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Life Span Development Theories of Development – Ch. 2 Heredity and Environment – Ch. 3 June 10, 2004 Class #2 Chapter 2: Theories of Development Questions Central to Theories Do early experiences of breast-feeding or bonding or abuse linger into adulthood, even if they seem to be forgotten? How important are specific school experiences in human intelligence? Can a person develop moral values without being taught them? Does culture elicit behavior, e.g., is violent crime more common in one place than another; for example, in China or Canada? If your parents or grandparents schizophrenia, or alcoholism, will you develop them suffer from depression,? Of all questions—Why or Why not? When and How?, So What? What Theories Do Developmental theory— systematic statement of principles and generalizations that provides a coherent framework for studying development What Theories Do… Theories form basis for hypotheses that can be tested by research studies formulating right question is more difficult that finding right answers generate discoveries offer insight and guidance by providing coherent view Types of Theories Different Types grand theories—comprehensive, traditional theories originated in psychology minitheories—theories that focus on specific area of development originated more in sociology through study of social groups and family structures emergent theories—new, comprehensive groupings of minitheories multidisciplinary approach includes historic events and genetic discoveries Grand Theories Grand Theories—powerful framework for interpreting and understanding change and development that applies to all individuals in all contexts, across all contents Psychoanalytic Theory Psychoanalytic theory interprets human development in terms of motives and drives Behaviorism Behaviorism is built on laws of behavior and processes by which behavior is learned focus: ways we learn specific behaviors that can be described, analyzed, and predicted with scientific accuracy Laws of Behavior Conditioning—any process in which behavior is learned Classical conditioning —Ivan Pavlov process by which a neutral stimulus become associated with a meaningful stimulus stimulus and response (respondent conditioning) Operant conditioning—B. F. Skinner process by which a response is gradually learned via reinforcement or punishment also called instrumental conditioning Social Learning Extension of learning theory that includes modeling which involves people observing behavior and patterning their own after it Modeling process in which people observe, then copy behavior Alfred Bandura—most likely to occur if model is admired or observer is inexperienced self-efficacy motivates people to change themselves and their contexts Cognitive Theory Focuses on the structure and development of thought processes, which shape perceptions, attitudes, and actions. Example: Jean Piaget’s 4 Stages Emergent Theories Emergent theories arise from several accumulated minitheories and may be the new systematic and comprehensive theories of the future Sociocultural Theory Seeks to explain growth of individual knowledge, development, and competencies in terms of guidance, support, and structure supplied by the society human development is the result of dynamic interaction of the developing persons and their surrounding culture Sociocultural Theory Guided participation—tutor engages learner in joint activities, providing instruction and direct involvement in learning Apprenticeship in thinking—mentor provides instruction and support needed by novice Sociocultural Theory Zone of proximal development—range of skills learner can perform with assistance but not independently learner is drawn into learning by teacher Cultural variations: Basic principles are universal, but skills, challenges, and opportunities vary from culture to culture, depending on the values and structures of the culture’s society Epigenetic Theory Emphasizes the interaction between genes and the environment—the newest developmental theory stresses that we have powerful instincts and abilities that arise from our biological heritage. Timing and pace of certain developmental changes are genetically guided performism—everything is set in advance by genes and then is gradually manifested in the course of maturation What Theories Can Contribute Psychoanalytic theory has made us aware of importance of early childhood experiences Behaviorism has shown effect of immediate environment on learning Cognitive theory helps us understand how intellectual process and thinking affect actions Sociocultural theory has reminded us that development is embedded in a rich and multifaceted context Epigenetic theory emphasizes interactions between inherited forces and immediate contexts Eclectic Perspective This is the approach taken by most developmentalists in which they apply aspects of each of the various theories rather than staying with just one The Nature-Nurture Controversy Is it heredity or environment that shapes us? How much is a result of any given characteristics, behavior or pattern of development is a result of genes and how much is a result of experiences Policy and practice: nature/nurture theories are implicit in many public policies Theoretical Perspectives on Hyperactivity and Homosexuality AD/HD and homosexuality—How and to what extent are nature and