PSY 244 Exam 1 review
PSY 244 Exam 1 review PSY 244
Popular in Devel Psych Infancy - Chldhd
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This 90 page Class Notes was uploaded by Jordyn on Friday April 1, 2016. The Class Notes belongs to PSY 244 at Michigan State University taught by C. Durbin in Spring 2015. Since its upload, it has received 21 views. For similar materials see Devel Psych Infancy - Chldhd in Psychlogy at Michigan State University.
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Lecture 1 Why learn about child development o Extremely rapid change in all areas of development o High degree of intertwined development Historical foundations Important themes Methods for studying child development Reasons for learning about child development Raising children Choosing social policies Understanding human nature o Fun fact: children cant smile for happiness until 8 weeks Raising children Parenting o How their parents parented them o Parenting books Opinion based or evidence based Education o Well educated kids will benefit older generation Social policy o Should we be giving kids condoms o Should we be vaccinating kids Martin preschool case… Manhattan beach o 60 kids victims—child porn o First mom who reported it was called psychotic o Interviewers of children asked questions in a way that made children believe things that may have not happened Dolls and reenact—is this “play” or did this actually happen Your friend said you played the naked game are you calling your friend a liar o Trial lasted 3 years—found him not guilty Many children in the U.S. are victims of sexual abuse (estimated 61,740 reported cases in 2012) o More than 40% of cases are un reported—most children are younger than 5 False accusations are rarer than corroborated cases Sexual abuse is associated with significant psychological and physical harm for many children False memories of sexual abuse can also be harmful Kids can be told a story that they can believe actually happened—lost in a mall Understanding human nature Each child is a tiny laboratory of cause and effect Developmental research provides important insights into some of the most intriguing questions regarding human nature Child from an inadequate orphanage in Romania—weren’t looked at even when receiving food when they were able to receive it o By age 6 the physical development of the Romanian born children had improved in absolute terms and compared to British comparison group o Longer they were deprived the more obvious their effects were Physical development: lower weight Intellectual development: lower levels of intellectual development Social development: atypical development accompanied by abnormal brain activity, lower levels of neural activity in amygdala Social reform movements Legal issues concerning childhood o Industrial revolution left the earliest research on child development (child labor laws 18 and 19 century in US and Europe) Child laborers had very little social or legal protection Impetus for research on environmental contributors to child development Public education as an important impetus for research THEME 1: Nature and nurture: how do nature and nurture together shape development NATURE= Environment Nurture/genome= individuals complete set of heredity information o All human characteristics are created through interaction of genes and environment o How does this interaction shape development? Child as agent (agency) Three of the most important contributors during children’s first years are their: o Attention patterns Babies can turn their heads and pick what they think is more interesting o Use of language Once kids can talk about language they can interact more o Play Older children and adolescences choose many environments, friends, and activities for themselves o After kids go out of their house its easier for kids to get out of their parents control THEME 3: continuity/discontinuity: in what was is development continuous, and in what ways is it discontinuous? Continuous development—gradual process o Pine tree—looks the same but looks bigger and bigger o Changes with age occur gradually, in small increments o Development occurs skill by skill and task by task Discontinuous development—sudden dramatic changes o Caterpillar, goes into cocoon and then becomes butterfly o Changes with age include occasional large shifts o Qualitative differences occur o Piaget, Freud, Erikson, and Kohlberg were stage theorists Piaget’s conservation-of-liquid quantity problem Two glasses of same size at same level—same amount of milk Two glasses one skinner—taller glass has more milk THEME 4: mechanisms of development: how does change occur? Describing development is one thing… Discovering how it occurs and why is another Scientific study of development=discovering cause and effect Effortful attention involves voluntary control of ones emotions and thoughts, it includes processes such as inhibiting impulses, controlling emotions and focusing attention Childhood development of connections between anterior cingulate and limbic system are mechanisms that underlie improvement of effortful attention Interaction of genes and environment determines both what changes occur and when those changes occur THEME 5: the sociocultural context: how does the sociocultural context influence development? Sociocultural context o Influence’s every aspect of children’s development Bronfenbrenner: bioecological model o Most important component, involve people with whom children interact o Institutions are influential and are important Less tangible sociocultural factors include o Historical era—50 years ago, far fewer children in the united states attended child care centers o Economic structure—there are far more opportunities today for women with young children to work outside the home o Cultural beliefs—receiving child care outside the home does not harm the children o Cultural values—the value that mothers of young children should be able to work outside the home if they wish Understanding sociocultural contextual influences Cross-cultural comparisons o In many countries, including demark country in which this mother and child live, mothers and children sleep together for the first several years of the child’s life Table 1.2 We often underestimate the importance of broader sociocultural contexts (such as SES) in favor of micro environments (the home) Development is associated by ethnicity, race, and socioeconomic status THEME 6: individual differences: how do children become so different from one another? Scarr’s factors related to differences in children o Genetic differences o Differences in treatment by parents and others o Differences in reactions to similar experiences o Different choices of environments Individual differences among children arise quickly in development Different children (even ones in the same family) often react to the same experience in completely different ways THEME 7: research and children’s