Lecture 2- Measuring Individual Differences Flashcards
Outline Adoplhe Quetelet
- Stats
- BMI
- Normal Distribution
1796-1874
- Tried to define ‘the average man’
- Founded social sciences and statistical testing
- systematic application of statistical methods to humans
- ‘social mechanics’ or ‘social physics’
- Developed the Body mass index - aka the Quetelet index
- Found that BMI sat on a normal distribution - where each individual can be compared on this graph
- so you could compare to the norm
What were the components involved in Quetelet’s normal man?
Tried to define the characteristics of the normal man
- Not just physical characteristics, but also behaviours, mind and soul
- Also personality
Outline Galton’s work in depatures from the average
- SD
- Significantly influenced by Quetelet
- His interests were about differences and deviation from the norm
- He was interested in those who deviated from average - the top end more than the low end however
- Came up with Standard Deviation
- Eugenics
How did Galton and Quetelt differ?
Quetelet looked at what made people normal
Galton looked at what made people different from normal
Define latent traits/ variables
- SDB
- We often canot measure things directly
- E.g. cannot physically observe psychological traits - you need clever ways of studying them - e.g. tests
- Need to monitor social desirablility bias however
Outline Charles Spearman
- Stats
- Factor Ana
- Latent
- He wanted to find a way of measuring latent variables and specifically, intelligence
- Developed statistical methods to study latent variables
- Proprosed the notion of ‘G’ - the underlying variable that determined
- Developed the use of factor analysis to find G
Define factor analysis
- reduction
- Explores patterns of correlation between the items on a particular measure - Trying to find ‘G’ variables by collating data into groups
- Form of data-reduction: hard to deal with lots of measured items, so you identify similarities, patterns and ‘latent’ variables
Outline What spearman did, like who did he test
Spearman tested schoolchildren with tests of different skills, e.g. •Memory •Spatial abilities •Mathematical abilities • Vocabulary
Spearman examined the relationships between scores on each test, he found a positive manifold
Outline Positive manifold
If you score highly in one domain, you are likely to score highly on the others
- this supports ‘G’ - if youre smart, you are intelligent across all domains
Outline Spearmans theory of intelligence
General intelligence (g) - the mental energy that underlys intelligence
Influences specific abilities (s)
- maths, spatial and verbal intelligences
These both influence your performance on an intelligence test
How did Spearman influence measurement strategies
- Change in attitude and approaches - there was a race to create a good intelligence test, based off G
- More rigourours standardised testing, so there can be comparison
- Larger samples, designed to be all-inclusive approaches to measureing intelligence
Outline the 3 Wechsler tests
- Wechsler-Bellevue Scale (1939)
- Wechsler Adult Intelligence Scale (WAIS) 1955
- adults 16-75 - Wechsler Scale for Children (WISC) 1955
- children 5-16
- These tests examined much broader domains, and a number of different abilities
Outline the Wechsler Adult Intelligence Scale
- non-verbal
- Deviation IQ
- The first intelligence test that involved non-verbal/ spatial tasks
- Verbal and Non-verbal reasoning ability
- Completed by large numbers of people to identify norms across different age groups
- Wechsler came up with DEVIATION IQ - as an improvement for Termans IQ
Outline Termans Intelligence Quotient (IQ) equation
100 X (Mental age ÷ chronological age)
- This is bad because couldnt apply to adults - age would increased but intelligence would stay the same
- therefore IQ would decrease with age
- would not produce a normally distributed graph
Outline Wechslers Deviation IQ equation
100 X (actual test score ÷ expected score for age)
- compares others scores to those from people of similar age
- would produce a normally distrubted graph
What were some of the domains the WAIS studied?
- Verbal vs performance
1) Verbal IQ
- Verbal Comprehension
- Verbal Memory
2) Performance IQ
- Perceptional Organisation
- Processing speed
Outline Ravens Progressive matrices
- Deviation from Standardised norms
Raven’s Progressive Matrices (1938)
- Based on the concept of ‘g’
- Aimed to develop a test that was free of cultural influences - non-verbal problems and abstract reasoning. Because it was found that western students did best on verbal tests
- Your overall score is based on your deviation from standardised norms
- Features non-verbal tasks (e.g. spatial/ pattern recognition)
X - Is it truly culture free
Outline Thurstone’s theory of 7 primary mental abilities
‘G’ was made up from:
- Perceptual Sped
- Associative memory
- Spatial Visualisations
- Number
- Verbal Comprehension
- Reasoning
- Word Fluency
What was Thurstones critcism of spearman?
- Language
Argued that Spearmans tests on: memory, spatial abilities, mathematical abilities, Vocabulary
- all rested on language abilities, and that he hadnt really seperated out the domains of intelligence
- this explains why there was positive manifold
Outline Cattell’s theory of intelligence
He agreed about ‘g’, but just said there were 2 forms
Argued ‘g’ (general intelligence) was made up of two things:
1. Fluid Intelligence (Gf)
- doesnt really change, cant be taught,
- includes stuff like primary reasoning and problem solving
- Crystallised Intelligence (Gc)
- environment and taught
- developed and improved
- factual form of IQ
- education helps
What did John Carroll do?
- Inbetween
- 3 stratum
- Looked at like 450 studies, to try and produce a fundamental model of IQ
- what comes in between ‘g’ and ‘s’ ?
