Lecture 6 Individual & Group Differences (Catherine

Question 1

Provide an overview of the key areas related to Intelligence testing & IQ ability

Answer 1

• IQ stability & instability
• Individual differences in intellectual ability & IQ
• Group differences in intellectual ability & IQ
• Age, The Flynn-effect, cross-sectional vs longitudinal studies
• Gender
• SES
• Race/ethnicity/indigene
• Beyond the norms:
• Intellectual ability
• Intellectually gifted

Question 2

Provide evidence that Group scores in IQ remain stable over time

Answer 2

*Individual’s test scores remains relatively stable after the age of 6 years:
1. 3rd grade school boys (n=613) reassessed 10 years later: r= 0.72
2. 13yr old (n=4500) reassessed at 18 years: r= 0.78
3. 3yr old reassessed at 4 years: r= 0.83 (very good)
3yr old reassessed at 12 years: r= 0.46 (not so good- a lot has changed in the 9 year period)
4. 2-5.5 yr old reassessed 10 years later: r= 0.65, 25 years later: r=0.85 (very good!) overall r=0.59
*By about 16-18 years of age, IQ remains pretty stable

Question 3

What are the implications that Group scores in IQ remain stable over time?

Answer 3

Implications:

*Good Predictive Validity of the tests
OR
*Predictive Validity of IQ tests is confounded with stability of the environment of longitudinal studies

Question 4

Why are group IQ scores more stable with age?

Answer 4

Possible explanations are:

1. Cumulative nature of intellectual development
2. Environmental stability
3. Prerequisite learning skills

Question 5

Provide evidence that Individual IQ scores can be more unstable over time

Answer 5

California Guidance study (n=222)
*6yr vs 18 yr - test-retest correlations were high (around 0.60)
*59% of children IQ increased by up to 15
*37% of children IQ increased by up to 20
*9% of children IQ increased by up to 30!!!
This is incredible!

Question 6

What are some of the factors affecting a child’s intellectual development?

Answer 6

• Change in family structure/home
• Poor home conditions
• Change in parents SES
• Adoption
• Severe or prolonged illness
• Therapeutic, remedial, educational or counselling intervention programmes

Question 7

When viewing the correlation between IQ scores compared at different time periods, what is an important consideration?

Answer 7

• The correlation tells us the variance is the same/stable
• The correlation does not tell us that someone with an IQ of 100 still has an IQ of 100 10 years on, merely that the group overall is consistent

Question 8

What did Capron & Duyme find from their 1989 Adoption study published in Nature?

Answer 8

• Children reared by higher SES parents had a higher IQ
• Change enhances IQ independent of the SES of the biological parent
• SES of biological parent does have some effect

Question 9

What have been the findings of some longitudinal studies into the effect of SES on IQ score?

Answer 9

• without early intervention in low SES groups, IQ score declines from the baseline over time
• In High SES groups, IQ score increases from the baseline over time

Question 10

The Rochester Longitudinal Study by Sameroff et al., (1987, 1993) found 10 risk factors associated with decreases in IQ score. What were these?

Answer 10

1. mother had history of mental illness
2. Mother did not go to high school
3. Mother had severe anxiety
4. Mother had rigid attitudes
5. Few mother-child interactions
6. Head of household in semi-skilled job
7. > more than 4 siblings
8. Father not living at home
9. Child belongs to a minority group
10. Family had > (more than) 20 stressful events in child’s 1st 4 years (!)

Question 11

What was the impact for the children in the Rochester Longitudinal Study by Sameroff et al., (1987, 1993) who had 4 or more of the risk factors?

Answer 11

Those children had decreased IQ in the retest phase (1993)

Question 12

What do we need to bear in mind when considering Group and individual differences of Age, Gender, Culture/Race, Indigene?

Answer 12

Our results should be stratified by age, gender, culture in the standardisation process as a result it is important that we do not compare one group with another, as this can lead to inappropriate interpretations.
*For instance, we recognise & accept gender differences in the sub-sets, but the overall IQ score is standardised according to group norms so should not have differences

Question 13

How are IQ scores standardised by age?

Answer 13

• IQ scores are standardised by 9 age groups from age 16 through to 74 years old
• The WAIS uses raw scores on the sub-sets but the overall IQ score is standardised according to group norms

Question 14

What are the standardised scores for IQ tests?

Answer 14

96% range between 70 - 130
68% range between 85 - 115
0.1% have an IQ 55 or below
2% have an IQ 70 or below
14% have an IQ between 71 - 84
34% have an IQ between 85 - 99
34% have an IQ between 100 - 114
14% have an IQ between 115 - 129
2% have an IQ 130 -145
0.1% have an IQ above 146

Question 15

Why is it inappropriate to compare IQ scores across ages?

