Chapter 3 -- The Nature and Nurture of Behavior



Chapter 4 In-class Notes, ’16 – Nature, Nurture, and Human DiversityBehavior genetics, nature, nurtureNucleus: book; chapters -- chromosomes (paper: DNA); words – genes (expressed or inactive); letters – nucleotides-the human genome – only slight differences, traits are gene complexes-twin studies – identical (monozygotic) versus fraternal (dizygotic) – differences in heredity, environment, extraversion versus introversion, neurotic AKA reactive, unstable vs. stable -Thomas Bouchard study – identical twins raised apart (“the Jims”)-Biological vs. Adoptive Relatives: “the stunning finding”:-adoptive homes, parents do influence:temperament:heritability:-why it can vary from study to study-individual differences NOT equal to group differences-nature enables nurture -- gene-environment interaction-The New Frontier: molecular behavior genetics / issues, epigenetics, self-regulating, epigenetic marksEvolutionary Psych: Understanding Human NatureEvolutionary psych, natural selection, breeding dogs and foxes, mutations; one possible explanation for similarities -- tastes, behavior, sexuality, gender differences, fears, sex differences between men and women-evolutionary sexuality explanation:MEN:WOMEN:-critiquing the evolutionary perspective: social scriptsCulture, Gender, and Other Environmental Influences: interactions-prenatal environment-experience and brain development; Rosenzweig experiment; critical periods, pruning-parents’ influence:-peer influence: what, extremes-culture influence: norms, personal space, individualism versus collectivism (table 4.2 pg. 158), -cultural neuroscienceGender Development: men versus women on: aggression, social power, connectedness; -male answer syndrome, interdependence, side-by-side, face-to-face, tend and befriend, independenceNature: X chromosome, Y chromosome, testosterone – effects; puberty – primary sex characteristics, secondary sex characteristics, menarche, disorder of sexual development / sex reassignment surgery Nurture: gender role, gender identityhow do we learn them?, social learning theory, gender-typing , androgyny, gender schemas, gender expression – androgyny, transgender, transsexual, sexual orientationReflections: both, but not just genes and culture: individual choice, faith and reason, awe….Chapter 4 In-class Notes, ’16 – Nature, Nurture, and Human Diversity (with spaces)Behavior genetics, nature, nurtureNucleus: book; chapters -- chromosomes (paper: DNA); words – genes (expressed or inactive); letters – nucleotides-the human genome – only slight differences, traits are gene complexes-twin studies – identical (monozygotic) versus fraternal (dizygotic) – differences in heredity, environment, extraversion versus introversion, neurotic AKA reactive, unstable vs. stable -Thomas Bouchard study – identical twins raised apart (“the Jims”)-Biological vs. Adoptive Relatives: “the stunning finding”:-adoptive homes, parents do influence:temperament:heritability:-why it can vary from study to study-individual differences NOT equal to group differences-nature enables nurture -- gene-environment interaction-The New Frontier: molecular behavior genetics / issues, epigenetics, self-regulating, epigenetic marksEvolutionary Psych: Understanding Human NatureEvolutionary psych, natural selection, breeding dogs and foxes, mutations; one possible explanation for similarities -- tastes, behavior, sexuality, gender differences, fears, sex differences between men and women-evolutionary sexuality explanation:MEN:WOMEN:-critiquing the evolutionary perspective: social scriptsCulture, Gender, and Other Environmental Influences: interactions-prenatal environment-experience and brain development; Rosenzweig experiment; critical periods, pruning-parents’ influence:-peer influence: what, extremes-culture influence: norms, personal space, individualism versus collectivism (table 4.2 pg. 158), -cultural neuroscienceGender Development: men versus women on: aggression, social power, connectedness; -male answer syndrome, interdependence, side-by-side, face-to-face, tend and befriend, independenceNature: X chromosome, Y chromosome, testosterone – effects; puberty – primary sex characteristics, secondary sex characteristics, menarche, disorder of sexual development / sex reassignment surgery Nurture: gender role, gender identityhow do we learn them?, social learning theory, gender-typing , androgyny, gender schemas, gender expression – androgyny, transgender, transsexual, sexual orientationReflections: both, but not just genes and culture: individual choice, faith and reason, awe….Chapter 3 -- The Nature and Nurture of Behavior – complete notesVersion 1 Genes: Our Bio BlueprintBody cells:-DNA-chromosomes-nucleotidesLocated inside the nucleus (library) of each cells in the human body are the chromosomes (46 books-23 from your mother’s egg and 23 from your father’s sperm). This threadlike structures of chromosomes are composed of DNA (deoxyribonucleic acid) molecules. Segments of the DNA, called genes (words) are the biochemical units of heredity that make up the chromosomes. Genes are also capable of synthesizing particular proteinsthe building blocks of our physical development. Each genes are composed of biochemical nucleotides (letters - ATCG). The smallest human chromosome (Y) has 50 million nucleotide; the largest chromosomes has 250 million. Around 3.1 billion paired nucleotides define the genes that determines our individual biological development.