Few people agree on exactly what “intelligence” is or how to measure it. The nature and origin of intelligence are elusive, and the value and accuracy of intelligence tests are often uncertain. Researchers who study intelligence often argue about what IQ tests really measure and whether or not Einstein’s theories and Yo Yo Ma’s cello playing show different types of intelligence.
Intelligence is a particularly thorny subject, since research in the field has the potential to affect many social and political decisions, such as how much funding the U.S. government should devote to educational programs. People who believe that intelligence is mainly inherited don’t see the usefulness in special educational opportunities for the underprivileged, while people who believe that environment plays a large role in intelligence tend to support such programs. The importance and effects of intelligence are clear, but intelligence does not lend itself to easy definition or explanation.