Intelligence & genetics

Question 1

Heritability is true for a given ___ at a given ___

Answer 1

population. Time

Question 2

We share __ % of our genes with chimps & other humans. Therefore, we are looking at the __-__% of genes not shared by all humans

Answer 2

97%+. 1-2%

Question 3

There are 3 approaches to IQ. What are they and which have genetic studies adopted?

Answer 3

Psychometric, info processing & developmental. Psychometric

Question 4

Genetic evidence comes from 3 types of study:…

Answer 4

Family studies, twin studies & adoption studies

Question 5

How much genetic variance is shared by parent-offspring (first degree), full siblings (first degree), half siblings (second degree) & cousins (third degree)?

Answer 5

1/2, 1/2, 1/4, 1/8

Question 6

Do siblings or parent-offspring show larger IQ correlations?

Answer 6

Siblings

Question 7

MZ twins develop from…vs. DZ twins develop from…

Answer 7

A single fertilised egg vs. two separately fertilised eggs

Question 8

When comparing MZ & DZ twins, same-___ DZ twins are used because they tend to be treated more alike & MZ twins are always same-___

Answer 8

Sex. Sex

Question 9

Give 2 formulae which can be used to estimate heritability (h2)

Answer 9

h2 = 2 (Rmz - Rdz) or h2 = 2 (Rdz)

Question 10

By comparing Rmz & Rdz we can tell a) whether IQ has a genetic component by identifying a sig difference & b) whether the genetic effect is ___ e.g.

Answer 10

Additive e.g. if Rmz is twice Rdz then the genetic component of IQ is additive. If Rmz is greater than twice Rdz then the genetic component is interactive

Question 11

Name 2 methods which are used to fit twin data to statistical models of the genetic contribution to intelligence

Answer 11

Maximum likelihood estimation (Chi squared), multiple regression model fitting

Question 12

On a twin-by-twin basis we can see large similarities between the ___ of mental development score spurts & lags

Answer 12

timing

Question 13

Tambs (1984) found an usually large IQ heritability value (.8) most likely because the twins were…

Answer 13

40 years of age

Question 14

A child’s IQ is correlated with its mother’s level of education & IQ - to an even greater extent as the child grows older. Am I referring to the adoptive/birth mother & adopted/birth child?

Answer 14

The birth child-birth mother

Question 15

The lecture slides argue that the shared environment shapes IQ. TSB adoption studies in 2 ways - name them

Answer 15

Genetically unrelated adopted siblings’ IQs correlate at .32. Adoptive parents-adopted children’s IQs correlate at .19, suggesting a lesser role for the shared environment

Question 16

Interestingly the correlation between the IQs of genetically unrelated adopted siblings drops to 0 beyond ___ because the environment is no longer ___

Answer 16

Childhood. Shared!

Question 17

Name some environmental influences on IQ

Answer 17

Social class, quality/ amount of schooling, family size, nutrition, health

Question 18

In statistical model fitting different models attribute IQ variance to differing numbers of factors. E.g. a model of the IQs of family members which splits…genetic influences &…shared environmental influences has a better fit

Answer 18

Additive & nonadditive. Cousin vs. parent-offspring vs. siblings vs. twins

Question 19

There is ___ contribution of the shared environment to specific abilities

Answer 19

Less

Question 20

The gene linked to reading disability is the ____ gene

Answer 20

6p21

Question 21

Piaget conservation task performance has ___ by 1/2 SD in a generation. Height has high heritability but also shows a version of the ___ effect

Answer 21

Fallen. Flynn