PSYC 4220H Unit 1

Which of the following is NOT a function of glial cells?

Conduct electrical signals away from one neuron and to another.

A team of researchers is studying whether stable individual differences exist in sleeping behavior at various ages. They decide to test 3 month olds, 6 month olds, and 9 month olds. What type of design?

Cross-Sectional

3 types of designs to study development over time:

Cross-Sectional, Longitudinal, Microgenetic.

According to developmentalists...

Development is influenced by the joint workings of nature and nurture.

Which factor is NOT one identified by Scarr (1992) as leading children from the same family to develop differently?

Differences in IQ

Emily, a bilingual 2-year-old, is making a visit to the university to participate in a research study about how her brain responds immediately after hearing specific words. Which technique are the researchers MOST likely to use?

ERP (event-related potentials)

Experience that children in an experimental group receive - and which children in a control group do not receive - is the

Independent Variable

According to Society for research and child development, which is NOT stated ethical principle for conducting research with children?

Information about child must not be revealed to the parent or guardian.

Joey notices in a picture one of his sex chromosomes is smaller than the other. What is the name of the type of image Joey is looking at?

Karyotype

Place the researchers in chronological order:

Plato, Aristotle, Locke, Earl of Shaftesbury, Darwin

Physical, social, cultural, economic, and historical circumstances that make up a child's environment:

Sociocultural context

Infants have an innate preference for:

Sweet foods

Infants REM sleep may make up for their lack of visual stimulation while sleeping. True or false?

TRUE

By administering the same test to the same group of participants under similar conditions 2 or more times, a researcher can measure ______ reliability.

Test-retest

Studies have shown that children's testimony is usually accurate when which condition is met?

The interviewer does not ask leading questions

In context of mechanisms of developmental change, the study of the development of "effortful attention" provides insights into:

The role of brain activity, genes, and learning experiences.

An individual's sex is determined by:

The sex chromosomes contributed by the father.

Turtle shell technique is an example of a successful intervention the helps preschoolers cope with what?

Their own anger.

Roman Orphanage study illustrated:

Timing of experiences influences their effects

3 main methods to design a study:

descriptive (describe and document), correlational (predict), experimental (explain why behavior occurs)

Concept of the active child refers to:

how children contribute to their own development.

Violent video games have a ______ effect on children's behavior.

minimal

According to the text, which reason is NOT stated for studying child development?

proving or disproving certain child psychologists' theories

Plato and Aristotle believed that the proper raising of children was important because children's basic nature would otherwise lead to their becoming

rebellious and unruly.

Darwin's published article presented one of the first methods for studying children, which included

systematic descriptions of his son's day-to-day development.

CONTEXTS FOR GATHERING INFO ON CHILDREN - 3 MAIN CONTEXTS -

INTERVIEWS, NATURALISTIC OBSERVATION, STRUCTURED OBSERVATION.

How many genes do a child and his identical twin have in common?

All

What is considered the ideal Behavior Genetics Design?

An Adoptive Twin Study

Roger hears the sound of a loud engine overhead, and looks up to see a small plane about to land in a field nearby. These TWO pieces of information are likely linked to what area of Roger's brain?

An Association Area.

Which developmental disorder is the result of unexplained genetic causes?

Autism Spectrum Disorder (ASD)

3.2 - BEHAVIOR GENETICS

BEHAVIOR GENETICS assumes that all behavioral traits are, to some extent, heritable. -Researchers try to tease apart genetic and environmental contributions by taking advantage of differences observed among a population. 1) To extent that genetic factors are important, individuals who are genotypical similar should be phenotypically similar. 2) To extent that environment is important, individuals reared together should be more similar than individuals reared apart. QUANTITIVE GENETICS RESEARCH DESIGNS: -Statistical methods used to study "naturally occurring genetic and environmental variation" in population by comparing phenotypes of individuals who vary in amount of genomic DNA they share. -Mainstray - family study - determines whether phenotypic traits are CORRELATED with the degree to which people are genetically related. TWIN STUDY: -compares correlations for monozygotic (MZ) twins and same sex dizygotic fraternal (DZ) twins -EQUAL ENVIRONMENTS ASSUMPTION - assume pre and post natal environments were the same. This has been questioned! -If correlation was higher for identical twins, genetic factors would be responsible. LIMITATIONS: -parents of MZ twins may treat them more similarly than parents of DZ twins. -Among MZ twin pairs, noteable differences in degree of placental sharing (chorionicity) -Some MZ twins share placenta, and some (similarly to DZ twins) do not -So, can't assume environment of MZ pairs and DZ pairs are equally similar. ADOPTION STUDY: -Do people correlate more with biological relatives or adoptive relatives? -If correlations for twins reared apart and twins reared together are similar, no environmental affect. -These studies can be confounded. -Children's phenotypes shape their environments. HERITABILITY: -Statistical estimate of how much of the measured variance on a phenotypic trait among individuals in a given population is attributable to genetic differences among those individuals. -Look at average r (correlation) for different relationships (ex. MZ twins, sublings, half siblings) for a trait (ex. intelligence) -MZ twins resemble each other in IQ more than do same sex DZ twins. -Still, env factors are reflected in the fact that MZ twins aren't identical in IQ. And, MZ twins reared together are more similar than those reared apart. -"Heritability" is commonly mistakenly applied to individuals, but it APPLIES ONLY TO POPULATIONS. -ex. Heritability of intelligence is 50% -means that for population studied, 50% of variation is due to genetic differences among members. -Heritability estimate applies only to a particular population living in a particular environment. -Heritability estimates reflect the environments of the populations from which they are derived! -ex. 2 different populations, measuring reading ability - Brazil (lots of variability in educational opportunities) and Finland (all kids have good education). Heritability estimate lower in Brazil - reading outcomes are more influenced by the environment. -Even for the same trait in the same population, heritability estimates can change as a function of developmental factors. -ex. PHENOTYPE-ENV correlation - people actively construct their own environment as they get older (whereas young kids have no choice in their environment). Older kids follow their own (genetically mediated) preferences to shape their environment. -As twins get older, the degree of variance in intelligence accounted for by their genetic similarity increases, because their shared genetics are causing them to choose/shape similar environments!! (Counterintuitive, not obvious, really think about it). -High heritability does not imply inmutability: does not mean that the traits cannot change. -ex. IQ - highly heritable, but can change with proper intervention! -Not obvious, but true, due to genetic mediation (genetics explaining how we choose/shape our environment): Heritability of intelligence increases with age. -Studies of heritability still mainly WEIRD (White, Educated, Industrialized, Rich, Democratic) participants. -Problematic, given that the generalizations being drawn are intended to account for heritability irrespective of culture. -Large sample sizes - one way to solve the problem. -Also, include broader range of participants. MOLECULAR GENETICS RESEARCH DESIGNS -Link genes and behavior. -DNA-based methods permit analysis of large samples of unrelated individuals - useful to study developmental disabilities. -Even when root of a disorder is alleles of a single gene, doesn't mean one gene is responsibe. Gene starts a cascade effect, turning on/off many genes, affecting development. -GENE ANOMALIES - extra, missing, or abnormal genes. -Most traits of interest to developmental scientists are POLYGENIC - affected by interaction of many genes. -So, GWAS useful to detect many SNPs. -GENOME-WIDE COMPLEX TRAIT ANALYSIS (GCTA) helps identify genetic mediator variables (genetics explains/mediates relationship between predictor and outcome), by taking advantage of genetic resemblence across many individuals. -GCTA used large sample of kids of different ages to show that the SAME GENES are implicated in HERITABLE ASPECTS OF INTELLIGENCE ACROSS AGES, with increasing effects of heritability as we age! -In some cases, quantitative genetics (ex. classic twin studies) and molecular genetics render divergent/opposing estimates of heritability. -Molecular genetics studies have vastly larger sample sizes and include more diverse participants. -Twins may be unrepresentative because only in WEIRD societies, In-Vitro Fertilization (IVF) has increased amount of twins. ENVIRONMENTAL EFFECTS: -Children in same family do not necessarily share the same family environment. -ex. First child - parents are poor and inexperienced. 2nd child - parents are experienced. -Effects of environment - many experiences of small effect working together. -Environments are much harder to measure than genes. -Complex phenotypes also hard to assess in large scale experimnts.