--Human genome researchers have discovered the common sequence of the 3.1 billion letters within the human DNA. --human genomes complete the instructions for making an organism. It consists of all the genetic material in its chromosomes. The human genome has 3 billion weakly bonded pairs of nucleotides organized as coiled chains of DNA.--Human traits are influenced by gene complexes many genes acting in concert (height, length of bones etc.)Evolutionary Psych:-the study of the evolution of behavior and the mind, using principles of naturalselection.-helpful for understanding the reproductive advantages of human aggression.Breeding selection (microevolution)- selective breeding that could change certain traits, or emphasize certain traits that are already in the DNA. Natural selection has favored genes that designed both behavioral tendencies and information-processing systems that solved adaptive problems faced by our ancestors, thus contributing to the survival and spread of their genes. It is the principle that, among the range of inherited trait variation, those that lead to increased reproduction and survival will most likely be passed on to succeeding generations.Mutation - a random error in gene replication that leads to a change in the sequence of nucleotides; the source of all genetic diversity.Of our relatively few genetic differences, only 6% are genetic differences among races. Only 8% are genetic differences among groups within a race. The restover 85%are individual variations within local groups.Over generations, the genes of individuals not so disposed tended to be lost from human gene pool. As further mutations occurred, genes providing an adaptive edge continued to be selected. The result, say evolutionary psychologists, is behavioral tendencies and a capacity for thinking and learning that prepared our Stone Age ancestors to survive, reproduce, and send their genes into the future. Nature selected the fittest adaptations, which also include the human diversity that suits Arctic and equatorial dwellers to thrive in their distinct environments.--Evolutionary psychologists study how natural selection has shaped our behavioral tendencies. They reason that if organisms vary, if only some mature to produce surviving offspring, and if certain inherited behavior tendencies assist that survival, then nature must select those tendencies. They believe this helps explain gender differences in sexuality.SexualityGender - in psychology, the characteristics, whether biologically or socially influenced, by which people define male and female.Gender differences in attitudes extend to differences in behavior. Casual hit-and-run sex is most frequent among males with traditional masculine attitudes (Pleck & others, 1993). Men also have a lower threshold for perceiving warm responses as a sexual come-on. In study after study, men more often than women attribute a woman’s friendliness to sexual interest (Abbey, 1987; Johnson & others, 1991). Misattributing women’s cordiality as a come-on helps explain men’s greater sexual assertiveness (Kendrick & Trost, 1987). The unfortunate results can range from sexual harassment to date rape.Evolutionary Explanation : biologists explains that while a woman incubates and nurses an infant, a male can spread his genes through other females. Our natural yearnings are our genes’ of reproducing themselves.MEN: In 37 cultures judge women as more attractive if they have a youthful appearance. Evolutionary psychologists say that men drawn to healthy, fertile-appearing womenwomen with smooth skin and a youthful shape suggesting many childbearing year to comehave stood a better chance of sending their genes into the future.WOMEN: also feel Attracted to healthy looking mean, but especially to those who seem mature. Dominant, bold, and affluent (Singh, 1995). Such attributes, say the evolutionary psychologists, connote a capacity to support and protect (Buss, 1996, 2000; Geary, 1998). Some 150 studies of gender and risk taking reveal that in 14 of 16 realms (including intellectual risk taking, physical skills, smoking, and sex) men are the greater risk takers (Byrnes & others, 1999). In explaining why 16- to 14-year old men show more bravadoand are therefore nearly three times more likely than young women to die in auto crashes.Criticism:-- If men were uniformly loyal to their mates, might we not reason that the children of committed, supportive fathers more often survived to perpetuate genes? Might not men also be better off bonded to one womanboth to increase the otherwise slim odds if impregnation and to keep her from the advances of competing men? Might not a ritualized bonda marriagealso spare women from chronic male harassment? Evolutionary explanations for why humans tend to pair off monogamously.--Cultural expectations bend the genders, and what’s attractive varies somewhat with time and place.--Some gender differences in mate preferences do seem universal across cultures. But again, critiques questions whether such gender differences may to some extent be byproducts of a culture’s social and family structures.