Intelligence derives from the Latin verb intellegere; per that rationale, “understanding” (intelligence) is different from being “smart” (capable of adapting to the environment). Scientists have proposed two major “consensus” definitions of intelligence:
(i) from Mainstream Science on Intelligence (1994), a report by fifty-two researchers:
A very general mental capability that, among other things, involves the ability to reason, plan, solve problems, think abstractly, comprehend complex ideas, learn quickly and learn from experience. It is not merely book learning, a narrow academic skill, or test-taking smarts. Rather, it reflects a broader and deeper capability for comprehending our surroundings — “catching on”, “making sense” of things, or “figuring out” what to do.