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PSY2105 Midterm: Midterm

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University of Ottawa
Brenda Baird

Chapter1–BackgroundandTheories • Developmental psychology: devoted to study of changes in behaviour and abilities over the course of development • It has two main goals: o Description: identify behaviour (when do babies detect colour) o Explanation: determining causes and processes that produce behavioural changes (involves examining a child’s genes and environment) • Main difference between developmental psychology and child psychology is that developmental psychology studies all life stages • Research has been focused on children for 5 major reasons: o Period of rapid development: much change occurs from embryo to adolescent o Long term influences: events and influences of early years strongly affect later development o Insight into complex adult processes o Real world application: research and study benefit children with real world problems such as poverty, illiteracy and drugs o Interesting subject matter: children are intriguing to many including writers and scholars in other fields of study • Current views that children require special attention, care and protection and they should value education th o Child psychology didn’t exist until the 20 century and before this children were exploited and valued as they are today • John Locke o All children born equal and mind of newborn like a “tabula rasa” – a blank slate o Neither innately good or evil – product of upbringing and environment • Jean-Jacques Rousseau o “Father of French Romanticism” o Born with ideas that unfold with age o Predictable series of stages o Innate processes driving force of development o Theory referred to as Nativism – human development results from inborn processes that guide emergence of behaviours in a predictable manner • Johann Gottfried von Herder o Language and traditions of community shape minds of community’s members o Cultural relativism – belief that each culture must be evaluated separately o Focused on language – the means by which cultural practices are passed down • Charles Darwin o Natural selection – process in which certain characteristics increase chance of survival and are more likely to be passed on o His views led to the principle of recapitulation – the development of an individual repeats the development of the species o Baby biography: observing and recording behaviour of own children • G. Stanley Hall o “Father of Child Psychology” o Favours theory of recapitulation o Founded and became first president of American Psychology Association • James Mark Baldwin o First academic psychologist in Canada o Used baby biography o Development through stages influenced by heredity and environment • John B. Watson o Adopted Locke’s views that behaviour understood in terms of experience and learning o Behaviourism: human development results from conditioning and learning processes o Focused on the physiological workings of the body ▪ Didn’t believe in introspection – thought that psychology was observable and not about what people are feeling inwardly o Learning through association (Pavlov) • Arnold Gesell o Development guided by biological processes ▪ Biological processes driving development known as maturation o Determined that children develop at different rates through the first large scale study • Sigmund Freud o Psychoanalytic thought o Each child born with certain amount of sexual energy, the ability to experience physical pleasure o Theory of personality formation – adult personality results from childhood experiences o Repression: Freud’s term for process through which desires or motivations driven into unconscious typically occurring during phallic stage o Interactions perspective: theory that human development results from combination of inborn processes and environmental factors • Erik Erikson o Development continues through life o Psychosocial model o Identity, a component of personality, develops through the 8 stages of development in life and motivates progress through the stages • Nature versus nurture o Hall and Gesell take the nature position o Locke, Rousseau and Watson take the nurture position • Normative versus ideographic development o Whether research should focus on identifying commonalities (normative) or on the causes of individual difference (ideographic) o Normative research focuses on individual child and their development from stage to stage o Idiographic research determines factors that produce diversity • Four theories that psychologists associate with o Cognitive development o Sociocultural o Environmental/learning o Evolutionary • Cognitive development o Piaget studied this approach ▪ His area of interest was genetic epistemology: study of children’s knowledge and its changes with development ▪ Used clinical method – semi-structured interview with questions designed to probe children’s understanding of various concepts o Children different ages see world differently • Cognitive structures o Children understand world by acting/operating on it o Schemes: Piaget’s term for cognitive structures of infancy; action patterns by which child understand the world ▪ Schemes involved an object and the child’s reaction to it ▪ # and complexity of schemes define a child’s intelligence • Two main function stressed by Piaget o Organization: tendency to integrate knowledge into interrelated cognitive structures o Adaptation: tendency to fit with environment in way that