--Social consequences of evolutionary psychology: does it suggest a genetic determinates that strikes at the heart of progressive efforts to remake society (Rose, 1999)? Does it undercut ethical theory and moral responsibility? Could it be used to rationalize?Critics maintain that evolutionary psychologists make too many hindsight explanations.Behavior genetics: Predicting Individual DifferencesBehavior genetics - the study of the relative power and limits of genetic and environmental influences on behavior.Behavioral geneticists more intensively assess our differences from one another. How much are our differences shaped by our differing genetic blueprints? And how much by our environmentevery external influence, from maternal nutrition while in the womb to social support while nearing the tombreacting to our genetic traits? To what extent are we formed by our upbringing? Our culture? And by our current circumstances?Twin Studies-Genetic influence between Identical vs. Fraternal Twins:Identical twins - twins who develop from a single fertilized egg that splits in two, creating two genetically identical organisms. They are nature’s own human clonesindeed, clones who share not only the same genes but the same conception, uterus, birth date, and cultural history.Identical twins are more similar than Fraternal twins on both extraversion (outgoingness) and neuroticism (emotional instability/temper). A person whose identical twin has Alzheimer’s disease has a 60% risk of sharing the disease.If you have an identical twin who has divorced, the odds of your divorcing go up 5.5 times.Identical twins are more similar than fraternal in many ways-in abilities, personality traits, and interests.Identical twins who parents treated them alike were not psychologically more alike than identical twins who were treated less similarly. Research on 336 Canadian twin pairs also shows a substantial genetic influence on attitudes toward reading, organized religion, playing sports, and assisted suicide (Olson & others, 2001).Fraternal twins - twins who develop from separate eggs. they are genetically no closer that brothers and sisters, but they share a fetal environment. They are genetically no more similar than an ordinary brothers and sisters.Fraternal twins risk only 30% chance of sharing Alzheimer’s disease if one twin is affected by the disease.If your fraternal twin has divorced, then the chance of your divorcing up is 1.6 times, (compared to the odds with a not-divorced twin). -Thomas Bouchard study – identical twins raised apart (the Jims) When the twins were tested measuring their intelligence, personality, heart rate, and brain waves, the Jim twinsdespite 38 years of separationwere virtually alike as the same person tested twice.--Moreover, separated twins shared an environment for at least their first 9 months. They share an appearance, and the responses it evokes. And adoption agencies tend to place separated twins in similar homes. When environment are similar, the impact of environment looks smaller relative to heredity. Adoptions studiesAdoption creates two groups of relatives:1. The adoptee’ genetic relatives (biological parents and siblings2. Environment relatives (adoptive parents and siblings).For any given trait we can therefore ask whether adopted children are more like their adoptive parents, who contribute a home environment, or their biological parents who contributed their genes (nature vs. nurture). While sharing the same home environment, do adopted siblings come to share traits?Stunning findings:Adoptee’ traits bear more similarities to their biological parents to their care giving adoptive parents.Two adopted children reared in the same home are no more likely to share personality traits with one another than with the child down the block.Adoption studies show that, although personalities of adopted children do not much resemble those of their adoptive parents, adoption matters (Brazens & Schechter, 1990).A pair of adopted children or identical twins will have more similar religious beliefs if reared in the same home (Kelley & De Graaf, 1997; Rohan & Zanna, 1996).In adoptive home, child neglect an abuse and even parental divorce are rare. Despite a somewhat greater risk of psychological disorder, most adoptive children thrive, especially when adopted as infants (Benson & others, 1994;Wierzbibki, 1993).Adoptee scores higher than their biological parents on intelligence tests.7 out of 8 report feeling strongly attached to one or both adoptive parents.They generally become happier and more stable people than they would have been in a stressed or neglectful environment.Clearly, to benefit from adoption, children need not have personalities that resemble those of their adoptive parents.Nature:Temperament StudiesPhysiological test reveal that anxious, high-strung infants have high and variable heart rates and reactive nervous system (Kagan & others, 1992). They become more a physiologically arouse when facing new or stranger situations. Compared with fraternal twins, identical twins have more similar temperaments. Such evidence adds to the emerging conclusion that our biologically rooted temperaments help form our enduring personalities (McCrae & others, 2000; Rothbart & others, 2000).temperament - a person’s characteristic emotional reactivity and intensity.HeritabilityUsing the twin and adoption methods, behavior geneticists can mathematically estimate the heritably of any traitthe extent to which variation among individuals can be attributed to their differing genes. Heritability refers instead to the extent to which differences among people are attributed to genes. As environment become more similar, heredity as a source of differences necessarily becomes more important. The heritability of a trait may vary, depending the on the range of populations and environments studies.Heritable individual differences need not imply heritable group