Lecture Notes for HDEV: Human Lifespan Development, 6th Edition

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1Chapter1H i s t o r y , T h e o r i e s , a n d M e t h o d sChapter OverviewThis chapter provides the general introduction to the field of developmental psychology. Itbeginswith a definition of child development and a discussion of the purposes and goals oftheory and research in the fieldof developmental psychology.Abrief survey of the pioneers inthe field of developmental psychology, includingJohnLocke,Jean-JacquesRousseau,G.StanleyHall,AlfredBinet,WilliamPerry, andGisellaLabouvie-Vief,is followed by adescription and evaluation ofeach of the majorperspectives onchild development—psychoanalytic,learning(behavioralandsocialcognitive theories),cognitive,biological,ecological,and sociocultural. Next, the nature-nurture, continuity-discontinuity, and active–passive controversies in the fieldof developmentare overviewed. Finally, research methods aredescribed(naturalistic-observation,case study, correlation, experimental research, longitudinalresearch, cross-sectional studies, and cross-sequential research), including a presentation of thegeneral idea behind the scientific method, ways of gathering information in child developmentalscience, the correlational method (and its limitations), and how to approach and designexperiments.The chapter ends with anoverview ofthespecial methods neededtoassessdevelopment over time, specificallylongitudinal versus cross-sectional research and the ways inwhich the cross-sequential research design handles the advantages and disadvantages of each, aswell as adiscussion oftheethical issues in research with children.Chapter Learning ObjectivesHaving read the chapter, students should beable toachieve theobjectivesgiven below.•Explain what child developmentis•Describe why it is important to study child development•Discuss the history of child development•Compare the different developmental views across time•Compare thedifferent major theories of child development•Analyze the major controversies in the study of child development•Identifyandcompare different research methods used inthestudyofchild development•Explain the purposeof each of the different research methods discussed in thischapter•Describe the different ethical considerations when conducting developmental researchChapter Outline

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2I.The Development of the Study of Human Development•Developmentalpsychologyis the discipline that studies the physical, cognitive, social,and emotional development of humans.•In ancient times and inthe Middle Ages,children oftenwereviewed asinnately evil anddiscipline was harsh.•Englishphilosopher John Locke(1632-1704)believed that the child came into the world asatabula rasa—a “blanktablet” or clean slate—that was written on by experience.•Jean-Jacques Rousseau(1712-1778), a Swiss-French philosopher, arguedthatchildren areinherently good andthat,if allowed to expresstheirnatural impulses, they will developinto generous and moral individuals.•G. Stanley Hall (1844-1924) is credited with founding child development as an academicdiscipline and bringing scientific attention to focus on the period ofadolescence.•French psychologist Alfred Binet (1857-1911), along with Theodore Simon (1872-1961),developed the first standardized intelligence test near the beginning of the20thcentury.•In the20thcentury, psychologistsbeganto take on alife-span perspective,in which theyviewed human development as occurring throughout the individual’s lifetime.oWilliam Perry and Gisella Labouvie-Vief, for example, havestudiedthedevelopmentofcognitive complexityfromadolescenceto lateadulthood.oK. W. Schaie and othershavestudiedtrends invarious mental abilities throughoutmiddle and late adulthood, showing that some abilities decline in middle and lateadulthood, but others that represent the accumulationof decadesof knowledge canadvance into lateadulthood.II. Theories of Development•John B. Watson(1878-1958), the founder of Americanbehaviorism,viewed developmentin terms of learning theory.oHe generally agreed with John Lockethatchildren’s ideas, preferences, and skills areshaped by experience.•Arnold Gesell expressed the opposing idea that biologicalmaturation—theunfolding ofgenetically determined traits, structures, and functions—was the main principal ofdevelopment.A. The Psychoanalytic Perspective•A number of theories fallwithin the psychoanalytic perspective.oEach owes its origin to Sigmund Freud andviews children—and adults—ascaught in conflict.

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3•The expression of basic drives, such as sexand aggression, conflict with parentalexpectations, socialrules, moralcodes, even laws.oBut the external limits—parental demands and social rules—are brought inside orinternalized.oOnce internalization occurs, the conflicttakes place between opposinginnerforces.•Freud’s theory ofpsychosexual developmentand Erik Erickson’s theory ofpsychosocial developmentarestagetheoriesthat see children developing throughdistinct periods of life.oEach suggests that the child’s experiences during earlystages affect the child’semotional and social life at thetime and later on.SigmundFreud’s Theory of Psychosexual Development•SigmundFreud’s (1856-1939) theory of psychosexual development focused onthefollowingthree parts of the personality.oId: It ispresent at birth andisunconscious.▪It represents biologicaldrives and demands instant gratification, assuggested by a baby’s wailing.oEgo: Itcurbs the appetites of theid and makes plans that are in keeping withsocial conventionsso that a person can find gratification but avoidsocialdisapproval.oSuperego: Itdevelops throughout infancy and early childhood.▪Itbrings inwardthewishes and morals ofthechild’s caregivers and othermembersof thecommunity.•According to Freud,thefollowingarethefive stages ofpsychosexualdevelopment.oOralstage: Duringthe first year of life,“oral”activitiessuch assucking andbitingbring pleasure and gratification.oAnalstage:During this stage, gratificationisobtained through control andelimination of wasteproducts.oPhallicstage:During thisstage, parent-child conflict may develop overmasturbation, whichmany parents treat with punishment and threats.oLatencystage: Byage five or six, Freud believed, children enterthis stageduringwhichsexual feelingsremainunconscious,childrenturn to schoolwork,and they typicallyprefer playmates of their own sex.oGenitalstage: Thefinal stage of psychosexualdevelopmentbeginswith thebiological changesthatusher in adolescence.▪Adolescents generallydesire sexual gratificationthroughintercoursewitha member of the other sex.