Answer 15

• It is not meaningful to compare a 17 year old with a 70 year old because of age related changes in IQ
• The IQ scores must be standardised by cohort not across the age range.

Question 16

What are the main findings from Cross-Sectional analysis of Age-related changes in IQ?

Answer 16

• Verbal scores (crystallised intelligence) remain stable with age
• NonVerbal scores (fluid intelligence) declines with age

Question 17

What are the main limitations of Cross-sectional studies?

Answer 17

They are confounded by changes in culture and age

even one generation has seen significant changes in healthcare, diet, technology, media, educational opportunities

Question 18

What are the strengths and weaknesses of a Longitudinal design?

Answer 18

weakness:

• practice effects
  
  • small IQ increase on retest
  • age related (old people = less increase)
  • practice effect up to 4 months
  • studies have recorded high increase following practice effect
  • is practice effect an artefact?
• Selective attrition
  
  • some people more likely to remain
  • higher IQ associated with longer life & motivation

Strengths:
continuation of individuals

Question 19

What was ideal about the Seattle Longitudinal Study?

Answer 19

It was a Cross-Sequential Design, (AKA cohort sequential) which incorporates the best elements of a Cross-sectional and a Longitudinal

Question 20

What were the key the design aspects of the Seattle Longitudinal Study?

Answer 20

• 1956 took 200 adult participants
• re-assessed & re-recruited every 7 years
• Cross-sectional: comparison of ages
• Longitudinal: continuation of individuals
• 6000 people participated
• 26 of the original 200 remained
• got data from 3 generations

Question 21

What were the key findings of the Seattle Longitudinal Studyr?

Answer 21

*No uniform pattern in age-related change across ALL intellectual abilities (The Full IQ scale is not sufficient to measure this)
*Important interactions between: ability x age & ability x cohort were found which complicated things
*Gender differences were found
*Cross Sectional Studies over-estimate declines in intellectual ability prior to age 60
*Individual differences in successful ageing:
no heart disease, high SES, good environment, flexible personality, high cognitive status of spouse, maintenance of high processing speeds

Question 22

What were the key findings of the Seattle Longitudinal Study related to Crystallised & Fluid intelligence over age?
Where Crystallised intelligence is accumulated information & verbal skills, which increase for age
& fluid intelligence is the ability to reason abstractly, which steadily declines from middle adulthood onwards

Answer 22

• Men decline earlier on crystallised intelligence whereas
• Women decline earlier on fluid measures
• Women are concerned with accuracy
• Men are concerned with speed

Question 23

What are the main changes in Intellectual ability as found by the Seattle Longitudinal Study?

Answer 23

• Before 60 there is not a huge decline in ability by group
• The main area of decline is that of perceptual processing speed (which incidentally will negatively impact all speeded tests)
• The other areas of intelligence: Reason, spatial, number, vocab and verbal memory do not decline dramatically

Question 24

The Seattle Longitudinal Study implemented Cognitive Training for their participants, what was the outcome?

Answer 24

• Two-thirds of the sample improved intellectual ability
• A Crucial finding was that cognitive training interventions reduces age related decline immensely.
• The more cognitively active we are, the better we maintain our cognitive ability
• NB Sleep is also crucial to intellectual functioning

Question 25

What are the key points of the Flynn-Effect?

Answer 25

* IQ tends to increase by 3 points every decade * This is why we cannot be compared against a 20 year old who took the test 30 years ago * Need to constantly re-norm scores to account for cohort changes

Question 26

What are the possible explanations for the Flynn-Effect?

Answer 26

*Participant Characteristics - increase education, increased familiarity with IQ tests Methodological explanations - Changes in measure (e.g. WAIS to WAIS IV), change in motivation, effort, change of environmental factors (constant improvements), *Biological explanation - improved nutrition, infectious diseases, heterosis (the opposite of inbreeding) *The Flynn-Effect may reverse as we may get lazy with all the constant access to data

Question 27

There are 3 key studies that explored IQ sex differences, what were the studies, and what did they find?

Answer 27

The studies found that men had higher 'g' than women - 3-4 IQ points - Lynn (1992) - 5 IQ points - Lynn & Irwin (2004) - 3.63 IQ points - Jackson & Rushton (2006)

Question 28

What did Hedges & Nowell (1995) find about sex differences in IQ?

Answer 28

Results are dependent upon which tests are used: * Sex differences are small & stable over time * Males have a larger variance (there are more males at the higher & lower ends of the IQ scale) * Males typically outnumber females among high-scorers * Women show advantages in memory, reading, verbal fluency, * Women outnumber men at University

Question 29

When considering Group Differences in Sex and IQ scoring what are the key points?

