Lecture 3 Flashcards
1
Q
IQ tests - the psychometric approach
A
- refer to use of psychometric tests to measure intelligence or specific skills and abilities
assumes that intelligence is something that can be tests
Gardner would argue there are different types of intelligence and isn’t one single core intelligence - achievements in life should be taken as evidence - standardised assessment - testing instructions
test duration
testing environment
makes sure test is repeatable and not due to changes - use of tests isn’t the only approach - interview, panel of experts, achievements
- more objective and specific
systematic
replicable
reliable - useful = act as predictors
need to look at history and evidence
2
Q
do psychometric tests matter?
A
- education - correlate highly with IQ tests hard to know what is causality - employment not huge amount of employers who use IQ tests - governmental policy - research can be used in: - selection - diagnosis - evaluation
3
Q
measuring intelligence
A
FRANCIS GALTON
- first to discuss early scientific terms of intelligence
- to measure intelligence need to look at family history
those who are eminent - eminent relatives
not environment but genetic inheritance
first to suggest twin and adoption studies as method to measure
- believed physical markers of intelligence
- led to discovery all fingerprints are different
- tested participants: looked at personal and family history
- testing involved thing measurements of height, head length, strength, vision, hearing and reaction times
4
Q
Intelligence tests
A
- Alfred Binet and Theodore Simon in 1994
aim: identify mentally handicapped children - make sure provide special education - tasks of increasing difficulty to represent cognitive development in children 3-10 years
following lighted match with eyes, shaking hands, naming objects, filling missing words - recognised developmental changes in intelligence
- used sample of 50 children to develop test
Mental age = level of test passed compared with actual age
handicapped if intelligence < actual age - move to USA: Stanford-Binet Test
adapted to american children
additional item
bigger and more representative sample of 1,000
5
Q
Intelligence tests continued:
A
IQ = intelligence quotient (stern, 1912) IQ = mental age/actual age x 100 mental age = actual age = 100 mental age < actual age = < 100 mental age > actual age = > 100 - provides single index of intelligence - used independent of actual ages Army Alpha and Beta tests - verbal and non verbal intelligence of army receipts during world war 1
6
Q
WAIS (Wechsler Adult Intelligence Scale)
A
- widely used, comprehensive test of intelligence
- provides several indices of intelligence
- covers ages 17 - 90
- several editions each standardised on large samples
7
Q
Ravens Progressive Matrices
A
- non verbal test of intelligence
- perceptual relations, mental rotations, analogical reasoning
- didn’t require people to have specific knowledge - less influence by education levels
Verbal analogies General knowledge Vocal Arithmetic - more accurate and specific answer higher you score Block design Matrix reasoning Digit symbol
8
Q
IQ
A
- IQ is calculated by looking at how much an individual score different from their mean age group
IQ scores assume a normal distribution in population - age group mean is set to 100 and SD to 15
9
Q
The normal distribution
A
- relative frequency of value in general population
10
Q
Intelligence tests: features
A
- variety of tasks to examine multiple abilities
accuare estimate
more abilities closer to G
long and short versions
reliable estimates obtained by test of reading ability - standardised administration
establish and follow same procedure
avoid confounds relating to different assessors
WAIS requires individual administration - norm referencing
individual performance compared to representative sample - internal reliability: same concept or ability
- test-retest reliability - fluctuate by up to 15 IQ points
- validity
test should be measuring what it says
correspond to implicit or explicit theories
should correlate to external measures taken at same time (concurrent) or future (predictive)
11
Q
Development of intelligence
A
- increase in intellectual growth in childhood and early adolescence
take into consideration that children change a lot
levels off in late adolescence - coincides with rapid brain development - prefrontal cortex
- intelligence mirror increases in abilities measured IQ tests
- expansion of general knowledge
language
Average vocab 2 yrs = 50-300, 6yr: 14,000; 16 yrs = 40,000 - better performance of tests in Gf
- processing speed - visual matching tasks
locate and circle two identical numbers in a row of six numbers
short term memory capacity - digit span: 5yrs, 4. 12 yrs: 6. adults: 7 - abilities related to frontal lobe function (planing, verbal fluency, design fluency, mental flexibility)
12
Q
The elderly: Changes in IQ with age
A
- IQ scores change in adulthood and old age
- different effects for different forms of intelligence
- verbal IQ shows gradual increase and gradual decline
still as good in 80s as was in 20s - procedural IQ - steep drop from 30
13
Q
Stability of intelligence: Scottish IQ survey
A
- given to all children born in 1921 and attending school in scotland
aims: - discover rates of mental deficiency in scotland
- estimate distribution of intelligence
tests included:
following directions
same-opposites
word classification
analogies
reasoning
proverbs
arithmetic
spatial terms - test highly correlated with Binet Test
- second survey - 1938 (intelligence dropping?)