promote survival; involves two processes ▪ Assimilation: interpreting new info in terms of existing structures (ie. Calling all men Dad) ▪ Accommodation: changing existing cognitive structures to fit with new experiences (ie. Different labels belong to different men) • Through this that intelligence grows o Interplay of assimilation and accommodation is constructivism – belief that children actively create knowledge rather than passively receive it from the environment • Four stages of development in Piaget’s model: o Sensorimotor: 0-2 years; simples reflexes and interaction with people and objects o Preoperational: 2-6 years; use words and numbers o Concrete operations: 6-11 years; logical problem solving with concreate objects o Formal operations: 12 through adulthood; higher level abstract thinking • Information processing model (a cognitive theory) o The key parts ▪ Stimulation enters our senses ▪ Processes in the brain act on this sensory info, encoding and sorting it ▪ Output = our behaviour o Concerned with why cognitive process change with age • The Sociocultural Model o Considers social process, cultural practices and everyday contexts of development o Vygotsky’s theory: development a product of culture; development mainly mental such as thought, language and reasoning ▪ Develop the above social interactions ▪ Tools of intellectual adaptation – thinking and problem solving techniques acquired from culture ▪ Learn by problem solving with others ▪ Main theme – internalization whereby children develop by incorporating through language knowledge and tools of thought • Bronfenbrenner’s Ecological Model o Ecological perspective: study of development focusing on individuals within environmental contexts o Child possesses a variety of characteristics: ▪ Developmentally generative: capable of influencing people in ways important to the child ▪ Developmentally disruptive: causing problems in environment with negative effect on child o Transactional influence: bidirectional or reciprocal relationship in which individuals influence one another’s behaviours ▪ Ie. Child sent to better schoolchild’s improved academic resultsaffecting environment by attracting friends with high career goalsand so on in an ongoing cycle o Macrosystem (culture)exosystem (social systems affecting child but not directely participating in such as neighbours and media)mesosystem (interrelationships among microsystems)microsystem (environment closest to child including friends, family, health services, school)child • Environmental/Learning Models o Great deal of behaviour acquired not inborn o Learning: relatively permanent change in behaviour that results from practice or experience • B.F. Skinner o Accepted role of Pavlovian conditioning of reflexes o Behaviour falls in two categories ▪ Respondent: based on reflexes controlled by specific stimuli; the smaller category ▪ Operant: voluntary behaviour controlled by its consequences; the larger category • Types of Learning o Habituation: decline/disappearance of behaviour following repeated stimulus o Classical conditioning: neutral stimulus acquires power to elicit a behaviour ▪ Stimulus generalization: when a stimulus close to the conditioned stimulus can also become conditioned ▪ Extinction: when condition association becomes unlearned o Operant learning: likelihood of operant behaviour depends on reinforcing and punishing consequences ▪ Reinforcer: making behaviour more likely • Positive: presentation of something pleasant • Negative: removal of something unpleasant ▪ Punisher: making behaviour less likely • Positive: TV privileges or a favourite toy • Negative: spanking or a failing grade • Social Learning Theory o Bandura believes that learning processes as well as cognitive development responsible for child development ▪ Cognitive development is affected by learning processes o Observational learning: learning by observing others o Observer (child) receives vicarious reinforcement: reinforcing consequences experienced when viewing a model that affects the observer ▪ Vicarious punishment exists too o Imitation: behaviour resulting from copying a model o Response inhibition: not displaying a behaviour that has just been modelled; often a result of vicarious punishment o Bandura’s model has 4 stages ▪ Learning/acquisition: Attentional processes and retention processes ▪ Performance/production: production processes and motivational processes o Reciprocal determinism: Bandura’s proposed process describing interaction of person’s characteristics and abilities (P), behaviour (B), and environment (E) ▪ Each (P, B, and E) affect each other • Behaviour and Evolution o Ethology: study of development from an evolutionary perspective o Considers human development within context of entire animal kingdom o Changes in behaviour have to be determinant: ▪ Immediate: recent experiences or current state (hungry, tired or angry) ▪ Evolutionary: genes and behaviours have been selected for over generations • Classical ethology o Used non-human animals for study o Lorenz and Tinbergen were zoologists whose work laid groundwork for applications of ethology towards child developments • Innate mechanisms: innate or inborn mechanisms can be characterized by four qualities o Universal to all members of species o Require no learning or experience o Stereotyped – occur the same way each time o Only minimally affected by environmental influences o Model action patterns: chains of responses or complex sequences of innate behaviours ▪ Ie. When spider spins