The field of _________ is concerned with how variations in behavior and development result from the interaction of genetic and environmental factors.

Behavior Genetics

Which statement is inaccurate?

Boys are more often the victim of infanticide (killing a baby) than girls. So, what IS ACCURATE? -Male fetuses are more sensitive than females to teratogens. -Boys are more likely to experience fetal distress during childbirth. -Male fetuses are more susceptible to spontaneous abortion during pregnancy.

Which practice is becoming more common in the United States?

Cesarian Sections

Chapter 1

Chapter 1 -In a study in lat 1950s about kids, by the time they were 10 years old, prenatal and birth problems were consistently related to psychological difficulties only if the children also grew up in poor rearing conditions. -Most children had biological and environment developmental problems, but there are exceptions! -Spanking has been shown to make children's behavior worsen. -Better to respond to children's anger with sympathy. Also time-outs. -One study taught children to use "turtle technique" when angry at other kids. (Curl up like a turtle and think it through). -Effects of these techniques can be long term. -Research also important for broad social policy. -META ANALYSIS - statistical method combining results from independent studies, used to summarize average effect size and statistical significance across several research studies. -When 3-5 year olds are not asked leading questions, their testimony in court is usually accurate but lacking in detail. -Especially for young kids, an interviewer's bias and phrasing can affect their testimony. -Also study human development to better understand human nature. -NATIVISTS argue that evolution has created capabilities that are present even in infancy (ex. basic properties of physical objects, plants and animals, and people) -EMPIRICISTS say infants and young kids lack specialized capabilities, but have learning mechanisms to learn quick. -AMYGDALA - brain area involved in emotional reactions. -The timing of experiences influences their effects later on in life. -In one study, the later the age of adoption from an orphanage, the greater the long-term harmful effects of early deprivation. -Unlike contemporary researchers, early philosophers based their conclusions on observations of just a few children. -Starting in 20th century, psychologists started using scientific method. -Philosophers' thinking influences today's thinking -Plato and Aristotle interested in nature and nurture -Said welfare of society depends on proper raising of children -Plato said raising boys was a challenge. Said self control and discipline most important. -Aristotle agreed, but twas concerned with fitting the needs of the individual child. -Plato thought children have innate knowledge (ex. can recognize other animals from birth onward) -Aristotle thought mind of an infant is a blank slate. -John Locke also said mind is blank slate at birth. Said nurture is important - most important aspect of rearing- growth of character. -Said parents should set example and avoid indulging the child. But, once self discipline is instilled, relax the authority. -In contrast, Jean-Jacques Rousseau said parents and society should give children maximum freedom from the start. Children learn from spontaneous interactions. No formal education until age 12. -Current debates are more based on research. -From reviewing research, Kagan concluded that children have an innate moral sense. 5 abilities that our primate relatives lack. SOCIAL REFORM MOVEMENTS: -During industrial revolution, kids worked in hazardous conditions. -Earl of Shaftesbury's effort brought a law forbidding employment of kids younger than 10. -Started research conducted for the benefit of children. -Darwin published article - "A Biographical Sketch of an Infant" - observations of his son. Systematic description - one of the first methods to study children. -Darwin's evolutionary theory employs variation, natural selection, and inheritance - influences modern developmentalists' thinking. 7 Basic Questions about child development: 1) How do nature and nurture together shape development? -Nature: biological endowment: the genes we receive from our parents. Genetic inheritance influences every aspect of our makeup. -Nurture: wide range of physical and social environments that influence development, including the womb, homes, schools, community, people. -"Either/or" phrasing of nature and nurture is misleading - joint workings of both. Ask how they work together. -ex. Both genes and environment affect the likelihood of Schizophrenia. Interaction: substantial likelihood for children who had schizophrenic biological parents AND were adopted into a troubled family. GENOME: each person's complete set of hereditary information. Influences AND is influenced by a person's behavior and experiences. -DNA is constant through life, but genome includes proteins that regulate gene expression by turning genes on and off. -Epigenetics: study of stable changes in gene expression, mediated by the environment. METHYLATION: biochemical process that reduces expression of a variety of genes and is involved in regulating reaction to stress. -Studies show increased methylation in cord-blood DNA of newborns with depressed mothers. -Nature and Nurture: complex interaction. 2) The active child - how do children shape their own development? -Infants shape their development with selective attention - choose to look at mom and prefer to look at objects that move and make sound. -"Crib Speech-" 9-15 month toddlers practice speaking ALONE. -Young children's play - internally motivated - they do it for joy and learning. -Older children's play influences self control and rule following. -Children's contribution to their own development strengthens as they age. 3) How is development continuous or discontinuous? -CONTINUOUS: gradual, small changes. -DISCONTINUOUS: sudden changes. -For the discontinuous argument, people reference the liquid-quantity phenomenon - young kids unable to tell that the amount of liquid in 2 different types of glasses is the same. Older kids can tell. -So, we ask what changes occurred to make kids so different at different ages? -STAGE THEORIES - propose that development occurs in a progression of distinct, large, discontinuous age-related stages. Sudden, unified changes. -Best known stage theory - Jean Piaget theory of COGNITIVE DEVELOPMENT - 4 stages of cognitive growth between birth and adolescence. -ex. 2-5 year olds can only focus on one aspect of an event at a time. -ex. 2-5 year olds only notice the height of the glass, not the width. -In the past 20 years, many have found that changes are gradual, not sudden. -Development occurs task by task, not in a broadly unified way. -Whether continuous or discontinuous can look different with different perspectives. -ex. When you look at height at each age, change looks continuous. When you look at amount of growth each year, discontinuous (spike in adolescence). 4) MECHANISMS OF CHANGE - HOW DOES CHANGE OCCUR? -Developmental mechanisms can be behavioral, neural, genetic. -Effortful thinking- when people are controlling thoughts and emotions, brain activity especially intense in connections between the limbic area (emotional reactions) and anterior cingulate + prefrontal cortex (setting and attending to goals) - changes reflect genetics and environmental changes. -Specific genes influence the production of NEUROTRANSMITTERS - chemicals involved in communication among brain cells. -Variations in kids' genes are associated with effortful attention. -Among children with a certain form/allele of a gene in question, parenting has more of an effect on effortful attention. For kids with other alleles, parenting less important. -Learning can change the wiring of brain system. -So, experiences influence brain processes and gene expression, just as the brain and genes influence reactions to experiences. -Sleep important in promoting learning, but type of learning changes with maturation of hippocampus. -In 1st 18 months after birth, sleep promotes learning of GENERAL, FREQUENT PATTERNS. -After 24 months, after a nap, they remember specifics of what they learned, but not an increased memory of general patterns. -Active Systems Consolidation Theory - 2 interconnected areas (hippocampus and cortex) simultaneously encode new information during learning. -Cortex - produces abstraction of general patterns over many experiences. -Hippocampus - earn details of new information after one or two experiences. -In older kids and adults, hippocampal memories are replayed during sleep, allowing cortex to extract general patterns from the specific memories in the hippocampus. Works in reverse too. -Benefit of sleep for infant memory - cortex. -For preschoolers - hippocampus. -Cortex matures first. 