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4Evaluation•Freud’sviews aboutthe anal stage haveinfluenced child-care workers torecommend that toilettraining not be started too early or handled punitively.oHisemphasis on the emotional needs of children has influenced educators tobe more sensitive to the possible emotional reasons behind a child’smisbehavior.•Freud’swork has also been criticized.oFor one thing,Freud developedhistheoryon thebasis ofcontacts with adultpatients (mostly women)(Henley, 2019), rather thanobservingchildrendirectly.oSomeof Freud’s own disciples,including ErikErikson,believethat Freudplacedtoo much emphasis on basic instincts and unconscious motives.Erik Erikson’s Theory of Psychosocial Development•Erik Erikson(1902-1994)modified Freud’s theory andextendeditthrough the adultyears.oErikson’s theory, likeFreud’s,focuses on thedevelopment of the emotionallife and psychologicaltraits, but Eriksonfocuses on social relationships ratherthan sexual or aggressive instincts.oTherefore, Eriksonspeaks ofpsychosocial developmentrather thanofpsychosexual development.oFurthermore,Eriksonplacesgreater emphasis on the ego, or the sense of self.•Erikson(1963)extended Freud’s five stages to eight to include the concerns ofadulthood.oRather than labelhis stages after parts ofthe body, Erikson labeled themafterthelife crisis—an internalconflictthat attends each stage of psychosocialdevelopment—that people might encounter duringthat stage.•Early experiences affect future developments.oSuccessful resolution of each crisisbolsterschildren’ssense ofidentity—ofwhotheyare and whatthey standfor—and theirfutureexpectation of futuresuccess.•Erikson’s views,likeFreud’s, haveinfluencedchild rearing,early childhoodeducation,andchild therapy.oFor example,Erikson’s viewsaboutan adolescentidentitycrisis—aperiod ofinner conflict during which one examines one’s valuesand makes decisionsabout one’s life roles—haveentered the popular culture andhave affected thewaymany parents and teachers dealwith teenagers.

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5Evaluation•Erikson’s views are appealing in thatthey emphasize the importance of humanconsciousnessand choice.oThere is also some empirical support forthe Eriksonianviewthatpositiveoutcomesof early life criseshelp put people on the pathto positivedevelopment(Gfellner &Cordoba, 2017; Marcia, 2010).B.The Learning Perspective:Behavioral and Social Cognitive TheoriesBehaviorism•John B. Watsonargued that ascientificapproach to development must focusonobservablebehavior only and not on things like thoughts, fantasies,and other mentalimages.•Classical conditioningisasimple form of learningin which an originallyneutralstimulus comesto bringforth, or elicit, the response usually brought forth by asecond stimulus as a result of being paired repeatedlywith the secondstimulus.•Behaviorists argue that much emotional learningis acquiredthrough classicalconditioning.•Inoperantconditioning,children learnto do something because of itseffects.•B. F. Skinner introduced the key concept ofreinforcement.oReinforcers are stimuli that increasethe frequency of the behavior they follow.•Skinner distinguished between positive and negative reinforcers.oPositivereinforcersincrease the frequency of behaviors when they areapplied.Foodandapprovalusually serve as positive reinforcers.oNegativereinforcersincrease the frequency of behaviors when they areremoved.Fearacts as a negative reinforcer inthat its removal increases thefrequency of the behaviors preceding it.•Extinctionresults from repeated performance of operant behavior withoutreinforcement.oPunishmentsare aversive events that suppress ordecreasethe frequency of thebehavior they follow.•Operant conditioning is used every day in thesocializationof young children.oParents and peers influence children to acquire behavior patterns they considerto be appropriate to their gender through the elaborate use of rewards andpunishments.oBoys may ignore other boys when they play with dolls and housekeeping toys,but play with boys when they use transportation toys. This type of conditioningis obviously restrictive and harmful when it countersthe child’s personal

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6desires.Social Cognitive Theory•Social cognitivetheoristssuch as Albert Bandura(1986, 2011)have shown thatmuch learning occurs byobserving other people, reading, and viewing charactersinthe media.•Observational learningoccurs when children observehow parents cook, clean, orrepair a broken appliance.•Insocialcognitive theory, the people after whomonepatternsone’sown behaviorare termedmodels.Evaluation of Learning Theories•Learningtheories allow peopletoexplain, predict, and influence many aspects ofbehavior.•Manyof the teachingapproaches usedin educational TV showsare basedonlearning theory.C.TheCognitive Perspective•Cognitive theorists focus on people’s mental processes.•One cognitive perspective iscognitive-developmental theory, advanced by Swissbiologist Jean Piaget (1896-1980) and further developed by many theorists.oThistheory holds that the child’s abilities to mentally represent the world andsolve problems unfold as a result of the interaction of experience and thematuration of neurological structures.Cognitive-Developmental Theory•Through his studies, Piaget realized that when children answered questionsincorrectly,their wronganswers still often reflected consistent—although illogical—mental processes.•Piaget usedthe followingconceptsto describe and explain cognitive development.oSchemes: It is apattern of action or mental structure that is involved inacquiring or organizing knowledge.oAdaptation: Itistheinteraction between the organism and the environment.Itconsists of assimilation andaccommodation, which occur throughout life.oAssimilation: Itistheprocess by which someone responds to new object oreventsaccording to existing schemes or ways of organizing knowledge.

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7oAccommodation: Itisthemodification of existing schemes to permit theincorporation of new events or knowledge.oEquilibration:It is thecreation of an equilibrium, or balance, betweenassimilation and accommodation.Piaget’sStagesof Cognitive Development•Piaget identified four major stages of cognitivedevelopment:sensorimotor,preoperational,concrete operational, andformal operational.•BecausePiaget’stheory focuses on cognitive development,its applications areprimarily in educational settings.•Piaget’s theory ends with formal operational thought.Evaluation•Manyresearchers, using a variety of methods,find that Piaget mayhaveunderestimatedtheages when children are capable of doing certainthings.oIt alsoappears that many cognitive skills may develop graduallyand not indistinct stages.Information-Processing Theory•Many psychologists and educators speak of people as having working or short-termmemory and a more permanent long-term memory (storage).oThus, many cognitive psychologistsfocus on informationprocessing inpeople—theprocesses by which people encode (input) information, store it(long-term memory), retrieve it (place it in short-term memory), andmanipulate it to solve problems.•People’sstrategiesfor solving problems are sometimes referred to astheir“mentalprograms” or “software.”oIn this computer metaphor,people’sbrains are the “hardware” that runstheirmental programs.oPeople’sbrains—containing billions ofbrain cells calledneurons—becometheirmost “personal”computers.•When psychologists who study information processing contemplate cognitivedevelopment, they are likely to talk in terms of thesizeof the person’s short-termmemory and thenumber of programsshe or he can run simultaneously.