welfare: how can research promote children’s well being Education o Effortful control Health policy o Screen time Parent child relationships The software emphasizes that learning makes children smarter by building new connections within the brain Methods for studying child development Scientific method o Question, hypothesize, test the hypothesize, draw a conclusion regarding the hypothesis Relevance to hypotheses: do they hypotheses predict in a straight forward way what should happen on these measures Interrarer reliability: the amount of agreement in the observations of different raters who witness the same behavior Test-retest reliability: the degree of similarity of a child’s performance on two or more occasions Internal validity: the degree to which effects observed within experiments can be attributed to the factor the researcher is testing External validity: the degree to which results can be generalized beyond the particulars of research Contexts for gathering data about children Observations o Naturalistic observation Naturally occurring contexts vary on many dimensions, it is often hard to know which ones influenced the behavior of interest Many behaviors occur only occasionally in everyday environments, researcher’s opportunities to study them through naturalistic observation are reduced o Structured observation Does not provide as much information about children’s subjective experiences and does not provide as natural of a situation Correlational designs Variabes o Attributes that vary across individuals and situations, such as age, sex and popularity Correlation o Association between two variables o Range from 1.00 (strongest positive correlation) to -1.00 (strongest negative correlation) Correlational designs o Studies intended to indicate how two variables are related to each other o Goal of correlational designs is to determine whether children who differ in one variable also differ in predictable ways in other variables Direction is positive when high values of one variable are associated with high values of the other and low values of one are associated with low values of the other; direction is negative when high values of one are associated with low vales of the other Correlation does not equal causation Cause-effect inference in correlation is not justified. Why? o Direction of causation problem: the concept that a correlation between two variables does not indicate which, if either, variable causes the other o Third variable problem: the concept that a correlation between two variables may stem from both being influenced by some third variable Correlations influence many variables of great interests—age, sex, race, and social class among them—cannot be studied experimentally Useful in describing relations among variables Experimental designs How would you define experimental designs Essential characteristics o Random assignment o Experimental control o Inference about causes and effects allowed Cross-sectional vs longitudinal designs Cross sectional—showing differences between different people Longitunal—same person over a period of time Chapter 2 Prenatal development Preformationism o Miniature, preformed humans logged inside mothers egg or fathers sperm o 17 century drawing of a tiny figure curled up inside a sperm and the miniature person would enlarge after entering the egg—we must not let our preconceptions dominate our thinking that we see what we want to see Epigenesis o Aristotle (4 c.) o Proposed emergence of new structures and functions during development Conception o Humans originate from union of two gametes (sperm from father; egg from mother) o Gametes are produced through meiosis and contain 23 chromosomes; when united 23 pairs result Almost all eggs are formed prenatally; sperm production continues throughout life o The egg is the largest human cell (only cell visible by naked eye)— sperm are among the smallest Process of reproduction Egg launched from ovary into fallopian tube Triggered by sexual intercourse, egg released and as many as 500 million sperm enter vagina High failure rate due to genetics or other defects; survival of fittest (differential by sex of fetus) Prenatal development: sex differences Males o Sperm carry y chromosome; lighter and faster than egg o 120 to 150 males conceived for every 100 females o Higher c-section birth; higher rate of developmental disorders Females o Ratio at birth is 106 males to 100 females o Higher risk for culturally approved infanticide and pre-implantation sorting/selection Cultural United states influence people to have babies because of tax reduction Marriage squeeze o In china boys are more desirable than women so when men look for partners they have trouble because there’s less women to choose from —marriage rate going down Unmarried men are more violent Encourages prostitution and abduction of women for sale as brides Prenatal development: sex differences o The US male-to-female mortality ratio>1 across the life span o Spike in adolescence and early adulthood—peaking at 3 male deaths for every female death—causes? Periods of prenatal development Conception to 2 weeks—germinal o Begins with conception and lasts until the zygote becomes implanted in the uterine wall. Rapid cell division takes place 3 to 8 week—embryonic (embryo) o Following implantation, major development occurs in all the organs and systems of the body. Developmental takes place through the processes of cell division, cell migration, cell differentiation, and cell death as well as hormonal influences 9 week till birth—fetal (fetus) o Continued development of physical structures and rapid growth of the body. Increasing levels of behavior, sensory experience and learning Developmental processes Four developmental processes o Cell division: zygote embryo fetus o Cell migration: movement from point of origin o Cell differentiation: embryonic stem cells; cell and function specialization o Cell death (apoptosis): selective death of specific cells Hormone influence o Important to cell differentiation Mitosis: cell division that results in two identical daughter cells Phylogenetic continuity Humans share many characteristics and developmental process with other species Animal models can enhance understanding of human development o Fetal alcohol spectrum disorder o Existence of fetal learning Early development: cephalocaudal development principle Day 4: inner cell mass arranged into hallow sphere End of week 1: implantation in uterine lining During week 2: inner cell mass differentiates into three layers After implantation: neural tube created: brain, spinal cord Summary of prenatal development Embryo at 4 weeks o Four folds in front head develops o Primitive heart beating and circulating blood o Arm and leg buds Fetus at 5 ½ to 8 ½ weeks o Differentiation beings in nose, mouth palate o By 8 ½ weeks these are separate structures o Time when clef palate can occur Fetus at 9 weeks o Rapid brain growth o All internal