5) HOW DOES SOCIOCULTURAL CONTEXT INFLUENCE DEVELOPMENT? -Physical, cultural, social, economic, and historical environment. -ex. Urie Bronfenbrenner bioecological model - most obvious components are people and physical environment. -Society matters, and reflects values, attitudes, beliefs, traditions -Cross Cultural Comparison - compare kids of different cultures. -Kids in America usually sleep in separate room from the parents after 2 months (American culture - independence). -Also differences WITHIN cultures, regarding race, ethnicity, SES. -CUMULATIVE RISK - accumulation of disadvantages over years of development. -But, there are exceptions - children who overcome obstacles - resilience reflects personal qualities and relationships. 6) HOW DO CHILDREN BECOME DIFFERENT FROM EACH OTHER? -4 factors leading kids of same/different families to be different: 1. Genetic Differences. 2. Differences in treatment by parents and others. 3. Differences in reactions to similar experiences. 4. Different choices of environments. -Even identical twins are genetically different. At conception, genomes are same, but mutations and modifications occur. -Majority of genes are identical for all humans. -Siblings differ in 50% of the genes on which people differ. -Differential treatment is often associated with preexisting differences in kids' characteristics (ex. harsh treatment toward the mean kid). 7) HOW CAN RESEARCH PROMOTE KIDS' WELL BEING? -SCIENTIFIC METHOD - all beliefs may be wrong. Test beliefs with question, hypothesis, conclusion. -Thinkers of the past used scientific method too. -4 steps: question, hypothesis, method, use data for conclusion. -What distinguishes scientific from non-scientific is Methods. -Measure must be relevant to the hypothesis. -2 other qualities good measures most possess - reliability and validity. -RELIABILITY - degree to which independent measures of a given behavior are consistent. -INTERRATER RELIABILITY - how much agreement between observers. -TEST RETEST RELIABILITY - measures of performance on same test, administered under same conditions, are similar in different occasions. -VALIDITY - test measures what it is supposed to measure. -INTERNAL VALIDITY - whether effects observed within experiments can be attributed to the factor you're testing (rule out 3rd variables). -EXTERNAL VALIDITY - ability to generalize. -Reliability is necessary for internal validity, and both are necessary for external validity. CONTEXTS FOR GATHERING INFO ON CHILDREN - 3 MAIN CONTEXTS - INTERVIEWS, NATURALISTIC OBSERVATION, STRUCTURED OBSERVATION. -STRUCTURED INTERVIEWS - all participants are asked the same questions - useful for self reports on same topics for everyone. -Young children - questions given orally. -Older children - questionnaires. -CLINICAL INTERVIEW - questions are adjusted in accord with the answers the interviewer provides. -Positive - can yield a lot of data quickly and have in depth information about individuals. -Negatives - answers often biased (people misremember and misunderstand things). NATURALISTIC OBSERVATION - examination of ongoing behavior in an environment not controlled for by the researcher - good for observing how kids behave in their usual environments. -Limitation - naturally occurring contexts vary in many dimensions - hard to know which ones influenced behavior. -Also, some behaviors only occur occasionally in everyday environment. -Overcome these with Structured Observation. STRUCTURED OBSERVATION - design a situation that will elicit behavior and then observe how kids behave. -ex. Mothers ask their kid to not play with a toy and then leave the room. The compliant kids obeyed, even when she was gone. -Advantage - all kids being studied encounter identical situations - allows you to generalize to certain situations. -Doesn't provide extensive information like interviews, or the open ended everyday data of naturalistic observations. -Context is less natural. Artificial. -Best type of data gathering depends on the goal of research. -VARIABLES - attributes that vary across individuals and situations, like age, sex, popularity. -CORRELATIONAL DESIGN - how are 2 variables relayed? -Correlation -1 to 1. Close to 0 is weak. -Correlation is not causation, due to... -Direction-of-causation-problem - correlation doesn't indicate which variable is the cause. -Third Variable Problem - correlation may stem from a 3rd variable. -Often, correlational designs used because researchers can't do experiments (ex. can't randomly assign someone to a sex or age), or unethical. -EXPERIMENTAL DESIGN - group of approaches that allow inferences about causes and effects to be drawn. -2 techniques are critical - RANDOM ASSIGNMENT and EXPERIMENTAL CONTROL - ability of researchers to determine the specific experiences of participants during course of an experiment. -Simplest design - one COMPARISON/CONTROL GROUP (treated similarly to experimental group but not given the variable of interest) and EXPERIMENTAL GROUP -INDEPENDENT VARIABLE - variable the experimental group receives. -DEPENDENT VARIABLE - effect. -Experiments aren't always possible and ethical, and raise external validity concerns - can the lab setting generalize to the real world? -3 types of designs to study development over time: Cross-Sectional, Longitudinal, Microgenetic. CROSS-SECTIONAL - kids of different ages are compared on a given behavior over a short period / at the same time. -Can show similarities and differences between young and old kids, but don't yield information about patterns of change for individual kids over time. LONGITUDINAL DESIGN - same participants studied over a long time. -Hard, because participants may drop out (attrition). -Cross-Sectional designs are far more common. More practical, easier. -Selection-attrition - certain type of participants drop out. -Also, testing effects of repeated testing. -Longitudinal designs only used for studying stability and change in individuals over time. -Age-related changes in typical performance - cross sectional used. -Repeatedly testing children can threaten external validity. (Testing effects may make the group unrepresentative). MICROGENETIC DESIGN - specifically designed to provide an in depth depiction of the processes producing change. -Not broad like the last 2. -Same participants are studied repeatedly over a short period. -Recruit kids on the verge of a change, heighten their exposure to a type of experience believed to produce the change, and intensively study change as it is occurring. -Greater number of sessions over a shorter time, compared to longitudinal. -These do not study the long term. -Used when basic pattern of age-related change has already been established, and the goal is to understand how. ETHICAL ISSUES: -Do not harm. -Get consent from parents (and kids, if old enough). -Protect anonymity. -IRBs review studies, but the researcher is responsible for meeting standards. -3 main methods to design a study - descriptive (describe and document), correlational (predict), experimental (explain why behavior occurs) -Usually, large sample is more representative, but a small representative sample is better than a large non representative. -DOUBLE BLIND PROCEDURE: participants and researcher don't know who is in which group. Internal Validity - whether the effects observed within experiments can be attributed with confidence to the factor that the researcher is testing. Microgenetic Design: reveals individual change patterns over short periods in considerable detail. Thinkers of the past proposed interesting hypotheses, but lacked scientific methods.

