Nature v. Nurture
Nature v. Nurture
Nature
“I’m not good at math because no one in my family is good at math, we don’t have the “math” gene.
Nurture
“I’ve become a great baseball player as I practice all the time.”
The Middle Passage or Culture
The Middle Passage or Culture
The Middle Passage or Culture
The Middle Passage or Culture
The Middle Passage or Culture
Genetic Contributions to Development
genome: all genetic possibilities of a species
(humans have 3.1 billion)
structure of our genetics:
DNA → Genes→ Chromosomes
Genetic Contributions to Development
Genotype v. Phenotype
genetic make-up v. observable traits
Dominant gene v. Recessive gene
expressed gene v. not expressed gene
Brown v. Blue Eyes
Brown v. Blue Eyes
Heritability
→ Everything about a plant or animal depends on both its heredity and the environment in which it is expressed.
→ Heritability is the extent to which INDIVIDUAL differences among a POPULATION of people are attributed to genes and not to the environmental influence in which they occur.
Heritability
→ Heritability is a measure of the degree to which people are different due to their genes (vs. the environment affecting genetic expression).
→ Heritability involves both NATURE and NURTURE!!
→ A heritability score of 0.00 means NO variation. A heritability score of 1.00 means TONS OF variation.
Heritability
All Eskimos have black hair because there is only one allele (genetic version) for black hair among Eskimos.
The heritability for having black hair among Eskimos is 0.00 (or zero).
Meaning, the environment has no impact on the hair color of Eskimos. There is no genetic variation.
Heritability
In our genetic make-up, extraversion or introversion can be expressed.
Based on twin and adoption studies, the heritability for extraversion is 0.35.
There is some genetic variation.
A heritability of 1.0 would be LOTS of genetic variation.
Predisposition
A vulnerability to possible expression of a gene or environmental influence
*We as humans have a predisposition to not want our mouths washed out with soap, as it causes us to vomit!
*Are you likely to suffer cancer?
*Are you likely to suffer bipolar disorder?
Mutations of Sex Chromosomes
Turner’s Syndrome (XO)
-Females lack 2nd X on 23rd pair
-Short webbed necks, immature
appearance, eyelid folds are heavy, receding
chins, sterility
-Social and academic immaturity
Mutations of Sex Chromosomes
Fragile X Syndrome
-Both males and females have a string on
thin DNA on a 23rd chromosome
-Two-thirds show severe to mild mental
challenge
Mutations of Sex Chromosomes
Kleinfelter’s Syndrome (XXY)
-Males
-Tall, long arms, long legs, some breast
development, high-pitched voice, sterility
Mutations of Sex Chromosomes
Double Y Syndrome (XYY)
-Tall and large
-Intellectual impairment, don’t consider
consequences of behavior, lacking theory of
mind (unable to perceive others’ points of view)
-A disproportionate number of men in prison
have XYY
Prenatal Development
Conception: moment sperm and ovum unite and share a total of 46 chromosomes
Gestation: period of pregnancy
Germinal (zygotic) period (0-10 days): rapid cell division and zygote travels fallopian tube and then implants on uterine wall
Prenatal Development
Embryonic period (10 days to 2 months):
-Now called the embryo
-Rapid growth and cell differentiation
-Organs and genitals form
-Umbilical cord and embryonic sac form
Prenatal Development
Fetal period (2 to 9 months):
-3rd month: movement of limbs
-4th month: mom feels movement
-5th month: almost all neurons have developed
-6th month: brain activity similar to newborn
-7-9th months: weight gained and specialization of
organs continues
Prenatal Development
Teratogens: diseases that create birth defects
(mutations); rubella, measles, syphilis,
herpes
Radiation: leads to deformity
Toxic chemicals: leads to deformity
The Newborn
*For every 100 females,126 males are born
Rooting, sucking, and grasping reflex
-Rooting: head and mouth movement to
seek mother’s breast for milk
-Sucking: mouth movement and swallowing
-Grasping: holding tightly to objects, i.e.,
adult fingers
The Newborn
The brain is at 25% of its size:
-100 billion neurons
-neural growth of dendrites and myelin continues
after birth (“Eat buttered bread and whole milk for
myelin!”)
-Cell connections develop rapidly during the first 4
years of life
-These neural connections are one type of
maturation (physical development through stages)
Homosexuality is Natural and Nurtured Behavior
* Both homosexuals and heterosexuals share the goal of an intimate relationship (both sexual and emotional) with another person
* Both homosexuality and heterosexuality demonstrate behavioral predispositions
Lesbians have more interest in “masculine” play as children, gay men have
more interest in “feminine play” as children
* Homosexuals share biological predispositions: brain, genetic, and hormonal manifestations
* Evolutionary psychology defends homosexuality as necessary to the species
Rates of homosexuality help control for overpopulation
* Homosexuality occurs across several - if not all - animal species
The Subjective Experience of Emotion
To what degree do we engage others with our emotion? (Eastern v. Western cultures)
To what degree do we express our emotion? (Eastern v. Western cultures)
How do people and cultures differ in their expression of emotion, i.e., through gesture?
Emotional Expression
-The chameleon effect: we mimic body posture of those with whom we’re communicating
-Mirror neurons and empathy
The chameleon effect
The chameleon effect
The chameleon effect
The chameleon effect
The chameleon effect
The chameleon effect
Stress
Types of Stress
eustress = good stress
starting in a new school, meeting new people, new possibilities
distress = bad stress
inability to make a decision
Causes of Stress in Nature
Autonomic Nervous System
Cortisol
Norepinephrine (adrenaline)
Traumatic Brain Injury (TBI)
Injury
Illness
Causes of Stress in Nurture
Poverty
Racism
Income
*The greater the income disparity, the higher the mortality rate
Catastrophe (hurricane, tornado)
Every day stress
Consequences to Stress in Nature
Lymphocytes - B (fight bacteria) and T (fight cancer, viruses) deplete under distress, leading to vulnerability to illness
Vulnerability to heart disease (a key indicator to a high stress society)
Consequences to Stress in Nurture
Drug use
A sense of loss of self-control due to racism, poverty, leading to self-fulfilling prophecy
PTSD
Treatments for Stress in both Nature and Nurture
Psychophysiological
Health and wellness
Behavioral medicine
Health psychology
Yoga
Alternative care
Whole vitamins
Biofeedback
Hypnosis
Acupuncture
Spas
Manicure/pedicure
See the MD