organs present o Sexual differentiation starts Fetus at 11 weeks o Heart achieves basic heart structure o Spine and ribs visible o Major division of brain Fetus at 16 weeks o Growth in lower body accelerates o Movement increases, breathing movements, and some reflexes o External genitalia developed Fetus at 18 weeks o Covering of fine hair and greasy coating to protect skin o Thumb-sucking visible Fetus at 20 weeks o More time spent with head down o Facial expression components present o Weight gain and cramped quarters in amniotic sac Fetus at 28 weeks o Brain and lung development increases survival rate o Eyes can experience REM movement o Neutral activity similar to newborn o Weight tripled Fetal behavior Sight and touch o Minimal visual experience; more tactile experience o Vestibular experience function before birth Taste o Flavors in amniotic fluid, taste sensitivity, and fetal preferences present (DeSnoo research) Smell o Amniotic fluid odorants provide olfactory experiences Hearing o Prenatal environment rich with sounds o External sounds audible to fetus o Response to sounds by sixth month o Transitory heart-rate deceleration occurs with auditory stimulation Behavioral cycles Rest activity cycles o Emerge at 10 weeks and become stable by second half of pregnancy Circadian rhythms o Near the end of pregnancy the fetus’s sleep and wake states are similar to those of the newborn o Newborn circadian rhythms are not mature Fetal learning ~30 weeks gestation, the fetus decreases responses to repeated or continued stimulation—simple form of learning called fetal habituation Preferences (ex: flavors ingested In utero; mothers voice) Fetal learning is rudimentary & cannot be ‘jump started’ Habituation: occurs in response to a repeated stimulus o As the first stimulus is repeated it becomes familiar and the response to it gradually decreases o When a new stimulus occurs, the response recovers o The decreased response to the repeated stimulus indicates the formation of memory for it o The increased response to the new stimulus indicates discrimination Recognize rhymes presented before birth (sound, not meaning) o Sucking—if they suck then they are interested when they stop sucking then they lose interest Prefer smells, tastes, and sound patterns that are familiar NNS= non-nutritive sucking Hazards to prenatal development Miscarriage o ~1/3 conceived fetuses do not survive to birth 2/3 of these occur before pregnancy is clinically detectable o Majority of embryos that miscarry very early have severe defects Environmental influences o Teratogens o Timing is a crucial factor o Sensitive periods Major organ systems most vulnerable during period in which they are developing Type of disorder gives clue to when the ‘insult’ occurred o Victims of “minamata disease” include individuals who were exposed to methylmercury prenatally Sensitive periods of prenatal development The most sensitive or critical period of prenatal development is the embryonic period During the first 2 weeks before implantation in the uterus the zygote is generally not susceptible to environmental factors All the major organs of the brdy undethoes all or a major part of its development between the 3 and 9 week Public policy & scientific interference Null hypothesis (H0)= there is no effect of the agent on birth/child outcome vs H1 = there is an effect Cannot prove the null hypothesis; can only rule out H1 Interpreting findings: ‘no amount can be proven to be safe’ o Because no one has every tested bubblegum Problems with this interpretation Effect sizes: large vs. small Smoking during pregnancy Cigarette smoking during pregnancy is correlated with retarded growth, low birth weight, cognitive & behavioral problems But... o 3 variable/confounding variables (correlational studies not particularly helpful for ruling these out) o Other designs: controlling for 3 vars; sibling control (guasi- experiemntal designs); genetically informative o Results: 1) not casual for child behavior problems, academic outcomes, newborn apgar scores asthma; 2) possibly casual for low birth wt (ES: -84 grams (2.96 oz) if mom smokes > 20 ciagrettes/day) Twin studies, or mom with more than one kid if smoking while pregnant with one but not the other has an effect Smoking can effect because: o May have poor diet when smoking o If you cut back you can get tense and worked up o Less education correlated with smoking Kids whose parents smoke in the house will have effected hearing and if they cant hear they will have hearing/learning language Face up to wake up Parents can reduce the risks of SIDS o SIDS—sudden infant death syndrome o Putting babies to sleep on their backs rather than their stomachs Face up to wake up o Eliminating smoking o Using firm mattresses and no pillows as bedding for infants o Avoiding wrapping infants in lots of blankets or clothing Since the beginning of this campaign SIDS in the US has declined to half of its previous rate Alcohol use during pregnancy Alcohol o Most common human teratogen o Leading cause of fetal brain injury o Most preventable cause Who drinks? o More likely: white women; older than 35 years; employed Maternal alcoholism can lead to fetal alcohol spectrum disorder (FASD), which is associated with mental retardation, facial deformity, and other problems Small eyes horizontally, smooth philtrum (area above mouth), thin upper lip Roughly 1 in 1000 infants born in the United States has FAS Data on effects of alcohol use Low to moderate consumption (typ defined as <2 drinks/day) is not reliably associated with effects on pregnancy or child outcomes Greater consumption (binge drinking) has more reliable effects Illegal drugs Effects appear to be less reliable than those of alcohol Some early concerns (ex: crack babies) appear to have been exaggerated o Born addicted to drugs and went through withdrawal o Babies turned out fine Maternal factors: depend on the outcome of interest Relatively major effects** o Nutrition o Disease status o Age (birth vs childhood outcomes) Relatively minor (if any) effects o Maternal emotional state Most of these studies use maternal reports for both IV & DV Dutch famine (WWII): fetal programing—starvation Outcomes o Diabetes o High blood pressure o Reduced DNA methylation of an insulin growth gene o Schizophrenia o Lower employment They adapted to no food—so when they could eat they would gain weight really fast The birth experience Beginning o Approximately 38 weeks after conception, (40 weeks first 2 were before you even ovulated) contractions of the uterine muscles begin, initiating the birth of the baby o Maturing lungs of the fetus may release a protein that triggers the onset of labor During o Fetus experiences squeezing during birth o Research on the birth process has revealed that many aspects of the birth experience have adaptive value and increase the likelihood of survival for the newborn Diversity of childhood practices Across cultures Within