web or mother bear cares for newborn ▪ Triggered by innate releasing mechanism such as environmental stimulus • Sensitive periods: periods during which certain behaviours are learned more easily than others • Applications to Human Development o Lorenz suggested that shape of baby’s head and sound of cry act as stimulus to mother o Bowbly was first to attract child psychologists to an evolutionary perspective ▪ Based on fact that certain evolutionary behaviours are crucial to development o Sociobiology: attempts to discover evolutionary origins of social behaviour ▪ Genes influence social behaviours as well as physical Chapter2–ResearchMethods • Scientific method: system of rules used by researchers to conduct/evaluate their research • A theory: a set of statements describing relation between behavior and factors assumed to affect it o A well supported statement by evidence from research is a law or principle o A statement not yet supported by research is a hypothesis o Theories (1) organize research and (2) guide new research • Objectivity means that investigations can be agreed upon by everyone such as by all those who study child psychology o It prevents bias from personal beliefs and; o Permits any scientist to perform same research • Objectivity meets its goals by: o Observable behaviour: study assimilation by watching child with new experiences and social skills while child plays with peers o Measurable behaviour: distinguishing between behaviour o Quantifiable behaviour: quantify behaviour and factors that influence it such as # of kids in a classroom or time child spends reading • Descriptive research: based on observation with no attempt to determine systematic relations among variables o Observing and interviewing children and those they interact with o Baby biographies use this method Three methods for performing descriptive research: • (1) Observation methods or naturalistic observation: systematic observation of behaviour in a natural setting o Minimize bias by ignoring motives (ie. If one child hitting another on the back was friendly or aggressive) o Many video observations, but must hide camera as knowledge of being recorded can change behaviour • (2) Interview methods: collecting information through verbal reports such as interviews or questionnaires o Interviews can be (1) open-ended where child responds freely like in conversation or (2) structured with the researcher asking specific set of question ▪ (1) is more qualitative and (2) is more quantitative ▪ Open-ended uncover child’s values and beliefs • (3) Case studies: a research method that involved only a single individual o Sometimes unclear if behaviour of one child can then be generalized; external factors affect behaviour • Correlation research: finding relationships between variables o Behaviours can be variables such as # of times a child asks teacher for help (frequency), how loudly baby dries (intensity), or how long a child practices piano (duration) o Correlation can indicate a relationship but it does not prove cause and effect • Experimental research: allows us to draw conclusions about cause and effect o Altering one variable to determine if change in the other o Independent can be a characteristic of the individual while the dependent variable is their behaviour o Quasi-experimental studies allow comparison of groups differing on some important characteristics ▪ Less control over independent variable – ie. Study boys and girls, but there will be other factors affecting them other than gender so can not say all cause is placed on gender • Longitudinal research: an approach to studying children at different ages o Correlation by (1) measuring behaviour at one age and then comparing that behaviour at another age or (2) experimental by introducing a manipulation at one age to examine effect at a later age in developments o Research questions involved with this type of study include (1) stability or persistence of behaviours and (2) effects of early experiences on later behaviours o Disadvantages of longitudinal study include: ▪ (1) Attrition – loss of individuals in the study due to family moving or illness ▪ (2) Repeated testing – study concerned with intelligence requires IQ tests taken often; this makes child test-wise and artificially improves their performance ▪ (3) Lasts for many years so instruments or issues being tested may become outdated ▪ (4) Large research staff and long hours required; therefore, expensive • Cross-sectional Research: research method where people of different age studied simultaneously to examine age-related differences in some aspect of behaviour o Age of child becomes the independent variable o Advantage: less time consuming o Disadvantages: ▪ (1) Can’t investigate behaviour stability because different influences on different people ▪ (2) Cohort effect: people of age-group affected by factors unique to their generation • Cross-sequential o Combination of longitudinal and cross-sectional o If data similar in cohort and time then confident in results • Microgenetic studies: research method where small number of individuals observed repeatedly to study expected changes in developmental processes o Behaviours can be discontinuous – that is they are relatively stable for a period then abruptly move to a higher level o Microgenetic studies involves studying age group where this change in behaviour is expected to occur • Cultural research o Cross-cultural studies: designed to determine influence of culture on some aspect of development