- comparisons showed small increase
550 participants volunteered to take part in second study - cognitive ageing - tested multiple times until age of 90
- IQ scores show significant stability from late childhood to adolescence to adulthood
age 11 and 80: r=0.66
age 11 and 90: r=0.54
14
Q
Intelligence and Education
A
- IQ scores correlate highly with school attainment
- IQ scores correlate with education indices
- correlations also found with IQ tests which dont have similarities with education material
- strong predictive validity
IQ scores at 11 –> predict GCSEs
IQ at 9 –> education achievement at 12 - students with high IQ do well and enjoy school
What else would contribute? - personality traits
- motivation
- learning experience
- teaching quality and structure
- school ethos
Can parental support mediate the effect? - correlations between SES or income and educational achievement significantly but lower than between IQ and educational achievement
15
Q
Intelligence and Occupation
A
- IQ scores correlate with job status
- IQ correlation vary across studies - generally high r=0.45
- cannot be fully explained by other factors like socioeconomic status (SES) or education
- IQ correlates with ability to successful complete work training
- IQ correlates with job performance r=0.54
much better predictor than other indicators:
CV
previous knowledge of candidate
Job interview
education of candidate - prediction varies depending on complexity of job with more complex jobs showing higher correlations
Low predictions - driver, clerical worker (r=0.37, r=0.32)
high predictions: manager (0.69), nurse, surgeon, accountant (0.74), engineer (0.70) - high IQ workers gain promotion and increase salary
- high IQ ability allows access to more prestigious, more highly paid jobs
lawyers, doctors, engineers - effects mediated by education, job training and job complexity
16
Q
Intelligence and health
A
- IQ quality correlates with mortality rates
- IQ correlates with survival rates later in life
- IQ scores of 1M swedish conscripts
- IQ predicts death by CHD, accidents, suicide and other causes
- look at effect of education on prediction the relationship between IQ and mortality causes become weaker
- indices of general health e.g. blood pressure and BMI did not affect relationship
- IQ does not predict death by cancer
17
Q
Intelligence and mental health: SZ
A
- patients with SZ show significant decrease in IQ scores ~15
deficit evidence on early on in disease not result of treatment or chronic effects - intelligence impaired long before onset of SZ
lower IQ predictor of SZ - high correlation between SZ and intelligence
- linked genetic influences
- genes responsible for individual differences in intelligence
18
Q
Intelligence and mental health: Bipolar disorder
A
- likelihood intellectual impairment linked to severity of disorder
linked to episodes of psychosis
less severe cases show more specific problems with attention, verbal learning and executive functions
19
Q
Is bipolar disorder linked specifically with high intelligence?
A
- large cohort study (900,000) in sweden examined academic achievement at 16ys and likelihood of subsequently developing mental disorder
- 280 developed bipolar
low and high achievers more likely to develop bipolar compared to those performing at average level
20
Q
Intelligence and mental health
A
- incidence of SZ and bipolar as function of grades at 16 in same cohort of swedish children
- SZ affects those with low grades with bipolar affects both end of continuum
- socio-economic factors taken into account
- link with high grades tended to greater for humanities subjects
21
Q
Intelligence and mental health: Bipolar disorder 2
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- swedish study showed non-linear correlation with grades but no intelligence itself
- other factors could be responsible: attendance, motivation, memory, creativity, attention, diligence, social skills
- high performance on arithmetic reasoning ask correlated with increase risk of bipolar
- high performance on visuo-spatial task correlated with reduce risk of bipolar disorder
22
Q
If there is a link between intelligence and bipolar what is the mechanism involved?
A
- elements of hypomanic patients behaviour can benefit educational attainment
enhanced access to vocab, good memory, creativity, innovation
exaggerated emotional responses which can use useful artistic expression
enhanced stamina - presence of these same elements in children couples with predisposition to hypomania may lead to developing bipolar
- the converse could hold true for low achievers who should be showing predominantly signs for depressive and low mood
23
Q
Intelligence and mental health: mechanism
A
- IQ affects mortality by affecting a series of intermediate factors
- higher IQ = better education = better occupation = more money = better health care provision
diagnosis and care - higher IQ = better education = improved disease and injury prevention
health related behaviours (no smoking, exercise, better diet, fewer risk, taking behaviours - cannot discount genetic factors which can influence both IQ and susceptibility to disease
24
Q
Genetic and environmental factors in intelligence
A
- differences in intelligence = genes and environment
25
What is heritability?