cultures: childbirth practices change over time within a given society The newborn infant: state of arousal o State: level of arousal and engagement in the environment Ranges from deep sleep to intense activity The newborn infant: six states of arousal Quiet sleep 8 hours Active sleep 8 hours Alert awake 2.5 hours Active awake 2.5 hours Crying 2 hours Drowsing 1 hour There are substantial individual and cultural differences in how much time babies spend in the different states The new infant: sleep Newborns sleep twice as much as young adults The pattern of two different sleep states changes dramatically o REM Active sleep state associated with dreaming in adults and is characterized by quick, jerky eye movements under closed lids 50% of newborn total sleep time Decreases to 20% by age 3 or 4 and remains low for rest of life o Non-REM sleep A quiet or deep sleep state characterized by the absence of motor activity or eye movements and by regular slow brain waves, breathing and heart rate The newborn infant: crying Crying o Adaptive value o Early in infancy, crying reflects discomfort or frustration o Crying is gradually a more communicative act Characteristics o Increases after birth and peaks around 6 weeks; decline to about 1 hour daily for first year o Peal time is late after noon and evening Crying and soothing o Strategies Rocking, singing, holding infant to shoulder, providing pacifier, swaddling, soothing touch, placing small drop of sweet substance on tongue o Colic Causes unknown, more than 1 in 10 U.S. infants infected, typically ends around 3 months of age, leaves no ill effects With experience parents become better at interpreting the characteristics of the cry itself Infants cries followed different acoustic patterns that mimicked the pitch patterns in their home language Negative outcomes at birth Infant mortality= death during the first year after birth st o Rates in the U.S. are the 31 highest among selected developed nations o 2x higher in african-american than in European American infants o Biggest correlate: poverty and lack of health insurance Infant mortality in less developed countries o Breakdown in social organization due to war, famine, major, epidemics, extreme poverty o 1/10 infants die before age 1 in Afghanistan, Mali, and Somalia Afghanistan has one of the highest IMRs in the world o United states has a high IMR The newborn infant Low birth weight (LBW)=less than 5.5 pounds o 8% in the US Very low birth weight=less than 3.3 pounds o Higher rates of physical and developmental outcomes Premature=LBW infants born at or before 35 weeks after conception Small for gestation age (SGA) o LBW infants whose birth weight is substantially less than the norm for their gestational age Low birth weight o Medical complications, developmental difficulties ect. o Most suffer no long-tern effects o Extensive parent contact and more touch for infants in neonatal intentive care and widely used interventions Conclusions from infant health and development project (IHDP) o Many interventions reduce relatively modest gains that diminish overtime o Success is tied to initial health status of infant cumulative risk is tied to outcomes Multiple-risk models o Risk factors tend to occur together o A negative outcome is more likely when there are multiple risk factors o Despite multiple risk facts, some individuals do well o Children who grow up in families with multiple risk factors are more likely to develop psychiatric disorders than children from families with only one or two problematic characteristics Quiz # 1, PSY 244 (Fall, 2015) # 1: True/False. More male fetuses miscarry than female fetuses, but more males are born than females. # 2. Select one answer. The term habituation refers to: A) deceleration of fetal heart rate in response to novel smells; B) instability of fetal learning after birth; C) adaptation of the fetus to the cramped space of the uterus; D) decrease in response to repetition of the same stimulus. # 3. Select one answer. Harmful agents (such as toxins) can negatively impact prenatal development. The degree to which exposure to these agents negatively impacts development is determined by all of these except: A) maternal age at the time of exposure; B) the dose (amount of the harmful agent); C) the length of exposure to the agent; D) the timing of the exposure (i.e., the week(s) of pregnancy in which the exposure occurs). # 4. True/False. The term ‘effect size’ refers to the magnitude of an association between two variables. Lecture 3 Nature and nurture Heredity and environment influence individuals characteristics Not either/or, but and Modern genomics: o Similarity with other species o Origins of individual differences are complex Three key elements Genotype: genetic material an individual inherits Phenotype: observable expression of the genotype, including body characteristics and behavior Environment: every aspect of the individual and his or her surroundings, other than genes Parents and childs genotypes Genetic material is passed on as chromosomes—long, threadlike molecules made up of DNA from parent to offspring o DNA (deoxyribonucleic acid) molecules carry all the biochemical instructions involved in the formation and functioning of an organism Genes—sections of chromosomes—are the basic units of heredity for all living things; 2 percent of human genome All biochemical instructions involved in the formation and functioning of an organism are carried Human heredity This micrograph shows the 23 pairs of chromosomes in a healthy human male Chromosomes of each homologous pair are roughly the same size Notable exception is the sex chromosomes: Y< X A woman’s karyotype would contain two X chromosomes Sex determination by sex chromosomes Female: XX Male: XY A gene on the Y protein that triggers testes formation production of testosterone masculinization of other structures, including the brain Individual variation Several mechanisms contribute to genetic diversity o Mutations: changes in sections of DNA caused by random or environmental factors o Random assortment: shuffling of the 23 pairs of chromosomes in the sperm and egg; chance determines which member of the pair goes into the new sperm and egg o Crossing over: sections of DNA switch from one chromosome to another during meiosis How do genes shape psychological processes? Although every cell in your body contains copies of the genes you received from your parents only some of those genes are expressed Genes impact structure and process through protein synthesis and regulation of other genes Developmental changes in genetic effects Regulator genes control the continuous switching on and off of genes that underlie development across the life span A given gene influences development and behavior only when it is turned on External factors can affect the switching on and off of genes One form of genetic expression dominance ~ 1/3 human genes have > 2 different forms, known as alleles