Intelligence as an “individual difference” Intelligence and personality are the most ubiquitous individual differences (e.g., commonly measured) Individual differences = stable human psychological characteristics which vary between people
Abstract thinking ability (Terman, 1921) Capacity for knowledge and knowledge possessed (Henmon, 1921) Capacity to learn from experience (Dearborn, 1921) Many definitions of intelligence
"The capacity to acquire capacity." (Woodrow, 1921) Ability to adapt to the environment. (Colvin, cited in Sternberg, 1982) “ a general factor that runs through all types of performance." (Jensen) Many definitions of intelligence
"A global concept that involves an individual's ability to act purposefully, think rationally, and deal effectively with the environment." (Wechsler, 1958) Many definitions of intelligence
"ability to solve problems, or to create products, that are valued within one or more cultural settings ( Gardner, 1983/2003, p. x)" Many definitions of intelligence
" The global capacity to profit from experience and to go beyond given information about the environment” (Gerrig et al., 2008) Many definitions of intelligence
Statistically determined by correlations </li></ul>Galton’s ideas of intelligence
<ul><li>Galton’s controversially postulated </li></ul><ul><ul><li>Genetic superiority and inferiority
Started Eugenics movement </li></ul></ul><ul><li>Galtonian view </li></ul>Galton’s ideas of intelligence
<ul><li>Alfred Binet & Théophile Simon </li><ul><li>Mental age (MA)
Chronological age (CA) </li></ul><li>Lewis Terman </li><ul><li>Stanford-Binet Intelligence Scale
Intelligence Quotient (IQ) </li></ul></ul>The origins of intelligence testing
Alfred Binet and his colleague Théodore Simon practiced a more modern form of intelligence testing by developing questions that would predict children’s future progress in the Paris school system. Alfred Binet
<ul><li>In the US, Terman adapted Binet’s test -> the Stanford-Binet Test.
Terman used Stern’s formula for Intelligence Quotient (IQ): </li></ul>Assessing intelligence: Lewis Terman
Intelligence scores become stable after about seven years of age. In numerous studies, stability of intelligence scores have been determined (Angoff, 1988; Deary et al., 2004). Stability or Change?
Recent studies indicate some correlation (~ .40) between brain size and intelligence. As brain size decreases with age, scores on verbal intelligence tests also decrease. Is intelligence neurologically measurable?
Standardisation </li></ul></ul>Features of formal assessment
<ul><li>Reliability is the stability or consistency of scores produced by an instrument
Measured over time and space </li></ul>Concept of reliability
Types of reliability <ul><li>Test-retest Reliability </li><ul><li>Test on two occasions
Measured by a correlation </li></ul><li>Parallel Forms </li><ul><li>Different versions of a test </li></ul><li>Internal Consistency </li><ul><li>Similar scores across different parts </li></ul><li>Split-half Reliability </li><ul><li>Odd vs even numbers on test </li></ul></ul>Time 1 Time 2 Form A Form B 1, 3, 5, 7 = 2, 4, 6, 8 =
Concept of validity <ul><li>Extent to which a test measures what it was intended to measure
Normal curve Standardized tests establish a normal distribution of scores on a tested population in a bell-shaped pattern called the normal curve.
Extremes of intelligence A valid intelligence test divides two groups of people into two extremes: the mentally retarded (IQ 70) and individuals with high intelligence (IQ 135). These two groups are significantly different.
<ul><li>Intellectual disability </li><ul><li>Onset before 18 years old
Intellectually disabled people required constant supervision a few decades ago, but with a supportive family environment and special education they are more able to care for themselves. Intellectual disability
Charles Spearman </li><ul><li>Spearman’s “g” </li></ul><li>Raymond Cattell </li><ul><li>Crystallised and Fluid Intelligence </li></ul></ul>Psychometric theories of intelligence
Spearman proposed that general intelligence (g) is linked to many clusters that can be analyzed by factor analysis. e.g., people who do well on vocabulary examinations do well on paragraph comprehension examinations, a cluster that helps define verbal intelligence. Other factors include a spatial ability factor, or a reasoning ability factor. General Intelligence
General intelligence Thurstone, a critic of Spearman’s g, suggested seven clusters of PRIMARY MENTAL ABILITIES: <ul><ul><ul><li>Word Fluency
Operation </li></ul>Guilford's structure of the intellect
Wechsler developed the Wechsler Adult Intelligence Scale (WAIS) and later the Wechsler Intelligence Scale for Children (WISC), an intelligence test for preschoolers. David Wechsler
WAIS measures overall intelligence and 11 related aspects to assess clinical and educational problems. David Wechsler
<ul><li>Analytical intelligence </li><ul><li>Basic information processing skills </li></ul><li>Creative intelligence </li><ul><li>Ability to deal with novel versus routine problems </li></ul><li>Practical intelligence </li><ul><li>Ability to adapt to different contexts, and to select and shape contexts </li></ul></ul>Robert Sternberg's Triarchic Theory
<ul><li>Gardner (1983, 1999) supports Thurstone’s idea that intelligence comes in multiple forms.
