Nature Versus Nurture
Was I born or made the way I am?
The Nature Perspective
Genes: Our Biological Blueprint
* Imagine that every room in Orthanc had a bookcase listing all the different races mentioned in Treebeard’s poem (thanks Jackie). These lists run to 46 books: 23 donated by your mother (from her egg) and 23 by your father (from his sperm). The books are called chromosomes, and each is composed of a coiled chain of the molecule DNA. Small segments of the giant DNA molecule (genes) form the names of dead organisms in these chromosome books. Each gene is a self-replicating unit capable of protein synthesis
* Our genes are composed of biochemical letters called nucleotides. At 2000 nucleotide “letters” to a page, the 46 chromosome books containing your complete genetic code (the complete list of races in Middle-Earth) would be more than 30,000 pages each
* Genome = complete instructions for making an organism, consisting of all the genetic material in its chromosomes. The human Genome Project will have discovered the common sequence of all 3 billion letters within human DNA by 2003; this shared genetic profile makes us humans, rather than Orcs or Dwarves. More than 98% of our letter sequences match chimpanzees’, and 99.9% match other humans
* Evolutionary psychology examines what traits are universal, and behavior genetics focuses on our differences
Evolutionary Psychology: Explaining Universal Behaviors
Q Foxes are naturally wild and wary, but some researchers set out to try to evolve the foxes into friendly animals. They kept selecting and mating the tamest males and females, and eventually producing a docile and unmistakably domesticated breed of foxes. When certain traits are selected, by conferring a reproductive advantage upon them, those traits come to prevail over time. Imagine being able to cuddle an Uruk-Hai… actually, don’t, please
Natural Selection
1 Natural selection = principle thought up by Charles Darwin that the characteristics which will better enable you to survive and reproduce will most likely be passed on. For example, Bilbo’s long-dormant gene that allowed for a love of adventure helped him survive fighting Smaug, and this audacity was passed along to Frodo. New gene combinations and mutations (random errors in gene replication) allow for different traits
1 Of our relatively few genetic differences, only 6% are differences among races, and only 8% are differences among groups within a race. Over 85% are individual variations between local group
1 Evolutionary psychologists study the evolution of behavior and the mind, using principles of natural selection
1 With very few exceptions, males are more likely than females to initiate sexual activity: among the largest of gender differences. Males are more accepting of casual sex, masturbate more often, view more porn, think about sex more, have more partners, and more often attribute a woman’s friendliness to sexual interest. Women, by contrast, are more selective J
1 Evolutionary psychologists argue that the reason for these wide disparities is the fact that sperm are cheap compared to eggs. Men want to spread their genes, and look for healthy, young women who appear fertile, while women look for healthy, mature, dominant, and affluent men who can support and protect them. “Druish princesses are often attracted to money and power, and I have both, and you KNOW it.” –Dark Helmet (Rick Moranis) in Spaceballs
1 Critics argue that evolutionary psychology starts with an effect and works backward to propose an explanation. Some believe that evolutionary speculations about sex and gender only serve to reinforce male-female stereotypes, and that cultural expectations also bend the genders (because ideals can change with time and place)
Behavior Genetics: Explaining Individual Differences
“ Behavior geneticists = scientists who study the relative power and limits of genetic and environmental influences on behavior
“ Environment = every external influence (nothing genetic)
Twin Studies
~ Identical twins = genetically identical siblings who developed from a single fertilized egg that split in two. Extremely helpful in studies to separate environment and heredity
~ Fraternal twins = genetically no more similar than ordinary brothers and sisters, because despite being born at the same time, they developed from separate eggs
~ In explaining individual differences, genes matter. A person whose fraternal twin has Alzheimer’s disease has a 30% risk of sharing the disease; if the twin with Alzheimer’s is identical, the risk is 60%. Similarly, if you have a fraternal twin who has divorced, the odds of your divorcing go up 1.6 times (compared to those with a not-divorced twin); if your identical twin has divorced, the odds of your divorcing go up 5.5 times
~ Studies of identical twins separated at birth have proved that genes do influence personality. Parental perceptions (whether parents think their twins are identical or fraternal) hardly matter. Separated twins did share an environment for at least their first nine months in the womb; they share an appearance; and adoption agencies often tend to place them in similar homes
Adoption Studies
ê Adoption studies are also relevant because they create two groups of relatives (the adoptee’s genetic relatives and environmental relatives), so we can speculate if adopted siblings come to share traits with non-related people when they share a home environment
