Psychometrics
Dr Jacqui McKechnie
Psychometric Tests
General Tests
WAIS and WISC
Specific Tests
BDI and BAI
Personality Tests
MMPI-II
Projective Tests
Rorschach inkblot test
Theories of Intelligence
Spearman (1904)
Two-Factor Theory of Intelligence.
1) a general factor - g factor
2) specific factors
Thurstone (1938)
7 ‘primary mental abilities’
Gardner (1983)
Multiple intelligence - 6 types
Guildford (1967)
120 different factors
Goleman (1995)
Emotional Intelligence
Crystallised Intelligence
specific knowledge e.g. vocabulary
increases with age
depends on level of education
influenced by environmental
factors
Fluid Intelligence
basic powers of reasoning and problem solving
Cattell’s IQ test
starts to decline at 21 years
falls steeply after 60
years
influenced by genetic factors
Intelligence Tests
Binet & Simon (1905) - developed tests for children based
on concept of mental age.
•
IQ not fixed
•
would help to direct education
•
should not be used as a label
Stanford - Binet Scale adapted for American children by
Terman & Yerkes.
It was used for classification
•
IQ score - fixed
•
could rank order individuals
•
differences attributed to innate genetics
Intelligence Quotient
mental age
x 100
chronological age
Adults
standardised to make the average result 100
This makes the average IQ 100.
95% score
68 - 132
68% score
84 - 116
Types of IQ test
British Ability Scales developed in 1970’s
Individual tests:WAIS - Weschler Adult Intelligence Scale
WISC - Weschler Intelligence Scale for Children
Verbal - vocabulary, arithmetic, reasoning
Performance - picture completion, block design
Group:- AH test - Alice Heim
Group comparison, economical
Sample Questions
1. Give the next but one member of the series:
1/2,
3/5,
5/8,
7/11
…… 11/17
2. Here are words denoting five generations in one family.
Which has two, and only two, younger relations:
grandmother, great-grandson, son, father, grandson
3. Here is to there as these is to:
yonder, that, others, those,
this
Reliability and Validity
Selection
There may be biases inherent in the items chosen.
Reliability
It is important that if the same people are tested they give the
same results.
•
Test-retest method
•
Split-half reliability
•
Alternate-forms reliability
Validity
Do tests measure what they claim to measure?
Does the test result predict performance?
•
Predictive validity
•
Face validity
•
Content validity
•
Concurrent validity
•
Construct validity
•
Consensual validity
Response Bias
How do we make sure that the test isn’t producing a
tendency to answer the questions in one way rather than
another?
•
•
•
•
Questions themselves could be producing the
answers.
The way a question is phrased can also produce a
response.
People try to present themselves in the best light
possible.
Are tests biased towards certain cultures?
Social desirability response set
Acquiescence response set
Reliability
3 - 5yrs
r = +0.5
12 - 14yrs
r = +0.9
r = +0.7
66yrs
Validity
IQ & academic achievement
r = +0.4 - 0.7
IQ & occupational status
r = +0.5 - 0.6
IQ & income
r = +0.3
Inheritance of Intelligence
Burt (1955)
80% hereditary
Kamin (1984)
0% hereditary
20% environmental
100% environmental
Identical twins
Fraternal twins
Separated identical twins
Siblings
Foster children reared together
r = 0.87
r = 0.53
r = 0.66 - 0.77
r = 0.5
r = 0.2
Intelligence and Race
IQ scores between black and white Americans have shown
differences of 15 points.
Jensen (1969) stressed biological differences
Environmentalists:
•
tests were culturally biased
•
environment may be different
•
black people may experience prejudice and
discrimination
Scarr and Weinberg (1976) adoption study - black children
had IQ 25 points higher.
Tyler (1965)
IQ differences between black Americans in north and
south.
Educational differences account for up to 24 points in IQ
tests
Yerkes (1921)
Administered IQ tests to 125,000 young men in US army.
Goddard (1913)
Administered IQ test to immigrants to USA.
Items Relate to the Culture of the Edwards River Community
many
1. What comes next in the sequence: one, two, three, ___________
?
tree
2. As wallaby is to animal, so cigarette is to ________________
?
(Choose from leaf, tree, tobacco, habit, lung cancer)
3. One of the following items may not be classified with salt water
crocodile. Which one? black snake
(marine turtle, frilled lizard, budgerigar, black snake)
4. Which items may be classified with sugar?
all of them
(honey, witchetty grub, flour, water-lilies)
eat
5. We eat food and __________
water. Supply the missing verb.