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8D.TheBiological Perspective•The biological perspective directly relatesto physicaldevelopment: to gainsin heightand weight;developmentof the brain;anddevelopmentsconnected with hormones,reproduction, and heredity.EvolutionaryPsychology and Ethology:“Doing What Comes Naturally”•Evolutionarypsychology and ethology were heavily influenced by the19th-centurywork ofCharles Darwinand by the workof20th-century ethologistsKonrad Lorenz,and Niko Tinbergen.•Ethology—study of behaviors that are specificto aspecies—is concernedwithinstinctive,or inborn,behavior patterns.•The fieldofevolutionary psychologystudiesthe ways in which adaptation andnatural selection areconnected with mental processes and behavior.oOne ofthe concepts of evolutionary psychology is that not onlyphysical traitsbut alsopatterns of behavior, includingsocial behavior, evolveand aretransmitted geneticallyfrom generation to generation.oThe behavior patterns are termedinstinctiveorspecies-specificbecause theyevolved within certainspecies.•The nervous systems ofmost, and perhaps all, animalsare “prewired” to respondtosome situations in specificways.oThese behaviors are “built in,” or instinctive.oThey are also referred to as inbornfixed action patterns(FAPs)—astereotyped pattern of behavior that is evoked by a “releasing stimulus.”•During prenatal development, genes and sex hormones are responsible for thephysical development of female andmale sex organs.•Researchinto the ethological perspectivesuggests that instinct may play a role inhuman behavior.E.The Ecological Perspective•Ecologyis the branch of biology that deals withtherelationshipsbetween livingorganisms and the environment.•Theecological systems theoryof developmentaddresses aspects of psychological,social, and emotional development as well as aspects of biological development.oEcological systems theorists explaindevelopmentin terms of theinteractionbetweenpeopleand the settings in which they live(Bronfenbrenner & Morris,2006).•According toUrie Bronfenbrenner(1917-2005), forexample,peopleneed to focus on

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9the two-way interactionsbetween the child and the parents, not just maturationalforces(nature) or child-rearing practices (nurture).oBronfenbrennersuggested thatpeoplecan view the setting orcontexts of humandevelopmentas consisting of multiple systems, eachembedded within the nextlarger context(Bronfenbrenner & Morris, 2006;Losike-Sedimo, 2018).•From narrowest to widest,Bronfenbrenner’ssystemsareas follows:oMicrosystem: Thisinvolves theinteractions of the child and otherpeoplein theimmediate setting, suchas the home, the school,or the peer group.oMesosystem: Thisinvolves theinteractions ofthevarious settings withinthemicrosystem.For instance, thehome andtheschoolinteract duringparent–teacherconferences.oExosystem: Thisinvolves theinstitutions in whichthechild does not directlyparticipate but which exertanindirectinfluence on the child.For example, theschool board is part of the child’s exosystem because board members put togetherprograms for the child’s education, determine what textbooks will be acceptable,and so forth.oMacrosystem: Thisinvolves theinteraction of children with the beliefs, values,expectations, and lifestyles of their cultural settings.oChronosystem: Thisconsidersthechanges that occur over time.For example, theeffects of divorce peak about a year after the event, and then children begin torecover.F.The Sociocultural Perspective•The socioculturalperspectiveteaches thatpeople are social beings who are affected bythe cultures in whichthey live.•Developmentalists use the termsocioculturalin a couple of different ways.oOne refers quite specifically to thesociocultural theoryof Russian psychologistLev Semenovich Vygotsky(1896-1934).oThe other addresses the effect of human diversity on people, including suchfactors as ethnicity and gender.Vygotsky’s Sociocultural Theory•Whereas genetics is concerned with the biological transmission of traits fromgeneration to generation,Vygotsky’s(1978)theoryis concerned with thetransmission of information and cognitive skills from generation to generation.oLike Piaget,Vygotsky sees the child’s functioning as adaptive, and the childadapts to his or her social and cultural interactions.•Key concepts in Vygotsky’s theory includethe following:

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10oZone ofproximal development(ZPD): This refers toa range of tasksthatachild can carry out with the help of someone who is more skilled, as in anapprenticeship.oScaffolding: This isVygotsky’sterm fortemporary cognitive structures ormethods of solving problems that help the child as he or shelearnsto functionindependently.G.HumanDiversity•The sociocultural perspective asserts thatpeoplecannot understand individuals withoutawareness ofthe richness oftheir diversity(Markus, 2016; Tatto et al., 2017).oFor example, people differ in their ethnicity(culturalheritage, race,language, andcommon history), their gender, and their socioeconomic status.•Studying diversity is important so that students have appropriate educationalexperiences.oTo teach students and guide their learning, educators need to understandchildren’s family values and cultural expectations.•Gender is another aspect of human diversity.oIt is the psychological state of being male or being female, as influenced bycultural concepts of gender-appropriate behavior.oExpectations of females and males are often polarized by cultural expectations.oMales may differ from females in some respects, but history has created moreburdens for women than men as a result.oHistorically, females have been discouragedfrom careers in the sciences, politics,and business.oWomen today earn more than half of the undergraduate degrees in the so-calledSTEM field of biology, chemistry and mathematics (Cheryan et al., 2017).oWomen are making inroads into academic and vocational spheres such asmedicine, law engineering, and the military—traditionally male fields.oMost college students in the United States are female, but there remain many partsof the world in which women are prevented from obtaining an education(Yousafazi & Lamb, 2013).III.Controversies in DevelopmentA.The Nature-Nurture Controversy•Researchers are continually trying to sort out the extentto which human behavior is theresult ofnature(heredity)and ofnurture(environmental influences).oScientists seek the natural causes ofdevelopmentin children’s genetic heritage,

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11the functioning of thenervous system, and in maturation.oScientists seek theenvironmental causes of development in children’s nutrition,cultural and family backgrounds, and opportunitiesto learn about theworld,including cognitive stimulationduring early childhood and formal education.•Today,nearly all researchers agreethat nature and nurture play important roles in nearlyevery area of development.B.TheContinuity-Discontinuity Controversy•Some developmentalists view human development as acontinuous process in which theeffects of learning mountgradually, with no major sudden qualitative changes.oIn contrast, other theorists believe that a number of rapidqualitative changes usherin new stages of development.•Stage theorists such as SigmundFreudand JeanPiagetsawdevelopmentasdiscontinuous.oThey sawbiological changes as providing the potential for psychologicalchanges.•Certain aspects of physical development do occur in stages.oHowever, psychologists disagree on whether developments in cognition occur instages.C.The Active-Passive Controversy•Historical views of childrenas willful and unruly suggestthat people have generallyseen children as active, even ifmischievous (at best)or evil (at worst).oJohnLocke introduced aview of children aspassive beings (blanktablets);experience“wrote” features ofpersonality and moralvirtue on them.•At one extreme, educators who viewchildren as passivemay assume that theymustbemotivated tolearn by their instructors.oAt the other extreme, educators who viewchildren as active may assume that theyhave a naturallove of learning.•These debates are theoretical.oScientists value theoryfor its ability to tie together observations and suggestnewareas of investigation, but scientists also follow anempiricalapproach.oThat is, they engage in research methods to find evidence for or against varioustheoretical positions.IV. How do We Study Development?•Strong arguments orreference to authority figures are not evidence.•Scientific evidence is obtained only by gathering sound information and conducting