Chapter 2: Prenatal Development and Newborn Period

Chapter 2: Prenatal Development and Newborn Period -Fetuses can detect and learn from a range of stimuli from outside world and inside mother's body. -Prenatal development - astonishingly rapid and dramatic change -Aristotle asked "Does prenatal life start with a fully formed individual composed of a full set of tiny parts, or do many parts of the body develop in succession? -He argued for the latter - EPIGENESIS - emergence of new structures and functions during development. -GAMETES/GERM CELLS - each one contains only half of genetic info found in other cells. -Gametes are produced in MEIOSIS - eggs and sperm receive only one member from each of the 23 chromosome pairs. -Egg (largest cell in female body) launches from ovaries into fallopian tube -Egg moves toward uterus, emitting a chemical signal to sperm. -If sex happens near time when egg is released, CONCEPTION, union of sperm and egg is possible -Any sperm that do get to the egg in the fallopian tube are healthy. -When sperm head penetrates outer membrane of the egg, a chemical reaction seals the membrane, preventing other sperm from interring. Tail falls of, contents of head enter, and nuclei of the 2 cells merge. Fertilized egg - ZYGOTE. -Later, umbilical cord runs from fetus to placenta, burrowed in the uterus wall. Fetus floats in amniotic fluid inside the amniotic sac. -4 major developmental processes underlie transformation of zygote to embryo to fetus 1) MITOSIS - division to 2 cells. -Through continued cell division, zygote multiplies. 2) CELL MIGRATION - movement of newly formed cells. -ex. Neurons move from inside embryonic brain to outer development brain. 3) CELL DIFFERENTIATION - Initially, all of the EMBRYONIC STEM CELLS can give rise to any of the cell types in the body. -After several cell divisions, cells start to specialize. -Cell location and gene expression helps determine what type of cell a stem cell becomes. 4) CELL SUICIDE/APOPTOSIS: ex. readily apparent in hand development - formation of fingers depends on death of cells between ridges in hand plate. Death is preprogrammed for the cells that disappear from the hand plate. -Follows specific timeline programmed into the cells. (Video Notes): -After 1 week, cluster of egg cells attaches to uterine wall, and intersection forms the embryonic cells and amnion. -Primary yolk sac forms outer section. Provides nutrients to embryo in 2nd and 3rd weeks. -In 3-8 week period, embryo forms organs (ex. brain) -Fetal stage: Week 9 - birth. Beginning - develops strong heartbeat. By the end - organs reach maturity. -Hormones have major influence through prenatal development. Play crucial role in sexual differentiation. -Regardless of genes, all human fetuses can carry male or female genetalia. -Presence of ANDROGENS (class of hormones including testosterone) leads to male genetalia -Source of androgens IS the male fetus, at week 8 -One case of the "active child" -Other important hormones - steroids like GLUCOCORTICOIDS - limit fetal growth and helps fetal tissues mature. -Toward end of gestation, fetus increases production of these hormones to facilitate maturation of key organs. EARLY DEVELOPMENT: -By the 4th day after conception, cells arrange themselves into a hollow sphere with a buldge of cells, called the INNER CELL MASS, on one side. -This is the stage where IDENTICAL (MONOZYGOTIC) TWINS most often originate. They split in half of the inner cell mass. Have same genetic makeup. -FRATERNAL (DIZYGOTIC) TWINS - 2 eggs released from ovary into fallopian tube and are both fertilized. -2 diff eggs and 2 diff sperm. Genetically equal to regular siblings. -If all goes well (less than half the time), zygote embeds itself in uterine lining and becomes dependent on mother for sustenance. -Ball of cells starts to differentiate. -Inner cell mass becomes EMBRYO, and the rest of the cells become ELABORATE SUPPORT SYSEM (INCLUDING AMNIOITIC SAC AND PLACENTA) that enable embryo to develop. -Inner cell mass grows from 1 to 3 layers. -Top layer - nervous system, nails, teeth, inner ear, eye lens, outer skin. -Middle layer - becomes muscles, bones, circulatory system, inner skin, internal organs. -Bottom layer - digestive system, urinary tract, lungs, glands. -After embryo develops 3 layers, U shaped groove forms down the center of the top layer. Folds at top of groove fuse, creating NEURAL TUBE - top becomes the brain and the rest becomes the spinal cord. -AMNIOTIC SAC - membrane with clear, watery fluid where fetus floats. Fluid acts as buffer, keeping temperature and cushions fetus. -PLACENTA - rich network of blood vessels, weighing one pound, extending into tissues of mother's uterus. -90% of cells in placenta come from the fetus. -Not just afterbirth. Critical role. -Semipermeable - permits exchange of materials in bloodstream from fetus to mothers, but prevents blood from mixing. -Oxygen, nutrients, minerals, and antibiotics transported to placenta by mom's blood. They cross placenta and enter the fetal bloodstream. -Waste products from fetus cross placenta in opposite direction, removed by mom's normal excretory processes. -Placental membrane also defends fetus from dangerous toxins. -Still, harmful elements can cross it. -Amniotic sac connected to placenta via UMBELICAL CORD - tube with blood vessels running to the fetus. -Earlier development takes place at faster pace than later development, and areas near head develop earlier than those far away - CEPHALOCAUDAL DEVELOPMENT. -During last 3 weeks of prenatal development, fetus triples its weight. -Also, develops behaviors and learns from experiences. FETAL EXPERIENCE AND BEHAVIOR: -depsite their very different environments (discontinuity), fetuses and children show surprising similarities (continuity). MOVEMENT: -5 or 6 weeks and on - fetus moves spontaneously. -7 weeks - hiccups - possible burping reflex. -Swallowing - they swallow amniotic fluid, which is excreted back out into amniotic sac. Helps digestive system. -At 10 weeks, promotes respiratory readiness by "fetal breathing" - move chest - no air taken in - amniotic fluid pulled into lungs and expelled. Initially infrequent and irregular but increases in rate and stability. TOUCH: -Hand-mouth contact -Choice of thumb to suck predicts right handedness. -As it grows larger, bumps against the wall of the uterus. -By full term, fetal heart rate responds to maternal movements, suggesting their vestibular systems (sensory aparatus in inner ear providing info about movement and balance) functions before birth. SIGHT: -Not totally dark in the womb, but visual experience is minimal. -By third trimester, have visual preferences. -When Ultrasound lights shined in, they prefered top-heavy displays (resembling correctly oriented faces) over bottom-heavy displays (inverted faces). TASTE: -Fetus has a sweet tooth. -In a study, they ingested more amniotic fluid when it was sweetened. SMELL: -Amniotic fluid takes odors of what mom ate. -Amniotic fluid comes into contact with fetus's odor receptors through fetal breathing, giving fetus olfactory experience. -Prenatal scent learning plays impactful role in many species' early developmental processes, demonstrating PHYLOGENETIC CONTINUITY - humans share many characteristics and developmental processes with other animals due to shared evolutionary history. -GESTATION - between conception and birth - being carried in the