week 6

Question 1

What is genotype

Answer 1

genetic complement, coded in DNA that we inherit from our parents

Question 2

What is phenotype

Answer 2

outward manifestation of the individual

Question 3

Heritability

Answer 3

proportion of phenotype variance that is due to genetic differences

Question 4

Environmental influences

Answer 4

Family environment, shared environment: children raised in the same home will be more similar
Non-shared environment: even children raised in the same home will have different experiences growing up

Question 5

More environmental influences

Answer 5

Socioeconomic status, prenatal health, birth order, family size, culture, education

Question 6

Early origins

Answer 6

relationship between eminence and families
An eminent man is a man who demonstrated consistent intellectual and creative leadership
Boys adopted by eminent men and raised in privilege less likely to be eminent than natural-born privileged sons of eminent men

Question 7

Animal research

Answer 7

Tolman 1924 and Tyron 1940 selectively bred two strains of rats
Maze bright= quickly run through maze and find food
Maze dull= much slower at learning to find food in maze

Question 8

Methods to study

Answer 8

family studies
twin studies
adoption studies

Question 9

Family studies

Answer 9

Investigate the similarity of family members in respect of intelligence
First degree relatives: parents, siblings, children (50% genetic similarity)
Second degree: Grandparents, Grandchildren, aunts, uncles, nephews, nieces (25% genetic similarity)
Third degree: great-grandparents, great-aunt, Aunt-uncles, first cousins (12.5% genetic similarity)

Question 10

Twin studies

Answer 10

Monozygotic or identical twins: identical genotype, 100% genetic similarity MZ=0.87

Dizygotic or Fraternal twins: Genetically no more alike than other siblings. 50% genetic similarity DZ=0.53

Assumption: environments are matched but MZ more genetically similar than DZ

Question 11

Control Genes

Answer 11

to investigate influence of genetics need to manipulate the environment of MZ twins

Question 12

Twin studies part 2

Answer 12

Cyril Burt was a British educational psychologist
Burt attributed difference in intelligence to genetics
work is caused controversy: claimed he had fabricated his data and his research assistants, Raw data could not be found

Research to support: Bouchard and McGue 1981 MZ twins reared apart. 72 Ridley 1999

Question 13

Limitation of sparated Twin studies

Answer 13

Some MZ twins actually found to be living in different branches of same family, participants difficult to recruit
selective placement
Twins separated at birth but what about prenatal environment, Are twins representative of general population, majority of twin studies focused on middle class samples

Question 14

Virtual twins

Answer 14

Fullerton virtual twin study: adopted by one year of age, siblings age difference 9 months or less, same grade at school, absence of any birth events that may affect development, current age of 4 years of older, same sex and mixed sex pairs studied
Completed sub scales from WISC-II correlations 0.30 at time one and 0.11 at time two, modest relationship to no relationship
Importance of shared genes over shared environment increases over time

Question 15

Adoption studies

Answer 15

adopted families share no genetic similarity but do share same home environment

Question 16

Texas adoption study

Answer 16

300 families who had adopted children from for unwed mothers
Initially correlations between adopted parents and children similar to correlations with their biological children
Environment influences intelligence when children are small but as they develop influence of environment decreases and genetics increases

Question 17

Summary of what is known

Answer 17

Highest correlations most genetically similar individuals
Lowest correlation least genetically similar or no genetic relationship
Those reared together more similar than those reared apart