- proportion of individual differences in trait that can be explained by genetic factors in a specific environment
environmental factors are (1-h2)
- heritability is not the proportion of train that can be attributed to genetic influence
- can be inferred by examining groups that differ in genetic similarity
comparing twins, siblings
- intelligence can be seen as another heritable trait
height, weight, personality traits
- heritability doesn't mean immunity
heigh is heritable but increases across generations
- supportive and impoverished environments will affect heritability
affect expression of genetic trait
- environmental differences within or between societies could affect heritability
lower estimates of heritability in developing countries
heigh h2: nigeria = 62%, jamaica = 76%, US (black americans) = 87%
mean height: S.korea 6" > N.Korea
26
heritability: evidence
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- family studies
keeping environment relatively constant
average 50% genetic similarity
- twin studies
better control of environmental factors
excellent control of genetic similarity
- adoption studies
keeping environment relatively constant
no genetic similarity
```
27
Twin study
- MZ twins: single fertilised egg - divided into two embryos
MZ twins 100% genetic similarity: identical twins
always same sex
- DZ twins - two simultaneously fertilised egg producing two embryos
DZ twins 50% genetic similarity
either same or different sex
- should we consider DZ twins simply as fraternal siblings
28
Heritability and intelligence
- high estimates of heritability
range of estimates 40-80%
parents and children IQ will be similar irrespective of whether they live together or not
- environment can still affect heritability
vocab acquisistion
29
Heritability estimates of specific abilities across the life span
- estimates of heritability increase with age of participants from childhood to adulthood and drop again in old age
MZ twins reared apart tested as adults h2 > 70% and c2 < 10%
- no evidence that environmental impact increases with age
family environment interferes with expression of heritability
adults can select their own environments
- not clear what causes the drop in old age - variation in cognitive decline
30
Issues with genetics: twin & adoption studies
- twin and adoption studies could over- or under estimate genetic influence on intelligence
- environment of MZ twins more similar than DZ twins
treated more similarly, have more common friends and spend more time together
doesn't explain that other psychological traits do not have the same correlations e.g. personality and SZ
- adoption agencies do not allocate children randomly
preference for middle and high income families
environmental impact on intelligence higher on low SES families
- twin adoption studies could over or under estimate genetic influence on intelligence
- environment of MZ twins more similar than DZ
- similar friends, lifestyle and treated more similarly
doesn't explain that other psychological traits do not have same correlations e.g. personality, SZ
- adoption agencies do not allocate children randomly
preference for middle and high income families
environmental impact on intelligence on low SES families
31
Issues with genetics: assortative mating
- people partner in a non random fashion
affects variance of traits within population
- positive assortative mating: most people tend to partner with similar people
looks, intelligence, religious or political beliefs
- negative assortative mating: some people will choose to partner with dissimilar people
- positive assortative mating increased genetic similarity whereas negative assortative mating decreases genetic similarity
32
Environmental influences on intelligence - biological variables: nutrition
- IQ difference between breastfed and non breastfed children (ranging from 2-6 IQ points across studies)
- subsequent large scale studies and meta analyses found the effect of breastfeeding linked to mothers IQ and family related factors
mothers IQ correlated with both children's IQ and likelihood to breastfeed
removing familial influence removed effect of breastfeeding
Belfort (2013) found a 3.7 IQ point advantage on verbal intelligence at children tested at age 7
accounted for maternal IQ and other factors
received huge amount of press interest
even if not important in intelligence, breastfeeding has many health benefits
33
Environmental influences on intelligence - biological variables: : Iodine
- mineral essential in the synthesis of thyroid hormones
- thyroid gland is involved in control of metabolic activities, energy production, oxygen consumption, body weight and growth
- iodine deficiency causes mental retardation
- development of the brain during pregnancy and first 3 years after birth is sensitive to iodine deficiency
- many countries add iodine to cooking salt as supplement
further inland
- severe IQ deficits with people with iodine deficiency
- adequate supplement reduced the deficit considerably (difference 8.7 IQ points)
- children testes 3.5 year after iodine supplement introduced showed significant increased in IQ
34
Environmental influences on intelligence - biological variables:: Iron
- iron-deficiency anaemia is the most common nutritional disorder in the world
10% in developed counties and 40% in underdeveloped countries
affects brain growth and function
'window on vulnerability' - during first 2 years
- it affects behaviour and cognitive development of children
reduce IQ, attention span and emotional responsiveness
- effects confounded by socioeconomic factors
poorer environments/countries more likely to suffer due to iron deficient diet
IQ deficit exaggerated as result
- not clear whether iron supplements can reverse the cognitive deficit
35
Environmental influences on intelligence - biological variables: : Lead
- highly poisonous can lead to brain and kidney damage and cause miscarriage or premature births
- the port-pirie longitudinal studies look at effects of lead on children intelligence following large number of children from birth to adolescence
- port-pirie town close to large lead smelting plant
- IQ scores varied proportionally to lead concentration in blood samples
- high concentration worse the deficit
- performance consistent across testing session
- persistent effect as result of prenatal and antenatal exposure
36
Prenatal factors: alcohol
- foetal alcohol syndrome caused by heavy alcohol consumption during pregnancy
craniofocal abnormalities, stunt growth
- more likely to occur in binge drinkers
- affects the brain (structure and function) and results in extremely severe IQ deficits
- additional cognitive deficits
memory, attention, motor difficulties, impaired social skills
37
prenatal factors: tobacco/alcohol
- light drinking (1-6 units per week) during pregnancy the results unclear
many studies report no harmful effect to child
others show effects mediated by presence of enzymes responsible for breaking down alcohol
- government advice is to avoid drinking altogether both during pregnancy and if planning to get pregnant
protect foetus during first few weeks of pregnancy
- excessive cigarette smoking during pregnancy can also result in intellectual deficits
at 18 years children of mothers who smoked excessively ~ 6 IQ points less than non smokers