differences. If some individuals are genetically disposed to be more aggressive than others. Putting people in a new social context can change their aggressiveness.Nature enables Nurture--Genes and environmentnature and nurturework together like two hand clapping, with the environmet reacting to and shaping what nature predisposes. For psychological traits, human difference are nearly always the result of both genetic and environmental variations. Gene-Environment InteractionOur genetically influenced traits evoke significant responses in other. Thus, an aggressive child may be yelled at by a teacher who talks warmly to the child’s model classmates. This helps explains my identical twins rear in different families recall their parents’ warmth as remarkably similar. Fraternal twins recall their early family life more differentlyeven if rear in the same family. Moreover, as we grow older we also select environments well suited to our natures.We are the product of a cascade of interactions [the dependence of the effect of once factor (such as environment) on another factor (such as heredity).] between our genetic predispositions and our surrounding environments. Our genes affect how people reacts to and influence us.The New Frontier: Molecular Genetics - sub field of biology that studies the molecular structure and function of genes.Molecular genetics quest to find the specific genes that influence behavior. In dozens of labs worldwide, molecular geneticists are teaming with psychologists in search of genes that put people are risk for genetically influenced disorders. Genetic tests can now reveal who is at risk for at least a dozen diseases. Aided by inexpensive new techniques for scanning relevant DNA snips, medical personnel may soon be able to give would-be parents a read-out on how their fetus’ genes differ from the normal pattern and what this might mean. with this benefit come risks of labeling people. Might such labeling lead to discrimination or self-fulfilling prophecies? Prenatal screening also poses other ethical issues. Blueprints for “designer babies” are, of course, constrained by the reality that it takes many genes to influence behavior in combination with complex environments. By “selecting” our certain traits, we may deprive ourselves of future Handels, and van Goghs, Churchills and Lincolns and Dickinsontroubled people all.Nurture: environmental influence;Genetic influences predict roughly about 40-50% of our individual variations in many personality traits. When asked what accounts for the rest, many people presume it is parental nurture. Parental influence is “enormously powerful in determining what happens to a child,” and “whether a child acquires discipline and self esteem and becomes a well adjusted, productive person is largely a function of parental input” (Hewlett and West, 1998).How Much Credit / Blame Do Parents Deserve? (vs. “pop” psych)Parents typically feel enormous pride in their children’s successes, and guilt or shame over their failures. But do parents really produce future adults with an inner wounded child by being overbearingor uninvolved? Pushyor distant? Shared influencesincluding home influences that sibling sharetypically account for less than 10% of children’s personality differences. Psychologists searching for environmental influences they know exist are like astronomers seeking the hidden “dark” matter which they know the universe contains. It’s there, somewhere, but where? Here, for starters, are four: prenatal environment, early experience, peer influence, and culture.Prenatal environmentNurture begins in the womb, as embryos receive different nutrition and varying levels of exposure to toxic agents. Even identical twins may receive not-so-identical prenatal nurture. Early indications are that, compared with same-placenta identical twins, those who develop with separate placentas are somewhat less similar in their psychological traits (Phelps & others, 1997).Experience and Brain development:Experience helps develop the brain’s neural connections. Even if forgotten, early learning help prepare our brain for thought and language, and also for later experiences. There is a biological reality to early childhoodwhile the excess connections are still on callyoungsters can most easily master the grammar and accent of another language. Lacking any exposure to language before adolescence, the person will never master any language.The brain’s development does not, however, end with childhood. Throughout life our neural tissue is changing. Both nature and nurture sculpt our synapses. Sights and smells, touches and tugs activate and strength then some neural pathways while others weaken from disuse.Diamond’s experiment in 1972: reared some young rats in a solitary confinement (impoverished environment) and others in a communal playground (enriched environment). Those living in the enriched environment, which stimulated a natural environment, usually developed a heavier and thicker brain cortex.Peer Influence:Peer influence may exceed parental influences, argues Judith Harris (1998, 2000a).Part of the similarity to peers may result from a “selection effect,” as kids seeks out peers with similar attitudes and interests. Parental nurture is essential to our early survival, and parental influence is especially discernible while children are in the home. But in the long run, we are destined to play, work with, and mate with peers.Although individual parents may have limited influence on their children, a group