive difficulties o 70% successful, resulting in about 40,000 deliveries and 52,000 newborn babies in the U.S. each year o In vitro fertilization is another reproductive technology that has become increasingly common o Called the "test-tube" baby o 60,000 babies in the U.S. are born this way o With in vitro fertilization, a woman is given hormones that stimulate the ripening of several ova o These are removed surgically and placed in a dish of nutrients, to which sperm are added o Once an ovum is fertilized and begins to duplicate into several cells, it is injected into the mother's uterus o The overall success rate of assisted reproductive techniques, as measured by live births, is about 50% However, success declines steadily with age, from 55% in women age 31 to 35 to 8% in women age 43 o 45% of in vitro procedures result in multiple births o Rate of low birth weight is nearly four times as high as in the general population o In virto fertilization may be used to impregnate a woman (called a surrogate) with a couple's fertilized ovum Prenatal diagnosis and fetal medicine Prenatal diagnostic methods are medical procedures that permit detection of developmental problems before birth Women of advanced maternal age are prime candidates for amniocentesis or chorionic villus sampling Ultrasound, commonly used during pregnancy to track fetal growth, permits detection of gross structural abnormalities Ultrafast fetal magnetic resonance imaging, in which a scanner magnetically records detailed pictures of fetal structures By inserting a needle into the uterus, doctors can administer drugs to the fetus "annotating" the genome is identifying all its genes and their functions, including their protein products and what these products do Gene therapy is correcting genetic abnormalities by delivering DNA carrying a functional gene to the cells Proteomics are scientists who modify gene-specific proteins involved in disease Prenatal diagnostic methods Amniocentesis o The most widely used technique o A hollow needle is inserted through the abdominal wall to obtain a sample of fluid in the uterus o Cells are examined for genetic defects th o Can be performed by the 14 week after conception; 1 to 2 more weeks are required for test results o Small risk of miscarriage Chorionic villus sampling o A procedure that can be used if results are desired or need very early in pregnancy o A thin tube is inserted into the uterus through the vagina, or a hollow needle is inserted through the abdominal wall o A small plug of tissue is removed from the end of one or more chorionic villi, the hairlike projections on the membrane surrounding the developing organism o Cells are examined for genetic defects o Can be performed at 9 weeks after conception; results are available within 24 hours o Entails a slightly greater risk of miscarriage than does amniocentesis o Also associated with a small risk of limb deformities, which increases the earlier the procedure is performed Fetoscopy o A small tube with a light source at one end is inserted into the uterus to inspect the fetus for defects of the limbs and face o Also allows a sample of fetal blood to be obtained, permitting diagnosis of such disorders as hemophilia and sickle cell anemia as well as neural defects o Usually perfomred between 15 and 18 weeks after conception but can be done as early as 5 weeks o Entails some risk of miscarriage Ultrasound o High-frequency sound waves are beamed at the uterus; their reflection is translated into a picture on a video screen that reveals the size, shape, and placement of the fetus o By itself, permits assessment of fetal age, detection of multiple pregnancies, and identification of gross physical defects o Also used to guide amniocentesis, chorionic villus sampling, and fetoscopy o Sometimes combined with magnetic resonance imaging to detect physical abnormalities with greater accuracy o When used five or more times, may increase the chances of low birth weight Maternal blood analysis o By the second month of pregnancy, some of the developing organism's cells enter the maternal bloodstream o An elevated level of alpha-fetoprotein may indicate kidney disease, abnormal closure of the esophagus, or neural tube defects, such as anencephaly (absence of most of the brain) and spina bifida (bulging of the spinal cord from the spinal column) o Isolated cells can be examined for genetic defects Ultrafast fetal magnetic resonance imaging (MRI) o Sometimes used as a supplement to ultrasound, where brain or other abnormalities are detected and MRI can provide greater diagnostic accuracy o Uses a scanner to magnetically record detailed pictures of fetal structures o The ultrafast technique overcomes image blurring due to fetal movements o No evidence of adverse effects Preimplantation genetic diagnosis o After in vitro fertilization and duplication of the zygote into a cluster of about 8 to 10 cells, 1 or 2 cells are removed and examined for hereditary defects o Only if that sample is free of detectable genetic disorders is the fertilized ovum implanted in the woman's uterus Arrange for a physical exam, consider your genetic makeup, reduce or eliminate toxins under your control, ensure proper nutrition, consult your doctor after 12 months of unsuccessful efforts at conception Adoption Adopted children and adolescents tend to have more learning and emotional difficulties than other children Environmental contexts for development Bronfenbrenner's ecological systems theory emphasizes that environments extending beyond the microsystem powerfully affect development The macrosystem, or broad social climate of society, its values and programs that support and protect children's development The Family The family introduces children to the physical world by providing opportunities for play and exploration of objects Creates unique bonds among people Within the family, children learn the language, skills, and social and moral values of their culture A sense of isolation or alienation from the family, especially from parents, is generally associated with developmental problems Contemporary researchers view the family as a network of interdependent relationships Bidirectional influences exist in which the behaviors of each family member affect those of others System implies that the responses of all family members are related These system influences operate both