womb. -NURTURE BEGINS PRENATALLY!!! HEARING: -prenatal environment - noisy - mom's heartbeat, blood flow, breathing, digestive sounds. -Mom's voice particularly prominent. -Fetus heart rate changes when mom speaks. -During last trimester, external noises (ex. music) elicit movement and heart rate. -In a study, preterm infants exposed to womb sounds had larger auditory cortexes than control groups, suggesting that maternal sounds may facilitate brain development before full gestation. -Sound plays a major role in prenatal learning. FETAL LEARNING. -Fetus learns in last 3 months of pregnancy, after the central nervous system is adequately developed to support learning. -Evidence of this: -Infants can remember souunds they heard in the womb. -HABITUATION: happens to fetuses: a decrease in response to repeated/continued stimulation. Becoming bored. -DISHABITUATION: when a perceptible change in the stiumulus occurs, it becomes interesting again. -Fetus learns and remembers sound of mom's voice. -After birth, they prefer to hear noises they are used to from the womb. -Newborns remember the scent of amniotic fluid and prefer foods mom ate while pregnant. -Still, "Prenatal education programs" probably a waste, because fetus learns about general sounds, not any specific content. -Most common error - SPONTANEOUS ABORTION/MISCARRIAGE - most occur before woman knows she's pregnant. -Majority of miscarried embryos have defects (ex. missing/extra chromosomes) -Factors influencing miscarriage are present across many cultures. -Across childbearing years, at least 20% of women experience at least one miscarriage. -TERATOGEN - an external agent that can cause damage or death during prenatal development. -Effects are heavily influenced by timing. -SENSITIVE PERIOD - when organism is most sensitive to external factors. -different for each organ system (systems form at different times) -Most sensitive period overall is embryonic period -Week 3 - week 9 - every major organ system undergoes development -First 2 weeks - zygote not susceptible -ex. Taking thalidomine drug in 1960s in week 4-9 (limb development) - babies born with no arms. Sensitive periods for many organ systems occur before woman might realize she is pregnant. -Most teratogens show a DOSE-RESPONSE RELATION - greater the fetus's exposure to potential teratogen, the more lkely the fetus will suffer severe damage. -Teratogens frequently occur in combination. Cumulative effects. ex. hard to separate out the many aspects of living in poverty. -Negative effects of prenatal experience may not be immediately evident. FETAL PROGRAMMING - BELATED emergence of effects of prenatal experience, affecting physiology in adulthood. -ex. Effect of inadequate prenatal nutrition on adult obesity. -ex. Dutch Hunger Winter - fetuses metabolisms were set prenatally and were not reset when nutrition reached normal levels. -Effects of teratogens can also vary according to individual differences in genetic susceptibility (in mom and fetus). -SLEEPER EFFECTS -impact of an agent may not be apparent for many years. DRUGS: -Almost all drugs of abuse are dangerous for prenatal development. -7% of pregnant women take anitdepressants. Evidence about whether these medications are harmful to fetus is inconclusive. -One solution - non pharmaceutical depression treatments. -Opoids (ex. heroin) mimmick neurotransmitters and can weack havock of the developing brain. -Fetuses can become addicted -NEONATAL ABSTINENCE SYNDROM (NAS) - form of drug withdrawl seen when fetuses exposed to opioids in the womb are born. -Low birth weight, breathing and feeding problems, seizures. -Co-presence of other maternal drug use increases NAS chance -Treatment for NAS newborns - often requires methadone and morphine. MARIJUANA: -commonly used by young people and becoming more legal. -Data on effects are inconclusive, because effects are difficult to tease a[art from effects of cigarrettes and alcohol. -Associated with problems of attention, impulsivity, learning, memory. -But, worst effects are from cigarrettes and alcohol CIGARRETTES: -Mom and fetus lose oxygen -Slowed growth, low birth weight, sudden infant death syndrome (SIDS), low IQ, hearing deficits, ADHD, cancer. -There is a dose-response relationship. -Effects of smoking are greatest in early gestation. -Some infants with SIDS had altered levels of serotonin, making it difficult to respond to a lack of oxygen. -Parents should remove any barriers to breathing (ex. put baby to sleep on its back). ALCOHOL: -Leading (and most preventable) cause of fetal brain injury. -Rates are highest in Europe, and lowest in middle east. -Alcohol in blood crosses placenta into both the fetus's bloodstream (direct) and the amniotic fluid (indirect: Fetus gets it by drinking amniotic fluid) -Fetus less able to metabolize alcohol, so it stays in his system longer. -FETAL ALCOHOL SPECTRUM DISORDER (FASD) - comprises continuum of birth defects - facial deformities, intellectual disabilities, attention problems, hyperactivity, and more. -Fetal Alcohol Effects (FAE) - term used for individuals who show some (not all) of the effects. -About 1-5% of kids in US (larger than we thought). -Low birth weight, ADHD, delays in cognitive development and school achievement. ENVIRONMENTAL POLLUTANTS: -ex. burning of coal, water pollution, pesticide use -These things can disproportionatly affect people in poorer areas. -Lead exposure linked to ADHD. MATERNAL FACTORS: -Mom provides fetus's most immediate environment. AGE: -infants born to girls 15 years or younger 13-14 times more likely to die than infants born to 23-29 year old moms. -The rate of teen pregnancy in US is declining. -But, there is a dose response relationship with risk of negative outcomes for mom and fetus increasing with maternal age. (Many educated women wait until 40s. Can be dangerous. Higher risk for Autism (ASD)). -Causal pathways differ for mom and dad, regarding having babies at old age and developmental disorders. Only mom contributes to prenatal environment and birth circumstances. Dad contributions lie more in mutations and chromosomal abnormalities. NUTRITION: -prenatal vitamins are frequently used, but many women don't know they are pregnant during crucial early periods of gestation. -Malnutrition common in impoverished families, so often coincides with host of other risk factors associated with poverty (difficult to isolate effects) -But, there have been studies that lookeed at people of all income and education levels experiencing hunger (ex. Netherlands WWII) DISEASE: -ex. Moms with rubella (3 day measles) can harm kid -STIs are also hazardous to fetus -Cytomeglovirus (CMV) - a type of herpes - present in 50-70% of women of reproductive age in US - damage fetus nervous system and hearing. -HIV sometimes passed to fetus in womb or during birth. -Zika - hearing and vision and intellectual loss and seizures -Microcephaly - condition (small head) resulting in 6% of fetuses from mom with Zika -Higher rates of microphely for fetuses of women with Zika during FIRST TRIMETER -Zika transmitted sexually, body fluid, and mosquito -Virus affects fetus cortical-neural progenitor cells - stunted brain growth. MATERNAL EMOTIONAL STATE -harmful alterations in the HYPOTHALMIC-PITUITARY-ADRENAL (HPA) AXIS and HORMONE CORTISOL, a glucocorticoid which helps regulate stress in mom and fetus. -Glucorticoids slow fetus growth. -FETAL PROGRAMMING suggests that altered hormonal environment for fetus leads to long term changes in how adults cope with stress via disrupted HPA axis functioning. -In wealthy countries, minority pregnant women report higher stress. Pregnant women in less wealthy countries even higher. -One study used in vitro fertilization, suggesting that PRENATAL environment, not shared genetics, was strongest predictor of later outcomes. (For weight and antisocia behavior). For child anxiety, POSTNATAL maternal stress was strongest predictor. 