ê Surprisingly, studies have shown that whether biologically related or not, people who grow up together do not resemble one another much in personality; rather, their traits bear greater similarities to their biological parents than to their adoptive parents. Two adopted hobbits raised in the same hobbithole are no more likely to share personality traits with one another than with the hobbit down the road
ê Still, adoption does matter; parents influence their children’s attitudes, values, manners, faith, and politics
ê Adoptive parents are carefully screened, so adopted children usually thrive, especially when adopted as infants. They often grow up to be more altruistic than average, and smarter than their biological parents
Temperament Studies
? Temperament = the intensity and emotionality with which a person characteristically reacts. The temperament of an infant usually persists throughout his or her entire life. Twins who share identical genes are more likely to have similar temperaments
? Studies with monkeys have shown that heredity overrides rearing; even when raised by easygoing foster mothers, monkeys who were genetically predisposed to be uptight still reacted anxiously to stress. With humans too, it is believed that temperament is largely inherited
Heritability
R Heritability = the degree to which variation among individuals is attributable to their differing genes. It is impossible to say what percentage of an individual’s personality or intelligence is inherited
R As environments become more similar, hereditability as a source of differences becomes more important. For example, if rabid Legolas fangirls were raised in barrels to the age of 20, in identical environments, fed through holes, their individual IQ score differences could only be explained by heredity. If all people had similar heredities but were raised in drastically different environments, heritability would decrease
R Individual differences in height and weight are highly heritable, but nutritional rather than genetic influences explain why today’s adults are taller and heavier than those of a century ago. Heritable individual differences need not imply heritable group differences
R Humans have an enormous adaptive capability. Genes and environment – nature and nurture – work together like Aragorn wielding Anduril, with the environment responding to and shaping what nature predisposes. It is impossible to ask whether your intelligence or personality is more a product of your genes or environment
Gene-Environment Interaction
ä The effects of gene and experience intertwine. For example, compare two babies, one an Elf, genetically predisposed to be absolutely gorgeous, the other a Dwarf, far less so. The Elf baby will attract more affectionate and stimulating care than the Dwarf, and thus develop into a warmer and more outgoing person; he/she will then seek activities and friends that further encourage social confidence. This shows that our genetically influenced traits evoke significant responses in others
ä From conception onward, we are the product of a plethora of interactions between our surrounding environments and our genetic predispositions. Children experience parents differently, depending on their own unique qualities
The New Frontier: Molecular Genetics
‘ Molecular genetics = subfield of biology that examines the molecular structure and function of genes. Researchers quest not for the Holy Grail, but instead to identify the specific genes that influence behavior. Each trait is influenced by a combination of genes
‘ There are risks and ethical issues to prenatal screening. This has caused sex-selective abortions that have led to millions of “missing women”; should parents be allowed to freely choose for health, brains, beauty, athleticism? In addition, it is important not to label people in ways that might result in discrimination or self-fulfilling prophecies.
The Nurture Perspective
~ Genetics explain roughly 40 to 50 percent of our individual personalities. Parental and communal nurture “plays an enormously powerful role”
Parents deserve credit and/or blame for our traits.
Ø Parents feel enormous pride in their children’s successes, and guilt or shame over failures.
Ø Society blames the “bad mothering” phenomena for many problems. (The lack of or excursion of too much attention)
Ø The balance that makes parenting- (overbearing vs. uninvolved)
(overprotective vs. distant)
(pushy vs. ineffectual)
Ø Shared environmental influences, like growing up in the same household account for about 10 percent of shared personality traits. ( a brother and sister should act as different as if they were selected randomly from the community population)
Ø Searching for exact environmental conditions that directly effect behavior is like chasing after your own tail, so the book basically says these are some common ones-
Prenatal environment, early learning experiences, peer influence, culture and gender.
Prenatal environment, or nurture, behinds in the womb, as embryos receive varying exposure to nutrition and toxic agents.
Ø Some identical twins share a placenta, some don’t, so that they share the exact same blood or don’t which exposes them to different conditions.
Experience helps develop the brain’s neural connections.
Ø Even if you forget things early in life, they still prepare you for thought, languages and later experience.
Ø Things that live in a more enriching and varied environment develop heavier, more mature and complex brains.
How nature and nurture effect growth.
Ø Children whom grow up in impoverished environments score higher on IQ tests at age 12 if given stimulating infant care, because their brains are less crowded.
Ø Young people can learn languages, older people can’t because young people have excess neural tissue.