directly and indirectly Direct influences Studies of families of diverse ethnicities show that when parents are firm but warm, children tend to comply with their requests Children whose parents discipline harshly and impatiently are likely to refuse and rebel The behavior of one family member helps sustain a form of interaction in the other that either promotes or undermines children's well-being Indirect Influences Bronfenbrenner calls these indirect influences the effect of third parties Coparenting is mutually supporting each other's parenting behaviors Children who are chronically exposed to angry, unresolved parental conflict have serious emotional problems resulting from disrupted emotional security o Internalizing difficulties (especially among girls), such as feeling worried and fearful and trying to repair their parents' relationship o Externalizing difficulties (especially among boys), including anger and aggression o Grandparents can promote children's development both directly, by responding warmly to the child, and indirectly, by providing parents with child-rearing advice, models of child-rearing skill, and even financial assistance Adapting to change Parents devote less time to physical care and more to talking, playing games, and disciplining These new ways of interacting encourage the child's expanding motor, cognitive, and social skills While the adolescent presses for greater autonomy, the parent presses for more togetherness Historical time period also contributes to a dynamic family system Families in industrialized nations have become more diverse than ever before Socioeconomic status and family functioning Socioeconomic status (SES) combines three related, but not completely overlapping, variables o Years of education o The prestige of one's job and the skill it requires, both of which measure social status o Income High levels of stress contribute to low-SES parents' greater use of coercive discipline As early as the second year of life, higher SES is associated with enhanced cognitive and language development and with reduced incidence of behavior problems As a result, they attain higher levels of education, which greatly enhances their opportunities for a prosperous adult life Affluence Affluent parents – those in prestigious and high paying occupations – too often fail to engage in family interaction and parenting that promote favorable development Among affluent (but not low-SES) teenagers, substance use was correlated with anxiety and depression, suggesting that wealthy youths took drugs to self-medicate – a practice that predicts persistent abuse Poorly adjusted affluent young people report less emotional closeness, less supervision, and fewer serious consequences fo rmisbehaviors from their parents, who lead professionally and socially demanding lives Parental affection, acceptance, and monitoring of the adolescent's whereabouts and activities predict favorable adjustment in affluent young people, just as tey do for youths in general Poverty About 15% - 46 million Americans – are affected by poverty Those hit hardest are parents under age 25 with young children and older adults who live alone Joblessness, a high divorce rate, a high rate of adolescent parenthood, and inadequate government programs to meet family needs are responsible for poverty Poverty rate is higher among children than any other age group 2.5-3.5 million people in the U.S. experience homelessness in a given year 40% of the homeless are children and youths Due to a decline in the availability of government-supported low-cost housing and an increase in poverty Beyond the Family: Neighborhood and schools Neighborhoods o Neighborhoods offer resources and social ties that play an important part in children's development o Neighborhood resources have a greater impact on economically disadvantaged than on well to do young people o Higher SES families depend less on their immediate surroundings for social support, education, and leisure pursuits o How do family-neighborhood ties reduce parenting stress and promote child development? Parental self worth Parental access to valuable information and services Child-rearing controls and role models Direct assistance with child rearing Schools o School is a formal institution designed to transmit knowledge and skills that children need to become productive members of their society o Regular parent-school contact supports development at all ages The Cultural Context Cultural values and practices Cultures shape family interaction, school experiences, and community settings beyond the home- in short, all aspects of daily life Subcultures: groups of people with beliefs and customs that differ from those of the larger culture Extended-family households in which parents and child live with one or more adult relatives A likely reason for such far-reaching effects is that intergenerational shared parenting is consistent with the Hispanic cultural ideal of familism, which places an especially high priority on close, harmonious family bonds, frequent contact, and meeting family needs Two broad sets of values on which cultures and subcultures are commonly compared: collectivism versus individualism In cultures that emphasize collectivism, people stress group goals over individual goals and value interdependent qualities, such as social harmony, obligations and responsibility to others, and collaborative endeavors In cultures that emphasize individualism, people are largely concerned with their own personal needs and value independence- personal exploration, discovery, achievement, and choice in relationships Though the most common basis for comparing cultures, the collectivism-individualism distinction is controversial because both sets of values exist, in varying mixtures, in most cultures United States is more individualistic than most Western European countries, which place greater weight on collectivism Public Policies and Child Development Public policies are laws and government programs designed to improve current conditions United States does not rank well on any key measure of children's health and well-being Cultural values of self-reliance and privacy have made government hesitant to become involved in family matters Children must rely on the goodwill of others to make them an important government priorities Former welfare recipients who must take very low-paying