Assessing And Measuring Intelligence

Intelligence testing

• Research: Assesses cognitive development, often for participant selection in studies

• Diagnostic: Identifies learning disabilities or gifted learners

• Forensic: Evaluates legal competency in legal settings

3 types of psychometric testing

• Achievement test

• Aptitude test

• Intelligence test

Achievement test

• Measures information learned & retained over time

• Measures knowledge

Aptitude test

• Measures specific skills, talents, and natural abilities

• Can predict one’s future academic success or occupational placement

Intelligence test

• Measurement of one’s ability to learn based upon multiple cognitive skills

• Measures learning potential

Wechsler tests of intelligence

• Most commonly used series of IQ tests, with international versions and age appropriate levels

• Considered the clinical standard for intelligence measurement (WAIS III and WISC IV)

• Scores are compared to statistical averages, not age, and are defined by standard deviations

WAIS III

Intelligence scale for adults

WISC IV

Intelligence scale for kids

Wechsler IQ bell curve

• Intellectually disabled

• Below average

• Average

• Above average

• Gifted

• Genius

Intellectual disabled

• IQ: 55 to 70

• Population: 2%

• Terman’s classification: Imbeciles

Below average

• IQ: 70 to 85

• Population: 14%

• Terman’s classification: Morons

Average

• 100 is the mean

• IQ: 85 to 115

• Population: 68%

Above average

• IQ: 115 to 130

• Population: 14%

Gifted

• IQ: 130 to 145

• Population: 2%

Genius

• IQ: 145 to 200

• Population: 0.1%

Intellectual disabilities

• Psychometrically defined by IQ scores below 70

• 2% of the population

• 85% of the intellectually disabled population is considered mild as in they show some cognitive impairments but are still able to function independently or with minimal support

• Some of these individuals are savants

Savants

Individuals with extreme cognitive deficiencies but are gifted in specific areas such as math, memory, music, or art  

Causes of intellectual disabilities

• Genetics: Conditions like down’s syndrome and phenylketonuria (PKU)

• Prenatal teratogens: Birth defects and fetal alcohol syndrome

• Physical brain injury: Head trauma, stroke, asphyxiation, and cerebral palsy

• Environmental factors: Infantile neglect, disease, and language deprivation

Phenylketonuria (PKU)

Genetic disorder where the body cannot break down phenylalanine, an amino acid, leading to brain damage if not treated

Teratogens

Substances or factors that cause birth defects or developmental abnormalities in a fetus, such as alcohol, drugs, or infections