Samuel McNerney in Scientific American:
Recall this pivotal scene from the 1997 movie, Men in Black. James Edwards (Will Smith, or Agent J) arrives at the headquarters of MiB – a secret agency that protects Earth from extraterrestrial threats – to compete with “the best of the best” for a position. Edwards, a confident and cocky NYPD officer, completes various tests including a simulation where he shoots an ostensibly innocent schoolgirl. When asked why, Edwards explains that compared to the freakish aliens, the girl posed the biggest threat. He passes the test: potentially dangerous aliens are always disguised as real humans. Agent K (Tommy Lee Jones) offers him a position at MiB and the remaining candidates’ memories are erased. They return to normal life without ever realizing that the aliens were a ruse – a device for Agent K to detect how sagacious the candidates really were.
This wily test of intelligence and mindfulness is defined by two characteristics. The first is that most people fail it; the second is a subtle trick intentionally implemented to catch careless thinking (the schoolgirl for example). Narratives in literature and film that incorporate this test go something like this: scores have tried and failed because they overlooked the trick – even though they confidently believed they did not – until one day a hero catches it and passes the test (Edwards).