Answer 29

*Sex differences in IQ exist *They are small but relatively stable over time *There are sex differences in scores of sub-sets *It is not psychometrically sound to compare women & men overall IQ as the tests are designed not to skew towards gender *Males typically do better than females in non-verbal performance IQ tests & 'g' *Women show advantages in memory, reading, vocabulary Age and Sex interacts: Women decline earlier in 'active' abilities, whereas Men decline earlier in 'passive' abilities

Question 30

When considering Intelligence and Culture and Race what are the key points?

Answer 30

* Cultural Differences Exist - But is this really a factor of IQ or is it more that the Main problem is that Tests are skewed toward English-speaking, middle-class populations * Words for snow - fairer for Eskimos * Culture fair tests of intelligence or adapted standard test * We cannot measure across culture and expect fairness

Question 31

When considering Intelligence and Culture and Race what is the Bell Curve Controversy?

Answer 31

* Jensen (1969) and Hernstein & Murray (1994) presented evidence that black Americans were less intelligent than white Americans on standardised intelligence tests - This was interpreted as white Americans being innately more intelligent (genes of white Americans were higher IQ) * Dickins & Flynn (2005) looked at IQ from 1972 - 2002 found Black Americans have gained approx 5.5 IQ points * Black Americans have only recently gained access to educational & other opportunities * SES may be more relevant than Race * Environmental causation * individual scores vary considerably * Stereotype threat: fear of confirming negative stereotype can raise anxiety during testing

Question 32

Why might the distribution of IQ for the indigenous Population be shifted to the left of the distribution as compared to the distribution of non-indigenous people?

Answer 32

*There is no difference between European indigenous and Australian indigenous people *the findings do not control for: -schooling -parenting style -culture - no culture free tests of IQ -nutrition & health care gap These issues change everything: all tests are skewed to white, middle-class, Western North Americans, how can an indigenous person be expected to perform equally?

Question 33

When considering Intelligence and Culture and Race what is the pattern for specific social groups in USA, is it a Bell Curve?

Answer 33

* US Population distribution - bell curve * all other groups negative slope: - Ever incarcerated: peaks at 75-90 * for every other group majority score at below 75 - Poverty - Chronic welfare recipient - Had illegitimate baby - High school drop out

Question 34

When considering Test Bias, what do we need to be aware of with regard Group and individual differences of Age, Gender, Culture/Race, Indigene?

Answer 34

* People from a different culture than the culture the test was designed for will always be disadvantaged * Methodological issues may confound significant differences (need to dissociate group differences from test bias) * Race, Ethnicity & Gender differences are all affected by test bias * Bias in Content Validity - does the test measure what it is supposed to measure for different groups? * Bias in Predictive-Criterion-Validity - does the test provide a valid prediction of ALL individuals future performance? * Bias in Construct-Validity - does the test result provide meaningful insight into current theory for ALL cultures equally?

Question 35

What is the Floor and Ceiling of IQ tests? and, What is the IQ value associated with intellectual giftedness, and intellectual disability?

