LPI T3

Question 1

Heritability

Answer 1

estimate of the average proportion of variance for any behaviour, thought to be accounted for by genetic factors across the population how far variability in phenotypic variance is attributable to genotypic variance.

Question 2

Twin Studies

Answer 2

possibility of comparing different types of genetic makeup to compare genetic influence because different types of twins share different proportions of genes dizygotic 50% monozygotic 100%

Question 3

Critique of Twin Studies

Answer 3

on their own not insightful potentially because all children share an estimated average of 50 per cent of their genes withtheir parents and their siblings using observation, interview or questionnaire measuresalso presents a problem because similarities betweenpersonalities might be because of environmental influence(e.g. an extraverted son might be like his extraverted father

Question 4

Behavioural Genetics

Answer 4

looks at the relationships between genes, environment and behaviour estimating the extent of genetic heritability of behaviour across a population; stating the genetic heritability of that behaviour in terms of shared variance

Question 5

Additive Assumption

Answer 5

two dimensions that determine heritability: the genetic part and (2) the environment (outdated for genetic heritability) E+G= 100

Question 6

Genetic Heritability

Answer 6

Assessment of how any extent of phenotypical manifestations in a child are caused by their genetic inheritance

Question 7

Examples for Phenotypes?

Answer 7

physical appearance, behaviour, intelligence, personality, observable/measurable properties

Question 8

H^2 ?

Answer 8

Estimated average of genetic heritability across a population taken from samples of studies^2* (rmz-rdz)

Question 9

What are the three main methods of assessing genetic heritability?

Answer 9

Family Studies, Twin Studies, Adoption Studies Plomin 2004

Question 10

The problem with Family Studies? (2)

Answer 10

Robert Plomin 2004 on their own they tell us very little about g.i. because children are assumed to share an estimated average of 50% with their siblings and parents similarities found using observation, interview or questionnaire mesures might be because of the environmental influence of the parent -> solution twin and adoption studies

Question 11

Family Studies

Answer 11

Researchers examine associations between parental and child behaviour within a family

Question 12

Adoption Studies

Answer 12

possibility of comparing different types of genetic makeup to compare genetic and environmental influence at the same time because different types of twins share different proportions of genes if two twins show similar behaviours despite being raised in different environments = evidence genetic heritability all these studies are considered when examining genetic inheritance

Question 13

What does and doesn’t genetic inheritance refer to?

Answer 13

Heritability estimates doesn’t refer to specific individuals but certain populations of people so MZ, DZ, Family members, parents and children

Question 14

What does a heritability estimate of 50% mean?

Answer 14

it doesn’t mean we inherited this amount from genes but that across a certain population the genetic heritability of a certain trait is estimated at an average of 50%

Question 15

Concordance Rate

Answer 15

probability that a percentage of blood relatives exhibited in a particular trait will/does overlap with other scores in a sample => average of all rates is the heritability estimate

Question 16

Explain h =”font-size:x-small;”>2

Answer 16

In twin studies correlations between MZ are usually twice as high so estimates are derived by doubling the difference in correlations between MZ and DZ

Question 17

Who were behavioural geneticist who commented on the estimation of heritability of personality based on American, Australian and European samples at the end of of the 20th centurary? How high was their estimate?

Answer 17

Plomin (1996) & Riemann and De Raad (1998) estimated a moderate heritability of personality from genetic factors, accounting for between 20 and 50 per cent of phenotypic variance.
| P.199

Question 18

What is the key takeaways from the adoption studies?

Answer 18

correlations for MZ reared apart are greater than for DZ reared together and apart suggests a genetic influence on personality for both extraversion and neuroticism

Question 19

In general, the studies summarised here suggest substantial heritability for genetic influence on personality. Genetic factors can sometimes explain as much X per cent of the variance within the main personality dimensions.

Answer 19

40-50%
|Pedersen et al. (1988) p.200

Question 20

Who brought about the change from additive assumption to heritability estimates?