Dominant allele—gene that s always expressed if it is present Recessive allele is not expressed if a dominant allele is present Homozygous—having 2 of the same alleles Heterozygous—2 different alleles MOST PSYCHOLOGICAL CHARACTERISTICS ARE NOT GOVERNMENT BY DOMINANCE PATTERNS Polygenic inheritance Traits are governed by more than one gene Applies to most traits and behaviors of interest to behavioral scientists Role of the environment in the phenotype Childs observable characteristics o Result from interaction of environmental factors and child’s genetic makeup Given genotype o Develops differently in different environments because of continuous interaction of genotype and environment PKU: Example of genotype-environment interaction Phenyletonuria (PKU)—caused by a defective gene on chromosome 12—are unable to metabolize phenylanine With early diagnosis and a properly restricted diet, mental retardation resulting from PKU can be avoided Genetic transmission of diseases and disorders >5,000 human conditions are known to have genetic orgins Recessive gene: PKU, sickle-cell anemia, TaySachs disease, cystic fibrosis Single dominant gene: Huntington’s disease, neurofibromatosis Polygenic inheritance: some forms of cancer, heart disease, Type 1 and 2 diabetes, asthma, asthma, psychiatric disorders, behavior disorders Sex linked inheritance: male-pattern baldness, red-greem color blindness, hemophilia, duchenne muscular dystrophy, fragile-X syndrome Chromosomal anomalies: Down syndrome (trisomy 21), Klinefelter syndrome (XXY), Turner syndrome (XO) Child as agent: creating ones environment By virtue of their nature and behavior they evoke certain kinds of responses from others They also actively select surroundings and experiences that support their interests, talents, and personality characteristics Behavior genetics Understanding how variation in behavior and development results from the combination of genetic and environmental factors Underlying premises: o Behavior patterns should run in families o Individuals reared together should be more alike than those reared apart Family study Correlations between the measure of the trait in individuals with different relationships % of genes in common btw family members should correlate with their similarity on the traits ~ heritability Family studies of intelligence IQ scores correlation Identical twins: 0.83 in common Siblings: 0.47 Cousin 0.15 Most common focus of behavior genetics family studies has been intelligence Specialized family-study Identical twins reared apart o Similarities in traits like IQ, reaction to stress, and traditionalism o Twins reared together are more similar than twins reared apart Identical (MZ) twins resemble one another in IQ more than same-sex fraternal (DZ) twins Identical twins are not identical in IQ Behavioral genetics Heritability o Correlations for identical twins vs fraternal twins o Identical > fraternal Adoption studies o Are adopted children more like their biological or their adopted relatives o Environmental effects ~ similarity of adoptive children & adoptive relatives Limitations o They apply only to populations, not to individuals Environmental effects Shared environment (ex: growing up together in the same family) o Little effect of shared environment on some aspects of development o Ex: sharing a home, having same parents educational level—can experience the same things differently No shared environment effects include experiences unique to the individual o Sharp difference within the same family and outside the family o Nonshared environmental factors increases differences among family members Behavior geneticists have found little effect on shared environment on some aspects of development Siblings may have quite different experiences within the same family and their experiences outside the family may diverge sharply The primary effect of nonshared environmental factors environmental factors is to increase the differences among family members Structures of the brain o Cell body: contains the basic biological material that keeps the neuron functioning o Dendrites: receive input from other cells and conducts it toward the cell body o Axon: conducts electrical signals to connections with other neurons Connections are called synapses Structures of the brain: the neuron The cell body manufactures proteins and enzymes, which support cell functioning, as well as the chemical substances called neurotransmitters, which facilitate communication among neurons The axon is the long shaft that conducts electrical impulses away from the cell body Many axons are covered with a myelin sheath, which enhances the speed and efficiency with which signals travel along the axon Branches at the end of the axon have terminals that release neurotransmitters into the synapses—the small spaces between the axon terminals of one neuron and the dendrites or cell body of another The dendrites conduct impulses toward the cell body. An axon can have synapses with thousands of other neurons Structures of the brain: Glial cells Brain’s white matter Outnumber neurons 10 to 1 o Play a role in communication within the brain o Add formation of myelin sheath Disorders affecting myelin have severe consequences o Multiple sclerosis: immune system attacks myelin o Schizophrenia and bipolar disorder: defects in gene that regulates myelin production How does the structure of the human brain come into being? For example, glial cells form a myelin sheath around certain axons, providing insulation that increases the speed and efficiency of information transmission Developmental processes How does the structure of the human brain come into being? It is a partner ship between nature and nurture Neurogenesis and neuron development Neurogenesis o Proliferation of neurons through cell division o Is largely complete by about 18 weeks after conception Neurons o Number around 100 billion before birth o Migrate to their destinations, where they grow and differentiate o Can be inhibited by stress—loud noises, starvation Myelination o Fatty sheath of myelin forms around some axons to increase speed and information processing abilities o Beings deep in brain before birth and continues into earth adulthood o Occurs at differentiated rates throughout brain structures Axons elongate Dendrites form spines that increase their capacity to form connections with other neurons In the cortex, the most intense period of growth and differentiation occurs after birth Results suggests that neurogenesis later in life is not fixed and predetermined but is instead adaptive, increasing under rewarding conditions and decreasing in threatening environments Brain imaging techniques fMRI (functional magnetic resonance imaging) o Uses powerful magnet to produce colorful images representing cerebral blood flow in different areas of the brain o Will show you where in brain occurred but will be delayed so may be related to another stimulus Eeg—hard at showing