Cognitive · 50 flashes · ~3 min
Inspection Time Test
A 4 × 4 grid of keys. Press and hold the green key in the bottom left corner. A second later one of the other keys flashes red, very briefly, and then all of them turn red. Let go and tap the key that flashed first.
The flash gets shorter when you are right and longer when you are wrong, homing in on the duration at which you are right 80% of the time: your inspection time. Guess when you are not sure; a guess is right 1 time in 15. Three practice flashes, then 50, about four minutes.
Inspection time is one of the oldest measures of how fast the brain takes in information, and it correlates with intelligence: about −0.3 as measured, −0.5 corrected for unreliability and restricted samples, in Grudnik & Kranzler's meta-analysis (2001). Use a computer or phone in a quiet moment, and keep your eyes on the grid.
Almost done!
Two optional questions, asked once: your age and sex let the results be broken down by who took the test.
Sex as at birth; gender as you identify. Languages you grew up speaking; several are fine, separated by commas. Leave blank anything you would rather not say.