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12research.A.Gathering Information•Researchers use variousmethods to gatherinformation.oFor example,they may ask teachersor parents to report on the behavior ofchildren, useinterviews or questionnaires with adults, or study statisticscompiledby the government or the United Nations.Naturalistic Observation•Naturalistic-observationstudies are conducted in“thefield”;that is, in the natural,or real-life, settings in which they happen.oIn field studies,investigators observe the natural behaviorof children insettings such as homes, playgrounds, andclassrooms and try not to interferewith it.The Case Study•Thecase studyis a carefully drawn account of the behavior of an individual.oParents whokeep diaries of their children’s activities are involved ininformalcase studies.•In addition to direct observation, case studies may include questionnaires,standardized tests—a test in which an individual’s score is compared to the scoresof a group of similar individuals—and interviews.B.Correlational:Putting Things Together•Researchersusethe correlational methodto determine whether one behavior or traitbeing studiedis related to,or correlated with,another.•Correlation coefficientisa numberranging from+1.00 and–1.00that expresses thedirection (positive or negative) and strength of the relationships between two variables.•Positive correlationis a relationship between two variables in which one variableincreases as the other increases.•Negative correlationis a relationship between two variables in which one variableincreases as the other variable decreases.Limitations of CorrelationalInformation•Correlational information can reveal relationshipsbetween variables, butitdoes not

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13show cause and effect.•It may seem logical to assume that exposure to violentmedia makes people moreaggressive, but it may also bethat more aggressive peoplechooseviolent media.oThis research bias is termed aselection factor.C.The Experiment: Trying Things Out•The experiment is the preferred method for investigatingquestions of cause and effect.•In theexperiment, a group of researchparticipants receives a treatmentand anothergroup does not.oThe subjects are then observed to determine whether the treatment changes theirbehavior.•Experiments are usually undertaken to test ahypothesis—a proposition to be tested.Independent and Dependent Variables•Independent variableisavariable whose presence is manipulatedby theexperimentersso that itseffects can be determined.•Dependent variableis a measure of an assumed effect ofanindependent variable.Experimental and ControlGroups•Subjectsin theexperimental groupreceive the treatment,whereas subjects in thecontrol groupdo not.oAll otherconditions are held constant for both groups.Random Assignment•Subjects should be assignedto experimental or control groups on achance or randombasis.•Ethical and practical considerationspreventresearchers from doingexperimentsonthe effects of many life circumstances, such as divorce or different patternsof childrearing.•When experiments cannot ethically be performed on humans, researchers sometimescarry them out withanimals and try to generalize the findings to humans.D.Longitudinal Research: Studying Development over Time•Inlongitudinal research,thesame people are observed repeatedly over time,andchanges indevelopment, such as gains in height or changes in mentalabilities,are

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14recorded.•Incross-sectional research,children of different agesare observed and compared.oIt is assumed that when a large number of children are chosen at random, thedifferences found in the older agegroups are a reflection of how the youngerchildren willdevelop, given time.Longitudinal Studies•TheTerman Studies of Genius,begunin the 1920s,tracked children with highIQscores for more than 50 years.oMale subjects, butnot femalesubjects,went ontohigh achievementsintheprofessional world.oContemporary studies of women show that women with high intelligencegenerallymatch the achievements of men and suggest thatwomen of the earlierera were heldback by traditionalgender-role expectations.•Most longitudinal studies span months or a few years, not decades.oFor example, briefer longitudinal studies have found that the children ofdivorced parents undergo the most severe adjustment problems within a fewmonths of the divorce, peaking at about a year.•Longitudinal studieshave drawbacks.oFor example, it can be difficult toenlistvolunteersto participateina study thatwilllast a lifetime.oMany subjects fall out of touch asthe years pass; others die.Cross-Sectional Studies•Because of the drawbacksof longitudinal studies, most research that compareschildren of different ages is cross-sectional.•A major challenge to cross-sectional research is thecohort effect.oA cohortis a group of people born atabout the sametime.oAs a result, they experience culturaland other events unique to their age group.oIn other words, children and adults of different ages are not likely to haveshared similar cultural backgrounds.•Children of pastgenerations also grew up with different expectations about genderroles and appropriate social behavior.oWomen in the Terman study generally chose motherhood over careers becauseof the times.•In longitudinal studies, researchers know that they have thesame individuals as theyhave developed over 5, 25, even 50 years or more.oIn cross-sectional research, researchers can only hope that they will be

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15comparable.Cross-Sequential Research•Cross-sequentialresearchcombines the longitudinal and cross-sectionalmethodsso that many of their individual drawbacks areovercome.•In the cross-sequential study, the full span ofthe ideal longitudinal study is brokenup into convenientsegments.•Assume thatresearcherswish to follow the attitudes of children toward gender rolesfrom theage offourthrough the age of 12.oThe typical longitudinal study would take eight years.oResearchers can, however, dividethis eight-year span in half by attaining twosamples ofchildren (a cross-section) instead of one:four-year-oldsand eight-year-olds.•An obvious advantage to this collapsed method isthat the study is completed in fouryears rather thaneight years.oStill, the testing and retesting of samplesprovides some of the continuity of thelongitudinal study.•By observing both samples at the age of eight (atimelagcomparison),researcherscan also determine whether theyare, in fact, comparable or whether the four-yeardifferencein their birth date is associated with a cohort effect.E.EthicalConsiderations•Researchers adhere to ethical standards that are intended to promote the dignity of theindividual, fosterhuman welfare, and maintain scientific integrity.•These standards also ensure that they do not use methods ortreatments that harmsubjects.oResearchers are not to use methods that may do physical or psychological harm.oParticipants (and parents, if participants are minors) must be informed of thepurposes of the research and about the research methods.oParticipantsmust provide voluntary consent to participate in the study.oParticipantsmay withdraw from the study at any time, for any reasonoParticipantsshould be offered information about the results of the study.•These guidelines present researchers with a number of hurdles toovercome beforeproceeding with and while conducting research, but because they protect the welfare ofparticipants, the guidelines are valuable.