Answer 20

Authors such as US psychologists E. E. Maccoby (2000) and Plomin (2004), who researched and later critically suggested that the additive principle of determining heritability of personality (or any phenotype) is not applicable any more or even the concept of genetic inheritability all together.

Question 21

What are the two main issues with additive assumption?

Answer 21

1. estimating the environment (E) is usually done without utilising any direct measures of environmental factors. Ex.: researchers often compute genetic heritability, and then subtract that from 100 per cent.
2. when genetic heritability is large, it assumes that all environmental factors associated with that behaviour must be small. It is better to see human person- ality as a joint result of an interaction between the individ- ual’s genes and their environmental factors. Consequently, personality should not be seen as the result of ‘Genetics + Environment’ but rather ‘Genetics × Environment’. For example, it is better to view the relative influences of genes and environment on personality as the result of a long-term interaction, with environmental factors triggering certain genetic behaviours and the effects of the environment differing between individuals because of their genetic makeup.

Question 22

What are the six main considerations in behavioural genetics in terms of personality?

Answer 22

1. Conceptions of heritability and the environment
2. Different types of genetic variance
3. Shared versus non-shared environmental influences
4. The representativeness of twin and adoption studies
5. Assortative mating
6. The changing world of genetics

Question 23

What are the four main considerations in behavioural genetics as far as intelligence is concerned?

Answer 23

1. Conceptions of Heritability
2. Different types or genetic variance
3. The representativeness of twin and adoption studies
4. Assortative Mating

Question 24

Additive genetic variation

Answer 24

genetic variation in behaviour that is the total of the individual’s genes inherited from their parents

Question 25

non-additive genetic variances

Answer 25

dominant genetic variance and epistatic genetic variance or interactive genetic variance

Question 26

Epigenetics

Answer 26

process describing (epi)gene expression resulting from environmental factors that either suppress or activate our dispositions

Question 27

What is the Flynn effect influenced by (Neisser, 1998a)?

Answer 27

Length of schooling Test-taking sophistication: understanding and getting used to IQ tests as their incorporated into schooling → impact on non-verbal intelligence? Only 5 points increase when retaking Child-rearing: educational programmes Head start program for disadvantaged children: significant immediate gains but asymptotic curve Visual and technical environment: adverts are more subtle, learning through complicated visual materials → little evidence Nutrition

Question 28

What are the five processes by which Harris (1995) explains that non-shared environmental factors determine personality and intelligence?

Answer 28

1. context-specific socialisation 2. outside-the-home socialisation 3. transmission of culture via group processes 4. group processes that widen differences between social groups 5. group processes that widen differences among individuals within the group

Question 29

According to Kamin and Goldberger (2002), do twin studies over- or under-estimate the role of genetics? Why?

Answer 29

Twin studies overestimate the influence of genetics, because identical twins may have more similar environments than nonidentical twins.

Question 30

Why does Stoolmiller (1998) argue that placement strategies influence the conclusions that can be drawn from adoption studies regarding heritability?

Answer 30

Adoption agencies may favour placing children in more affluent households with less exposure to sociodemographic adversity. Therefore, the influence of economic status is never explored in these studies.

Question 31

What are the four environmental influences on intelligence discussed in the reading at the beginning of this lesson?

Answer 31

1. school and education 2. biological variables and maternal effects: nutrition, lead and prenatal factors 3. family environment: shared and nonshared environments within and outside the family factors, social class and socioeconomic status, birth order and family size 4. culture: decontextualisation, quantification and biologisation.

Question 32

In terms of the influence of education on intelligence, what did Nessier et al. (1996) find?

Answer 32

Nessier et al. (1996) found that education is both an independent and dependent variable. School attendance (education as independent variable) is likely to increase intelligence; and increased intelligence is likely to influence your school attendance, the duration of your schooling and the quality of your school (education as dependent variable).

Question 33

What’s the Wilson effect?

Answer 33

The heritability of IQ increases with age.