what part of the brain is showing where active, very quick response, so if you see a stimulus you’ll brain will be more active and will respond right away Synaptogenesis and synapse elimination Synaptogenesis o Each neuron forms synapses with thousands of other neurons Synaptic pruning o Overabundance must be eliminated o Synaptic pruning occurs at different times in different areas of the brain and is not fully completed until adolescence o Synapses that are rarely activated are eliminated o Continues for years after birth Adolescent development o The amount of gray matter increases dramatically in adolescence and then begins to decline Brain injuries in kids are easier to recover if it is in the front of their head than in their back because back is more developed than the front at that age As a consequence of hyperconnectivity, newborns may experience synesthesia —the blending of different types of sensory input The importance of experience Plasticity o Capacity of the brain to be affected by experience Two kinds of plasticity o General experiences o Idiosyncratic experiences Experience plays a central role in determining which of the brain's excess synapses will be pruned and which will be maintained Synapses that are frequently activated are preserved, a process described as “neural Darwinism.” Experience-expectant plasticity The normal structure and connections of the brain occurs in part as a result of general experiences that every human who inhabits any reasonably normal environment will have Developmental impairment results if expected experience is not available, as in the case of congenital deafness or blindness Experience of the external world plays a fundamental role in shaping the most basic aspects of the structure of our brain Sensitive periods Timing is key element in experience-expectant plasticity Few sensitive periods when the human brain is particularly sensitive to particular kinds of external stimuli exist Experience dependent processes Process through which neural connections are created and recognized as a function of an individuals experience Results come form nonhuman animals: rats, cats, monkeys Animals raised in enriched environments perform better on a variety of learning tasks Babies are amused by their hands and just looking around—stoned all the time Experience-dependent processes Process trough which neural connections are created and reorganized as a function of an individuals experience Results come from nonhuman animals: rats, cats, monkeys Animals raised in enriched environments perform better on a variety of learning tasks Brain damage and recovery Timing and plasticity play important roles o The worst time to suffer brain damage is when neurogenesis and neuron migration are occurring (during prenatal development and the first year after birth) o The greatest plasticity is observed when synapse generation and pruning are occurring during early childhood At age 6 children with congenital brain damage scored the same as normal children—children with brain damage failed to improve The body: Growth and maturation Compared with most other species, humans undergo a prolonged period of physical and cognitive growth Growth is uneven across age, occurring most rapidly during the first two years of life and early adolescence o Jake stopped growing but was tall and then all of his friends grew past him Growth is also uneven over different parts of the body Growth and maturation: variability Great variability occurs across individuals and groups in all aspects of physical development Secular trends: marked changes in physical development that occur over generations, resulting from environmental changes such as improvement in health and nutrition o Secular means time based—have changed over generations Example: Change that occurs during puberty, especially among American girls, relates to how an individual perceives and feels about her or his physical appearance, or body image Infant feeding Breast milk o Breast-feeding o Bottle-feeding Infant formula o Bottle-feeding Breastmilk and formula Formula is a scientific innovation that was life-saving in many instances o Babies without access to breast milk because mom dies ect Use of formula increased along w/ other societal changes that impact parental leave policies, parental employment, ect Recommendations regarding infant feeding are often emotionally fraught for parents What does the science tell us about correlates of BM use? BM> formula: infectous problems in newborns (diarrhea, respitory tract infections, otitis media, ect.) BM> formula: later obesity, diabetes, asthma BM> formula: higher IQ (esp in preterm infants) o 3.16 IQ points BM > formula: more rapid uterine conract, post-pregancy wt loss & lower risk of breast & overian cancer for moms Meta analysis*** Means quantifying the power of effects across large numbers of studies More conclusive than any single study Can include published and unpublished studies (file drawer problem) Still must be conducted properly More people in your study means you have a better idea of the result Kramer et al. (2008), JAMA Psychiatry <17,000 mothers of newborns were randomized to receive (or not) an intervention promoting breast-feeding Results: intervention group had IQ scores + 3.1 points relative to the control group Development of food preferences and regulation of eating Experience has a major influence on children’s food preferences & consumption Children whose parents try to control their eating habits tend to be worse at regulating their food intake themselves Obesity: a growing problems The proportion of children in the US who are overweight has tripled in the past four decades Genetic factors o The weight of adoptive children is more strongly correlated with their biological parents than with their adoptive parents o Identical twins are more similar in weight than fraternal twins Environmental factors o A higher proportion of the US population is obese today than earlier o Americans have taste fro high-fat, high-sugar foods in larger proportion size o Children get less exercise at home and school When children run around during recess they will perform better in school than if they were just sitting down all day Undernutrition 40% of the worlds children under age 5 are undernourished Almost always associated with poverty Malnutition affects development directly and indirectly by leading children to withdrawal from their environments to reduce energy expenditure Lecture 4 What’s the use of theories Provide a framework for understanding important observations Go beyond observations to raise crucial questions about human nature Motivate new research studies that lead to a better understanding of children No single theory accounts for all of it Jean Piaget History o Before appearance in 1920s, no recognizable field of cognitive development o Observing and describing conveys children’s thinking at different ages Paget’s view of