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16Discussion TopicsNature or Nurture?Few traits are influenced purely by nature or nurture. Nature seems to dictate predominantlyphysical characteristics, such as blood type and eye color.Bycontrast, nurture influences learnedabilities such as the specific language that one speaks. Babies are born with the ability tounderstand all the phonemes in the world’s languages.Butby six months,theycan onlydistinguish the phonemes in the languages being spoken around them. Most characteristics areinfluenced by a combination of nature and nurture. Point out to students that most psychologicaltraits are influencedby both of these forces, but physical characteristics may also be a result ofnature and nurture. For instance, weight is influenced by a person’s genetic makeup and bythediets in their environment.Everyday Examples of Classical Conditioning and Operant ConditioningHelp students understand how classical conditioning affects their behavior by pointing out a feweveryday examples. This can also help students master the confusing terminology associatedwith classical conditioning. Point out that this is really a learning of association.Following aresomeexamples.•ThunderstormsoUS= loud clap of thunderoUCR= jump or tense upoCS= lightningoUCR= tense up•Fast-foodcommercialoUS= picture of juicy, delicious burgeroUCR= hunger or salivationoCS= commercial jingle or songoUCR= hungerNote:Unlearned or unconditioned stimulus (US), unlearned or unconditioned response (UCR,learned or conditioned stimulus (CS)Operant conditioning is learning the effectsthata particular behavior incurs, whether that is areinforcement or a punishment. Stress that reinforcements increase the frequency of a behaviorand can be positive (something added) or negative (something taken away).Explain that thepositive and negative should be associated with addition or subtraction, not with goodor bad.The following are someeveryday examples.•Positive reinforcement: A teenager cleans her room to earn allowance.

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17•Negative reinforcement: A teenager cleans her room to stop the annoying nagging of herparents. Punishments decrease the frequency of a behavior and canbe either positive ornegative.•Positive punishment: A teenager is given additional choresfor failing to clean her room.•Negative punishment:A teenager is grounded for failing to clean her room, that is, hersocial life is removed. Note thata student who issent tohisroomthat isfilled withgadgets, such as aTV,acomputer,and aniPod, may not beexperiencinga punishment.Vygotskyvs.Piaget in TeachingThe developmental theories of Piaget and Vygotsky have implications for education.Havestudents discuss the following questions in terms of the perspectives of each theorist:WouldPiaget or Vygotsky see the value ofpeer tutoring? How much teacher intervention should occurin discovery learning? Which theorist provides a basic framework for helping teachers to knowwhat level of educational material is appropriate to teach to children of various ages? What arethe strengths of this perspective,and what are its limitations?Collecting DataWhile studying development, researches use various methods to gather information. Accordingto the text, researchers might ask the parents about the behavior of their children. Also,information about the development can be achieved by observation. What other methods canresearchers use to gather relevant data, while studying development? Can they use surveymethods? What would be the targeted audience for such a survey?Does the data from alreadyavailable research stay true to the changing conditions andtrends in the society? Can one rely onthe information that is already there?Discussthe different methods thatareavailable forcollecting dataand their advantages over the ones discussed in this chapter.Class Activitiesand ProjectsDesigning StudiesThere are many ways to examine issues of interest to child development. One issue that has oftenbeen investigated is the theory that watching violent TV shows causes aggression in children.Have students (either individually or in small groups) explain how they would study this usingthe methodsgiven below.1.Naturalistic observations: Where would you conduct these observations? What behaviorswould you look for?2.Case study: What kinds of behaviors would interestyou?3.Correlational study: What are the variables you are correlating? What would a positive

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18correlation indicate?What would anegativecorrelationindicate?4.Experimental study: What is theindependentvariable (IV)?What is thedependentvariable(DV)?What is theexperimental group?What is thetreatment group?Make sure students discuss what evidence would support and contradict the theory, as well as thepros and cons of each methodology.Modifying Child Behavior Using the Principles of Operant ConditioningHave students write a short paper making recommendations to a parent dealing with theirtwo-year-old’s temper tantrums to get a cookie in the grocery store. Make surestudentsidentifyparent responses that would reinforce the tantrums and make them increase (e.g., giving attentionto the childorgiving him or herthe cookie),as well as behaviors that would extinguish thebehavior (e.g., ignoring them). Also, have students include a section on the possibleconsequences of spankinginthis situation. Areview by E. Gershoff (2002) is available inPsychological Bulletin, 128(4),539-579which students canuse for this activity.Child Rearing Over Three GenerationsHave students interview their parents and grandparents about their experiences as children.Include in the interviewsuch parenting practices as sleeping arrangements, infant feeding,discipline, household chores and responsibilities, after school activities, and rules for dating inadolescence. Encourage students to be creativewhen theythink about other changes and/ordifferencesforhow children experienced childhood, even in recent times. Have studentsorganize their findings into a chart;list theirexperiences down the left-hand side of the paper andtheirthreegenerations across the top. Havestudentshighlight the differences that surprised themthe most.Scaffolding in Real Life: Assembling Puzzles with ChildrenIf possible, invite children of various ages to class (i.e., atwo-year-old,four-year-old, andsix-year-old). Have students help the children put together age-appropriate puzzles. Then havestudents discuss the ways in which theyhelped toscaffold the children’s thinking.Studentswillnoticethat the degree of assistance givento the younger childrenwas more(perhaps showingthem where the pieces go)when comparedwiththe older children (perhaps only suggestingtostart with the outside edges). This can also work as a class discussion if child participants are notavailable.Demonstrationof Classical Conditioning: 3, 2, 1, POP!

Lecture Notes for HDEV: Human Lifespan Development, 6th Edition - Page 20 preview image

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19A simple demonstration can help students grasp the concepts involved in classical conditioning.Kohn and Kalat (1991)discussedan activity involvingseveral air-filled balloons and a long dartor pin.To replicate this activity, studentsshould inflate theballoonsasmuchas possible so theywill easily pop. Tape the balloons to a table in front of the class. Ask students to pay attention totheir responses as you conduct the demonstration.Then, count down “3, 2, 1,” and pop the firstballoon(if you are in a large auditorium, try doing this activity near a microphone so that theloud pop produces a startle response). Repeat this for the next few balloons. On the last balloon,count down, but then missthe balloon. Most students willactuallynot flinch to the lastcountdown. Ask the students to describe their responses. Then, help students to identify theaspects of classical conditioning:UCS= loud popping sound, UCR= flinching or other startlereaction, CS= countdown or hand movement, UCR = clinching muscles to prevent flinching.Studentsmay have trouble identifying these components.Correlational Research and the Effects of Divorce on ChildrenHave students work through the following research questions concerning the effects of divorceon children. This activity can be usedas a way of expanding their understanding of researchdesign and related concepts (naturalistic,correlational,experimental designs, developmentalchange investigation, independent and dependent variables, cause and effect, confounds,andethical considerations).1.Why do we think there might be consequences of divorce on child development?Whatkinds of naturalistic observational research may have supported these conclusions?2.What might be some of the specific consequences of divorce on child development?Whatkinds of correlational studies might be conducted by developmental psychologists toexamine whether or not there were reliable and valid relationshipsbetween divorce andthese consequences?What are the possible confounding variables in this type of research?3.What might be some of the issues concerning age differences in relationships betweendivorce and negative consequences? How could these be examined?4.What kind of evidence mightsuggestthat divorce causes negative consequences?Whatother explanations might there be for any correlational findings between negativeconsequences and divorce? What kind of research needs to be conducted to determinecause and effect in this case?In this research,whatis (are) the independent variable(s),andwhatis (are) the dependent variable(s)?5.In regard to ethical concerns, would any of this research be questionable? What mightthose be,and how should a researcher deal with them?Theoretical Positions of Developmental TheoriesOne way for students to appreciate the similarities and differences of the many developmentaltheories presented in this chapter istoexaminethe stance each theory takes on the controversies