2.3) The Birth Experience. -Contractions of muscles of uterus begin, initiating birth. -Maturing fetus lungs may release a protein triggering the onset of labor. Fetus contributes to process by rotating in head-down position. -Birth is painful for mother (tissue stretching) but not baby (squeezing). -Squeezing temporarily reduces overall size of fetus head, allowing it to pass through pelvic bones. -Also stimulates production of hormones that help fetus withstand mild oxygen deprivation during birth and regulate breathing after birth. -Forces amniotic fluid out of lungs. -Pressure causes plates of skull to temporarily overlap. Corrects itself after birth. Soft spot - temporary spot between plates. -Childbirth practices vary enormously with cultures. -US women in labor had 32% chance of delivering by cesarean (C Section). Rate relatively high compared to other countries, but declining. -Of all women who had a C section (in a study), nearly half did not appear to have any pregnancy complications. (Other reasons - doctor convinience, etc). -Other cultures want to immediately integrate newborn into family - home births. -While home births are increasing in US, hospital births remain safer. -Practices are changing. -In US, social dimensions of birth icnreasingly recognized by hospitals, who now employ MIDWIVES and DOULAS to comfort mom. Shift accompanied by decreased use of delivery drugs. More skin-skin contact for mom and baby, and more engaging in the process. -Parents taking more birth classes through organizations like Lameze. -Western practices increasingly common in other societies, to improve survival. STATE OF AROUSAL: STATE: continuum of arousal, ranging from deep sleep to intense activity. -There are 6 states. Substantial individual and cultural differences in how much time babies spend in diff states. In western culture: 2.5 hours alert awake. 2.5 hours active awake. 2 hours crying. 8 hours quiet sleep. 8 hours active sleep. 1 hour drowsing. SLEEP: -Average newborn sleeps twice as much as young adults. -Pattern of 2 diff sleep states (REM and non-REM) changes dramatically with age. -RAPID EYE MOVEMENT (REM) SLEEP - active sleep state associated with dreaming in adults. Characterized by quick, jerky movements under closed lids - distinctive brain activity, movement, irregular heartbeat, and breathing. -Non-REM Sleep - quiet sleep, absense of motor activity or eye movement. Regular, slow brain waves, breathing, heart rate. -REM - 50% of newborn's total sleep time. Declines to 20% by 3 or 4 years and remains low. -REM might help infant visual system. -REM also allows natural jerking movements (myoclonic twitching) that occur exclusively in REM. Helps build sensorimotor maps. -Helps linking motor patterns with the sensations they evoke. -Neonates' slumbring brains do not become disconnected from external stimulation to the same extent that the brains of older people's do. Can learn during sleep. -Newborns likely to be awake during part of parents' sleep time, but gradually learn to sleep through the night. -Studies have shown improvement in sleep behavior with no negative effecs on infant stress (cortisol) or infant-mother attachment when parents slowly increased delays in responding to crying infant. -Bedtime fading (bedtime shifted later to ensure sleepiness, and then gradually moving earlier) helps too -Babies in Kenya distribute sleep through day and night. Constantly with mom. Parents unconcerned with sleeping patterns CRYING: -cry for many reasons -crying increases, peaking at 6-8 weeks -Decreases at 3-4 months. Here, crying bouts increase in late afternoon and evening. -Parents need to understand it is normal. -SHAKEN BABY SYNDROME - caregivers react with abuse that can result in head trauma and death SOOTHING: -moderately intense and continuous/repetitive stimulation -SWADDLING - wrap baby tight, tactile stimulaton and warmth. Used in many cultures. -Research has supported both ideas - quick responding to infant distress is good and bad. -Cultural - mothers in Fiji respond quicker than in US. COLIC - excessive, inconsolible crying by a yung infant for no apparent reason. -Not rare. -Ends by 3 months. No long term effects. -Parents should seek social support NEGATIVE OUTCOMES AT BITH: APGAR SCORE - evaluation method for evaluating health of newborn immediately following birth, based on skin tone, pulse rate, facial responses (grimmacing), arm and leg activity, and breathing -Perfect score is rare INFANT MORTALITY: -Death during 1st year after birth - now rare in industrialized world -US is at all time low, but way higher than Canada, Japan, Australia -Its RELATIVE RANKING has gotten worse. Might be due to poverty (lack of health insurance) Avg newborn weights 7 and a half pounds Below 5.5 pounds - considered LOW BIRTH WEIGHT (LBW) -MANY LBW ARE PREMATURE/PRETERM - born at 35 weeks or earlier (1/10 babies in US). -Others are SMALL FOR GESTATIONAL AGE - may be full or pre term, but weigh less than what is normal for their gestational age (weeks since conception) -Very LBW babies (VLBW) very vulnerable -Numerous causes of LBW and prematurity -Teratogens -Pollution -Skyrocketing of twin, triplet, and other multiple births as result of treatment for inferility (fertility drugs and in vitro fertilization promote several eggs). -LBW - negative behavioral, academic, social outcomes - possibly due to white matter reduction, ventricular enlargement, and other abnormal brain outcomes. -A strong predictor of outcomes for VLBW infants is maternal education and SES. -FOr majority of LBW children, negative effects gradually diminish. INTERVENTION PROGRAMS: -Until recently, hospitals minimalized parents' contact with LBW infants. -Now, they encourage it -KANGAROO CARE - variation of skin-skin care - caregivers act as incubators for temperature and breastfeeding. -Breastfeeding promotes healthy brain development. -LBW infants spend time in neonatal intensive care unit (NICU). Important for them to experience gentle touch there. -LBW infants - developmental milestones are delayed, linked to gestational age at birth more so than chronological age after birth. -Children born preterm are more likely to become victims of child abuse. -Cumulative risk - more risks infant endures = lower chance of good outcome. Risk factors tend to occur together (ex. mom who drinks also smokes) Cumulative effects often happen in poverty -African American babies born in areas with systemic racism more likely to be LBW than in other areas. -Still, many births go well. -DEVELOPMENTAL RESILIENCE - successful development in spite of multiple developmental hazards. -Resilient children usually have personal characteristics and responsive care from someone to help them. REVIEW: -Placenta - protects developing embryo from dangerous toxins. -Disproportionately large head of fetus - result of CEPHALOCAUDAL DEVELOPMENT. -Sight - least active while fetus is in the womb.