nurture involved in each case? Evidence from AD/HD research that it can come from either Theoretical Perspectives on Hyperactivity and Homosexuality Earlier assumptions about homosexuality: more nurture than nature. As hypotheses tested, nurture was revealed as less crucial sexual orientation may be a matter of nature sexual expression may be a matter of cultural attitude (nurture) but not sexual orientation evidence supporting nature as main factor (e.g., affect of genetic linkage, prenatal hormones) Theoretical Perspectives on Hyperactivity and Homosexuality Ideology often adds to complexity and polarization of opinions on many subjects when nature and nurture are considered Important to separate assumptions from facts done via research and testing of hypotheses Why is someone gay or straight? Psychologists really don’t fully understand the causes of sexual orientation Lets look at some biological explanations… Concordance rates: MZ > DZ A homosexual gene? LeVay (1991): INAH3 Concordance rates Eysenck (1964) Bailey and Pallard (1991) Reported a higher incidence of homosexuality among men whose MZ twin was gay than among men whose DZ twin was gay Twin study Homosexual men Co-twin was more than twice as likely to be homosexual if the twins were MZ Bailey, Pallard, Neale, & Agyei (1993) Replicated earlier study using homosexual women Same results A homosexual gene? Hamer et al. (1993) Examined families of homosexual men Found significantly more gay relatives on mother’s side of family Maternal uncles and sons of maternal aunts (male cousins) Might their be a homosexual gene on the X chromosome? Hamer et al. (1993) They continued the investigation and found that most of the homosexual men had a region in the X chromosome that was similar suggesting a genetic basis… But not for all suggesting another reason Important implication to all this: It may be possible for non-homosexual women to pass on this gene LeVay (1991) Examined hypothalamic tissue from: 19 gay men, all of whom died of AIDS 16 heterosexual men, six of whom had died of AIDS 6 women of unknown sexual orientation LeVay (1991) Found neuroanatomic differences between homosexual and heterosexual men… INAH3 was two to three times larger in heterosexual men than in gay men LeVay (1991) As the first suggestion that there was a neuroanatomic difference between gay and heterosexual men, LeVay's finding garnered a great deal of public attention, and a great deal of controversy about both its scientific and its social implications Other reasons??? Investigators have assessed every possible psychological cause of sexual orientation that you could think of… The findings when looking at the backgrounds of those that are heterosexual, homosexual, or bisexual are? Chapter 3: Heredity and Environment What is a gene made out of? Genes are made from chromosomes. People have 23 pairs of chromosomes. DNA consists of a double helix, whose parallel strands consist of both pairs held together by hydrogen bonds. Each chromosome in the DNA contains instructions for stringing together amino acids. These instructions are used in different combinations with the chemicals adenine (A), thiamine (T), guanine (G) and cytosine (C). Conception Fertilized egg with two pronuclei Within 72 hours it’s divided into 8 cells Once the sperm penetrates the egg, the two nuclei fuse to become one, with 23 chromosomes from the father and 23 chromosome from the mother. A zygote is the single cell formed from the fusing of the sperm and ovum. After four days there are about 100 cells and it is now called a blastocyst. The organism’s genetic inheritance is set for life once the chromosomes pair up. Is it a boy or a girl? In the 23rd pair of chromosomes women are XX and men are 1. XY Every ovum that the woman produces is XX Men will produce half 2. Y sperm and half X sperm because his 23rd pair contain both 3. Different factors can determine the sex of the embryo such as when: A man carries a gene that causes his X or Y gene to be immobile. The alkaline or acidity levels of a woman’s uterus can help either the X or Y gene. Stress can cause an XY embryo to be expelled. 1. 2. 3. 4. A zygote may split in the early stages of development, which creates separate identical zygotes Monozygotic twins are identical because they originate from the same zygote Dizygotic twins are formed when two separate ova are fertilized by two separate sperm. They share half their genes, similar to siblings. Factors that can increase the chances of twins are: A woman’s age A woman’s ethnic group Medical intervention A family history of having twins Let’s split! Mary-Kate and Ashley Olsen What else do genes do? Once the zygote reaches it’s eight-cell stage, cells begin to specialize to become different parts of the body. Genes code protein so that they can give instructions to other genes to shut on and off at different stages of life. For instance, to absorb nourishment, to multiply and to die. Phenotype is a person’s actual appearance and behavior, which are the results of both genetic and environmental influences How do gene’s interact? Additive genes interact additively so that there are fairly equal contributions from all the genes involved. They affect traits such as skin color and height. A dominant gene is the member of an interacting pair of alleles whose influence is more evident in the phenotype. A recessive gene is