First Hour - How can one measure intelligence? Intelligence I First Hour - How can one measure intelligence? What is Intelligence? Early Intelligence testing Producing a good intelligence test The normal distribution Reliability and validity Longitudinal and cross sectional studies of intelligence

Intelligence: The ability to learn from experience The ability to adapt to the surrounding environment The ability to understand and control one’s own thinking process (metacognition) BUT one must understand the role of culture in intelligence….

The Stanford-Binet version of IQ: The WAIS version of IQ:

Test: “...a standardized instrument, consisting of items, for obtaining a reliable sample of some valid aspect of a person’s behavior (e.g. thinking and reasoning abilities).” standardized items reliable valid

Reliability Test-retest reliability Alternate-forms reliability Split-half reliability Validity Criterion validity - real life measures Content validity – items measure what they propose to measure Construct validity – test captures the multi-dimensional nature of the quality measured

Longitudinal vs. cross-sectional comparisons (cell contains birth year) 60 1944 1944 Age of individuals 50 1944 1954 1944 40 1964 1984 1994 2004 Year in which the data were collected

IQ and age: cross-sectional vs. longitudinal comparisons 105 — 100 — 95 — 90 — 85 — 0 — | 25 30 35 40 45 50 55 60 65 70 IQ scores Age in years longitudinal (single group) cross-sectional (different groups)