of parents can influence the culture that shapes the peer group. Culture calls “parents’-group-to children’s-group-effects” (Harris, 2000b). Parental influence can occur as parents help select their children’s peers/Other psychologists remind us that there is some power, too, to individual parenting. The power of parenting to shaper our differences is clearest at the extremesthe abused who become abusive, the neglected who become neglectful, the loved but firmly handled children who become more self-confident ad socially competent.Parental nurture is like nutrition. It may not matter whether we grew up with parents who toilet trained us early or late, but it sure helps to have someone we belong to and cares about us.Culture:Culture is the behaviors, ideas, attitudes, and traditions shared by a large group of people and transmitted from one generation to the next (Brislin, 1988).Each cultural group evolves its own normsthe rules for accepted and expected “proper” behavior.When cultures collide, their differing norms often befuddle. For example, if someone invades our personal spacethe portable buffer zone we like to maintain around our bodieswe feel uncomfortable. Cultures also varies in their expressiveness and pace of life. So rapidly can cultural fashions, idea, inventions and habit change that evolutionary psychologists have a termmemesfor these self replicating cultural mutations. Memes, like genes, compete to get copied, not into our cells but into our memories and media (Blackmore, 1999).Child-rearing practices are not immune to the variation in cultural values from one time and place to another. Children across place and time have thrived under various child-rearing systems. Different child-rearing cautions among different countries cautions us against presuming that our culture’s way is the only way to rear children successfully.Because we are so mindful of how others differ from us, we often fail to notice the predisposed similarities by or shared biology. Cross-cultural research can help leading us to appreciate both our cultural diversity and our human kinship.The Nature and Nurture of GenderThe Nature of GenderIn domains where mean and women have faced similar challengesregulating heat with sweat, developing tastes that nourishthe sexes are similar. But in some domain pertinent to mating, evolutionary psychologists contend, guys act like guys whether they are elephants or rural peasants etc. such differences between the sexes arise, genetically, from their differing sex chromosomes and, physiologically, from their differing concentrations of sex hormones.Males and females are variations on a single form. Seven weeks after conception, you were anatomically indistinguishable from someone of the other sex. Then your genes activated your biological sex. Your sex is determined by your 23rd pair of chromosomes, the sex chromosomes. The member of the pair that came from your mother was an X chromosome. From you father, you received the once chromosome out of 46 that is not unisex. This was either an X chromosome, making you a girl, or some, making you a boyY chromosome. The Y chromosome includes a single gene that throws a master witch triggering the testes to develop and produce the principal male hormones, testosterone, which about the 7th week starts the development of external male sex organs.The Nurture of GenderIn psychology, as in the theater, a role refers to a cluster of prescribed actionsthe behaviors we expect of those who occupy a particular social position. One set of norm define our culture’s gender rolesour expectations about the way men and women behave.Gender and Child-Rearing = society assigns each of useven those few whose biological sex is ambitious at birthto a gender, the social category of male or female. He inevitable result is our strong gender identity, our sense of being male or female. The varying extents, we also become gender-typed. that is, some boys more than others exhibit tradition all masculine traits and interests etc.Social learning theory assumes that children learn gender-linked behaviors by observing and imitating and by being rewarded or punished. A later version of social learning theory called social0cognitive theory also recognizes the importance of children’s emerging gender conceptions (Bausy & Bandura, 1999).Gender schema theory, which also combines social learning theory with cognition: out of your struggles to comprehend the world came concept or schemes, including a schema for your own gender (Bem, 1987).Postscript issues: Genes and Culture : Where there is variation, natural selection and heredity, there will be, on some scale, evolution. The unique gene combination created when our mother’s egg engulfed our father’s sperm also helped form us, as individuals. Genes forms us. But it is also true that our experiences help form us. Our life experiences in local environments and surrounding cultures help form us. This is a great truth about human nurture. Our experiences form us, as much as genes do.Individual Choices : our decision today design our environments tomorrow. Mind matters. Our hopes, goals and expectations influence our future, which enables culture to vary and to chance so quickly.Chapter 3: Nature, Nurture, and Human Diversity (notes version 2)Behavior Genetics, studies the relative effects in our genes (nurture) and our environmental (nature) on our individual differences in behavior and mental processesEvolutionary psychologyBehaviors, emotions, thinking capacities