where culture usually serves as the independent variable o Want to assess the universality of the phenomenon ▪ Differences in time/age that children begin to walk and develop other motor skills in different cultures due to differences in amount of encouragement they receive o Difficulty to measure the same behaviour – behaviour in one culture may seem strange in another o Cultural psychology: study of a single culture from the perspective of member of that culture ▪ Goal to identify values and practices important to them o Researchers may work/live for months or years as member of a culture and use ethnographic methods (living as member of culture and gathering info about culture through interviews and observation over long period of time) o Cultural psychologists study their own culture; whereas cross-cultural psychologists study cultures other than their own • Comparative research: study of behaviour across species (nonhuman) to provide info relevant to human development o Complete this type of research for two reasons: ▪ (1) Clues to evolutionary behaviour like humans (ie. Attachment between infant and mother) ▪ (2) Permits study that is prohibited on humans due to ethical reasons • Ethical Issues o Researchers must determine if risks of their study outweigh the potential value, in which case should not proceed o Must safeguard children’s rights and well-being o Potential risks include: ▪ Physical injury (rarely occurs) ▪ Psychological harm: child prevented from playing with a toy or are exposed to violent behaviour which produce negative emotions ▪ Violations of privacy: researcher may gain access to child’s school records without child knowing • Safeguards made to protect interest of child o Canadian Code of Ethics for Psychologists by Canadian Society and Ethical Principles of Psychologists and Code of Conduct by American Association o These codes include rules on topics such as nonharmful procedures, informed consent, parental consent, anonymity, unforeseen consequences, and informing participants o Research plant must be sent to hospital, university, or other institution where the research will be taking place in order for approval o Investigator must provide means of relieving negative emotions before child leaves Chapter3–Genetics • Majority of mutations are maladaptive • 90% of all genetic abnormalities result in miscarriages rather than live births • Genes can be made abnormal by drugs, radiation, viruses and chemicals • Polygenic inheritance: trait is determined by the number of genes • Incomplete dominance: dominant gene does not completely supress the recessive one; average of phenotypes expressed (white and red flower make a pink one or a cow with medium length hair) • Codominance: both phenotypes appear (ie. Flower that is red and white or a cow with long and short hair) • Hereditary disorders o Dominant allele can prevent disease phenotype if it is recessive o Dominant alleles that cause severe problems typically disappear from the species because affected individuals do not live to reproduce ▪ Sometimes passed on because not active until later in life (ie. Huntington’s disease) o People can carry alleles for disease that have no affect on them unless homozygous for that allele ▪ Tay-Sach’s disease: nervous system disintegrates, metabolism issue where lack enzyme to break down fat in brain cells o X-linked disorder: result from recessive genes located on the X-chromosome, leaving males vulnerable to them ▪ Ie. Hemophilia: serious bleeding disorder caused by low levels of protein required for clotting • Structural defects in chromosome: along with inherited disorders genetic problems may arise as a result of physical change to chromosomes • Autosomal disorders: disorders resulting from genes on non-sex chromosomes o Down-syndrome where there is a third copy (trisomy) of chromosome 21 o First disease to be linked to chromosomal disorder • Disorder of the Sex Chromosomes o Monosomy where embryo only has one X chromosome will likely fail to develop ▪ Ie. Turner’s syndrome where at birth baby appears female but eventually ovaries disappear and hormones necessary for sexual development not produced o Klinefelter’s syndrome where male inherits extra X chromosome thereby producing some female characteristics such as enlarged breasts and reduced male features such as an underdeveloped penis and very little chest hair ▪ Injections of hormones have been found to have positive outcomes for both Turner’s syndrome and Klinefelter’s syndrome • Effects of genes on human behaviour and development in three areas studied extensively: o (1) Intellectual abilities o (2) Psychiatric disorders (including children’s behaviour problems) o (3) Aspects of personality (including infant termperament) • Four methods used to investigate these areas include: o (1) Family studies o (2) Adoption studies o (3) Twin Studies o (4) Combination of these approaches • Family Studies: asks whether the phenotypic similarity on some trait follows from the genotypic similarity of the people being compared o Siblings on average share 50% of their genes o Henry Goddard proposed a genetic basis for intelligence o Distinguishing between hereditary and environmental influences is a major limitation of family studies ▪ Not all things that “run in the family” are controlled by genes4 o The degree of genetic similarity drops off as the degree of genetic overlap does o Studies have shown that children whose mothers have schizophrenia are 13 times more likely to develop the