Which population has an INCREASING rate of obesity?

Children in Africa

Which population has an increasing rate of obesity?

Children in Africa (kids in countries who are starting to adopt western habits)

Which finding might be the MOST likely to suffer from a direction-of-causation problem?

Children's social skills influence the number of friends they have.

First basic step in using scientific method:

Choosing a question

What is meta-analysis?

A method for combining an analyzing the results from several independent studies.

What percentage of American teens were considered obese in 2017?

15%

3.3) Brain Development

3.3) Brain Development -Basic units of brain information system - NEURONS - cells specialized for sending and receiving messages between brain and all parts of the body, as well as the brain itself. Constitutes gray matter of the brain. -Each neuron - 3 components: -CELL BODY, which contains basic biological material -DENDRITES - receive - fibers that receive input from other cells and conduct it toward the cell body in the form of electrical impulses. -AXON - send - a long shaft fiber that conducts electrical signals away from cell body to connect with other neurons. Many are covered with myelin sheath, which enhances speed and efficiency that signals travel along the axon. Branches on the end have terminals that release neurotransmitters into synapses (small spaces between the terminal of one neuron and the dendrites or cell body of another). An axon can have synapses with thousands of other neurons. -Neurons communicate at SYNAPSES - microscopic junctions between axon terminal of one neuron and dendritic branches of another. GLIAL CELL - equal in numbers to neurons - cells in brain that provide a variety of critical support functions. -They form a MYELIN SHEATH around axons (increases speed and efficiency of information transmission). -Function as neural stem and progenitor cells during prenatal, and some continue to do so in adulthood. -When brain is injured, some rapidly increase in number, protecting the brain. CEREBRAL CORTEX - constitutes 80% of human brain (greater proportion than in other species). -Most enlarged parts compared to other species are the parts that grow as children develop. -Includes 4 lobes. OCCIPITAL LOBE - processing visual info TEMPORAL LOBE - speech and language, processing emotion and auditory info PARIETAL LOBE - spatial processing and integration of information from different sensory modalities FRONTAL LOBE - "executive" cognitive control -Information from multiple sensory systems is processed and integrated in ASSOCIATION AREAS between major sensory and motor areas. -Complex mental functions have great interactivity across regions. -Cortex is divided into 2 CEREBRAL HEMISPHERES. -For the most part, sensory input from one side of the body goes to the opposite side of the brain, and motor areas of cortex control movements of opposite side of the body. Hemispheres communicate with each other through CORPUS COLLOSUM - dense tract of connective nerve fibers between the 2 hemispheres. CEREBRAL LATERALIZATION - specialization of hemispheres for different modes of processing. -Emerges early (ex. babies use right to process faces, left to process speech) -Individuals are not "right brained" or "left brained" NEUROGENESIS - proliferation of neurons through cell division. Begins 42 days after conception, ends midway through gestation. -But, humans do continue to generate new neurons through life. -Adult neurogenesis is affected by environment factors - it increases under rewarding conditions and decreases in threatening environment. During the first months and years of postnatal life: After birth, neurons move to ultimate destination: usually outward to developing neurocortex. As brain grows, neurons require guides. This is one of the functions of glial cells. When neurons reach destination, they first grow an axon - then, a "bush" of dendrites Axons elongate as they grow toward their targets Main change in dendrites - ABORIZATION - increases size and complexity of dendritic tree. Growth, branching, formation of SPINES on branches. This increases the dendrites' capacity to connect with other neurons. -Meanwhile, layers of cortex become thicker. MYELINATION - forming of myelin sheath around some axons (increases information processing) - prenatal - early adulthood. -Myelinated portions are white (white matter), and lie below gray matter (cell bodies) at cortex surface. -Begins deep in brain and moves up and outward into cortex. -Occurs rapidly first few months, slows in toddlerhood -Different areas myelinated at different rates (mature at different rates). -Sensory areas in back mature sooner than executive function areas in the front. (More mature when gray matter is replaced with white matter). SYNAPTOGENESIS - process by which neurons form synapses with other neurons, resulting in trillions of connections. -Occurs quicker in sensorimotor cortex than in frontal area. -Begins before birth and continues rapidly several years after. SYNAPSE ELIMINATION -SYNAPTIC PRUNING - occurs at different times in diff areas of brain - normal developmental process when synapses that are rarely activated are eliminated -Outer layers of cortex shrink at fastest rate during adolescence -Last area of cortex to mature - DORSOLATERAL PREFRONTAL CORTEX - viral for regulating attention, controlling impulses, foreseeing consequences, setting priorities, and other executive functions. Doesn't reach adult dimensions until after 20 years. Synaptic pruning until 30s. -ATYPICAL patterns of pruning for Autism (ASD) and Schizophrenia. -Young kids with ASD - larger brains. Greater synaptic densities and cortical thickness - reduced synaptic pruning -Schizophrenia - excessive pruning in adolescence (may be why symptoms show in adolescence) Because of brain's capacity to be molded/changed by experience (PLASTICITY), less information needs to be encoded in the genes. Number of genes involved in nervous system enough only to specify a small fraction of normal complement of neurons and neural connections. If brain was all hard wired, we couldn't adapt to environment. Plastic brain can recover from some injury because other areas take over. Children's brains more plastic - more likely to recover from brain damage. Nature-Nurture in building brain - 2 kinds: 1) Experience-Expectant Plasticity - general experiences infants have just by virtue of being human. 2) Experience-Dependent Plasticity - specific idiosyncratic experiences that children have as result of their life circumstances. EXPERIENCE-EXPECTANT PLASTICITY - species typical. -ex. Through evolution, human infants experienced visuals, voices, movement, etc. So, brain can EXPECT that input from these reliable experiences. -Benefit - fewer genes need to be dedicated to normal development. -Downside - heightened vulnerability 0 if experience the brain expects does not occur, development may be compromised. -ex. In kids with cataracts (vision is obscured), deprived of visual input, visual cortices reorganize to help process auditory info instead -Can work in other direction too - kids born deaf experience visual takeover of brain areas of the auditory system. SENSITIVE PERIODS: -Neural organization that occurs (or does not occur) during sensitive periods - typically irreversible -Often these periods are early in life (ex. Romanian Orphanage) -Adolescence - time of rapid brain change - sensitive period for cognitive and social processes EXPERIENCE-DEPENDENT: -research has focused on nonhuman animals - their environments can be readily manipulated -ex. rats, cats, and monkeys that grow up in rich environment (close to their natural environment) have more synapses, thicker cortex, perform better in learning tasks. -Adults who play wind instruments - thicker lip related cortical areas CEREBRAL CORTEX: brain's outer layer

3.4) Body - Physical growth and development

3.4) Body - Physical growth and development -Changes in body lead to changes in brain and behavior -Proportion of body fat is highest in infancy, gradually declining until 6-8 years -Body growth - most rapid in first 2 years and early adolescence. Uneven across time and body. GENES affect growth and sexual maturation by influencing production of hormones, especially growth hormone (secreted by pituitary gland) and thyroxine (by thyroid gland) -Influence of env factors evident in SECULAR TRENDS - marked changes in physical development that have occurred over generations. -ex. We're taller than we used to be, due to good nutrition since 1700s. -ex. Now, low SES girls likely to menstruate early. (obesity and stress both predictors). -Breastfeeding good for mom and baby -Fatty acids have positive effect on cognitive development, possibly because they increase myelination. -These findings are minor, and may be influenced by SES. VIDEO LECTURE: -Young child brain activity level high, and brain metabolizes nutrients at high rate, until 10. Age 10-20, declines. -High brain metabolism reflects remodeling of synaptic connections, and myelination. -After 2nd birthday, brain grows more slowly, due to closing of the gaps (sutures) between skull parts. -Children often clumsy, wobbly, and slow because corpus callous hasn't developed yet. -In US, # of newborns breast fed has increased. High compared to other wealthy countries, low compared to poorer countries. -Most young children have food neophobia - unwillingness to eat unfamiliar foods. -Best way to overcome this is repeatedly introducing new foods to taste. -Parental bribing and use of food to control kids' behaviors is a predictor of large body mass (BMI) -Infants understand that food choices reflect social conventions - expect people from their social group to share food preferences. -ASSOCIATIVE LEARNING also influences food choices. -ex. Fast food restaurants with toys. Rates of obesity have declined ages 2-5, but are increasing for adolescents. Majority of these kids live in developing countries that have adopted unhealthy western habits. GENETICS -Weight of adopted kids more linked to that of their biological parents than to their adopted parents -Identical twins more similar in weight than DZ twins -GWAS shows obesity is polygenetic -young children with difficult temperaments gain weight faster: impulsive -Obese kids more likely to be withdrawn and depressed

Birth usually occurs approximately ______ weeks after conception.