that seemingly allowed our distant ancestors to survive, reproduce, and send genes to future generationsParents, peers and cultureInfluence our beliefs and valuesGender Expectations influence how other perceive usMore alike then differentBehavior Genetics: Predicting Individual DifferencesEnvironment, every external influence from parental nutrition to the people and things around usBehavior geneticists study our differences and weigh the relative effects of heredity and environmentGenes: Our Codes for LifeBody composed of 46 chromosomes23 from father, 23 from motherCoiled chain of the molecule DNAGenes, small segment of the giant DNADo not directly guide out behaviorProvide code for creating protein moleculesEven your worst enemy could share 99.9% of your DNA, that 0.1 percent difference with interaction with different environments, gives you a completely different personGenome, complete instructions for making an organismChimpanzees and human differ by much less then 1% of their genomesdisplay obvious behavior differencesHuman traits are influenced by gene complexesmany genes acting in concertgenetic predispositions help explain our shared human nature and our diversityTwin StudiesIdentical Vs. Fraternal Twins Identical twins develop from a single fertilized egg splits into two genetically identical Fraternal twins develop from separate fertilized eggsGenetically no more similar than ordinary brothers and sister60% chance of sharing Alzheimer (identical)30% chance of sharing Alzheimer (fraternal)Personal traits and interests much more similar in identical than fraternalSeparated TwinsA Swedish study showed Separated identical twins had more dissimilar personalitiesMore alike if genetically identical than fraternalBeing separated at birth doesn’t simplify their personality differences “virtual twins”—same age, biologically unrelated siblings are much more dissimilar 3. Adoption StudiesPeople who grew up together do not much resemble on another in personalityAdoptees’ traits bear more similarities to their biological parents then to their care giving parents Environmental factors shared by a family’s children have virtually no impact on their personalities Child neglect and abuse and parental divorcee rare in adoptive home, adoptive parents are carefully screened Regardless of their personality differences between parents and their adoptive children, the children benefit from adoptionTemperament Studies Temperament, emotional excitability- reactive, relaxed and fidgety, or easygoing quiet and placidDifficult vs. Easy babiesIdentical twins have more similar temperaments, indicate that heredity may predispose temperament differences, Test shows- anxious, inhibited babies have high and variable heart rates and a reactive nervous systemBecome aroused when they see knew faces HeritabilityThe extent to which variation among individuals can be attributed to their gene differences Refers to the extent to which differences among people are attributed to genes As environments become more similar, heredity as a source of differences necessarily become more importantHeritability increases as environment decreasesIf people had different heredities but were raised in different environments, heritability would be much lowerGenetic influences help explain individual diversity in traitsGroup DifferencesIndividual differences in height and weight, are highly heritable, yet nutritional rather than genetic influences explain why as a group, adults are taller and heaver than those of century agoNature and Nurture Enormous adaptive capacityMany of our driven traits (eating) are affected by our cultureGenes and environment-nature and nurture- work together like two hands clappingGenes respond to the environmentPeople with identical genes but differing experiences have similar, not identical mindsGenes can influence a situation but environment pushes the influence into a habitIndividual differences Eating disorders are genetically influenced, some more at risk then others, but culture also “bends the twig”, eating disorders are primarily a contemporary Western cultural phenomenonGene-Environment Interaction Genes and experience are both important, they interact“Heredity deals the cards, environment plays the hand”Evocative interactions help explain why identical twins reared in different families recall their parents warmth as remarkably similar as if they had, had the same parentsFraternal twins recall greater variations in their early family life, even if reared in the same familyInteractions; the effect of one factor (environment) depends greatly on another factor (heredity)The New Frontier: Molecular Genetics Molecular genetics-subfield of biology that studies the molecular structure and functions of genesHeredity influences body weight but there is no single “obesity gene”Genes influence how quickly the stomach tells the brain “I’m full”Goal of molecular behavior genetics is to find some of the man genes that influence normal human traits (body weight, sexual orientation, and extraversion)Genetic tests reveal at risk populations for diseasesMolecular genetics seek links between certain genes or chromosome segments and specific diseaseTesting for an offspring sex has enabled selective abortion resulting in millions of “missing women”Evolutionary Psychology: Understanding Human NatureThe study of the evolution of behavior and the mind using principle of natural selectionNatural SelectionWhen certain traits are selected by conferring a reproductive advantage