1. Nature Versus Nurture What Makes you Who you Are?
Genetic Influence = Nature
Humans are % identical
Environmental influence = Nurture

2. Genes: Our Biological Blueprint
Genes (DNA that form chromosomes) are the units of heredity.
Chromosomes
threadlike structures made of DNA that contain the genes
46 in each cell
Most characteristics are determine by final sex chromosome (women XX or men XY)
Dominant
More active in influencing a trait (brown eyes)
Recessive
Only influences a trait when paired with identical gene

3. Genes: Their Location and Composition
In the nucleus of every cell we have 46 chromosomes……

4. Chromosomal Abnormalities
Turner’s syndrome
Single X
Klinefelter’s syndrome
extra X…(XXY)
Down syndrome
extra chromosome on 21st pair.

5. Evolutionary Psych
Certain traits are selected for and come to prevail over time
Seeks to explain why humans act the way they do.
Useful in raising the “why of behavior”

6. Look at our Behaviors…
Can you answer these questions using evolutionary psychology?
Why do infants fear strangers when they become mobile?
Why are most parents devoted to their children?
Why do we divide people into categories?
Why do we have more phobias about spiders and snakes than electricity and nuclear weapons?
Now, the big one?

7. Criticisms of evolutionary perspective
Start with an effect and then work backward
Underestimates cultural expectations and socialization
Absolves people from taking ethical responsibility for sexual behavior

8. Behavior Genetics Behavior Genetics
Focus on individual differences & extent to which we are shaped by genes & environment
Our genes effect how our environment reacts to and influences us. -Nature enables nurture

9. Twin Studies

10. Identical Twins Fraternal Twins
develop from a single fertilized egg that splits in two, creating two genetically identical organisms
Fraternal Twins
develop from separate eggs
genetically no closer than brothers and sisters, but they share the fetal environment
What are the different types of twins?
Identical
twins
Fraternal
Same
sex only
Same or
opposite sex

11. Cross-Sectional Studies
Research Methods
Cross-Sectional Studies
Longitudinal Studies
Participants of different ages studied at the same time.
One group of people studied over a period of time.

12. Twin Studies: The results
To summarize the countless amount of studies: twins (especially identical), whether or not they are raised in the same environment are very much alike in many ways.
Genes matter- discovery of identical twins separated at birth show similarities (Bouchard twins)

13. Adoption Studies
People who grow up together, whether biologically related or not, do not much resemble each other in personality.
Adoptees traits bear more similarities to their biological parents than to their adoptive.
Environment factors shared by the family
have little impact on personality.

14. Temperament
a person’s characteristic emotional reactivity and intensity
Emotionally reactive 3 yr olds developed into more impulsive/ aggressive 21 yr olds
What influences a person’s temperament is heredity....
Heredity
Trait that is capable of being passed down.

15. Hereditability
As environments become more similar, heredity as a source of differences becomes more important.
If all schools were uniform, all families loving, heritability (differences due to genes) would increase. (differences due to environment would decrease)

16. Gene- Environment Interaction
Our genetically influenced traits affect how people react to and influence us
Physical traits (height eye color) interact with envion. To influence things like popularity, etc
As we grow older we select environments suited for our genes
Genes react/work in conjunction with
environment
Twins with ident. genes but
differing experiences have
similar but not ident. behavior

17. We’re the product of both nature and nurture; our genes give us our biological potential; our environment, including culture, determines how we express it.
Children who aren't loved don’t grow. Children who have irritable natures may be harder to nurture. Intelligence is in our nature, but success depends on nurture.
Every human being inherits certain behavioral tendencies that helped our human ancestors survive and thrive, but what triggers these tendencies and how often they expressed varies across cultures and individuals.

18. Epigenetics
Study of changes in gene activity that do not involve alterations in genetic code.
Biological response to environmental stressor
May be passed to future generations
Markers activate genome and switch genes on/off
Bad
Evidence that lifestyle choices can alter markers
Gene of obesity to express themselves strongly vs. genes of longevity to express themselves weaker
Good
Learning to manipulate markers in lab
Treat illness – remove stressor marker will fade

19. Environmental Influence
Genetic influences predict ~40-50% of individual variation
How much should we blame our parents?
Experience does help develop brain’s neural connection
Pruning
Without experience a
child’s brain develops 20-30% smaller

20. Critical Period
Specific time period during development when a particular event has its greatest consequence
Occur when presence of certain kinds of environmental stimuli are necessary for development to proceed normally
Konrad Lorenz
Imprinting
Has to occur within day of hatching
Konrad Lorenz studied grey geese – within 36 hours imprint on the first thing moving it sees (His black boots). Essential for life and survival. Occurs within a fixed time period. In humans – starts before birth (recognizing parents’ voices) and occurs shortly after birth.

21. Brain cells is an impoverished environment.

22. Brain cells in an enriched environment.

23. Experience affects brain development
Impoverished
environment
Rat brain
cell
Enriched

24. What does this mean for humans?
If children are given stimulating infant care, they score better on intelligence tests by age 12 than counterparts.
Use it or lose it

25. A Trained Brain
A well-learned finger-tapping task activates more motor cortex neurons (right) than were active in the same brain before training (left)

26. Gender We already know the nature differences. Focuses on SEX:
XX v XY
Focuses on SEX:
We are going to discuss GENDER: What is the difference?

27. Gender Roles vs. Gender Identity
Role: Our expectations about the way men and women behave
Identity: our sense of being male/female
How do roles develop?
Social Learning Theory: learn gender-linked behavior by observation and reward or punishment
Examples?
Gender Schema Theory: learning what it
means to be a particular gender through cultural
experiences

29. Changing Attitudes about Gender Roles

30. Gender Identity Our own sense of male or female.
We realize our gender identity through gender-typing: acquiring gender (masculine/feminine) roles

31. Dr. Money & The Boy Without A Penis
Can A Boy Be Raised as A Girl?- Look into the theory of Gender Neutrality
How much of our gender identity is formed by nature and how much by nurture?
Dr. Money & The Boy Without A Penis

32. David Reimer Reflection
Reflect on the ethics in the particular case, citing specific guidelines discussed in the prologue of your book, and your insights.