Lecture Notes for HDEV: Human Lifespan Development, 6th Edition - Page 21 preview image

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20of child development (i.e., nature-nurture, active-passive, and continuity-discontinuity).Thetheories can be discussed in small groupsoras a class.Nature-NurtureActive-PassiveContinuity-DiscontinuityFreud’s Theory ofPsychosexualDevelopmentBothPassiveDiscontinuousErikson’s Theoryof PsychosocialDevelopmentBothActiveDiscontinuousWatson’sBehaviorismNurturePassiveContinuousBandura’s SocialCognitive TheoryNurtureActiveContinuousPiaget’sCognitive-DevelopmentalTheoryBothActiveDiscontinuousInformation-Processing TheoryBothActiveContinuousLorenz’s EthologyBoth (primarilynaturebut earlyexperience isnecessary)PassiveDiscontinuous (due toearly critical period)Bronfenbrenner’sEcological SystemsTheoryBothActiveContinuousVygotsky’sSocioculturalTheoryBothActiveContinuousConducting ResearchAsk studentsto selectsomenegative(coming late to the class)and positive(taking notes in theclass)behaviorsthat are common among students.After selecting certain types of behaviors, askstudents to make a note of the governing factors ofsuch behaviors.What methods would theyuse to assess such behaviors? If time permits, students should conduct a survey in their class orin groups to identify the governing factors of the behaviors chosen.

Lecture Notes for HDEV: Human Lifespan Development, 6th Edition - Page 22 preview image

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21AnswerKey:Truth or Fiction?As an introduction to each chapter, several statements are presented for students’consideration.This is an excellent first class activity. For each question,you can ask students how confidentthey are about their answers and, if they were confident (especially about questions they gotwrong), ask them where they thought their knowledge about the topic came from—personalexperience,anotherperson,anexpert perhaps, intuition,or commonsense.Use this discussion tohighlight the importance of investigation and hypothesis testing in developmental psychology foraccurate understanding of behavioral phenomena.Use of the scientific method involves collecting data on more than one person.The observationsneed to be made by an unbiased observer,andreliable and valid measurement instruments needto be used. In addition,careneeds to be taken to control for confounding influences. Many timesover the course of the semester, students will feel they already “know” something about a topicin child development only to find that the research does not support their position. Remindthemabout this discussion early andoften.1.During the Middle Ages, children were often treated as miniature adults.Truth.This does not mean that they weregiven more privileges, however. Instead,morewas expected of them(1-2).2.Nail bitingand smoking cigarettes are signs of conflict experienced during early childhood.Fiction.Actually,there is no evidence that nailbiting and smoking cigarettes are signsofconflict experienced during early childhood.The statement must therefore beconsidered“fiction”(1-2a).3.Research with monkeys has helped psychologists understand the formation of attachmentin humans.Truth.Researchers have exposed monkeys andother nonhuman animals to conditions thatwould be unethical to use with humans(1-4c).4.To learn how a person develops over a lifetime, researchers have tracked some individualsfor more than 50 years.Truth.It is true that researchers have trackedsome individuals for more than 50years tolearn how a person developsover a lifetime. The Terman study didjust that. What are theadvantages anddisadvantages of longitudinal research ascompared with cross-sectionalresearch?(1-4d)

Lecture Notes for HDEV: Human Lifespan Development, 6th Edition - Page 23 preview image

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22Additional Reading MaterialKohn, A. & Kalat, J.W.(1992).Preparingfor an important event: Demonstrating themodernview of classical conditioning.Teaching of Psychology, 19(2),100–102.Video SuggestionsTheories of Development(1997, Insight Media, 29 minutes)This video provides an overview of thecognitive, psychosexual, psychosocial, behaviorist,social-learning, and sociocultural theories of child development.Piaget’s Developmental Theory: An Overview(1989, Davidson Films, 25 minutes)This videoprovidesagoodintroduction or review of basic concepts, including interviews withchildren by David Elkind.Erik Erikson: A Life’s Work(1991,FilmsMediaGroup, 38 minutes)This videointegratesbiographical information about Erikson with an overview of hiseight-stagepsychosocial theory of human development.B. F.Skinner: A Fresh Appraisal(1999, Davidson Films, 40 minutes)This video includesboth archival and recent footage and is narrated by Murray Sidman.Itclarifiessome myths aboutbehaviorism in the context of presentation of his theory and research.His Own Best Subject: A Visit to B.F. Skinner’s Basement(2000, Davidson Films, 20 minutes)This video consists ofSkinner’s daughters discussingtheir father’saffectiontoward themandthe kind ofattentionhe gaveto them. They alsogive a tour of the basement in which heused towrite.Vygotsky’s Developmental Theory: An Introduction(1994, Insight Media, 28minutes)This video provides a presentationof the basic concepts and vocabulary of Vygotsky’sconstructivist educational approach to development.Innocence: What is a Child?(1997, Films for the Humanities and Social Sciences, 54 minutes)This video provides historicalperspectives on the construct of childhood innocence from the latenineteenthcentury to the present.Total Baby(1995,Filmakers Library, 59 minutes)This video discusseschildrearing as a reflection of societal and cultural views of the era andexamines ideas about childrenby different theorists (Aristotle,Dr. Spock).