disorder • Adoption studies: designed to address the issue of whether patterns result of genetics or environment o Adopted children are compared with the biological parents to determine effect of heredity and with their adoptive parents to determine effect of environment ▪ If correlation with one set of parents is stronger then indicative that environment/heredity has a stronger influence on the trait being studied o Colorado Adoption Project: 250 families with biological children compared with 250 family with adoptive children in a longitudinal study in 1975 ▪ Children tested on multiple traits, one being intelligence ▪ Findings clearly support the role of genetics in intelligence o Adoption studies provide evidence about the origins of problems in development ▪ One study sought to explain hostile and antisocial behaviours of adopted children ▪ Findings showed that many of these children were more likely to have biological parents with psychiatric disorders ▪ Also showed that children showing these behaviours were more likely to have adoptive parents who used harsh and inconsistent punishment o Positive correlation between biological parent’s psychiatric problems and the adoptive parents disciplinary practices ▪ Critical link was the child and researchers speculated that: • (A) The children initially inherited their behaviour problems from their biological parents • (B) These problems then evoked responses (harsh) from the adoptive parents • (C) The adoptive parents disciplinary actions then served to maintain the children’s problem behaviours • Twin Studies o Identical or monozygotic twins: twins who develop from a single fertilized ovum and thus inherit identical genetic material o Fraternal or dizygotic twins: twins who develop from separately fertilized ovum and who are thus no more genetically identical than regular siblings o If a trait is more similar in the identical twins than in the fraternal twins, should be able to conclude that the greater similarity results from the greater similarity of the genes o Twins studies used to address personality disorders ▪ If one identical twin experiences divorce, then the chance the other twin will experience divorce is 6 times that of the general population • 2 times that of the general population for fraternal twins ▪ Increase in risk of divorce is likely due to personality characteristics affected by genetic inheritance, not genes themselves ▪ Genes influence temperament o Developmental placing: the rate at which spurts and plateaus occur in and individuals physical and mental development ▪ Believe that developmental placing is guided by genes ▪ Identical twins show greater concordance (similarity) in their shifts in performance • Combination Studies o One problem with twin studies: how do we know that families treat a set of fraternal twins as they would a set of identical twins? o Parents and other may expect identical twins to act the same because of their identical looks o Method to avoid this problem is to study identical twins who were separated early in life and raised in different adoptive homes o Difficult approach to use because so few twins are raised apart o Minnesota Study of Twins Reared Apart ▪ 135 pairs of twins currently in their 50s ▪ Provides strong evidence for genetic influence on IQ – even when reared apart identical twins still had similar test scores • Average similarity was greater than fraternal twins growing up in the same home o Identical twins very similar in terms of many personality characteristics such as extroversion and neuroticism o Major limitation: because of selective placement practices followed by most agencies the homes in which adopted children are placed tend to be relatively homogeneous ▪ For example, generally placed in mid-high income families and so environmental effects associated with being reared apart in poverty not typically studied ▪ This suggests that adoption studies may underestimate environmental influences, simply by holding socioeconomic factors constant • Models of gene-environment interaction • Behaviour genetics: field of study that explores the role of genes in producing individual differences in behaviour and development • Gottesman’s Limit-setting Model o Suggests that genes interact with the environment by setting the upper and lower limits of our development – our environment and experiences then determine where we end up in this genetically determined reaction range ▪ Reaction range: the range of ability or skill that is set by the genes; value achieved within this range is determined by the environment ▪ Ie. Height makes for a better basketball player o Either poor genes or a poor environment can be overcome by strength in the other • Scarr’s Niche-Picking Model: genes play a role in the kind of environment the child experiences o Children play a role in producing their own environment – through their genes o Genes ensure that both genes and environment push development in the same direction – do so in three ways: ▪ (1) Passive-gene environment correlation – genes and environment affect development similarly because genes from parents are compatible with the environment the parents provide (this occurs mainly at infancy) • Ie. Musically inclined parents likely give birth to musically inclined children and provide a musical home environment ▪ (2) Evocative-gene environment correlation – genes and environment affect development similarly because genetically set predispositions of the child elicit compatible experiences from the