to an individual or a species- those traits over time will prevailNatural selection; among the range of inherited trait variation, those that lead to increased reproduction and survival will most likely be passed on to succeeding generationsMutation; random errors in gene replicationNew gene combinations are producedOur behavioral and biological similarities arise from our shared human genomeAn Evolutionary Explanation of Human SexualityGender Differences in Sexuality Gender; biologically and socially influenced characteristics by people are defined as male or female Natural Selection and Mating PreferencesMen in 37 cultures judge woman as more attractive if they have a youthful appearanceMen are drawn to healthy, fertile appearing womenAttracted to a sign of future fertilityWomen feel attracted to healthy looking men who seem mature, dominant, bold and wealthy Men are greater risk takersNature selects behaviors that increase the likelihood of sending one’s genes into the futureCritiquing the Evolutionary PerspectiveEvolutionary psychologist start with and effect and work backwards to an explanationUnderestimates cultural expectations and socializationsViewpoint absolves people from taking ethical and moral responsibility for their sexual behaviorCite the value of testable predictions based on evolutionary principlesParents and PeersA. Parents and Early experiencesFormative nurture that conspires with nature begins at conception, with the prenatal environmentPrenatal EnvironmentTwo thirds of identical twins share the same placenta and more similar prenatal environmentOther identical twins have different placentasOne placenta sometimes has a more advantageous placement that provides better nourishment and a better placental barrier against virusesExperience and Bain developmentExperience helps develop our brains neural connectionsEarly learning prepares our brains for thought and language and also for later experiencesNature and nurture sculpt out synapsesPeople who lack visual experience during the early years, peoples who’s vision is resorted by cataract removal never achieve normal perceptionsBrain cells that normally are assigned for vision have died off or been diverted to other usesSites, smells, touches and tugs activates and strengthen some neural pathways while other weaken from disuse We perform with increasing skills as our brain incorporates the learningHow Much Credit (or Blame) Do Parents Deserve?The power of parenting to shape our differences is clearest at our extremesThe power of the family environment also frequently shows up in children’s political attitudes, beliefs, and personal mannersPeer InfluenceChildren who seek out others who share their attitudes and interests, this selection effect contributes to peer group uniformityParents are important models for education, discipline, responsibility, orderliness, charitableness and the way of interacting with authoritiesPeers influence areas such as learning to cooperate with others, achieving popularity, and finding appropriate styles of interaction with people of a similar ageCultural InfluencesCulture is the behaviors, ideas, attitudes, values, and traditions shared by a group of people and transmitted from one generation to the nextSupports survival and reproduction with social and economic systemsCulture enables and efficient division of laborVariation Across CulturesNorms, the rules for accepted and expected behaviorPersonal space, the portable buffer zone we like to maintain around our bodiesVariation Over TimeIn today’s time our culture has doubled rate of divorce. A nearly tripled rate of teen suicide, a quadrupled rate of reported juvenile violent crimes a quintupled prison population and an escalating incidence of depressionMore hours at work, fewer sleep hours, and fewer hours with family and friendsWe are not able to explain these changes in the human gene pool which involves far too slowly to account for high speed cultural transformations Culture shapes our livesCulture and the SelfIndividualism- giving priority to one’s own goals over group of goals and defining one’s identity in terms of personal attributes rather then group identificationsCollectivism- priority to the goals of one’s group, extended family or work group, defining one’s identity accordingly (stereotype) Individualist strive for personal control and individual achievementThey feel relatively free to switch places of worship, leave one job for another, or even leave their extended family and migrate to a new placeConceptIndividualismCollectivismSelfIndependentInterdependentLife TaskDiscover and express one’s uniquenessMaintain connections, fit in, perform roleWhat MattersMe- personal achievement and fulfillmentUs- group goals and solidarity Coping MethodChange realityAccommodate realityMorality Self based; defined by individualsDefined by social networks (duty based)RelationshipsMany, often temporary or casual, confrontation acceptableFew close and enduring; harmony valued Attributing behaviorBehavior reflects one’s personality and attitudes Behavior reflects social norms and rolesCollectivist- loss of ones identityMay act shy in a new group and more easily embarrassed then other individualist friendsPeople in collectivist cultures place premium on maintaining harmony and making sure other never lose faceWhat people say reflects both what they feel and what they presume others feelPeople in individualist cultures have more personal freedom, take more pride in personal achievements, are