Psychometrics Dr Jacqui Mc Kechnie Psychometric Tests General

Psychometrics Dr Jacqui Mc. Kechnie

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 chronological age x 100

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, 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 - 5 yrs r = +0. 5 12 - 14 yrs r = +0. 9 r = +0. 7 66 yrs 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? (honey, witchetty grub, flour, water-lilies) eat all of them 5. We eat food and _____ water. Supply the missing verb.