Lecture Notes for HDEV: Human Lifespan Development, 6th Edition - Page 24 preview image

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23Research Methods for the Social Sciences(1995, Insight Media, 33 minutes)This video provides anoverview of thekey concepts of experimental design and reviews thedifferentsteps of the scientific method.Research Methods in Psychology(2001, Insight Media,28minutes)This video provides anoverview of theobservational and descriptive research designs (usesexample of correlational findings on aggressive behavior andvideo games).Key TermsDevelopmentalpsychologyLife-span perspectiveBehaviorismMaturationPsychosexual developmentStage theoryPsychosocial developmentLifecrisisIdentity crisisClassical conditioningOperant conditioningReinforcementPositive reinforcerNegative reinforcerExtinctionSocial cognitive theoryCognitive-developmental theorySchemeAdaptationAssimilationAccommodationEquilibrationEthologyEvolutionary psychologyFixed action pattern(FAP)EcologyEcological systems theoryMicrosystemMesosystemExosystemMacrosystemChronosystemZone of proximal development(ZPD)ScaffoldingNatureNurtureEmpiricalNaturalistic observationCase studyStandardized testsCorrelation coefficientPositive correlationNegative correlationExperimentHypothesisIndependent variableDependent variableExperimental groupControl groupLongitudinal researchCross-sectional researchCohort effectCross-sequential researchTime lag

Lecture Notes for HDEV: Human Lifespan Development, 6th Edition - Page 25 preview image

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1Chapter 2H e r e d i t y a n d P r e n a t a l D e v e l o p m e n tChapter OverviewThis chapter provides an overview of the biological processes of heredity and conception,including all of the basic structures (chromosomes, genes, and DNA) and processes (mitosis,meiosis, fertilization, and implantation) involved in the formation of a new human being.Students will learn the different causes and types of chromosomal and genetic abnormalities. Therelationship between genotype and phenotype in developmental outcomeis described, and thepotential disorders resulting from various chromosomal and genetic abnormalities are discussed.Research strategies for examining the contribution of genes and environment to development areintroduced. The chapter includes a discussion of infertility and genetic counseling, alternativepregnancy methods, and parental attempts to select the gender of their child. A brief discussionof the benefits of adopting children is presented. The chapter also describes the preimplantationgeneticdiagnosis process. Students will be able to compare the different stages of prenataldevelopment (germinal, embryonic, and fetal), after reading this chapter. Sexual differentiation isexplained in detail. The role of amniotic sac, amniotic fluid, and placenta in the development anddelivery process is presented. The changes in the fetus throughout the pregnancy cycle areexplained. Students will be able to identify the different types of teratogens that can affect thehealth of the developing fetus as well as the stage of development where harm can occur, afterreading this chapter. This chapter describes the impact of drugs that are the most likely to affectthe healthy development of a fetus (aspirin, thalidomide, hormones, vitamins, heroin, methadone,marijuana, alcohol, cocaine, caffeine, and cigarettes). The chapter concludes with a discussion ofthe environmental effects on the development of the fetus such as prenatal exposure to lead andthe age of the parents at conception.Chapter Learning ObjectivesAfter reading the chapter, students should be able to accomplish the objectives given below.•Explain the difference between a gene and a chromosome, and explain how a baby’s sex isdetermined•Describe the processes of mitosis and meiosis•Identify the difference between monozygotic and dizygotic twins and describe how theyare developed•Describe the process of genetic transmission, or how traits are passed from parents tochildren•Discuss the causes and characteristics associated with chromosomal and genetic

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2abnormalities•Explain how Down syndrome occurs as well as its physical markers•Describe how sex-linked chromosomal abnormalities occur•Identify and compare the different sex-linked chromosomal disorders (Klinefeltersyndrome and Turner syndrome)•Identify and compare disorders that have been contributed to genes (PKU, Huntington’sdisease, Sickle-Cell Anemia, Tay-Sachs disease, and Cystic Fibrosis)•Identify and compare sex-linked genetic abnormalities (hemophilia, Duchenne musculardystrophy)•Identify and explain different prenatal testing techniques used for various genetic disorders•Describe how studies of kinship, adopted children, and identical (monozygotic) versusfraternal (dizygotic) twins are used to explore the relative influences of nature (heredity)versus nurture (environment)•Explain the formation of eggs and sperm and where conception takes place•To define the following terms: “ova,” “endometrium,” “sperm cells,” and “spontaneousabortion”•Discuss the causes of infertility and the methods that couples can use to conceive•Discuss the benefits of adopting children•Describe the preimplantation genetic diagnosis process•Define and compare the different stages of prenatal development (germinal, embryonic,and fetal)•Explain how sexual differentiation occurs•Describe the role the amniotic sac, amniotic fluid, and placenta play in the developmentand delivery process•Describe changes in the fetus throughout the pregnancy cycle•Identify the different types of teratogens that can affect the developing fetus’ health as wellas the developmental stage where harm can occur•Describe the impact of drugs that are the most likely to affect the healthy development of afetus (aspirin, thalidomide, hormones, vitamins, heroin, methadone, marijuana, alcohol,cocaine, caffeine, and cigarettes)•Describe the environmental effects on the fetus’ development such as prenatal exposure tolead and/or the parents’ age at conceptionChapter OutlineThe field of biology that studies heredity is calledgenetics.I. The Influence of Heredity on Development

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3•Genetic influences are fundamental in the transmission of physical traits, such as height,hair texture, and eye color.•Heredity appears to be a factor in almost all aspects of human behavior, personality, andmental processes (Loehlin & Martin, 2018; Plomin & Haworth, 2009;Polderman et al.,2015).•Genetic factors are also involved in psychological problems such as schizophrenia,depression, and dependence on nicotine, alcohol, and other substances (Leonardo & Hen,2006; Lewis et al., 2013; Viding et al., 2013).A. Chromosomes and Genes•Chromosomesare rod-shaped structures found in cells.•Genesare the biochemical materials that regulate the development of traits.oSome traits,such as blood type, appear to be transmitted by a single pair of genes,one of which is derived from each parent.oOther traits arepolygenic, that is, determined by several pairs of genes.•Genes are segments of strands ofdeoxyribonucleic acid (DNA)—genetic material thattakes the form of a double helix composed of phosphates, sugars, and bases.B. Mitosis and Meiosis•There are two types of cell division:mitosisandmeiosis.•Inmitosis, strands of DNA break apart, or“unzip.”oThe double helix then duplicates. The DNA forms two camps on either side of thecell, and then the cell divides.oEach incomplete rung combines with the appropriate “partner” (i.e., G and C, Aand T) to form a new complete ladder. The two resulting identical copies of theDNA strand separate when the cell divides; each becomes a member of a newlyformed cell.oAs a result, the genetic code is identical in new cells unlessmutations—suddenvariations in a heritable characteristic—occur through radiation or otherenvironmental influences.•Sperms and ova (“egg cells”) are produced throughmeiosis, orreduction division.oIn meiosis, the 46 chromosomes within the cell nucleus first line up into 23 pairs.The DNA ladders then unzip, leaving unpaired halves of chromosome.oWhen the cell divides, one member of each pair goes to each newly formed cell.Each new cell nucleus contains only 23 chromosomes, not 46.Each pair ofchromosomes splits so that one member of each pair moves to the new cell.•When a sperm cell fertilizes an ovum, humans receive 23 chromosomes from theirfather’s sperm cell and 23 from their mother’s ovum, and the combined chromosomes