jobs that perpetuate poverty often engage in harsh, coercive parenting and have poorly adjusted children How does the United States compare to other Nations on Indicators of Children's Health and WEll-Being Indicator: Childhood poverty (among 20 economically advanced nations with similar standards of living) o U.S. rank: 20th o Some countries the United States trails: Canada, Iceland, Germany, United Kingdom, Norway, Sweden, Spain Indicator: Infant deaths in the first year of life (worldwide) o U.S. rank: 37th o Some countries the U.S. trails: Canada, Greece, Hungary, Ireland, Singapore, Spain Indicator: Teenage birth rate (among 28 industrialized nations) o U.S. Rank: 28th o Some countries the United States trails: Australia, Canada, Czech Republic, Denmark, Hungary, Iceland, Poland, Slovakia Indicator: Public expenditure on education as a percentage of gross domestic product (among 30 industrialized nations considered) o U.S. Rank: 13th o Some countries the U.S. trails: Belgium, France, Iceland, New Zealand, Portugal, Spain, Sweden Indicator: Public expenditure on early childhood education and child care as a percentage of gross domestic product (among 36 industrialized nations considered) o U.S. Rank: 32th o Some Countries the United States trails: Austria, Germany, Italy, Netherlands, France, Sweden Indicator: Public expenditure on health as a percentage of total health expenditure, public plus private (among 34 industrialized nations considered) o U.S. Rank: 34th o Some Countries The United States trails: Austria, Australia, Canada, France, Hungary, Iceland, Switzerland, New Zealand Looking toward the future Convention on the Rights of the Child: a legal agreement among nations that commits each cooperating country to work toward guaranteeing environments that foster children's development, protect them from harm, and enhance their community participation and self- determination Children's Defense Fund: a private, nonprofit organization founded by Marian Wright Edelman in 1973 – that engages in research, public education, legal action, drafting of legislation, congressional testimony, and community organizing Understanding the Relationship Between Heredity and Environment Children who are born into the same family (and who therefore share both genes and environments) are often quite different in characteristics Behavioral genetics is a field devoted to uncovering the contributions of nature and nurture to this diversity in human traits and abilities Both heredity and environment are involved in every aspect of development Polygenic traits (those due to many genes) such as intelligence and personality, scientists are a long way from knowing the precise hereditary influences involved Believe that heredity and environment are inseparable The Question, "How Much?" Heritability Heritability estimates measure the extent to which individual differences in complex traits in a specific population are due to genetic factors Kinship studies compare the characteristics of family members Most common type of kinship study compares identical twin Heritability research also reveals that genetic factors are important in personality Limitations of Heritability The accuracy of heritability estimates depends on the extent to which the twin pairs studied reflect genetic and environmental variation in the population Because the environments of most twin pairs are less diverse than those of the general population, heritability estimates are likely to exaggerate the role of heredity Heritability estimates are controversial measures because they can easily be misapplied Perhaps the most serious criticism of heritability estimates has to do with their limited usefulness Heritability of children's intelligence increases as parental education and income increase- that is, as children grow up in conditions that allow them to make the most of their genetic endowment The Question,"How?" Gene-Environment Interaction Gene-environment interaction means that because of their genetic makeup, individuals differ in their responsiveness to qualities of the environment Because each of us has a unique genetic makeup, we respond differently to the same environment When parenting is favorable, they gain control over their emotions and adjust as well as or better than other children But when parenting is unfavorable, they become increasingly irritable, angry, and poorly adjusted, more so than children not at genetic risk Gene-Environment Correlation Gene-environment correlation, our genes influence the environments to which we are exposed Passive and Evocative Correlation Passive correlation because the child has no control over it Second type of gene-environment correlation is evocative Children evoke responses that are influenced by the child's heredity, and these responses strengthen the child's original style Active Correlation At older ages, active gene-environment correlation becomes common Actively seek environments that fit with their genetic tendencies This tendency to actively choose environments that complement our heredity is called niche- picking Environmental influences on gene expression In gene-environment interaction, it affects responsiveness to particular environments Gene-environment correlation is viewed as driven by genetics, in that children's genetic makeup causes them to receive, evoke, or seek experiences that actualize their inborn tendencies Parents and other caring adults can uncouple unfavorable gene-environment correlations by providing children with positive experiences that modify the expression of heredity, yielding favorable outcomes Bidirectional: Genes affect children's behavior and experiences, but their experiences and behavior also affect gene expression Stimulation – whether internal to the child (activity within the cytoplasm of the cell, hormones released into the blood-stream) or external to the child (home, neighborhood, school, and society)- modifies gene activity Epigenesis means development resulting from ongoing, bidirectional exchanges between heredity and all levels of the environment Methylation is a biochemical process triggered by certain experiences, in which a set of chemical compounds (called a methyl group) lands on top of a gene and changes its impact, reducing or silencing its expression Development is best understood as a series of complex exchanges between nature and nurture