children’s nature Children are seen as: o Active learners o Learning many important lessons on their own o Intrinsically motivated to learn If you’re curious and engaged you’ll get more information Children’s most important constructive process o Generating hypotheses o Performing experiments o Drawing conclusions Piagets theory remains the standard against which all other theories are judged Piagets theory: central developmental issues Nature and nurture interact to yield cognitive development o Adaption: tendency to respond to the demands of the environment to meet ones goals o Organization: tendency to integrate particular observations into coherent knowledge Paget’s theory: sources of continuity Assimilation: translating new information into a form you can understand Accommodation: adapting current knowledge structures in response to new experiences Equilibration: balancing assimilation and accommodation to create stable understanding Piagets theory: sources of discontinuity Distinct, hierarchical stages are the discontinuous aspects of piagets theory o Qualitative change (vs. quantitative) o Applicable across topics and contexts o Brief transactions o Invariant sequence o Four stages: sensorimotor, preoperational, concrete operational, formal operational Children progress through four stages each building from the previous Sensorimotor stage=birth to 2 years At first infants activities center on their own bodies; later, their activities include the world around them Early goals are concrete; later goals often are more abstract Infants become increasingly able to form mental representations o Infants put everything in their mouth Intelligence grows rapidly in first years Piagets theory: Piaget’s A-not-B: Put toy under blanket A know you keep putting it under A, and then you but it under B and they cant understand that its not supposed to be under A Preoperational stage = 2 to 7 years Begin to represent experiences in language and mental imagery Symbolic representation = use of one object to stand for another Egocentrism = tendency to perceive the world solely from ones own point of view Centration = tendency to focus on a single perceptually striking feature of an object or event Piagets three mountains task How does the doll sitting across the table see the three mountains Most children under 6 choose the picture of how the mountains look to them o Cant separate their own perspective from other peoples Conservation: problems with concentration and failure to ignore the transformation in phase 2 Pour same sized glass they think is the same size in to a tall glass the kid will think the tall glass has more Most 4-5 year olds say the taller liquid glass has more liquid in it Stretch out the line of penny’s the wider line will have more penny’s Concrete operational stage = 7-12 years Begin to reason logically about concrete objects and events in their world o They can solve conservation problems Children cannot think in purely abstract terms or generates systematic scientific hypothesis-testing experiments Formal operational stage: 12 and beyond The ability to think abstractly and to reason hypothetically Can imagine alternative worlds and reason systematically about all possible outcomes of a situation Attainment of the formal operations stage, in contrast to the other stages is not universal Piagets theory and legacy The stage model depicts children’s thinking as being more consistent than it is Infants and young children are more cognitively competent than piagets recognized Piagets theory understands the contribution of the social world to cognitive development Piagets theory is vague about the cognitive processes that give rise to children’s thinking and about the mechanisms that produce cognitive growth Information processing theories Distinctive features o Specification of thinking processes (specific mental abilities) over time o Emphasis on structure (organization of the cognitive system) o Tasks analysis—used to help information-processing researchers understand and predict children’s behavior Limited capacity processing system Metaphor of the child’s brain as a computer system that becomes more sophisticated through brain maturation (hardware) & experience (software) Cognitive development arises from childrens gradually surmounting their processing limitations through: o Increasing efficient execution of basic processes o Expanding memory capacity o Acquisition of new strategies and knowledge The child as a problem solver The assumption that children are active problem solvers is central to information-processing theories o Problem solving involves a goal, a perceived obstacle, and a strategy or rule Ask mom when dad said no How good a child is at manipulating shows how smart they are o Children’s cognitive flexibility helps them pursue their goals The development of memory Sensory memory: sights, sounds, and other sensations that are just entering the cognitive system and are briefly held in raw form until they are identified o Sort memory o Can hold a moderate amount of information for a fraction of a second, its capacity is relatively constant over much of development Working memory: workspace in which information form the environment and relevant knowledge are brought together, attended to and actively processed o Is limited in both capacity and duration. Its capacity and speed of operation increases greatly over childhood and into adolescence Long term memory: information retained on an enduring basis o Can retain an unlimited amount of information indefinitely and the contents of long term memory increase enormously over development Executive functioning Executive functioning involves control of cognitive o Inhibiting things that are counterproductive o Enhancing working memory through use of strategies Chunking things o Being cognitively flexible Thinking about things in a different way Executive functioning increasing during preschool and early elementary years Brain maturation It continues for a particularly long time in the prefrontal cortex Peak is usually around 20 years old Explanations of memory development Basic processes are the simplest and most frequently used mental activities o Associating events with one and other Garage door opening dad coming home o Recognizing objects as familiar o Recalling facts and procedures What’s the capital of Utah o Generalizing from one instance to another Encoding People encode information that draws their attention or tat they consider important Children do not encode all of the important information in the environment Explanations of memory development Processing speed Mental strategies Content knowledge Processing speed The speed with which children execute basic processes increases greatly over the course of childhood o Putting pants on as child takes all day but eventually will increase speed Biological maturation and experience contribute to increasing processing speed and experience contribute