the member of an interacting pair of alleles whose influence is less evident in the phenotype X-linked genes are genes located on the X chromosome. Genotype vs. Phenotype Genotype is an organism’s entire genetic inheritance, or genetic potential. For instance, you might have inherited the genes that could lead you to become a great mathematician. Another example is that you may have inherited blue eyes. Phenotype is a person’s actual appearance and behavior, which are the result of both genetic and environmental influences. For instance, you might have the genes to become a great mathematician, but without the right environment, your talent may never be recognized. What is behavior genetics? Behavior genetics is the study of the genetic origins of psychological characteristics, such as personality patterns, psychological disorders and intellectual abilities. Sadness is one personality trait that is studied in behavior genetics. Alzheimer’s Disease Alzheimer’s is only purely genetic when it occurs before the age of 50 European Americans are at the highest risk of Alzheimer’s as they’re more likely to carry the gene The ApoE4 gene carry’s Alzheimer’s At age 85 the risk of senility levels off Non-genetic influences, such as lifestyle, play a big role in Alzheimer’s By being physically active and mentally alert, you reduce the risk of developing Alzheimer’s disease Schizophrenia “Roses are red, violets are blue, I’m a schizophrenic and so am I.” Bill Murray, What About Bob? Approximately 1 percent of the population is diagnosed with schizophrenia. Schizophrenia is a genetic trait that is that also appears to be strongly influenced by the environment. Physical elements, such as injury to the head, can also bring on schizophrenia. Alcoholism Inherited biochemistry makes some people highly susceptible to alcohol addiction addictive pull can be overpowering, or weak, or something in the middle may explain ethnic variations Alcoholism Not simply a biochemical reaction—it is psychological and physical, and biological; thus alcoholism is polygenetic, with alcoholics inheriting a combination of biochemistry-affecting and temperamentaffecting genes Culture counts too (whether alcohol is present in environment) Chromosomal and Genetic Abnormalities Here we notice disruptions of normal development origins of genetic and chromosomal abnormalities misinformation and prejudice add to problems of people with these abnormalities Genetic and Chromosomal Abnormalities A chromosomal abnormality occurs when there or more or less than 23 chromosomes in a gamete Genetic abnormalities arise when proteins do not code properly Most abnormal zygotes simply never begin to develop. The majority of the rest are not carried to term as they are spontaneously aborted (miscarried). Muscular Dystrophy Association Summer Camp Brandon, Florida Down Syndrome Some people with down syndrome are quite capable of doing things themselves, like this woman who does her own grocery shopping. The most common extra chromosome condition is Down syndrome. It affects people in varying degrees Young children with Down syndrome are likely to have a nice disposition At age 30, people with Down syndrome begin to age rapidly Life expectancy rate is low Genetic Abnormalities: Huntington’s Disease Most dominant disorders are not disabling, however Huntington’s disease is one of the few that is. It doesn’t appear until a person is between 35 and 45. By that time the person may have children, who have a 50/50 chance of inheriting it Testing can be done to see if a person carries the gene There is no cure for Huntington’s disease The first signs of Huntington’s disease are clumsiness, forgetfulness and involuntary movements As the disease progresses, the ability to think and control movements becomes harder and harder Eventually, the individual is unable to do anything Genetic Abnormalities: Tourette Syndrome Wolfgang Amadeus Mozart was thought to have had Tourette Syndrome. Tourette syndrome is a dominant disorder that can cause uncontrollable tics and outburst. It is 3 to 4 times more likely to occur in boys 30% of people with Tourette syndrome have uncontrollable tics and outbursts The other 70% have just an occasional twitch and other slight problems Genetic Counseling and Testing 1. 2. 3. 4. Genetic counseling is a process of consultation and testing that enables individuals to learn about their genetic heritage, including conditions that might harm any children they may have. People who should have genetic counseling are those with: Close relatives with a severe genetic condition Histories of miscarriages Women over age 35 and men over age 40 Couples from the same ethnic group or close relative Some people prefer not to be genetically tested if it might reveal an incurable genetic disorder, but they are more likely to consider it when they are deciding whether or not to have children. Genetic counselors are often able to give couples odds on whether or not their children could inherit their genetic disorders Scientists and genetic counselors advice high risk couples to use prenatal testing to determine any health problems the baby may have Conclusion Which plays a bigger role in human development, heredity or environment? Is Kate Hudson’s ability as an actor influenced by her environment or genes? Do you think her environment or her genes influenced her career choice?