NATURE, NURTURE AND HUMAN DIVERSITY (CHAPTER 4) - part 1
- one of the most fundamental questions... WHAT MAKES US WHO WE ARE?
- nature vs. nurture
nature: genes, DNA, heredity, born this way
nurture: anything and everything that is not genetic. It is the way you were raised, the
school you went to, your religion, culture, experiences, food, water, air, mothers
condition while pregnant
- most psychologists believe that it is a bit of both nature and nurture.
2. The Nature Component
A: Genes - our biological blueprint
- we have trillions of cells in our body, in every cell we have 46 chromosomes (except
egg and sperm) we get half from our mothers and half from our fathers.
- chromosomes are carriers of info, they carry it in the form of DNA.
- DNA consists of thousands of genes
- Genes are the basic unit of heredity. they provide the instructions to give the organism
- a single gene is sometimes responsible for a characteristic
- gene complexes are groups of genes that are responsible for characteristics
- nucleotides - biochemical building blocks
- A - adenine
- G - guanine
- T - thymine
- C - cytosine
- always come in pairs
- A & T
- G & C
- the alphabet of life
- it is the sequence of nucleotides that will determine what a gene does and does
- think of chromosomes as books...genes would be the words and nucleotides
would be the letters.
- human genome = 30,000 genes (around 30,000)
- every single human being on earth is 99.99% genetically similar to each other
- repartition of the 0.01% difference:
- 5% is differences among races
- 95% differences within a race
- nature genetics 2004: race does not exist biologically
- race is a social and cultural concept
- “meaningless concept” “ought to be abandoned”
Us and Other Organisms:
- we share 50% of our genes with bananas
- 44% with a fruit ﬂy & 30% with a daisy, for example B. Evolutionary psychology (EP)
- based on the theory of evolution that was developed by Darwin
- the main goal for any organism is to survive and transmit your genes into the future
- not all organisms survive because of natural selection
- only the ﬁttest will survive
- when the characteristics and the demands of the environment match, an organism is
- any behaviour or trait or characteristic that helped our ancestors survive is what we
see most of in organisms today.
- evolutionary psychologists are interested in things that are universal and common
- adaptation is one of our greatest traits. humans can solve problems.
- according to old surveys, men are more sexual than women
- this is not completely true, women and men have different attitudes towards sex
- Clark and Hatﬁeld 1978
- chose average looking people to ask other people who they thought were good
looking to sleep with them.
- many women said absolutely no
- many men said yes, why wait until tonight
- according to evolutionary psychology both men and women have the same goal, they
want to survive and transmit their genes into the future. however because of genes,
they have different ways of doing so
- men want to have multiple partners (best strategy to transmit most genes)
- women want to have 1 person (takes 9 months, need commitment)
B3. Critique of EP
- in the world today we have 18 tribes who believe that babies have multiple fathers.
- they encourage their women to have multiple partners
- the women in the tribes who had multiple partners were more likely to get pregnant
and less likely to have a miscarriage
- 80% of the children of the women who had multiple partners lived to be 15 years old
vs. 64% of women who had 1 partner.
- based on this fact, women should have multiple partners
- in opposition to evolutionary psychology
C. Behaviour and Genetics
- EP’s study things that are common to everyone
- behaviour and genetics focus on individual differences
- we differ from each other in multiple ways (looks, intelligence, risk of disease, etc)
- differences between individuals
- BG’s believe that who we are is an interaction between nature and nurture
- they study the degree to which the differences between each other is due to genetics
- how much does the environment, genetics, and the interaction between nature and
nurture contributes to what makes us different - they do not study the DNA
- they do twin, adoption, family, and temperament studies (see below)
C2. Twin Studies
- monozygotic = identical
- 1 sperm, 1 egg, same sex only,