to increased processing speed Two of these biological processes include myelination and increased connectivity among brain regions Increase with age in speed of processing on two tasks—increase is rapid in the early years and more gradual later Mental strategies Rehearsal: process of repeating information over and over to aid memory Selective attention: process of intentionally focusing on information that is most relevant to the current goal Content knowledge Example: autobiographical memory or the knowledge of events in ones life o Most adults remember nothing that occurred before the age of three years (infantile amnesia) o Verbal encoding, conversations with parents and physiological maturation seem likely to be involved in the encoding of infantile amnesia o With age and experience children’s long-term memories of their experiences becomes increasingly detailed and accessible Content knowledge is idiosyncratic—daughter knows all the Thomas the trains names but doesn’t know any letters because doesn’t care Overlapping waves theory of strategy use Children use a variety of approaches to solve problems o At any given time, children possess several different strategies for solving a given problem o With age and experience the strategies that produce more successful performance become more prevalent o Overlapping waves theory also hypothesize that children benefit form this strategic variability At any one age children use multiple strategies—with age rely on more advanced strategies Math strategies o Number line—need to know 9 is bigger than 7 o Counting on Planning Young children fail to plan in situation in which they would benefit from doing so o Incomplete maturation of frontal lobe o Over-optimistic about abilities and incorrect belied that they can succeed without planning o Hard to overcome tendency to solve the problem immediately, rather than take time to plan The frontal lobe (plays major part in inhabitation) is one of the last parts of the brain to mature Quiz 2 1. True/False. One reason that males have higher rates of certain genetic disorders is because they have only one X chromosome. 2. True/False. Most important psychological characteristics are determined by a single gene. 3. Which of the following is true? A) Dizygotic (DZ) or fraternal twins are as genetically similar to one another as are Monozygotic (MZ) or identical twins; B) heritable effects are evident when your similarity to biological relatives on psychological characteristics is associated with your degree of genetic overlap with those relatives; C) Identical twins raised together in the same home are much more similar to one another than are identical twins raised in different homes; D) Synaptic pruning is a process that can result in deterioration of cognitive functioning. 4. Name one of the 2 developmental periods in which brain development is particularly rapid. Infancy 0-2; or adolescence 12-17 Sociocultural theories Learning in an interpersonal context Engaging in guided participation Using cultural tools—teaching an older person how to use a phone but younger kids are really good at using phones compared Focus on the contribution of other people and the surrounding culture to children’s development Emphasize guided participation—process where more knowledged individuals organize activities in ways that allow less knowledgeable people to engage in them at a higher level than they could manage on their own Vygotsy Vygotsy’s work created controversy because his view of children’s nature was so different than piagets The russion psychologist was the founder of the sociocultural approach to child development o Very different work from piaget Vygotsky’s theory Children are social beings and social learners Development seen as continuous with quantitative change o Saw things as gradual not as steps like piaget Humans inclined to teach each other and to learn from each other (distinction from other species) o Intrinsically motivated to learn o Teach and learn from each other Thought is processed in which speech is internalized (private speech = talk- alouds) o Control by other peoples statements o Control by own private speech o Speech goes underground Vygotsky and contemporary sociocultural theorists have proposed a number of specific ideas about how change occurs through social interaction such as through guided participation Intersubjectivity = mutual understanding; extension of knowledge across persons Social scaffolding= meet child just beyond their capabilities o Want to help child acquire new skill is to teach them right beyond their capable—push them a little o Don’t want to teach them things they already know and don’t want to teach them something way beyond their capability—t-ball to baseball Dynamic-systems theories Emphasize how varied aspects of the child function as a single, integrated whole to produce behavior View how change occurs over time in complex systems Focus on relation among motor activities, attention and other aspects of children’s behavior o Ex: crawling Dynamic-systems theorist: view of childrens nature Motivators of development o From infancy onward, children are strongly motivated to learn about the world around them and to explore and expand their own capabilities o Infants interest in the social world is a crucial motivator of development Newborn: attention to human face Should I eat it usually how vegetarian starts 10 to 12 months: emergence of intersubjectivity Centrality of action o Pervasive emphasis on how children’s specific actions shape their development Reaching and grasping—once they grab and grasp they have better understanding then just learning what something is Categorizing Aiding vocabulary acquisition and generalization Shaping memory Educational applications of dynamic-systems theories A recent intervention based on dynamic systems research was successful in improving the reaching abilities of preterm infants o Experimental group—caregivers provide infants with special movement experiences Had Velcro mittens and could attach themselves to the object and could control it better o Control group—caregivers provide infants with special social experiences Infants would pick it up and drop it which made it harder to put in mouth and explore o Reaching improved in both groups, but the experimental group improved to a greater degree Lecture 5 Perception Vision Auditory perception Taste and smell Touch Intermodal perception Perception o Sensation Processing basic information form the external world by the sensory receptors in the sense organs and brian o Perception Organizing and interpreting sensory information about the objects, events and spatial layout of the surrounding world Development of perception You must learn how to see, hear, smell, taste as adults do o Involves categorizing, combining, ‘filing in the blanks’, bluring some distinctions & making others o ‘Perceptual narrowing’—some discrimination and detection abilities present