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4form 23 pairs.oTwenty-two of the pairs areautosomes—pairs that look alike and possess geneticinformation concerning the same set of traits.oThe 23rd pair aresex chromosomes, which look different from otherchromosomes and determine one’s sex.C. Identical and Fraternal Twins•Now and then, a zygote divides into two cells that separate so that each develops into anindividual with the same genetic makeup.oThese individuals are identical twins, ormonozygotic (MZ)twins.•If the woman produces two ova in the same month and they are each fertilized bydifferent sperm cells, they develop into fraternal twins, ordizygotic (DZ) twins.•As women reach the end of their childbearing years,ovulation—releasing of an ovumfrom an ovary—becomes less regular, resulting in a number of months when more thanone ovum is released.D. Dominant and Recessive Traits•Eachmember of a pair of genes is termed asanallele.•When both of the allele for a trait, such as hair color, are the same, the person is said tobehomozygousfor that trait.•When the alleles for a trait differ, the person isheterozygousfor that trait.•When the effects of both alleles are shown, there is said to be incomplete dominance orcodominance.•When adominantallele is paired with arecessiveallele, the trait determined by thedominant allele appears in the offspring.oDominant traitis a trait that is expressed.oRecessive traitis a trait that is not expressed when the gene or genes involvedhave been paired with dominant genes.•People who bear one dominant gene and one recessive gene for a trait are said to becarriersof the recessive gene.E. Chromosomal and Genetic Abnormalities•Chromosomal or genetic abnormalities can cause health problems.oSome chromosomal disorders reflect abnormalities in the 22 pairs ofautosomes (such as Down syndrome); others reflect abnormalities in the sexchromosomes (e.g., XYY syndrome).oSome genetic abnormalities, such as cystic fibrosis, are caused by a single pair

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5of genes; others are caused by combinations of genes.oDiabetes mellitus, epilepsy, and peptic ulcers aremultifactorial problems;they reflect both a genetic predisposition and environmental contributors.F. Chromosomal AbnormalitiesDown syndrome•Down syndromeis usually caused by an extra chromosome on the21stpair,resulting in 47 chromosomes.•People with Down syndrome have characteristic features that include a rounded face,a protruding tongue, a broad, flat nose, and a sloping fold of skin over the innercorners of the eyes.Sex-Linked Chromosomal Abnormalities•A number of disorders stem from an abnormal number of sex chromosomes and aretherefore calledsex-linked chromosomal abnormalities.oMost individuals with an abnormal number of sex chromosomes are infertile.•Approximatelyonemale in 500 hasKlinefelter syndrome, which is caused by anextra X sex chromosome (an XXY sex chromosomal pattern).oXXY males produce less of the male sex hormonetestosteronethan normalmales.•Approximatelyonegirl in 2,500 has a single X sex chromosome and as a resultdevelopsTurner syndrome.oThe external genitals of such girls are normal, but their ovaries are poorlydeveloped and they produce littleestrogen—thefemale sex hormone producedmainly by the ovaries.•Approximatelyonegirl in 1,000 has an XXX sexchromosomal structure,calledTriple X syndrome.oSuch girls are normal in appearance but tend to show lower-than-averagelanguage skills and poorer memory for recent events.G. Genetic AbnormalitiesPhenylketonuria•The enzyme disorderphenylketonuria(PKU)is transmitted by a recessive gene andaffects aboutonechild in 8,000.•Children with PKU cannot metabolize an amino acid called phenylalanine, so it

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6builds up in their bodies and impairs the functioning of the central nervous system,resulting in mental retardation, psychological disorders, and physical problems.Huntington’s Disease•Huntington’s disease(HD)is a fatal, progressive degenerative disorder and adominant trait affecting approximatelyoneAmerican in 18,000.•Physical symptoms include uncontrollable muscle movements.•Psychological symptoms include loss of intellectual functioning and personalitychange.Sickle-Cell Anemia•Sickle-cell anemiais caused by a recessive gene.•In sickle-cell anemia, red blood cells take on the shape of asickle and clumptogether, obstructing small blood vessels and decreasing the oxygen supply.Tay-Sachs disease•Tay-Sachs diseaseis also caused by a recessive gene.•It causes the central nervous system to degenerate, resulting in death.Cystic Fibrosis•Cystic fibrosis, also caused by a recessive gene, is the most common fatal hereditarydisease among European Americans.•Children with the disease suffer from excessive production of thick mucus that clogsthe pancreas and lungs.Sex-Linked Genetic Abnormalities•Some genetic defects, such ashemophilia—a genetic disorder in which blood doesnot clot properly—are carried on only the X sex chromosome.oFor this reason, they are referred to assex-linked genetic abnormalities.•One form ofmuscular dystrophy, Duchenne muscular dystrophy,is sex linked.oMuscular dystrophy is characterized by a weakening of the muscles, which canlead to wasting away, inability to walk, and sometimes death.H. Genetic Counseling and Prenatal Testing

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7•Genetic counselorscompile information about a couple’s genetic heritage to explorewhether their children might develop genetic abnormalities.•Prenatal—before birth—testing can indicate whether an embryo or fetus is carryinggenetic abnormalities.•Although amniocentesis and chorionic villus sampling is discussed next, it should benoted that their use is declining due to blood testing and ultrasounds becoming moresophisticated and providing a clearer picture early on in the pregnancy.Amniocentesis•Amniocentesisis usually performed on the mother at 14-16 weeks after conception,although many physicians now perform the procedure earlier.oIn this fetal-screening method, the health professional uses a syringe (needle)to withdraw fluid from the amniotic sac.oThe fluid contains cells that are sloughed off by the fetus.oThe cells are separated from the amniotic fluid, grown in a culture, and thenexamined microscopically for genetic and chromosomal abnormalities.•Amniocentesis carries some risk ofmiscarriage—expulsion of an embryo or fetusbefore it can sustain life on its own, most often due to defective development—although the extent of the risk is unclear.Chorionic Villus Sampling•Chorionic villus sampling (CVS)is similar to amniocentesis but is carried outbetween the9thand12thweek of pregnancy.oA small syringe is inserted through the vagina into theuterusand sucks outsome threadlike projections (villi) from the outer membrane that envelops theamniotic sac and fetus.•CVS has not been used as frequently as amniocentesis because CVS carries a slightlygreater risk of miscarriage.Ultrasound•Health professionals use sound waves that are too high in frequency to be heard bythe human ear—ultrasound—to obtain information about the fetus.oThese waves are reflected by the fetus, and a computer uses the information togenerate a picture of the fetus. The picture is termed asonogram.Blood Tests

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