1. Nature, Nurture and Human Diversity
Chapter 4

2. Nature Vs. Nurture Psychology’s Biggest Question
Regardless of upbringing, ethnicity or gender, all human beings tend to
Develop in infancy and toddlerhood in the same order (roll over, sit up, crawl, walk)
Are drawn to people with similar interests.
Laugh when happy
Grieve death or loss of a loved one

3. How does Genetics influence Behavior?
Each individual is comprised of genes that are inherited equally from our mother and father.
This unique combination ultimately is what makes us different from every other human being.
Behavioral geneticists study our differences and weigh the effects and interplay of heredity and environment.

4. Studying Twins
The most ethical way to study the nature-nurture debate is through the study of twins.
Identical Twins come from the same fertilized egg and therefore are genetically identical.
Fraternal Twins are siblings who developed from separate fertilized eggs. While they shared the same fetal environment, they are no closer genetically than any other siblings.

5. Studying Twins
Identical Twins can be slightly different in the following ways:
While they have the same genes, they don’t always have the same number of copies of those genes, which may explain why one twin is at greater risk for disease than the other.
If twins don’t share the same placenta (1 in 3), environment may provide better nourishment to one placenta and can contribute to differences.

6. Genetics and Twins
If 1 identical twin has Alzheimer's Disease, the other twin’s chances of developing it is 60%. For fraternal twins, it is 30%
Identical twins are more likely to be similar in the areas of extraversion and emotional instability than fraternal twins.
Odds of divorcing if an identical twin has divorced is higher than with fraternal twins.
BUT, studies reveal that identical twins report being treated more alike than fraternal twins.
Nature vs. Nurture????

7. Biological vs. Adoptive Relatives
Studies of adoptees reveal the following information:
Personalities of siblings (whether biologically related or not) who grow up together, are generally not similar.
In areas of agreeableness and extraversion, adoptive children are more similar to biological parents than adoptive parents.
Implies environment has less influence than heredity.
Important to remember that adoptive homes are less likely to be abusive, neglectful or subject to divorce.
Most adoptive children, while more likely to develop psychological disorder, thrive, especially when adopted at birth.

8. Temperament and Heredity
Temperament: a person’s characteristic emotional reactivity and intensity.
Temperament is apparent at birth
Easy: cheerful, relaxed, and predictable in patterns
Difficult: irritable, intense and unpredictable
Slow to warm up: tend to withdraw or resist new people and situations.
Temperament tends to persist over time
Identical twins tend to have more similar personalities than fraternal twins leading to belief that heredity highly influences temperament.

9. Heritability What is it?
Heritability is the extent to which variation among individuals can be attributed to their differing genes.
For example if height has a heritability of 90%, the extent to which observed differences among people’s height can be contributed to genetics.
IT DOES NOT MEAN that 90% of your height is determined by genes.

10. Nature vs. Nurture
While some traits occur regardless of environment (having 2 eyes or ears), others are only expressed in certain environment due to a necessity to adapt.
Calluses on laborers hands
A biological adaptation to friction
Human differences result from both nature and nurture.
Eating disorders may be genetically influenced but are must more prevalent in image obsessed Western cultures.

11. When Genes and Environment Interact…..
It is the interaction of genes and environment that may ultimately determine the end result.
Genetically influenced traits, such as temperament may lead to a specific environment (i.e. abusive or nurturing)
Our traits may cause us, as adults to choose specific environments.

12. Who are you drawn to….?

13. Evolutionary Psychology
The study of the evolution of behavior and the mind using principles of natural selection.
Natural selection: the principle that, among the range of inherited trait variations, those that lead to increased reproduction and survival will most likely be passed on through the generations.

14. Evolutionary Psychology
These adaptations that promote survival and reproduction are rooted deeply in generations past.
Love of sweets believed to come from a need of our ancestors to survive famine.
Love of sweets reinforced by overprocessed, unhealthy junk foods and contribute to growing obesity epidemic.

15. Evolutionary Explanations
Gender differences in Sexuality
A cross cultural study of 200,000 people in 53 nations found that men everywhere strongly agreed to “I have a strong sex drive” and “It doesn’t take me much to get sexually excited.” at a much higher rate than women.
58% of men as opposed to 12% of women in a study of nearly 5,000 Australians agreed that they would be “comfortable and enjoy having “casual” sex with different partners”.

16. Evolutionary Explanations
What are some evolutionary explanations for men’s attitudes towards sex?
Women view sex from a relational standpoint, while men view it from a recreational standpoint.
Historically, women chose partners wisely in order to reproduce; men chose “widely”.

