What this is: The Cognitive Reflection Test (CRT) is a famous set of questions introduced by psychologist Shane Frederick in 2005. Each one tends to invite a quick, confident answer — and rewards taking a moment to check it before committing.
How it works:
- Choose the Classic CRT (the original three questions, presented here in multiple-choice format — the original test used typed answers) or the Full Test (those three plus nine original reflection questions, each built on a different mechanism)
- Pick your answer from four options, then see the correct choice revealed with the reasoning worked out
- Optional Timed Challenge: 15 seconds per question. Pressure is exactly what pushes people onto quick answers, so this is a genuinely harder game mode — running out of time counts as a miss and reveals the answer. Since it also rewards reading speed (and any practice from an earlier run), treat it as its own challenge rather than a direct comparison with your untimed score
What it measures (and what it doesn't): The CRT measures reflective thinking — your tendency to override an intuitive first response and reason your way to the correct one. Media sometimes call it "the world's shortest IQ test," but that label oversells it: reflection is a thinking habit, not intelligence itself. Plenty of brilliant people miss these, and the habit of pausing to check is learnable.
Tips:
- When an answer arrives instantly and feels effortless, take one extra beat — verify it against the question's actual numbers
- Try quickly checking your answer by plugging it back into the question before locking it in
- Do the untimed version first, then come back for the Timed Challenge as a harder second game