environment (this occurs as children get older) • Ie. Children who read and speak early, due to their genes, may prompt parents to provide an environment with lots of books and educational games ▪ (3) Active-gene environment correlation – genes and environment affect development similarly because children seek out experiences that are compatible with their predispositions (this occurs as children gain more independence) • Ie. Children on their own seek out environments to fit their interests and talent o Environment is less a direct cause of the child’s development, but rather a guide for their genes • Plomin’s Environmental Genetics Model: children’s development outcomes related to their family environments for two reasons: o (1) Children share many genes with their parents who in turn provide the environment for their children o (2) Children evoke from their parents the sorts of responses and surroundings that suit their genes o Environmental genetics: how our genes influence our environments o Non-shared environment: concept used in behaviour genetics to refer to presumed aspects of the environment that children experience differently o Just because children live in the same family does not mean that they experience the same environment ▪ Parents often treat children differently and children react differently to the same events o With age, the psychological characteristics of an adopted child become increasingly similar to those of the biological mother – genes grow in importance as we age o Niche picking: as children grow older increasingly able to choose their own environment thus permitting their genes to operate in a more active way to influence their development • Bronfenbrenner and Ceci’s Bioecolgical Model: assigns more importance to the environment o Genes can only exert influences when certain experiences activate them o Proximal processes: interactions between the child and aspects of the microsystem that have positive effects on psychological functioning and that help maximize expression of the child’s genetic potential ▪ If proximal processes are weak then the genes won’t be able to fully express themselves and child’s development will remain below what it could have been ▪ When in a stable and rich with resources environment, best opportunity for child to develop their fullest abilities ▪ When in a disorganized and disadvantaged environment, proximal processes will prevent undesirable outcomes that might have otherwise occurred Chapter4–PrenatalDevelopment Stages of Prenatal Development • (1) Conception: combining of the genetic material from the male gamete (sperm) and the female gamete (ovum); otherwise known as fertilization o Every 28 days ovum produced and travels through fallopian tubes o Only 100 to 200 of strongest healthiest sperm travel to ovum and only one will penetrate the wall to fertilize it o Sperm + ovum = zygote which is formed within an hour of penetration • (2) The Period of the Zygote (Conception to Second Week) o Zygote multiplies rapidly as it makes its way to the uterus ▪ 4 day, 10cm journey o At first zygote a solid mass of cells, but becomes hollow sphere as it prepares to implant into wall of uterus o Cells begin to specialize o This process of “implantation” begins 6 days after fertilization and takes about a week ▪ Zygote settles into blood-enriched uterus lining o Ends two weeks after fertilization which corresponds to the first missed period • (3) The Period of the Embryo (Third to Eighth Week) o Embryo: developing organism from the third week when implantation is complete through the eighth week after conception o At first the size of an apple seed, all major internal and external structures form during this period ▪ This is the most delicate stage of pregnancy o In third week, inner cell mass differentiates into three parts: (1) endodermal layer, (2) ectodermal layer and (3) mesodermal layer o Each layer gives rise to different structures ▪ Endoderm – internal organs and glands ▪ Ectoderm – nervous system and sensory parts including ears, nose, mouth and hair ▪ Mesoderm – muscles, bone, the heart and sex organs o At beginning of fourth week, embryo looks like a tiny tube ▪ Rapid cell division makes the embryo curved with a distinguishable bump below the head (the heart) and tiny buds of limbs by the end of the fourth week o In fifth week, the head and brain develop rapidly o In the sixth week, differentiation of the limbs occur and can distinguish elbows, fingers and wrists o By the end of the eighth week, embryo has distinct human features ▪ Almost half of the embryo is the head • The prenatal environment o Amniotic sac, placenta and umbilical cord all develop by the end of the embryonic period ▪ Amniotic sac: watertight fluid-filled membrane that surrounds the embryo and maintains a constant temperature ▪ Placenta: through which mother and embryo exchange materials ▪ Umbilical cord: links the embryo to the placenta; houses blood vessels that carry materials to be exchanged (nutrients) o Waste products pass into mother’s blood to be carried away and excreted th • (4) The Period of the Fetus (ninth to 38 week) o fetus increases in size and weight ▪ growth slows around month 8 o External changes ▪ Heads grows less so proportionate and not 50% of the total body ▪ Skin thickens and loses its transparency in month 3 ▪ Facial features become more human looking ▪ Eye lids seal shut at month 3 and remain like that until month 6 ▪ Nails and hair o Growth of internal organs ▪ By month 3 brain has organized