Intelligence: theories and measurement

History of intelligence testing

• Galton late 1800s

• Binet early 1900s

• Terman

• Stern

• Goddard

• Army tests

• Spearman

• Wechsler

• Raven’s progressive matrix

• Thurstone

• Cattell

• Vernon and Carroll

Indigenous intelligence testing

• Many tests lacked cross-cultural validity

• Differences in how ‘intelligence’ is constructed and expressed in different cultural settings

• Cultural biases inherent to Western measures and norms

• Measured against Western ‘standard’

theories of intelligence

• Multiple intelligences

• Triarchic theory

How are IQ scores are interpreted?

• Mean = 100

• Standard deviation = 15

• Bell Curve'

• If a score is above 115 i5 is superior to gifted

• if a score is below 85 individual is borderline intellectually disabled to severely intellectually disabled

• Every sd

Theoretical foundations of intelligence Galton

• First attempt at developing intelligence theory

• central hypothesis was hamans differed in intelligence

• measured through responsiveness to stimuli (reaction time, eyesight and hearing, differentiate colours

Theoretical foundations of intelligence Galton Critique

• Sensorimotor measures do not reliably indicate intelligence

• However, some measures that Galton developed are still used today (e.g., reaction time)

• Was rooted in eugenics

IQ testing Binet early 1900s

• Father of IQ testing

• developed tests to identify children who need special education

• Binet-Simon scale

Binet-Simon Scale

• Included a series of 30 short tasks related to everyday life/problems

  • E.g. shaking hands, counting coins, naming objects in picture etc.

• The test items increased in difficulty to indicate levels of intelligence

• Could be used to determine a child’s ‘mental age’ and whether they were on par with other children their age

• Model for many future tests

Intelligence measurement Terman

• Lewis Terman found that Binet and Simon’s test did not work very well for Californian school-children

• Terman revised the test in 1916: adapting some of the items and writing 40 new ones.

• The revised test was known as the Stanford-Binet Revision

Stanford-Binet Revision

• The difficulty of test items increased and was used to indicate intelligence

• Terman used a more representative sample of children (1,000) to gain more accurate information on how children typically score on intelligence tasks

• Led to the beginnings of ‘standardised testing

Intelligence measurement Stern

• Developed the idea of the intelligence quotient

• noticed mental age varied proportionally to real age

• Terman adopted this procedure in the Stanford-Binet test and determined age norms for the test.

Intelligence quotient stern

mental age/chronological age x 100

Problems with Sterns measurement

• IQ did not vary equally with age

• Adults’ mental age stays the same but their chronological age

  increases, meaning their IQ drops with age

Henry Goddard

• Influenced by social ideologies at the time

• Intelligence seen to be inherited and he advocated for restricted reproductive rights among the ‘unintelligent’

• Suggested that ‘undesirables’ (e.g., those with alcoholism, prostitutes) had ‘mental deficiencies’ that were inherited

Misuse of intelligence testing Goddard

• Tested migrant’s to Ellis Island with the Binet-Simon tests to identify those considered to be “feeble minded”

• Led to restricted immigration. In 1928 Goddard reflected that “feeblemindedness was not incurable and that the feeble minded did not need to be segregated in institutions”

Army intelligence tests

• APA identified the need for rapid classification of US ww1 army recruits

• Robert Yerkes lead a group including Goddard and Terman to develop group intelligence testing

• Apha and beta versions

Alpha army test

variety of cognitive abilities based on both oral and written language

Beta army test

not reliant on literacy-based tasks (administered to those who were identified as poorer readers or who had less than 6 years experience speaking English)

Controversies of the army tests

• Tests did little to support the war effort, but did raise the profile of psychology

• Average age of tested soldiers was 13 years

• Results were used to support supposed ‘racial superiority’ and continued to influence restricted immigration policies and practices

• Unused booklets were used by educators and psychologists

  • Assumption that there was a test available which assessed intelligence

  • In the 1920s approx. 7 million children in the U.S. completed a ‘National Intelligence Test’ - not good as it wasn’t designed for them

Psychometric approach to intelligence

• Attempts to identify groups of items in a test that correlate highly with each other in order to discover underlying skills or abilities

• Psychometric theories of intelligence are derived from factor analysis

Factor analysis

Examines the patterns of responses to identify basic psychological dimensions

Psychometric Spearman

• Observed correlations among performance on a variety of tasks

• two factor theory

  • General ability (g)

  • specific abilities

Specific abilities

different types of tasks e.g. vocabulary, mathematics, spatial

g

he mental capability that underlies specific intelligence

Intelligence scales for adults and children: Wechsler

Designed tests to measure general intelligence (g) via performance on a range

of specific cognitive tasks (verbal/non-verbal)

