Intelligence (Chapter 11) Lecture Outline : History of intelligence IQ and normal distributions Measurement

Two Views of Intelligence n Psychophysical n Energy, sensitivity to physical stimuli n Galton (1883) and later Cattell (1890) proposed psychophysical tests measured ability n Contribution: Psychometrics n Mental judgement n Good sense, practical sense, initiative, reasoning n Binet & Simon (1916) diagnosed “mental defectives” in Paris n Contribution: Testing and IQ

What is an Intelligence Quotient? n IQ = (MA / CA) X 100 n MA = Mental age, CA = Chronomolgical age n 8 year old with MA of 12 has IQ of 150 n Problem across life span, such as someone age 30 with MA of someone 45

What is intelligence? n Goal directed adaptive behavior n IQ tests define a domain of skills necessary to succeed in school What is the goal? What is the environment being adapted to?

The normal curve of intelligence test scores n en.html en.html

Assessing intelligence n Stanford Binet- Revised: Short-term memory, Verbal, Quantitative, and Figural Abstract Reasoning n Wechsler Scales: Verbal, Performance, and Total IQ scores (WAIS-III, WISC-III, WPPSI) n Other tests: Leiter International Scales, Raven’s Matrices, Scholastic Aptitude Test (SAT)

Validity: Example of SAT n Face validity: Does the test make sense? n Predictive validity: Does it predict Acadia grades? n Concurrent validity: Were they related to Grade 12 grades? n Construct validity: Does the SAT measure the construct it is supposed to measure?

Reliability n Test-retest: Take the same test n Alternate forms: Two forms, such as early Stanford-Binet n Internal consistency: The extent to which items measure the same thing - psychophysical measures did not n Inter-rater reliability: Do 2 people score things the same?