In his classic 1923 essay, "Intelligence as the Tests Test It", Edwin Boring wrote "Intelligence is what the tests test." Almost a century of research later, we know that this definition is far too narrow. As long as a test is sufficiently cognitively complex and taps into enough diverse content, you can get a rough snapshot of a person's general cognitive ability-- and general cognitive ability predicts a wide range of important outcomes in life, including academic achievement, occupational performance, health, and longevity.