• Wechsler-Bellevue Scale

• Wechsler Adult Intelligence Scale (WAIS)

• Wechsler Scale for Children (WISC)

• Wechsler Preschool and Primary Scale of Intelligence (WPPSI)

• All participants are tested on the same items

Deviation IQ

Wechsler Deviation IQ

defined and scored IQ based on an individual’s actual score on the intelligence test relative to the average score obtained by others of the same age on the same tests

WAIS-5 - Adult subsets

• Verbal comprehension

  • similarities

  • vocabulary

• visual spatial

  • block design

• fluid reasoning

  • matrix reasoning

  • figure weights

• working memory

  • Digit sequencing

• processing speed

  • coding

WISC-5 – child subtests

• Verbal comprehension

  • Information

  • comprehension

• visual spatial

  • visual puzzles

• fluid reasoning

  • picture concepts

  • arithmetic

• working memory

  • digit span

  • picture span

• processing speed

  • coding

  • symbol search

Ravens Progressive Matrices

• Strong measure of ‘g’ • Mental ability associated with abstract reasoning

• Major non-verbal test, 60 matrices that increase in difficulty

• Considered to be less influenced by culture, especially language

• Children - adult

Multifactor theorists: Thurstone

• primary mental abilities that contributed to one’s overall intelligence

• An important alternate approach to Spearman's ‘g’

• Found 7 primary mental abilities via factor analysis

Thurstone’s 7 primary mental abilities via factor analysis

1. Verbal comprehension: reading, comprehension

2. Word fluency: generate and use words and letter effectively

3. Number: mathematical operations

4. Space: spatial visualisations

5. Associative memory: ability for rote learning/memory

6. Perceptual speed: perceive details, differences, similarities

7. Reasoning: inductive and deductive reasoning

Fluid and crystallised intelligence: Cattell

• Raymond Cattell suggested two related but distinct components of intelligence (factor analysis)

  • Fluid

  • Crystallise

• Age effects fluid and crystallised intelligence differently

  • Fluid decreases with age, crystallised increases with age

Fluid intelligence

• does not depend on prior knowledge, such as solving novel problems and processing new information

• ability to see relationships = primary reasoning ability

Crystallised intelligence

• Accumulated, stored information, such as knowledge of vocabulary and comprehension

• acquired knowledge and skills = factual knowledge

Hierarchical approaches: Vernon & Carroll

• Vernon proposed a hierarchy of mental abilities

• Carroll proposed a three-stratum model of cognitive ability

• General intelligence → various domains → narrow items to indicate domains

Multiple intelligences Gardner

• Supports Thurstone’s notion that intelligence comes in different packages

• 9 distinct and separate components to intelligence

• Suggests different cultures highlight certain intelligences and minimise others

• Numerous sources show distinct, autonomous intelligences

• Intelligence should be assessed via different activities

9 independent forms of intelligence

• Verbal-linguistic: verbal expression

• Logical-mathematical: analyse problems, solve abstract problems

• Spatial-visual: visualizing problems to arrive at a solution

• Musical: produce and analyse pitch, rhythm and sound

• Bodily-kinesthetic: using body and bodily movements to address a problem

• Interpersonal: sensing and understanding people’s feelings and motivations

• Intrapersonal: fully understand oneself, regulate oneself

• Naturalistic intelligence: recognise and classify things in the natural environment

• Existentialist: able to ask deep critical questions about the human experience

Triarchic theory

• Sternberg suggests that there are three different sub-theories of intelligence:

  • Componential (analytical)

  • Contextual (practical)

  • Experiential (creative)

Analytical facet

• academic problem-solving skills

• Analytical intelligence based on the joint operations of three components:

  • Metacomponents

  • Performance components

  • Knowledge acquisition components

Metacomponents

• control, monitoring and evaluating cognitive processes

• executive, higher order functions (give directions to the other two components)

Performance components

• Cognitive processes that enable us to encode stimuli, hold information in short term memory, make calculations, retrieve information from long term memory etc.

• execute strategies assembled by metacomponents

Knowledge acquisition components:

processes involved in learning and storing new information

Practical facet (contextual)

• Intelligence that operates in the real world

• Tacit knowledge – ‘action-oriented’

• Adaptation

  • ability to adapt to, or shape one’s environment

• Shaping

  • Adapting the environment to the individual

• Selection

  • Choosing one environment over another

Creative facet (experiential

• Automation

  • Little effort/thought required to engage in an activity/task

• Novelty

  • Using experiences to solve new problems