W8 Intelligence & Psychometric assesment Flashcards
Intelligence -
hypothetical mental ability, that enables people to direct their thinking, adapt to their circumstances and learn from their experiences.
Francis Galton’s theory of intelligence
Theory of Hereditary Genius (1869)
• Variation in ability within the population
• Variations are inherited
• nature vs nurture (biological predisposition vs environment)
• First to use questionnaire assessments
Alfred Binet & Theodore Simon’s theory of intelligence
• Identified typical intelligence for age
• Intelligence scale (1905,1908,1911)
• Mental age
• Developed norms f/ age: standards and expectations and tasks that one would expect children to perform in different ages
How norms for age (IQ) are calculated?
(mental age / chronological age) x 100 = IQ
Child aged 7 (chronological age) completed tasks for 7.7 years old (mental age) => (7.7 / 7)x100 = 110 => IQ = 110
IQ - ? how calculated?
Intelligence Quotient - Index of intelligence derived from scoring intelligence tests (Stern 1912)
originally calculated as (mental age / chronological age)x100
nowadays, calculated using percentile rankings which are then converted to equivalent IQ scores and projected onto a normal distribution curve
Charles Spearman (1940) theory of intelligence:
Two factor theory of intelligence: g (every person has - general intelligence, which helps us to survive) + s (special factors/abilities, for ex: the ability to read & understand)
g factor is more or less equal f/ everyone, what differentiates us is the s factor.
Performance on all tests comprise of g + s
Catell (1971) theory of intelligence:
• Crystallised intelligence (gc): the older you are, the more you have it. You learn by utilizing previous experiences.
• Fluid intelligence (gf): the younger you are, the more of it you have. You learn as you go along.
make up general intelligence
Howard Gardner (1993) theory of intelligence
Multiple intelligences – potentials rather than a general underlying intelligence.
- Linguistic
- Musical
- Logical / mathematical
- Spatial
- Bodily - kinesthetic
- Intrapersonal
- Interpersonal
2 areas that determine our IQ today:
2 dominant features: language (what makes us diff from animals) & practicality (use of knowledge)
Intelligence tests (IQ) -
• Two characteristics f/ IQ tests to be useful:
valid & reliable
Validity: performance on intellectual tasks correlates with performance on other tasks - is stable over time
Reliability: Consistency between tests infers an underlying level of general intelligence - g factor
Intelligence involves the ability to:
- think
- solve problems
- analyse situations
- understand social values, customs and norms
Two main forms of intelligence are involved in most intelligence assessments:
- Verbal intelligence, is the ability to comprehend and solve language based problems
- Nonverbal intelligence, is the ability to understand and solve visual and spatial problems
Usually we expect the results in the both parts the same (less than 7% difference)
Wechsler Intelligence Scale of Adults – Fourth Edition (WAIS-IV) - measures verbal (7) and non-verbal (7) intelligence
Verbal Subtests:
- vocabulary
- similarities
- arithmetic
- digit span
- information
- comprehension
- letter-number sequencing
Performance Subtests
- Picture Completion
- Digit Symbol Coding
- Block Design
- Matrix Reasoning
- Picture Arrangement
- Symbol Search
- Object Assembly
WAIS-IV Verbal Sub-tests: Vocabulary
“Listen carefully and tell me what each word means”
glove
tangible
WAIS-IV Verbal Sub-tests: Similarities
“In what way are food and petrol alike?”
“In what way are allow and restrict alike?”
WAIS-IV Sub-tests: Perceptual Reasoning / Matrix reasoning
Choose from pieces, which fits to the picture.
(blue and yellow pointy circle)
(triangles and circles in 9-spaced square)
WAIS-IV Attention or Auditory attention span: e.g. Digit-span
Person is asked to memorize numbers, the number of digits grows => we can see the attention span
3-5-1
4-6-5-9
7-5-8-2-4
9-2-6-5-1-0
8-3-4-1-7-9-2
1-7-6-2-5-4-9-3
WAIS-IV Attention
To identify which symbols can be found in both parts of the picture
WAIS-IV: Block design
Manual + blocks
the person has to reproduce the shapes in the manual w/ the blocks
The bell shaped IQ curve
- 95% of population are within +/- 2SDs of the mean (IQ 70 to 130)
- 68% (2/3) of the population have an IQ within 1SD of the mean
- Average is considered to be within +/- 1SD of the mean (85 -115)
Common Intelligence Tests
• Wechsler scales - WAIS, WASI, WISC, WPPSI
• Raven’s Progressive Matrices – non-verbal
• Cattell’s Culture Fair IQ Test
• National Adult Reading Test (NART)
• Bayley Scales of Infant &Toddler Development
Intellectual ability / disability
Very superior > 130
Superior 120-129
High Average 110-119
Average 90-109
Low average 80-89
Borderline 70-79
**Learning disability < 70 **
Mild 55-70
Moderate 40-54
Severe 25-39
Profound <25
Clinical uses of IQ tests (6):
- diagnosing and quantifying the extent of learning disability
- diagnosing and characterising specific learning difficulties
ex: dyslexia, attention deficit hyperactivity disorder (ADHD), dyscalculia, dysgraphia - assessing intellectual impairment following trauma (head injury, stroke, poisoning)
- Αssessing intellectual impairment associated with medical problems or disease processes (Alzheimers Disease, Dementias, Multiple Sclerosis, Psychosis)
- Αssessing intellectual capabilities in genetic or developmental disorders (Downs syndrome, foetal alcohol disorders)
- Assessing the suitability for particular occupations or educational opportunities
External influences on IQ test scores (6):
- Familiarity with the particular concepts and materials used
- Motivation to do well
- Distraction
- The way the test is administered
- Sensory problems
- Cultural issues - language, difference in world view
Internal influences on IQ test scores (3):
- Emotional state – anxiety, depression, bereavement
- Physical illness
- Mental illness - psychosis, schizophrenias
Gender differences in IQ score
- Test scoring designed to reduce any sex differences
- Males are better at performance tasks, females are better at verbal tasks
- Greater variation in males scores – more spread out – more males at extreme ends.
- Females scores tend to cluster around mean.
IQ testing at the age of 11 and re-tested at the age of 80:
- Stability in scoring
- Lower IQ scores at age 11 were later associated with: mortality, lifespan, more likely to develop lung cancer, more likely to experience psychiatric illness and/or dementia
Nature vs Nurture
• Heritability is the proportion of variation in intelligence attributed to genetic variation in a population.
• Heritability for intelligence in UK ranges between 40 to 70%
• “The more successful we are at equalising environments, the more genes account for the differences between us.” Prof. Robert Plomin (2007)
Environmental influences on intelligence
- Poor childhood nutrition (Guatemala, protein supplements => higher IQ test scores)
- Εxposure to environmental toxins (lead, mercury) leads to lower IQ test scores
- Exposure to certain drugs in utero (alcohol, cocaine) leads to lower IQ test scores
- Lack of exposure to an intellectually stimulating environment in childhood
- Neurological injury or disease
- Genetic disorders affecting brain development
Higher childhood IQ is associated with (6):
- Fewer adult hospital admissions for injuries/assault
- More likely to become vegetarian in adulthood
- Less likely to smoke
- Less likely to become obese
- Lower morbidity and mortality
- PTSD, severe depression and schizophrenia are less prevalent in higher IQ bands
Lower IQ is associated with:
- Lower socio-economic status
- Increased chance of hospitalisation due to violent assault
- Imprisonment
- Early death