Ø Children whom are born blind then surgically can see, never develop proper perceptions because part of the brain has reverted use to something else or died.
“Use it or loose it” – natural condition of maturing brain.
Ø Genes dictate overall brain architecture, but experience directs the details. – Your dad can be a great baseball player, but unless you practice, you won’t be.
Experience nurtures nature.
Peers powerfully socialize children and youth.
Ø Preschoolers who hate jelly, despite their parents telling them to eat jelly, will eat jelly if they are at a table full of preschoolers eating jelly.
Ø A kid hearing a Spanish accent at home and an Italian accent everywhere else will usually speak in an Italian accent. (“When in Rome, they become Romans”)
Ø Kids start smoking more because their friends do than their parents.
Ø Selection Effect- Seeking peers with similar attitudes and interests.
Ø Parental nurture is vital to early survival, but maturation will prove a greater influence from our peers, whom we are most likely to work, play and mate with. But parental influence is most seen at the extremes, abused kids abuse, tight knit communities have most successful kids.
Ø Parental nurture is more like nature than other influences, like nutrition, how we got it is less significant than the fact that you actually did get it, to make us feel like we belong to something that cares about us.
Parents: Peers:
Education, discipline, responsibility, Cooperation, popularity,
orderliness, charitableness, and interaction styles of interaction between
with authority figures. people of the same age.
Culture is the behaviors, ideas, attitudes, and traditions shared by a large group of people and transmitted from one generation to the next.
Ø In Japan, 99 percent of the population is Japanese and therefore internal differences in culture are nearly non-existent, as opposed to like New York or L.A where there is tons of harmonious variation and impregnated developing culture.
Ø Norms– accepted and expected behaviors in a culture.
Ø Personal space– “the portable buffer zone!”
Ø Cultures vary in their expressiveness, like Jews may see African Americans as kind, and fun but inefficient and African Americans may see Jews as efficient but cold hearted. Differences in beliefs, values, and daily life.
Ø Cultures also vary in their pace of life, some are very relaxed (Latino) or very fast and sneaky (Japanese).
Cultures naturally vary with time.
Ø Cultural memes- self-replicating cultural mutations get copied into memories and media as opposed to nature.
Ø Western Culture time variation- today we appreciate individualism, following conscious and beauty, thing through your personal aspirations and needs, but 100 years ago you would be raised to be disciplined, obedient and follow suit to survival.
Ø Asians and Africans prefer collectivism– giving priority to group goals and identity, they are more concerned with upholding things like mathematical achievements and family honor.
Ø We are all biologically similar, so we all speak and act similar, similarities far outweigh differences.
Gender illustrates that nature and nurture predispose our behavior.
Ø Some societies value kind, honest, intelligent traits,(modern countries), whereas others value just the mating aspect (Muslim countries) demonstrates the correlation between nature and nurture.
Ø Twenty-third chromosome, seven weeks after conception determines sex.
Ø X Chromosome – given automatically by mother.
Ø X or Y Chromosome- if X is given by father it’s a girl, if Y it’s a boy.
Ø During the 4th and 5th month of development in the womb, the tiny amount of testosterone or female hormones will cause the brain to develop slightly differently.
Ø Nature playing nurture- girls that get too much testosterone in the womb are more subject to become lesbians, influencing other people.
Although biologically influenced, gender is also socially constructed. What biology initiates, society accentuates.
Ø Role- cluster of prescribed actions, the actions we expect out of someone in a certain social position.
Ø One set of norms in culture is gender roles– the expected way men and women should act.
Ø Evolution does effect gender roles, making men more aggressive and less personal, making women more adept at interpersonal skills, but we also know that it isn’t rigidly fixed, as gender roles vary from culture to culture. –
— No culture is woman dominated, though it varies wildly, 48% of management positions in Sweden are women, 17 % in U.S. and 2% in South Korea.
Ø Gender roles vary over time as well as cultures- at the beginning of the 20th century only Denmark allowed women to vote, today Kuwait is the only democracy that doesn’t.
Ø Gender identity– Sense of being male or female.
Ø Gender-typed– Boys exhibit more traditionally masculine traits, girls distinctly feminine.
Ø Social learning theory– proposes that children learn gender roles by observing and imitating and by being rewarded or punished for doing so.
The -“Big boys don’t cry”- theory
Ø Gender schema theory– combines social learning with cognition and perspective. We view the world threw schemas, like a girl views the world through the lens of a girl.