Outline Carrols theory of intelligence
three-stratum theory of cognitive abilities (1993)
Stratum 3: at the top
- ‘G’
Stratum 2: in the middle
- 8 Sublevels of ‘g’
- including Cattell’s Gf and Gc
Straum 1: at the bottom
- further sublevels of g
Tests
Specific abilities - at the bottom, there are loads
- e.g. visual, auditory, memory, cognitive speed, processing speed etc
Whats a limitation of Carrolls theory?
X - very complicted, much more complicated that G/ Gf/ Gc
- cant really use this for tests
Outline the combined model: Cattell-Horn-Carroll
There are 16 broad intelligences, which divide into subcategories
What are the two areas/ professions that Theories of intelligence effect
- Researchers - aiming to define a true model of intelligence
- Testers- measures that assess range of abilities
- this leads to a produce that is of use in a wide number of domains
What are the evidence that brain volume and intelligence are linked
- Mental energy (Tiedmann, 1836)
- McDaniel (2005) - brain size and IQ positively correlated (0.03)
- Toga & Thompson, 2005 - Evidence for heritability of brain size
- MRI allows for deeper exploration
- there has never been a study that finds negative correlation between brain size and intelligence
Outline reaction time tests
- ECT
- Deary, Der & Ford (2001)
- Elementary cognitive tasks (ECT) - test processing speed and accuracy
- Reaction time is key
- Intelligence is determined by speed and accuracy of response
- Moderate correlation observed between IQ and RT tests (Deary, Der & Ford, 2001)
- ECT’s are good because they do not required any previous knowledge - everyone can do them
Outline Jensen, and the Jensen Box
- Supports the notion of ‘g’
- Speed of processing is seen as an underlying marker of intelligence
- there are 8 lights around a box, with a central light at the bottom. As soon as a light comes on, the speed to press it is tested - this is supposedly a measure of intelligence
Outline INspection time as a measure of intelligence
Shown two lines that are differing in lenghts, the ends of the lines are then covered, and you are asked which one was shorter
- each time, the amount of time you can look at the lines gets reduced
- intelligence = the shortest amount of time you can have looking at the lines and still get it right
What are the 4 uses for psychometric testing
- Research
- Diagnosis
- Evaluation
- Selection - for jobs etc
What are the 6 things that make a good psychometric test?
- Reliabiility
- Validity
- Length of test (depends on participante, e.g. age)
- They may get tired and do worse in later questions - Standardisation of administration and ease of scoring
- Comparison
- Value of findings
What are some limitions of psychometric tests?
X - tests only ever done once, need to look at how it changes over time
X - Predictive validity - does it tell us how someone will perform in a job environment
X - are we over tested? Practice effects
X - impact of the tests findings?
Define reliability
- two types
Consistency of a measure over time, or across different circumstances
- Internal reliability
- test-retest reliability
Outline Internal reliability
- Items correlate with each other well (>.30)
- Suggests they are measure the same latent variable/ construct
Outline test-re-test reliability
- Extent to which the responses on a measure remain stable over time
How do intelligence tests show internal reliability
- revisions
- There has been extensive development and revision to make sure that items which show levels of reliability have been omitted
How do intelligence tests show test-retest reliability, or does it?
- What did Benson (2003) find
- Assumes intelligence is a stable trait
- Benson, 2003 - found that scores on IQ tests fluctuate on re-test (Benson, 2003)
This could be due to alertness on that day, practice effects, lack of standardisation: pressure to do well, different instructions
What are the 2 examples of longitudinal intelligence studies?
- Jones & Bayley (1941) - Berkeley Growth Study
2. Deary et al (2004) - Scottish Mental Survey
Outline Jones & Bayley (1941) - Berkeley Growth Study
- Cohort of children tested annually from 1928
- IQ at age 18 correlated positively with IQ at 6 and 12
- at 6: .77
- at 12: .89
- very strong relationships
Deary et al (2004) - Scottish Mental Survey
Correlation of .73 between age 11 and 77 intelligence
- Intelligence scores at 11 also predictive of survival aged 76, and levels of physical fitness and independence
X - Cause and effect? - socioeconomics, better schooling at age 11 = better healthcare
Define Validity
- two types
Does a psychometric test measure what we intended it to?
- Does it actually test what we want it to? Does it actually measure intelligence
Two types:
1. Concurrent validity (comparison with other similar measures)
- Predictive Validity (predictive ability of the measure)
How do intelligence tests show concurrent validity?
- Neisser et al (1996)
Neisser et al (1996) found high levels of concurrent validity with other intelligence tests
How do intelligence tests show predictive validity?
- Laidra, Pullma & Allik (2007)
- Some evidence for it, in relation to health, school, performance, job performance etc
- Laidra, PUllma & Allik (2007) - found that performance on Raven’s progressive matrices was found to be best predictor of GPA
Outline the FLynn effect
Refers to the substantial and sustained increase in intelligence scores over time
- Flynn found that on average, non-verbal tests scores increased 15 IQ pointes per generation (On Ravens)
- Verbal tests show more moderate increases (9 points)
What were the 5 environmental factors that Flynn explained his effect with
- Length of schooling - we now stay in school until 18
- Test-taking sophistication - exposed to more tests
- Parenting Styles - more involved in school work
- Nutrition
- Environmental Change (Visual Stimulation) - devices
What are some cultural issues with psychometrics?
X - Are tests every truly ‘culture free’
X - stimulates social change - need to be careful not to publish harmful results towards genders or ethnic groups
X - focus on what constitutes intelligence varies across cultures - e.g. emphasising interpersonal intelligence or practical problem solving skills?
What does Benson (2003) say we can use intelligence tests for?
- Move towards more dynamic use of intelligence tests
- Need to help people understand their results better, identify areas of weakness and develop those areas