into functional divisions ▪ Nerve cells grow and establish connections ▪ Male sexual organs become apparent at the end of month 3 o Early signs of behaviour ▪ Month 3: capable of wiggling finger and toes ▪ Month 4: eyes sensitive to light through lids ▪ Month 5: loud noises may activate the fetus; fetus capable of kicking and turning o Toward independence ▪ Later stages of prenatal development ready the fetus to live outside the mother’s body ▪ Age of viability: age (presently 23 or 24 weeks) at which the infant has a chance to survive if born prematurely ▪ Major obstacle to independence is the immaturity of the air sacs in the lungs which exchange carbon dioxide for oxygen • Fetus also unable to digest food or control their body temperature ▪ Baby born after only 7 month will be able to survive with extra oxygen • Teratogens: a non-genetic agent that can cause abnormal development in the fetus o 90% of malformations end in spontaneous abortions after screening processes for development issues o Malformations caused be genetic defect, drugs, infectious disease, and other environmental hazards o Teratogens have a physical and behavioural impact o Limits to studies on potential teratogens – (1) test done on animals but might not have same effect as in humans and (2) some drugs may become harmful when taken with other drugs o How teratogens act: ▪ (1) Effect depends on the genetic makeup of the organism exposed to it • Thalidomide causes defective limbs in babies – rat testing did not prove this harmful effect and so human babies affected by this morning sickness drug • Sensitivity to alcohol – some babies affected by their mother’s drinking alcohol while others are not ▪ (2) Effect of a teratogen on development depends partly on timing • Teratogens can affect the parents’ germ cells o Fetus can be affected by drugs the pregnant grandmother took decades earlier or by the exposure of the father’s sperm to x-rays weeks before conception • Timing important – for first two to three weeks the fetus’ fluids do not mix with the mother’s ▪ (3) Effect of a teratogen may be unique • Although some common birth defects some are caused by a particular teratogen ▪ (4) Abnormal development caused by teratogens may be severe • Mental retardation or even death ▪ (5) Teratogens differ in how they gain access to the fetus • Radiation passes to the fetus directly through the mother • Chemicals travel through blood and across placental membrane ▪ (6) Likelihood and degree of abnormal development increase with level of exposure to the harmful agent • Types of teratogens o Therapeutic drugs ▪ Aspirin: miscarriages, bleeding and newborn respiratory problems ▪ Barbiturates: respiratory problems ▪ Thalidomide: deformed limbs, sensory deficits, defect of internal organs, and death o Street drugs ▪ Cocaine: premature birth, irritable newborn, and growth retardation o Alcohol: brain and heart damage ▪ Fetal alcohol syndrome: set of problems in the infant and child caused by alcohol use during pregnancy; causes facial malformation and mental disabilities o Tobacco: growth retardation and prematurity o Infectious disease ▪ HIV: facial malformations and AIDS in the infant ▪ Herpes: intellectual disability, eye damage and CNS damage o Caffeine: premature birth and lower birth weight o Environmental chemicals: usually chemicals at a large scale such as an industrial accident or concentrated dumping ▪ Example: miscarriages and stillbirths rose by 43% after people were eating fish from a bay that had been contaminated by concentrated dumping and had high levels of mercury • Nutrition o Nutrition is important because the baby is not only created by dividing cells but by cells that are increasing in size o When born, babies weigh billions times the weight of the fertilized egg! ▪ This mass comes from the mother o Quality of mother’s nutrition is probably the most important environmental influence on the baby o Ability to supply fetus with sufficient nutrients has to do with mother’s nutrition during and before pregnancy ▪ Even conception can be affected by poor nutrition o Stillborn infants who were malnourished had brains 1/3 the size of those who received a relatively good amount of nutrients o An enriched home environment may compensate for the malnutrition occurred during pregnancy and how severe it was o Malnourished babies may show delayed motor skills o Not only food quantity but food quality that matters o Excess of nutrients can also cause issues ▪ Too much vitamin A causes problems with the eyes and face • Maternal experiences and stress: most speculation on maternal experiences as influencer of fetus o High levels of anxiety in the mother has been found to cause newborn irritability, feeding and sleeping problems ▪ Mother with predisposition to anxiety can pass this on to her newborn infant o Anxiety does not always have negative effects; especially if mother well- nourished, financially stable, and carrying a wanted pregnancy • Parental age: optimal time for child bearing is between 20 and 34 o Births to mother over 35 has increased by 63% and birth to teens has declined significantly o Maternal age is associated with increased likelihood of baby having Down Syndrome ▪ Paternal age influential too – child may develop achondroplasia which is associated with bone deformities o Older mothers at risk for preterm births, difficulty during delivery and even maternal and infant mortality • Prevention of birth defects o Genetic counselling: practice of advising parents about genetic