Answer 35

``` Floor = 40 - Profound =<20-35 - Severe = 20-35 - Moderate = 35-50 - Mild = 50-70 intellectual disability = below 70 ``` intellectual giftedness = above 130 Ceiling = 145

Question 36

What are Learning Disabilities?

Answer 36

Impairments in speech, language, or reading - not always defects in general intelligence - they are deficits in specific abilities - such as those tested in the factor-analyses theories of intelligence (Spearman, etc) Nomenclature (the principle of naming) -Intellectual disability (ID) used to be referred to as MR (Mental Retardation) from the Latin for moving slowly this is now seen as derogatory so name changed

Question 37

Give the American Association on Intellectual & Developmental Disability (AAIDD) definition of Learning Disabilities

Answer 37

Intellectual disability is a disability characterised by significant limitation both in intellectual functioning and in adaptive behaviour as expressed in conceptual, social, and practical adaptive skills NB: Disability must originate prior to age of 18 years

Question 38

Give the American Association on Intellectual & Developmental Disability (AAIDD) definition of Learning Disabilities

Answer 38

Intellectual disability is a disability characterised by significant limitation both in intellectual functioning and in adaptive behaviour as expressed in conceptual, social, and practical adaptive skills NB: Disability must originate prior to age of 18 years

Question 39

What are the conceptual, social, and practical adaptive skills included in the AAIDD definition of Learning Disabilities that people need to function in their everyday lives?

Answer 39

Conceptual -receptive & expressive language, reading & writing, money concepts, self-direction Social -Interpersonal, responsibility, self-esteem, gullibility, naivete, following rules, obeying laws & avoiding victimisation Practical - Eating, dressing, mobility, toileting, taking medication, using telephone, managing transportation, housekeeping - maintaining a safe environment

Question 40

What is the prevalence of intellectual disability in Australia & what are the implications for people with an intellectual disability?

Answer 40

2. 5-3% of Australian population are intellectually disabled in some way 6. 5-7% of the population have borderline ID * Mild intellectually disabled children are often indistinguishable from others until adolescence when they have problems with more advanced academic work * 85% of those with ID are mildly disabled * Moderately disabled can benefit from vocational training * 95% of people with ID can hold jobs and live in the community

Question 41

What are some of the causes of Intellectual Disability?

Answer 41

* ID is caused by any condition that impairs development of the brain before birth or during childhood * There are several 100 causes, most common affect 60% of all those with ID - Chromosomal: Downs Syndrome, Fragile X - Prenatal factors: Foetal alcohol syndrome (FAS) - Perinatal Factors (During birth): starved of oxygen - Post-natal factors

Question 42

What are some of the legal implications of having (or not having) a diagnosis of Intellectual Disability?

Answer 42

*ID is over-represented in Criminal Justice System - (10%) yet only 3% of population - more easily led & prosecuted, - more keen to appease - exaggerated willingness to talk 22% of falsely convicted people had ID - poor comprehension of causality 73% of ID individuals did not understand their statements could be used against them -Is the USA, 20% of individuals put to death had ID, despite the supreme court ruling that ID was mitigating 26 states have now enacted legislation protecting ID individuals from execution

Question 43

Bearing in mind some of the legal implications of having (or not having) a diagnosis of Intellectual Disability, why would someone fake it?

Answer 43

* 3 points can be difference between death penalty or not; having to do military service; or getting specialist health, educational benefits or supports * Hall & Pritchatard (1997) showed that both incarcerated young offenders & postgraduate students could 'fake' IQ tests to score less than 69, however, it was identifiable * Almstrom et al., (2008) showed the composite scores differentiate borderline ID and intellectual impairment

Question 44

What are the implications of the Flynn-Effect for individuals with Intellectual Disability?

Answer 44

* Educational implications: when IQ tests are newly normed assistance increases * Financial Implications * Legal Implication because: if not re-normed the IQ cut off of 70 in 1974 captured 2.27%, in 1991 it would only capture 0.94% for all the reasons below * IQ changes 0.311 points/year * IQ changes 3 points/decade * IQ has changed 14.31 points over 45 years * The difference between the WISC-R & WISC-III = 5.3 points

Question 45

What is the prevalence of Intellectual Disability & criminal offending behaviours, and what are some of the caveats around these data?

Answer 45

* Prevalence of ID among adult & juvenile correction centres - USA up to 19.1% - UK 27%-32% - Australia 15%-17% * Low IQ is a significant risk factor for offending & re-offending * An important factor largely ignored until recently is Indigene

Question 46

What is the prevalence of Intellectual Disability & criminal offending behaviours, and what are some of the caveats around these data?

Answer 46

* Prevalance of ID among adult & juvenile correction centres - USA up to 19.1% - UK 27%-32% - Australia 15%-17% * Low IQ is a significant risk factor for offending & re-offending * An important factor largely ignored until recently is Indigene

Question 47

What are some of the challenges faced by people with intellectually giftedness?

Answer 47

* they develop asynchronously * may be labelled ID or ADD * can be intense * age 5-6: self-doubt, protective, highly anxious * by high school interpersonal skills decrease, isolation & anxiety increase * often Emotional intelligence will predict how well they do rather than IQ * Intervention IS necessary * Those treated with counselling/psychotherapy converted anxieties and conflicts into powerful visions, sense of destiny & charismatic personalities. * Those who did not resolve conflicts were largely underachievers and had self-destructive behaviours

Question 48

What are some of the challenges faced by people with intellectually giftedness?

Answer 48

* they develop asynchronously * may be labelled ID or ADD * can be intense * age 5-6: self-doubt, protective, highly anxious * by high school interpersonal skills decrease, isolation & anxiety increase * often Emotional intelligence will predict how well they do rather than IQ * Intervention IS necessary * Those treated with counselling/psychotherapy converted anxieties and conflicts into powerful visions, sense of destiny & charismatic personalities. * Those who did not resolve conflicts were largely underachievers and had self-destructive behaviours

Question 49

What are Clare's key points from Lecture 6?

Answer 49

* Individual differences exist in IQ that can lead to changes in IQ * IQ is relatively stable though SOME intellectual abilities decline with age * The Flynn-Effect causes IQ to increase over time - IQ is 're-set' when tests are 're-normed' * Gender differences exist for SPECIFIC intellectual abilities * ID criteria is extremely sensitive & has major implications * Indigenous populations are at-risk for low IQ and legal complications - consider the important legal implications & interventions * Intellectually gifted individuals are also a cause for concern & may require intervention