less geographically bound to their families, and enjoy more privacy Individualist report experiencing greater happiness than those in collectivist culturesThe benefits of individualist can come at the cost of more loneliness, more divorce, more homicide, and more stress-related disease Individualist cultures express more self focused “narcissism” along with demanding more romance and personal fulfillment in marriage, putting more pressure on the marriage Culture and Child-RearingMost parents in the westernized culture want their children to think for themselvesAsian and Africans live in cultures that focus on cultivating emotional closenessInfants and toddlers typically slept with their mothers and spent their days close to a family memberChildren in these cultures grow up with a stronger sense of family self a feeling that what shames the child, shames the family, and what brings honor to the child, brings honor to the familyDiversity in child rearing cautions us against presuming that our culture’s way is the only way to rear children successfully Development Similarities Across GroupsCross culture research helps us by leading us to appreciate both our culture diversity and our human kinshipDifference between groups are smallEthnic subgroups may behave differently and yet be influenced similarityDifferences are no more then skin color deepThough our language varies, yet reflects the universal principle of grammar, taste differs, reflect the common principle of hunger, social behaviors vary, reflect pervasive principles of human influence Gender DevelopmentGender; our assumed characteristics as male or femaleNature and nurture work together to create social diversity—genderTogether they create our differences and commonalities, by considering other gender variations Gender Similarities and DifferencesAmong 46 chromosomes, 45 are similarAverage woman has 70% more fat, possesses 40% less muscle and is 5 inches shorterEnters puberty two years sooner and will outlive her mail counterparts by five yearsWomen are more likely to dream equally of men and women, become sexually re- aroused after and orgasm, to smell faint odors, to express emotions freely, and in some situations to be offered help10 times greater risk for inquiring an eating disorderMen are four times more likely to commit suicide ort suffer alcoholismResearch has found difference in aggression, social power, and social connectednessDoes culture assign us these gender roles?Gender AggressionMen admit to more aggression; psychical or verbal behavior intended to hurt someone, then womenThe aggression gender gap, physical rather verbal, appears in everyday life un cultures at various agesMale to female murder ration; 9-1Men express more support for war and more violent sportsGender and Social PowerAround the world people view men as more dominant, forceful, and independent; women as more deferential, nurturing and affiliativeAs leaders men are more direct, autocratic; women, democratic, more welcoming of subordinates participation in decision makingHigher salary- menGender difference in power do appear to lessen with maturity, as middle age women become more assertive, while men become more empathic Gender and Social ConnectednessGirls play more one on one, boys in large groups; boys-rough, girls-less competitive Girls spend more time with friends, less time alongWomen have shown to be more independent, use conversation more to explore relationshipsMen use it to communicate solutionsWomen emphasize caring and provide most of the care to the very young and the very oldMen emphasize freedom and self-relianceMen dominate the ranks of professional skepticsWomen turn to others when stressed , turning to women compared to menThe Nature of GenderGender differences may be influenced by our differing sex chromosomes, and physiologically from out differing concentrations of sex hormones Sex determined by the 23 pair of chromosomesX chromosome; found in both women and men. Females have two, males have one. An X come from both parent produces a girlY chromosome is only found in males. When paired with an X chromosome form the mother, a male is producedTestosterone; both males and females have it, but the additional testosterone in males stimulates the growth of the male sex organs in the fetus and the development of the male sex characteristics Seventh week starts development of external male sex organs Sex related genes and hormones do influence gender differences in behavior, by influencing brain developmentMany gender differences are learned The Nurture of GenderGender is also socially constructedGender RolesRole; a cluster of predescribed social actions, the behaviors we expect of those who occupy a particular positionNorms define our gender role Our expectations about the way men and women behaveCulture shapes the way one thinks of how men and women are suppose to actThe sense of being male or female is a persons gender identitySocial learning theory processes that we learn gender behavior as we learn other things, through reinforcement, punishment and observationGender schema theory combines social learning theory with cognition Language influence boy and girls to be completely separate “ la table” “le train”Reflections on Nature and Nurture Our biology is established through natural selection People and customs in out environment direct towards specific roles and reward us for conforming to cultural expectations ................
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