Gardner noted that brain damage may diminish one type of ability but not others e.g., savants. </li></ul>Howard Gardner’s Theory of Multiple Intelligences
<ul><li>8 types of intelligence - speculates about a 9th – existential intelligence = ability to think about the question of life, death and existence.
Logical-mathematical, linguistic, naturalist, musical, spatial, bodily kinesthetic, interpersonal, intrapersonal (emotional) </li></ul>Howard Gardner’s Theory of Multiple Intelligences
Howard Gardner’s Theory of Multiple Intelligences
Brain function Studies of brain functions show that people who score high on intelligence tests perceive stimuli faster, retrieve information from memory quicker, and show faster brain response times.
Aptitude tests are intended to predict your ability to learn a new skill and achievement tests are intended to reflect what you have already learned. Aptitude and achievement tests
Heredity and IQ </li></ul><ul><ul><li>Heritability </li></ul></ul>The politics of intelligence
<ul><li>Environments and IQ </li><ul><li>Judith Kearins’ series of studies: No single explanation for behaviour </li></ul><li>Culture and the validity of IQ tests </li><ul><li>Graham Chaffey </li><ul><li>Invisible underachievers </li></ul><li>Claude Steele </li><ul><li>Stereotype threat (vulnerability) </li></ul><li>Harold Stevenson </li><ul><li>Hard work versus innate ability </li></ul></ul></ul>The politics of intelligence
<ul><li>No other topic in psychology is so passionately followed as the one that asks the question, “Is intelligence due to genetics or environment?” </li></ul>The politics of intelligence
Studies of twins, family members, and adopted children together support the idea that there is a significant genetic contribution to intelligence. The politics of intelligence
Two disturbing but agreed upon facts: <ul><li>Racial groups differ in their average intelligence scores.
High-scoring people (and groups) are more likely to attain high levels of education and income. </li></ul>Group differences in IQ scores
If we look at racial differences, white Americans score higher in average intelligence than black Americans (Avery et al., 1994). European New Zealanders score higher than native New Zealanders (Braden, 1994). Group differences in IQ scores White-Americans Black-Americans Average IQ = 100 Average IQ = 85
Differences in intelligence among these groups are largely environmental, as if one environment is more fertile in developing these abilities than another. Environmental effects
Adoption studies Adopted children show a marginal correlation in verbal ability to their adopted parents.
Adoption studies Studies of twins and adopted children also show the following: <ul><li>Fraternal twins raised together tend to show similarity in intelligence scores.
Identical twins raised apart show slightly less similarity in their intelligence scores. </li></ul>
Adoption studies Early neglect from caregivers leads children to develop a lack of personal control over the environment, and it impoverishes their intelligence. Romanian orphans with minimal human interaction are delayed in their development.
<ul><li>Goal of psychological assessment </li><ul><li>To make as accurate assessments as possible
Controversial area for psychology </li></ul><li>Three ethical concerns </li><ul><li>Fairness of test-based decisions
<ul><li>Creativity: </li></ul><ul><ul><li>Ability to generate ideas or products that are novel and useful to the circumstance </li></ul></ul><ul><li>Is creativity linked to intelligence? </li></ul>Creativity
Intelligence and Creativity <ul><li>Some correlation with intelligence.
Imaginative Thinking: The ability to see things in novel ways.
Adventuresome Personality: Seeks new experiences rather than following the pack.
Intrinsic Motivation: A motivation to be creative from within.
A Creative Environment: A creative and supportive environment allows creativity to bloom. </li></ul>
<ul><li>Divergent Thinking defined </li></ul><ul><ul><li>Ability to produce unusual but appropriate responses to problems
Fluid versus flexible thinking </li></ul></ul><ul><li>Weak to moderate correlation between IQ and Divergent Thinking </li></ul>Assessing creativity and the link to intelligence
<ul><li>Exemplary Creator </li><ul><li>Extraordinary abilities (e.g. Pablo Picasso) </li></ul><li>Risk Taking </li><ul><li>Uncharted Waters </li></ul><li>Preparation </li><ul><li>Acquisition of expertise </li></ul><li>Intrinsic Motivation </li><ul><li>Enjoyment and satisfaction </li></ul></ul>Extremes of creativity
<ul><li>Gerrig, R. J., Zimbardo, P. G., Campbell, A. J., Cumming, S. R., & Wilkes, F. J. (2008). Psychology and life (Australian edition). Sydney: Pearson Education Australia. </li></ul>References