17. Evolutionary Explanations
What do people find attractive in the opposite sex from a evolutionary perspective?
Men are drawn to youthful looking women; waist roughly 1/3 narrower than their hips (a sign of fertility). Teen boys often find older women (of child bearing age) attractive.
Women are drawn to men who will “stick around”; mature, dominant, bold, affluent, and show the potential for long-term mating.

18. Critiques of the Evolutionary Perspective
Tends to have a “hindsight bias”; looking to the past to answer questions now.
Does it suggest a strong genetic influences that undermines societal and personal responsibility?
Some studies have found that gender differences are culturally specific (i.e. culture of gender inequality vs. gender equality will determine what you look for in a mate.)

19. Experience, Parents and Peers
While genetic predisposition plays a part in who we are, it is our experiences that complete the picture.
Neural connections are directly affected by our experience.
Insufficient interaction may result in less neural connections.
Ex. If we are not exposed to language before adolescence, we will have great difficulty acquiring language.

20. Experience, Parents and Peers
PARENTING MATTERS!!!
A combination of genetics and parental influences ultimately impact the development of an individual.
Family environment often shapes (but not always) children’s future parenting styles, vocational and academic successes.

21. Experience, Parents and Peers
Peers are highly influential through life, but especially during childhood and adolescence.
Preschoolers will eat undesirable food when put at a table with peers who like it.
Teens who smoke usually have friends who smoke.

22. Cultural Influences
Culture: behaviors, ideas, attitudes, values and traditions shared by a group of people and is transmitted from one generation to the next.
Cultural Norms: rules for accepted and expected behaviors
Vary depending on culture of origin.
Video – Social Norms

23. Cultural Influences Variations across cultures Variations over time
Western Cultures: men shake hands
Arab Cultures: men kiss
Western Cultures: wear shoes in the house
Eastern Cultures: no shoes – considered dirty
Variations over time
Technology, pace of life, changed social norms related to marriage, race relations

24. Cultural Influences Individualist Cultures Views self as independent
Strives to be unique
Interested in personal achievement/self esteem
Have many relationships; often casual; confrontation is acceptable.
Behavior reflects own personality and attitudes
Collectivist Cultures
Views self as interdependent (to group)
Strives to belong
Interested in group goals, solidarity; family duty
Have few relationships; close and enduring
Behavior reflects social norms and roles

25. Cultural Influences on Childrearing
Childrearing practices reflect cultural values that vary across time.
50+ years ago, in US, obedience, respect and sensitivity to others was priority.
Today, in US, children are encourage to be themselves, discover creative talents, prioritize personal needs.
Asian and African cultures value emotional closeness and strong sense of “family self”
Encourage co-sleeping
Child’s behavior reflects upon the family (shame or pride)

26. Gender Development
Our biological sex at birth helps to define our gender – the combination of biological and social characteristics by which people define male or female.
Gender is a perfect example of how nature and nurture combined create similarities and differences.

27. Gender Similarities
Genetically, males and females share 45 of the 46 chromosomes. Only 1 pair are related to sex.
There are almost no differences across the sexes in areas of vocabulary, intelligence, happiness, self esteem and cognitive development.

28. Gender Differences Females: Enter puberty 2 years earlier
Live 5 years longer
Have more body fat
Smell fainter odors
Express emotions more freely
2x as likely to develop depression and anxiety.
Males:
4x more likely to commit suicide or suffer with alcoholism
Much higher likelihood to be diagnosed with autism, color blindness, ADHD and antipersonality disorder.
Tendency to behave in more physically aggressive ways.

29. Gender Differences
Studies on gender differences in social connectedness revealed:
Children: Boys tend to play in large groups with little intimate conversation and engage in competitive play. Girls play in small groups, often only with one friend and often imitate social relationships.
Adolescence: Girls spend more time with friends, more time on social networking internet sites than boys.
Adults: Women enjoy face to face talking and use conversations to explore relationships. Men enjoy doing activities side by side and use to communicate solutions.
Women’s relationships tend to bind families together.
Differences tend to peak in adolescence and diminish by age 50.

30. Is Gender Nature or Nurture?
Levels of testosterone (male sex hormone) are found in both sexes but are much higher in men.
Abnormal levels of testosterone can lead to more ambiguous gender identity.
Cultural norms related to gender roles drive the expectations about how males and females should act.
Scandinavian countries tend to embrace more gender equality than most countries; Middle Eastern and Northern Africian have the least gender equality.

31. Gender Identity
Society lends itself to shaping gender roles and aids individuals in their resulting gender identity – the sense of being male or female.
Social Learning Theory assumes children learn gender linked behaviors through observing and imitating, then by being rewarded or punished.

32. Social Learning is shaped by our schemas: concepts that help us make sense of the word. How strongly influenced you are by your schemas will ultimately determine your gender identity.