diseases and the likelihood that they might pass on a defective trait to there offspring ▪ Tests through blood testing ▪ This often occurs before conceiving a baby • Screening for abnormalities o Blood test was developed to detect excess phenylalanine in the blood (causes PKU) and mothers can change their diets to protect their babies from developing PKU o Ultrasound imaging: non-invasive procedure for detecting physical defects ▪ A device that produces sound-like waves of energy is moved over belly and reflections of these waves produces an image of the fetus o Amniocentesis: procedure for collecting cells that lie in the amniotic fluid ▪ Needle passed through mother’s abdominal wall into the amniotic sac to gather discarded fetal cells which can be examined for genetic and chromosomal defects o Chorionic villus sampling (CVS): procedure for gathering fetal cells earlier in pregnancy than is possible through amniocentesis ▪ Cells gathered at site of developing fetus o Endoscopic fetoscopy: fibre-optic endoscope inserted into uterus ▪ Allows physician to gather feta cells, visualize the fetus and even perform fetal surgery ▪ Treating defects prenatally can have serious complications o In vitro screening: screen embryos in the test tube before inserted into the mother ▪ Three days post fertilization in a petri dish the embryo can be tested for the sex of the baby and its DNA checked for abnormalities ▪ Costly procedure and not covered by provincial insurance • Treatment o If fetus found to be developing abnormally parents may decide to abort the pregnancy, but there are treatment options o Medical therapy ▪ Providing extra vitamins when inborn errors of metabolism result in deficiencies in the fetus ▪ Possible to provide therapy directly to the fetus • Cardiac and thyroid disorders have been treated directly o Fetal surgery: through fibre-optic endoscope o Fetal gene therapy ▪ Take sample of fetus blood and find a gene that is causing lack of enzyme in fetus’ blood ▪ Clip out that gene and insert a synthetic gene to “erase” the problem ▪ Inject into the fetus where they would survive, replicate and provide sufficient amounts of enzyme for normal development o Gene therapy is a rather experimental procedure ▪ Studies have encompassed somatic cells but not germ-line cells • Ethical considerations o If no treatments are available for a found disease in a fetus, the only options are to abort the pregnancy or bring a child with a serious disorder into the world o How disabling must the effect be to justify aborting the fetus? o Fetal surgery and gene repair also raise concern ▪ Expensive – not all families can afford them ▪ Experimental – can carry risks for both mother and fetus o As new technologies are developed, the fine line that separates the personal beliefs and feelings of the parents on one side and the government’s role to protect the rights of the fetus may become increasingly blurred Chapter 5 • Perinatal period: begins with birth, normally occurs @ 38 weeks gestation. Chemicals released in fetal brain that signal contractions ever 15-20 minutes, then shorter intervals. Complete birth process averages 8 to 16 hours. 3 stages of birth: • Uterine dilation: longest stage, uterus narrows and cervical opening dilates. Stage ends @ full dilation (10cm.) Contractions occur every 2-3 minutes by end of stage. • Fetus passes through cervix: contractions long and shortly spaced. Stage ends when baby is completely delivered. • Afterbirth: lasts a few minutes, delivery of placenta and other membranes. o Heart rate measures on fetus sometimes used to determine fetal distress (abnormal stress on baby.) If delivery is too slow, or baby is in unusual position doctor will perform caesarian section (surgical delivery of fetus.) Cultural attitudes towards birth: • Western countries see birth as illness (regular doctor visits, medication, in-hospital procedures.) Other countries see birth as everyday occurrence (South America women may give birth in public places.) Concept of risk: • Risk of physical deformations and risk of cognitive/social problems. • 3 indicators: o maternal/family characteristics (85% risk of problems linked to what happens in prenatal period. Mother’s behavior/nutrition, drug use, etc.) o physical compromise of newborn (low birth weight, need to adapt to external environment, may have difficulty breathing (anoxia=deficit of oxygen that affects brain), babies born pre-term/premature.) SGA=small for gestational age (fetal growth slowed/those born @ bottom 10% of their age) o performance on behavioral assessments (poor performance on standard tests.) Agpar exam: 5 vital functions (HR, respiration, muscle tone, response to stimulus, skin color.) Lower score=higher risk. Brazelton Neonatal Behavioral Assessment Scale: idea that newborns possess organized behaviors to react to stimuli. Observe baby in various states and create score (4 categories: attention/social responsiveness, muscle tone/physical movement, alertness/irritability/excitability, physiological responses to stress.) • prematurity stereotyping=nature of parent-baby interactions, people expect negative behavior from premature babies. Increases negative relationship with child. Organized Newborn: States of alertness: Peter Wolff, 6 different stages. Compare EEGs to show states that are distinct with ages (measure brain activity through electric changes.) o Deep sleep: regular breathing, eyes closed no movements, no activity
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