1. Unit 3: Biological Bases of Behavior
Module #7:
Environmental Influences on Behavior

2. Prenatal Environment
-Identical twins who share the same placenta (b) are more alike than those who do not (a), suggesting prenatal influences on psychological traits.

3. Experience and Brain Development
-Early postnatal experiences affect brain development. -Rats raised in enriched environments developed thicker cortices than those in impoverished environment.

4. Experience and faculties
-Early experiences during development results in remarkable improvements in music, languages and the arts.

5. Brain development & adulthood
-Brain development does not stop when we reach adulthood. -Throughout our life, brain tissue continues to grow and change.
More motor cortex neurons were activated (right) after training than before training (left).

6. Parental influences
-Parental influence is largely genetic. However, other socializing factors also play an important role. -Parenting should be given less credit and blame for their behavior. -A parent’s genes are a bigger factor than the way they raise their children.

7. Peer influences
-Children, like adults, attempt to fit into a group by conforming. -Conforming – To act the same as those around you. We do this to be accepted by the group. -Peers are influential in such areas as learning to cooperate with others, gaining popularity, and developing interactions. -Peer influence can be more powerful than parental influence.

8. Cultural influences
-Culture is composed of behaviors, ideas, attitudes, values and traditions shared by a group. -Humans have the ability to evolve culture. Animals act the same as they did for centuries. -We do and enjoy things differently than we did 100 years ago. -Electricity, plumbing, medicine, etc.

9. Variation across culture
-Each culture develops norms. -Norms - rules for accepted and expected behavior. They dictate what “proper” behavior looks like. -Men holding hands in Saudi Arabia is the norm (closer personal space), but not in American culture.

10. Norms
What are American norms? Individuality Timeliness Eye contact during talking Job – 9 to 5, 40 hours per week Education (luxury in other countries) Personal space!!!!!

11. Variation over time
-Cultures change over time. The rate of this change may be extremely fast. -In many Western countries, culture has rapidly changed over the past 40 years or so. -This change cannot be attributed to changes in the human gene pool because genes evolve very slowly.

12. Culture and self
Individualist – Cultures that nurture a person’s identity. “I” -Individualists put a greater priority on personal goals and personal attributes. -Strive for personal control and individual achievement. -Able to leave job, divorce, move to another city, change religions, etc.

13. Culture and self
Collectivist – Cultures that nurture a group identity. “We” -Family, groups, loyal friends define identity. (African & Asian cultures) -Groups provide values, network of caring, and security. -Sacrifice self for benefit of whole. -Results in greater shyness, loyalty, and deeper family connections.

14. Culture and self

15. Culture and self
Individualist… …have more freedom …pride in personal achievement …enjoy more privacy …celebrate innovation & creativity …respect human rights …more happiness Also more… loneliness, divorce, homicide, stress, etc.

16. Culture and self
Collectivist… …have pride in group achievement …based on emotional connections …network of support …fewer relationships, but stronger connections in those relationships But also… …have less freedom …ceiling on personal achievement

17. Culture & child-rearing
-Individualists (European) raise their children as independent individuals. -Collectivist cultures (Asian) raise their children as interdependent.

18. gender development
-Based on genetic makeup, males and females are alike, since the majority of our inherited genes (45 chromosomes are unisex) are similar. -Males and females differ biologically in body fat, muscle, height, onset of puberty, and life expectancy.

19. Aggression
-Men express themselves and behave in more aggressive ways than do women. -This aggression gender gap appears in many cultures and at various ages. -In males, the nature of this aggression is physical. -Men to women ratio for murder in US is 9 to 1. Canada: 7 to 1.

20. Gender & social power
-In most societies, men are more dominant, forceful, and independent -As leaders, men are more directive and autocratic. -Men are more likely to give opinions, talk assertively, interrupt, initiate touching, smile less, & stare. -Men emphasize freedom and self- reliance.

21. Gender & social power
-Women are more deferential, nurturing, and affiliative. -As leaders women are more democratic, welcoming of opinions, & compromising. -Women are more likely to express support and form more connections with people.

22. Biology of Sex
-Biological sex is determined by the 23rd pair of chromosomes. -XX = female, XY = male -The Y chromosome produces the male hormone, testosterone. -Females have testosterone, but less. -Men and women have differences in brain structures.

23. Gender roles
Gender roles – expectations of how men and women are supposed to behave. Gender identity – how a person views himself or herself in terms of gender.

24. Gender roles: Theories
Social learning theory – we learn social behavior by observing and imitating and being rewarded or punished. “Big boys don’t cry.” “Man up.” “That is un lady-like.”

25. Gender roles
Schema – mental way of organizing information around us. Ex. A horse is large, has four legs, and a tail. A child might mistake a cow for a horse at first because it fits into their schema. You produce a schema for what it is to be a boy or girl. Girl – long hair, sweet, etc.

26. Gender roles: theories
Gender schema theory – children learn from the cultures what it means to be a boy or girl and adjust their behaviors accordingly. -Our perceptions are shaped by what culture says is male and female. -I am male, thus I am masculine, strong, & aggressive.

27. Reflections on nature & nurture

28. Reflections on nature & nurture
Occam’s Razor –The simplest answer is usually the correct one. (also called Ockham’s razor) We are a product of nature AND nurture. Biological, socio-cultural, and psychological influences all combine to make us who we are!!!