38

Undernutrition/malnutrition contributes to nearly ______ of deaths among children under 5 years of age worldwide.

50%

The assumption that differences in monozygotic twins are caused entirely by genetic factors is called the _____________

Equal Environments Assumption

The fact that rats in cages with toys have more dendritic spines and more synapses per neuron than rats raised in cages without toys is an example of:

Experience-Dependent Plasticity

In order to generalize her findings, one needs...

External Validity

Chapter 3: Nature and Nurture:

GENOME: each person's complete set of DNA, including all of its genes. Gene synthesis - method for producing DNA. Humans have about 20,000 genes - fewer than previous estimates. Most of these genes are possessed by all living things. Genes make up about 1% of human genome. Much of the rest is non-coding/"junk" DNA - important regulators for protein coding. -GENOTYPE - inherited genetic material. -PHENOTYPE - observable expression of genotype (body and behavior). -ENVIRONMENT - every aspect of individual and surroundings (including personal experience) other than the genes themselves. 5 important relations: 1) PARENT'S GENOTYPE -> CHILD'S GENOTYPE. -One gamete from mom and one from dad create a zygote. -Nucleus contains CHROMOSOMES (which transmit genetic info) - long molecules, each made up of 2 strands of DNA. -Biochemical info of DNA is packaged in GENES - basic unit of heredity in all living things. -Each gene is a segment of DNA that codes proteins. -Genes affect development and behavior only through manufacturing of proteins. -Humans have 46 chromosomes divided into 23 pairs in nucleus of each cell. -Each chromosome pair carries (usually at corresponding locations) genes of the same type. -Each parent passes one chromosome to their offspring. -So, each individual has 2 copies of each gene (one from mom, one from dad). -One mechanism that promotes variability among individuals is the random assortment of chromosomes in the formation of eggs and sperm. -In gamete division, 23 pairs shuffle randomy. Chance determines which member of each pair goes into new egg or sperm. -Other than identical twins, odds of 2 people having same genotype close to 0. -Also, from MUTATIONS - change in a section of DNA -some are random, some caused by environment -those occuring in gametes (germ cells) can pass down to offspring. -most mutations are harmful. -but sometimes a mutation enhances an individual's genetic fitness (provide basis for evolution). SEX CHROMOSOMES - determines sex at birth. -Females - XX zygote, XX chromosome -Males - XY (Y chromosome is small) zygote, XY chromosome -Female - division of her germ cells results in all her eggs having an X. -Males - half of sperm have X, half have Y. So, sperm determines sex of child. -Gene on Y Chromosome codes protein that triggers prenatal formation of testes by activating genes on other chromosomes, triggering production of testosterone. 2) CHILD'S GENOTYPE -> CHILD'S PHENOTYPE -Phenotype - Physical AND behavioral characteristics -Genes also influence unobservable, intermediate phenotypes. -ENDOPHENOTYPES - (ex. brain and nervous system) - endophenotypes do not involve overt behavior, but mediate the pathway between genes and behavior. -Every cell contains copies of all the genes you have. Only some are expressed. -Some genes are turned on only in a few cells for a few hours and then switch off permanently - pattern typical during embryonic development. -Other genes are involved in basic functioning in most cells most of the time. -REGULATOR GENES - control activity (on/off) of other genes. Chain of events. Genes never function in isolation. -On-again, off-again functioning of individual genes results in enormous diversity in genetic expression. -External factors also affect switching on and off genes. -1/3 of human genes have 2 or more forms - alleles - alleles influence different outcomes of a characteristic (ex. eye color). -DOMINANT allele - if present, gets expressed -RECESSIVE allele - not expressed if dominant allele is present -HOMOZYGOUS - 2 of same allele -Heterozygous - one dominant, one recessive -When individual is homozygous, corresponding trait is expressed. Heterozygous: dominant allele expressed. -X chromosome - about 1500 genes. -Y Chromosome - 200 genes. -When a female inherits a recessive allele on the X chromosome from mom, she is likely to have a dominant allele from dad to suppress it, so she will not express that recessive trait. -When male inherits the same recessive allele on X chromosome from mom, he likely won't have dominant allele from dad to suppress it, so he will express the trait. -So, males more likely to have sex-linked disorders caused by recessive alleles on X Chromosome. -Dominant-recessive pattern pertains to few human traits - hair color, blood type, body hair, and many genetic disorders -Inheritance patterns are usually more complex -Ex. Intelligence linked to 500 genes. -POLYGENETIC INHERITANCE - many genes contribute to phenotypic outcome. 3) CHILD'S ENVIRONMENT -> CHILD'S PHENOTYPE -Remember, environemnt - everything but genes (including prenatal experiences) -PHENYLKETONURIA (PKU) - ex. of phenotype produced by a genotype-environment interaction - disorder related to a defective recessive gene on chromsome 12 that prevents metabolism of amino acid phenylanine. If infants with PKU gene are identified and kept on right diet, intellectual impairment can be avoided. So, genetic testing is important. -Another example: MAOA gene combined with severe maltreatment (environment) produces antisocial phenotype. -Parents' genes affect the choices they make to shape the envrionment of the child. -In a study, the non-transmitted parental alleles played an important role in creation of the child's environment. GENETIC NURTURE. 4) CHILD'S PHENOTYPE -> CHILD'S ENVIRONMENT -Restates "active child" theme - children the source of their own development -Children's personalities shape their environments. 5) CHILD'S ENVIRONMENT -> CHILD'S GENOTYPE - EPIGENETICS -Structure of genetic code remains fixed during lifetime, but expression is altered. -Encoding of proteins affects how genes are expressed as phenotypes. -Most studied as epigenetic mechanism - METHYLATION - silences gene expression. -Methylation is of interest to developmental psychologists - show how long term epigenetic effects of early adverse experiences affect gene expression -Early stress affects methylation in humans. -Also, through sperm cells of adult males, stress can be transmitted parent-child.

In recent decades, researchers have come to conclusion that, after infancy, developmental changes occur

Gradually

LECTURE

LECTURE -All change is gradual, continuous when you look at it a certain way. -Feuid, Erikson, Kohlberg (sociocultural, moral psychologists) - look at it from a discontinuous perspective. This is how distant family members see it when they visit every once in a while. -Parents, close family - see it as continuous. -Disruptions to earlier developmental processes will usually have more severe impacts. (Infant/Toddler). -ex. Sensitive, need exposure to things for sensory development. -ex. Need to hear language early on. -ex. Infants' eyesight is horrible. Need exposure to colors to develop eyesight. CRITICAL PERIOD - you need to develop something now or you never will. SENSITIVE PERIOD - you need to develop something, but if you don't, you could still develop it later. Stress - activation of HPA (pituitary region), related to amygdala. Impacts the brain structure and function (especially amygdala). Alters expression of genes through methylation (silences/turns off). Affects production of hormones and neurotransmitters responsible for stress response. -When interviewing child in court case, be careful. Avoid leading and repeating questions. Using doll better for older kids and kids who can imagine themselves as the doll.

Which type of design is used to study developmental change as it is occurring by observing participants numerous times over a relatively short span of time?

Microgenetic

Which statement is FALSE concerning cerebral lateralization?

Most humans are left brained or right brained, which affects their personalities and interests.

Nativists

argue that evolution has created capabilities that are present even in infancy (ex. basic properties of physical objects, plants and animals, and people)